JP6834122B2 - Flow velocity evaluation method and evaluation system - Google Patents

Description

The present invention relates to a flow velocity evaluation method and an evaluation system.

A method of measuring the flow rate of steam by using the heater method has been studied (see Patent Document 1).
Patent Document 1 discloses a method for measuring the flow velocity of a fluid flowing in a pipe. In this flow velocity measurement method, heat exchange is performed at a predetermined portion on the surface of the pipe, the temperature distribution in the pipe axis direction of the pipe is measured, and the flow velocity of the fluid flowing inside the pipe is obtained based on the measured temperature distribution.

JP-A-2015-148508

In the analysis of temperature distribution, for example, the processing of the finite element method takes time. As an example, if it takes 20 minutes to process one point, it takes one hour for three points, and it takes a lot of time to process at many points in the vicinity.
Therefore, it may take a long time to evaluate the flow velocity.

As a specific example, in the heater method, the theoretical value is fitted to the measured value of the temperature distribution to obtain the flow velocity. Since the temperature distribution of the theoretical value needs to be solved by using a numerical calculation with the flow velocity in the pipe as an input value, it takes a considerable amount of time for one calculation. Then, for fitting, it is necessary to calculate the temperature distribution corresponding to many flow velocities, so that it is difficult to analyze in a short time.

The present invention provides a flow velocity evaluation method and an evaluation system capable of shortening the time required for flow velocity evaluation.

One aspect of the present invention is an evaluation method for evaluating the flow velocity of a fluid flowing inside a pipe, and analyzes the half-value width of the temperature distribution in the pipe axial direction when heat is exchanged at a predetermined portion of the surface of the pipe. The value is calculated for a plurality of flow velocities, heat is exchanged at a predetermined portion of the surface of the pipe, the measured value of the half-value width of the temperature distribution in the pipe axis direction is measured, and the measured value of the measured half-value width is the most. This is a flow velocity evaluation method in which an analysis value having a close half-price width is selected and a flow velocity corresponding to the selected half-price width analysis value is determined as a flow velocity of a fluid flowing inside the pipe.

One aspect of the present invention is a method for evaluating a flow velocity, in which the half width of the temperature distribution in the tube axis direction is a feature amount that decreases as the flow velocity increases.

One aspect of the present invention is a heat exchange step in which heat is exchanged at the predetermined portion of the surface of the pipe, and a measured value of a half-value width of the temperature distribution in the pipe axial direction by performing the heat exchange in the heat exchange step. A measurement step for measuring, a calculation step for calculating the analysis value of a half-value width of the temperature distribution in the pipe axis direction when heat exchange is performed on the predetermined portion of the surface of the pipe for the plurality of flow paths, and the calculation step. By comparing the magnitude relationship between the analysis value calculated by the calculation process and the measured value of the half-value width of the temperature distribution in the pipe axis direction measured for the pipe, a plurality of flow paths according to the measured value are set. The error between the flow velocity setting step to be performed and the analysis value of the temperature distribution in the pipe axis direction for a plurality of flow paths set by the flow velocity setting step and the measured value of the temperature distribution in the pipe axis direction is the smallest. This is a flow velocity evaluation method including a flow velocity determining step of determining a flow velocity as a flow velocity of the fluid flowing inside the pipe.

In one aspect of the present invention, in the flow velocity setting step, the analysis value calculated by the calculation step for the flow velocity at the midpoint of the assumed flow velocity range and the measured half-value width of the temperature distribution in the pipe axis direction are obtained. This is a flow velocity evaluation method for setting the flow velocity at a new point according to the magnitude relationship with the measured value.

In one aspect of the present invention, the flow velocity setting step sets a flow velocity of three points or more, and the flow velocity determination step determines the flow velocity using the flow velocity of the three points or more set by the flow velocity setting step. , It is an evaluation method of the flow velocity.

One aspect of the present invention is a flow velocity evaluation method in which the flow velocity determination step uses a part or all of the flow velocity set in the flow velocity setting step.

In one aspect of the present invention, in the flow velocity determining step, the square error between the analyzed value and the measured value of the temperature distribution in the tube axis direction is calculated at each of the flow paths set by the flow velocity setting step. The first step, the 1-2 step for obtaining the relationship between the flow velocity and the square error, and the 1-3 step for determining the flow velocity having the smallest square error as a candidate for the flow velocity were determined. In the flow velocity candidates, the first to fourth steps of determining whether or not the squared error between the analyzed value and the actually measured value of the temperature distribution in the tube axis direction is equal to or less than a predetermined specified value, and the squared error are the above. When it is determined that the value is equal to or less than the predetermined specified value, the first 5 steps for formally determining the candidate for the flow velocity, and when it is determined that the square error exceeds the predetermined specified value, the flow velocity This is a flow velocity evaluation method including the first to sixth steps of changing the above and shifting to the first step 1-1 again.

In one aspect of the present invention, the flow velocity determination step calculates an analysis value of the relationship between the flow velocity and the half width of the temperature distribution in the tube axis direction at each of the flow paths set by the flow velocity setting step. Step -1 and step 2-2 in which the analysis value of the half width closest to the measured value of the measured half width is selected, and the flow velocity corresponding to the selected analysis value is determined as a candidate for the flow velocity. In the determined flow velocity candidates, the second and third steps of determining whether or not the squared error between the analyzed value and the measured value of the temperature distribution in the tube axis direction is equal to or less than a predetermined specified value, and the above. When it is determined that the square error is equal to or less than the predetermined specified value, the candidate for the flow velocity is formally determined, while in other cases, the flow velocity is changed and the process proceeds to the second step 2-1 again. This is a flow velocity evaluation method including the second to fourth steps of transition.

One aspect of the present invention is an evaluation system for evaluating the flow velocity of a fluid flowing inside a pipe, and analyzes the half-value width of the temperature distribution in the pipe axial direction when heat is exchanged at a predetermined portion of the surface of the pipe. The value is calculated for a plurality of flow velocities, heat is exchanged at a predetermined portion of the surface of the pipe, the measured value of the half-value width of the temperature distribution in the pipe axis direction is measured, and the measured value of the measured half-value width is the most. It is a flow velocity evaluation system that selects an analysis value having a close half-price width and determines a flow velocity corresponding to the selected half-price width analysis value as a flow velocity of a fluid flowing inside the pipe.

One aspect of the present invention is a flow velocity evaluation system in which the half width of the temperature distribution in the tube axis direction is a feature amount that decreases as the flow velocity increases.

One aspect of the present invention includes a heat exchanger that exchanges heat at the predetermined portion of the surface of the pipe, and a measuring unit that exchanges heat and measures a measured value of a half-value width of the temperature distribution in the pipe axis direction. , A calculation unit that calculates the analysis value of the half-value width of the temperature distribution in the pipe axis direction when heat exchange is performed on the predetermined portion of the surface of the pipe for the plurality of flow paths, and the calculation unit. A flow velocity setting unit that compares the magnitude relationship between the analysis value and the measured value of the half-value width of the temperature distribution in the pipe axis direction measured with respect to the pipe, and sets a plurality of flow paths according to the measured value. The pipe has the smallest error between the analysis value of the temperature distribution in the tube axis direction and the actually measured value of the temperature distribution in the tube axis direction for a plurality of flow paths set by the flow velocity setting unit. It is a flow velocity evaluation system including a flow velocity determination unit that determines the flow velocity of the fluid flowing inside the water flow path.

In one aspect of the present invention, the flow velocity setting unit has the analysis value calculated by the calculation unit for the flow velocity at the midpoint of the assumed flow velocity range, and the measured half-value width of the temperature distribution in the pipe axis direction. This is a flow velocity evaluation system that sets the flow velocity at a new point according to the magnitude relationship with the measured value.

In one aspect of the present invention, the flow velocity setting unit sets a flow velocity of three points or more, and the flow velocity determination unit determines the flow velocity using the flow velocity of the three points or more set by the flow velocity setting unit. , Flow velocity evaluation system.

One aspect of the present invention is a flow velocity evaluation system in which the flow velocity determination unit uses a part or all of the flow velocity set by the flow velocity setting unit.

In one aspect of the present invention, the flow velocity determining unit calculates the squared error between the analyzed value and the measured value of the temperature distribution in the tube axis direction at each of the flow paths set by the flow velocity setting unit. The first step, the 1-2 step for obtaining the relationship between the flow velocity and the square error, and the 1-3 step for determining the flow velocity having the smallest square error as a candidate for the flow velocity were determined. In the flow velocity candidates, the first to fourth steps of determining whether or not the squared error between the analyzed value and the actually measured value of the temperature distribution in the tube axis direction is equal to or less than a predetermined specified value, and the squared error are the above. When it is determined that the value is equal to or less than the predetermined specified value, the first 5 steps for formally determining the candidate for the flow velocity, and when it is determined that the square error exceeds the predetermined specified value, the flow velocity This is a flow velocity evaluation system that executes the 1st to 6th steps of changing the above and shifting to the 1-1 step again.

In one aspect of the present invention, the flow velocity determining unit calculates an analysis value of the relationship between the flow velocity and the half width of the temperature distribution in the pipe axis direction at each of the flow paths set by the flow velocity setting unit. Step -1 and step 2-2 in which the analysis value of the half width closest to the measured value of the measured half width is selected, and the flow velocity corresponding to the selected analysis value is determined as a candidate for the flow velocity. In the determined flow velocity candidates, the second and third steps of determining whether or not the squared error between the analyzed value and the measured value of the temperature distribution in the tube axis direction is equal to or less than a predetermined specified value, and the above. When it is determined that the square error is equal to or less than the predetermined specified value, the candidate for the flow velocity is formally determined, while in other cases, the flow velocity is changed and the process proceeds to the second step 2-1 again. It is a flow velocity evaluation system that executes the transitioning steps 2-4.

According to the above-mentioned flow velocity evaluation method and evaluation system, it is possible to shorten the time required for the flow velocity evaluation.

It is a figure which shows the schematic structure of the flow velocity measurement system which concerns on this embodiment. It is a figure which shows the main part structure of the flow velocity measurement system. It is a schematic diagram which shows the control unit 4. It is explanatory drawing which shows the example of dividing the area of a pipe 10 into a cell. It is a figure which shows the example of the relationship (when the flow velocity is 5 m / s) between the axial distance of a pipe 10 and the temperature of the surface 10a of a pipe 10. It is a figure which shows the example of the relationship (when the flow velocity is 20 m / s) between the axial distance of a pipe 10 and the temperature of the surface 10a of a pipe 10. It is a figure which shows the example of the relationship (when the flow velocity is 35m / s) between the axial distance of a pipe 10 and the temperature of the surface 10a of a pipe 10. It is a figure which shows the example of the half-value width P1 in the characteristic of a temperature distribution. It is a figure which shows the example of the maximum temperature P2 in the characteristic of a temperature distribution. It is a figure which shows the example of the area P3 of the temperature distribution waveform in the characteristic of a temperature distribution. It is a figure which shows the example of the relationship between a flow velocity and a half width. It is a figure which shows the example of the relationship between the measured value 401 of a temperature distribution, and the analysis value 411 of a temperature distribution. It is a figure which shows the example of the relationship between the flow velocity and the square error (the square error of the measured value of a temperature distribution and the analysis value of a temperature distribution). It is a figure which shows an example of the 1st processing group. It is a figure which shows an example of the flow velocity setting processing in the 1st processing group. It is a figure which shows the 1st example of the 2nd processing group. It is a figure which shows the example of the relationship between the flow velocity and the square error (the square error of the measured value of a temperature distribution and the analysis value of a temperature distribution). It is a figure which shows the 2nd example of the 2nd processing group.

Hereinafter, embodiments of the present invention will be described, but the following embodiments do not limit the inventions in the claims. Also, not all combinations of features described in the embodiments are essential to the solution of the invention.
The flow velocity measurement system (an example of a flow velocity evaluation system) according to the present embodiment determines the flow velocity of a fluid (for example, steam) flowing in a pipe arranged between a steam production device such as a boiler and a load facility. It is a measurable system.

FIG. 1 is a diagram showing a schematic configuration of a flow velocity measuring system 100 according to the present embodiment. FIG. 2 is a diagram showing a main configuration of the flow velocity measuring system 100.
As shown in FIG. 1, the flow velocity measurement system 100 according to the present embodiment includes a heating unit (heat exchanger) 2, a preheater 2b, a temperature measurement unit 3, a control unit (flow velocity calculation unit) 4, and a flow velocity. Including a total of 5. In FIG. 1, the pipe 10 is arranged between the steam production apparatus 20 (boiler or the like) and the load equipment 30. The steam from the steam production apparatus 20 flows through the pipe 10 and is sent to the load equipment 30. In the load equipment 30, steam or steam heat is utilized. The steam discharged from the load equipment 30 is collected as a drain, collected in a return water tank (not shown), and then re-supplied to the steam production apparatus 20. Further, a heat insulating material is wound around the pipe 10.

Here, in the present embodiment, the configuration in which the current meter 5 is provided in the flow velocity measuring system 100 is shown, but as another configuration example, a configuration in which the current meter 5 is not provided may be used. That is, a configuration in which the flow velocity is measured using the current meter 5 may be used, or a configuration in which the flow velocity is calculated from other information (may be an estimated calculation) may be used.

The heating unit 2 is for heating a predetermined portion by exchanging heat with the surface 10a of the pipe 10. In the present embodiment, the heating unit 2 is composed of, for example, a ring-shaped heater, and is arranged at a predetermined position on the surface 10a of the pipe 10 in the circumferential direction as shown in FIG. As a result, the heating unit 2 uniformly heats the surface 10a of the pipe 10 in the predetermined portion of the pipe 10 (the installation portion 11 of the heating unit 2). The heating unit 2 is electrically connected to the control unit 4, and its operation is controlled.
The heat exchanger referred to here transfers heat from an object having a high temperature to an object having a low temperature. The heater is an example of a heat exchanger.
In FIG. 2, the arrow B11 shows an example of the direction in which the fluid flows in the pipe 10.

The preheater 2b heats the fluid flowing in the pipe 10. The preheater 2b is provided to prevent the liquefaction of the gas fluid flowing in the pipe 10. For example, when the fluid flowing in the pipe 10 is steam, the preheater 2b heats the steam to prevent the steam from liquefying and adhering water droplets in the pipe 10 or the load equipment 30. ..

The temperature sensor group 3A is arranged on both sides (upstream side and downstream side) of the installation portion 11 of the heating portion 2 on the surface 10a of the pipe 10. The installation position of each temperature sensor group 3A is determined according to the distance from the installation portion 11. For example, taking the upstream side of the installation portion 11 as an example, each temperature sensor group 3A has a distance of 0 mm (millimeter), 6 mm, 14 mm, 24 mm, 36 mm, 50 mm, 66 mm, 84 mm, 104 mm from the end face of the installation portion 11. , 126 mm, 150 mm, 176 mm. Here, the distance of the installation portion 11 from the end face is 0 mm, which means that the temperature sensor group 3A is arranged along the end face of the heating portion 2. In FIG. 2, as the cross-sectional structure of the pipe 10, the vicinity of the downstream end face of the installation portion 11 (cross section viewed by arrow AA) and the distance of 24 mm from the downstream end face of the installation portion 11 (arrow BB). (Cross section by visual inspection) is shown.

As shown in FIG. 2, the temperature sensor group 3A is arranged so that the distance between the adjacent temperature sensor groups 3A increases by 2 mm as the distance from the installation portion 11 increases. Therefore, in the temperature sensor group 3A, the closer to the installation portion 11 (heating portion 2), the closer the sensors are arranged. As a result, it is possible to accurately detect the temperature of the surface 10a of the pipe 10 in the vicinity of the installation portion 11.

The temperature measurement unit 3 is composed of a plurality of (for example, 12 in this embodiment) temperature sensor group 3A. Each temperature sensor group 3A is arranged on the surface 10a of the pipe 10 along the pipe axis direction of the pipe 10. Each temperature sensor group 3A includes a plurality of temperature sensors 3a for measuring the temperature of the surface 10a of the pipe 10. In the present embodiment, each temperature sensor group 3A is composed of four temperature sensors 3a. The four temperature sensors 3a are evenly arranged in the circumferential direction on the surface 10a of the pipe 10. That is, the four temperature sensors 3a are arranged so as to be different in position by 90 degrees in the circumferential direction of the pipe 10. Each temperature sensor group 3A outputs an average value of the values measured by the four temperature sensors 3a as a measured value. As described above, the temperature sensor group 3A can output a highly reliable measurement result (temperature) by using the average of the values measured at a plurality of locations on the surface 10a of the pipe 10 as the measurement value.

The number of temperature sensors 3a constituting each temperature sensor group 3A is not limited to the four shown in FIG. 2, and may be one or more. For example, each temperature sensor group 3A is composed of two temperature sensors 3a, and the two temperature sensors 3a are arranged evenly on the left and right in the circumferential direction of the pipe 10 (so that the positions are different by 180 degrees in the circumferential direction of the pipe 10). It may have been done. As described above, each temperature sensor group 3A is provided with a plurality of temperature sensors 3a, and the average of the values measured at a plurality of locations on the surface 10a of the pipe 10 is used as the measured value to obtain a highly reliable measurement result (temperature). It is possible to output.

Based on the above-described configuration, the temperature measuring unit 3 can measure the temperature distribution of the surface 10a in the pipe axis direction of the pipe 10 from the measurement results of each temperature sensor group 3A. The temperature distribution measured by the temperature measuring unit 3 is transmitted to the control unit 4.

At least a part of the surface 10a of the pipe 10 is covered with the heat insulating material 12. In the present embodiment, the heat insulating material 12 is installed along the pipe axis direction so as to cover the heating unit 2 and the temperature measuring unit 3 (each temperature sensor 3a) provided on the surface of the pipe 10.

FIG. 3 is a schematic view showing the control unit 4. In FIG. 3, the arithmetic unit 50 is, for example, a computer system. The control unit 4 has an input device 60 and a display device (output device) 64 in addition to the calculation device 50. The calculation device 50 includes a converter 61 such as an A / D converter, an arithmetic processing unit (CPU: Central Processing Unit) 62, a memory 63, and the like. The measurement data (temperature distribution) sent from the temperature measurement unit 3 of the flow velocity measurement system 100 is converted by the converter 61 or the like as necessary and taken into the CPU 62. Further, the initial setting value, temporary data, and the like are taken into the calculation device 50 via the input device 60 and the like. The display device 64 can display information related to the input data, information related to the calculation, and the like.

The CPU 62 can calculate the flow velocity of the steam flowing inside the pipe 10 based on the measurement data and the information stored in the memory 63. The CPU 62 calculates, for example, the flow velocity of steam flowing inside the pipe 10 from the information stored in the memory 63 by using the measurement result of the temperature measuring unit 3 (the temperature distribution on the surface 10a of the pipe 10). The control unit 4 is an example of a flow velocity calculation unit.
Specifically, the memory 63 stores in advance (prior to the measurement of the flow velocity) the relationship information indicating the relationship between the temperature distribution on the surface 10a of the pipe 10 and the flow velocity of the fluid flowing inside the pipe 10. .. The memory 63 is an example of a storage unit. In the relational information stored in the memory 63, the flow velocity and the temperature distribution are associated with each flow velocity of the fluid.
Then, when the temperature measuring unit 3 measures the temperature distribution on the surface 10a of the pipe 10, the CPU 62 refers to the related information and is closest to the temperature distribution measured by the temperature measuring unit 3 (for example, the sum of the absolute values of the differences). The flow velocity associated with the temperature distribution (which is the smallest) is read out and used as the measured value of the flow velocity.

In this way, the memory 63 stores in advance the relationship information in which the temperature distribution and the flow velocity are associated with each other. Then, the heating unit 2 heats a predetermined portion with a ring heater (ring-shaped heater), and the temperature measurement unit 3 measures the temperature distribution in the pipe 10 in a state where the temperature distribution of the pipe 10 is in a steady state. .. Then, the control unit 4 refers to the relational information and sets the flow velocity associated with the temperature distribution closest to the temperature distribution obtained by the measurement as the flow velocity measurement value.

Next, a method of acquiring the related information stored in the memory 63 in advance will be described.
The relational information can be obtained by analyzing the heat transfer in the steady temperature state of the pipe 10 by the finite element method. In the following, a case where the control unit 4 performs the calculation of the finite element method will be described as an example, but the analysis of the finite element method may be performed using another computer.
In order to apply the finite element method to the pipe 10, the area of the pipe 10 is divided into cells (partial areas).

FIG. 4 is an explanatory diagram showing an example of dividing the region of the pipe 10 into cells.
The region A11 shown in the figure indicates a region in the pipe (a region through which a fluid flows). The area A12 indicates the area of the pipe 10 (the area of the pipe wall). Region A13 indicates a region of insulation wound around the pipe 10. Region A14 indicates a region of air outside the insulation. Further, arrow B11 shows an example of the direction in which the fluid flows in the pipe 10.

In the cell division for applying the finite element method, as shown in FIG. 4, the region A12 of the pipe wall of the pipe 10 is divided into three layers with an equal thickness. The three layers, the fluid region A11, the heat insulating material region A13, and the external air region A14 are divided into six layers in the radial direction of the pipe 10.
Further, with respect to the axial direction (longitudinal direction) of the pipe 10, the pipe 10 is evenly divided into relatively small widths such as 3 mm width.
Further, a ring-shaped heater is used as the heating portion 2, and as shown in FIG. 4, the thickness of the heating portion 2 in the longitudinal direction of the pipe 10 is ignored. In particular, it is approximated that the heating unit 2 enters heat into only one cell in the region A12 of the pipe wall of the pipe 10. Further, the influence of the capacity of the heating unit 2 itself is ignored (assuming that the capacity is sufficiently small).

Heat transfer with adjacent contacts includes convective heat transfer between the inner surface of the pipe and the fluid in the pipe, heat transfer in the pipe wall (inside region A12 in FIG. 4), heat conduction from the pipe wall to the heat insulating material, and in the heat insulating material. Heat transfer by convective heat transfer between the outer surface of the heat insulating material and the ambient air. Further, the outer edge of the cell at the end of the pipe sufficiently separated from the heating portion 2 is set as the heat insulating condition.
The following equation based on thermal balance (the following equation (1)) is set for each cell, and the control unit 4 analyzes it using the finite element method to calculate the temperature difference between the cells. As a solution method of the finite element method (solving simultaneous equations), for example, the Newton-Raphson method can be used. However, the solution method used by the control unit 4 is not limited to the Newton-Raphson method, and various solution methods that can be applied to simultaneous equations can be used.

Here, in the steady state, the sum of the amount of heat input from the adjacent cells becomes 0. The amount of heat released is expressed as minus the amount of heat input.
The thermal balance in the cell located at the coordinates (i, j) is expressed by the equation (1).

Q _{i, j-1} + Q _{i, j + 1} + Q _{i-1, j} + Q _{i + 1, j} = 0
・ ・ (1)

Here, let the coordinates of the cell adjacent to the cell located at the coordinate (i, j) be (i, j-1), (i, j + 1), (i-1, j), (i + 1, j). .. Further, Q _{i, j-1} , Q _{i, j + 1} , Q _{i-1, j} , and Q _{i + 1, j} each indicate the amount of heat input from the cell located at the coordinates indicated by the subscripts. If there is no adjacent cell, the amount of heat input from the cell is set to 0.
As described above, an equation based on thermal balance (Equation (1)) is set for each cell. The setting of the equation is performed by, for example, the user of the flow velocity measurement system 100, and is stored in the memory 63 of the control unit 4. Then, the control unit 4 performs an analysis by the finite element method for each set value of the flow velocity, and acquires the relational information showing the relationship between the temperature distribution and the flow velocity.

For Q _{i, j-1} , Q _{i, j + 1} , Q _{i-1, j} , Q _{i + 1, j} of equation (1), for example, any of the following equations (2), (3), and (4) Apply the right-hand side of.

Convective heat transfer: The amount of heat input from the fluid (fluid in the pipe 10) to the innermost cell of the cells of the pipe 10 is expressed by the equation (2).

Amount of heat input by convective heat transfer = α ・ A ・ Δt ・ ・ (2)

Here, α [W (watt) / (m ² (square meter) · K (Kelvin))] indicates the convective heat transfer coefficient.
A [m ² ] indicates the heat transfer area. Here, it is the area where the cell of the pipe 10 is in contact with the fluid in the pipe.
Δt [K] indicates the temperature difference from the adjacent cell. Here, the temperature difference at the contact portion between the pipe 10 and the fluid in the pipe is shown.

Radial heat conduction: The amount of heat input due to the radial heat conduction of the pipe 10 in the pipe 10 is expressed by the equation (3). That is, the amount of heat input from the cells of the pipes (cells obtained by cutting the pipes into meshes) adjacent to each other in the radial direction of the pipes is expressed by the equation (3).

Heat input due to radial heat conduction = 2π ・ λ ・ L ・ Δt / ln (ro / ri)
・ ・ (3)

Here, π indicates the pi.
λ [W / (m (meter) · K)] indicates the thermal conductivity of the material (for example, steel) of the pipe 10.
L [m] indicates the length of the cell in the pipe axial direction (axial direction of the pipe 10).
Δt [K] indicates the temperature difference from the adjacent cell as described above. Here, the temperature difference at the contact portion between the cells of the pipe 10 adjacent to each other in the radial direction of the pipe 10 is shown.
ln indicates the natural logarithm.
ro / ri [m] indicates the distance between cells in the radial direction (for example, the distance between the centers of cells).

Pipe axial heat conduction: The amount of heat input due to the axial (longitudinal) heat conduction of the pipe 10 in the pipe 10 is expressed by the equation (4). That is, the amount of heat input from the cell of the pipe 10 adjacent to the pipe axis direction is expressed by the equation (4).

Amount of heat input due to heat transfer in the tube axis direction = λAΔt / L ・ ・ (4)

Here, λ and L are as described above.
A [m ² ] indicates the heat transfer area as described above. Here, it is the area where the cells of the pipe 10 are in contact with each other (cells of the pipe 10 adjacent to each other in the radial direction of the pipe 10).
Δt [K] indicates the temperature difference from the adjacent cell as described above. Here, the temperature difference at the contact portion between the cells of the pipes 10 adjacent to each other in the pipe axis direction is shown.

Further, the following equation (5) is used for convective heat transfer.

^{_{N ud = 0.022 · X WT ·}} R ed 0.8 · P r 0.4 ·· (5)

Here, _Nud indicates the Nusselt number.
_Red indicates the Reynolds number.
P _r shows the Prandtl number (Prandtl Number).
X _WT is a coefficient for correcting the temperature, and takes a value according to the distance from the heating unit 2 (heater). In particular, the X _{WT raises the} temperature in the vicinity of the heating unit 2 (that is, increases the heat transfer). Hereinafter, X _WT is referred to as a heat transfer coefficient correction coefficient.

In this embodiment, the case where the accuracy is improved by using the heat transfer coefficient correction coefficient X _WT is shown, but as another configuration example, if the accuracy is sufficient, the heat transfer coefficient correction coefficient X _WT is used. A configuration that does not (a _{configuration that considers the heat transfer coefficient correction coefficient X WT} = 1) may be used.

The Nusselt number N _ud is expressed by the equation (6).

Nu = αi ・ di / λ ・ ・ (6)

Here, λ is as described above.
di [m] indicates the inner diameter of the pipe 10.
αi [W / (m ² · K)] indicates the thermal conductivity inside the pipe 10.

The Reynolds number _Red is expressed by the equation (7).

Re = u × di / ν ・ ・ (7)

Here, u [m / s (seconds)] indicates the flow velocity of the fluid flowing in the pipe 10.
ν [m ² / s] indicates the kinematic viscosity coefficient of the fluid flowing in the pipe 10.
di [m] indicates the inner diameter of the pipe 10.

Further, the Prandtl number _Pr is expressed by the equation (8).

Pr = ν × ρ × Cp / λ ・ ・ (8)

ν and λ are as described above.
ρ [kg (kilogram) / m ³ (cubic meter)] indicates the density of the fluid.
Cp [kJ (kilojoule) / (kg · K)] indicates the specific heat of the fluid.

Nusselt number N _ud of formula (5) is proportional to the convective heat transfer coefficient of the formula (2) alpha, it is possible to obtain the convective heat transfer coefficient alpha from Nusselt number N _ud. By introducing the heat transfer coefficient correction coefficient X _{WT as in the equation (5) and obtaining} the value of the Nusselt number Nu with high accuracy, the value of the convection heat transfer coefficient α can be obtained with high accuracy. By obtaining the value of the convection heat transfer coefficient α with high accuracy, it is possible to obtain the temperature difference between cells with high accuracy by the analysis using the finite element method, and thereby the analysis value of the temperature distribution in the pipe 10. The accuracy of can be improved.

The following equation (9) is also used for convective heat transfer.

W = _YHT・ G ・ C _p・ ΔT ・ ・ (9)

Here, Cp is as described above.
W [J (joule) / s] indicates the amount of heating by the heating unit 2.
G [kg / s] indicates the total flow rate of the fluid flowing through the pipe 10.
ΔT [° C. (degrees)] indicates the temperature rise of the fluid due to the heating of the heater of the heating unit 2.
_YHT is the ratio of the amount of fluid that contributes to the transfer of heat from the heater of the heating unit 2 (the amount of fluid that receives heat from the heating of the heater of the heating unit 2) to the total amount of fluid that flows through the pipe cross section. Shown. Specifically, the area of the entire fluid in the pipe cross section is S, and the area of the portion of the fluid in the pipe cross section that receives heat from the heating of the heater is S1, and is expressed as _{YHT = S1 / S.} In the _following, referred to as the temperature boundary coefficient _{Y HT.}

In this embodiment, _{the case where the accuracy is improved by using the temperature boundary coefficient Y HT} is shown, but as another configuration example, if the accuracy is sufficient, the temperature boundary coefficient Y _HT is not used (temperature). Boundary coefficient Y _HT = 1) may be used.

As described above, steam is passed through the pipe 10 to actually measure the temperature distribution and the flow velocity, and the analysis value of the temperature distribution (value obtained by the analysis using the finite element method by applying the general heat transfer equation). ) And the measured value, the measured temperature value was higher than the analyzed value in the vicinity of the heater installation position of the heating unit 2. In addition to the temperature deviation on the upstream side from the heater installation position of the heating unit 2 described above, the measured temperature value was higher than the analysis value also on the downstream side from the heater installation position of the heating unit 2. It is considered that one of the causes of this temperature shift is that, of the fluid flowing in the pipe 10, only a part of the fluid near the inner surface of the pipe 10 transfers the heat from the heater. Therefore, when the temperature boundary coefficient _YHT was introduced and recalculation was performed, the analyzed value and the actually measured value were in good agreement. In particular, by introducing both the heat transfer coefficient correction coefficient X _WT and the temperature boundary coefficient Y _HT , the analyzed value and the measured value were in good agreement.

_Making the value of the temperature boundary coefficient YHT smaller than 1 corresponds to reducing the amount of fluid that contributes to the heat transfer from the heater. When the amount of the fluid contributing to the heat transfer from the heater is small, the value of the temperature difference Δt in the equation (2) (the temperature difference at the contact portion between the pipe 10 and the fluid in the pipe) is calculated to be large. By introducing a temperature boundary coefficient Y _HT by calculating the value of the temperature difference Δt of the formula (2) with high accuracy, it is possible to improve the accuracy of analysis of the temperature distribution in the pipe 10.

The current meter 5 is an example of a flow velocity measuring unit, and measures the flow velocity of the fluid flowing in the pipe 10. By providing the current meter 5, the flow velocity measuring system 100 measures the temperature distribution in the pipe 10 and the flow velocity of the fluid flowing in the pipe 10. As a result, the flow velocity measurement system 100 acquires the correspondence between the temperature distribution on the surface 10a of the pipe 10 and the flow velocity of the fluid flowing inside the pipe 10 in the measured values.
In the present embodiment, the control unit 4 of the flow velocity measurement system 100 has a function of analyzing the heat transfer in the temperature steady state of the pipe 10 by the finite element method described above.

Here, if the temperature distribution and the flow velocity are measured for various flow velocities of the fluid flowing in the pipe 10, the relational information stored in the memory 63 can be acquired. However, if all the related information is to be acquired by actual measurement, the number of measurements will increase, and the burden of setting the flow velocity measurement system 100 (for example, the burden of adjusting the flow velocity of the fluid) will increase for the user of the flow velocity measurement system 100.
Therefore, the control unit 4 analyzes the heat transfer in the steady temperature state of the pipe 10 for each flow velocity of the fluid by the finite element method to acquire the relational information. As a result, the burden on the user to set the flow velocity measuring system 100 can be reduced. The control unit 4 is an example of the relationship information setting unit.

The control unit 4 analyzes the heat transfer in the temperature steady state of the pipe 10 based on the above equations (1) to (9). At that time, the control unit 4 sets _{the value of the heat transfer coefficient correction coefficient X WT and} the value of the temperature boundary coefficient Y _HT in advance (before performing the analysis for acquiring the relational information). The control unit 4 is an example of a temperature boundary coefficient value acquisition unit.
The control unit 4 prepares, for example, a plurality of combinations of a value of the heat transfer coefficient correction coefficient X _{WT and} a value of the temperature boundary coefficient Y _HT. Then, the control unit 4 is finite for each combination of the value _{of the heat transfer coefficient correction coefficient X WT and} the value of the temperature boundary coefficient Y _HT with respect to the flow velocity measured by the flow velocity measurement system 100 (the flow velocity measured by the current meter 5). The temperature distribution in the pipe 10 is calculated by performing the analysis by the element method. Then, the control unit 4 adopts a combination of the value of the _{heat transfer coefficient correction coefficient X WT and} the value of the temperature boundary coefficient Y _HT obtained by obtaining the analysis value closest to the measured value of the temperature distribution in the pipe 10.

As described above, in the present embodiment, as a method of obtaining the flow velocity of the fluid flowing inside the pipe 10 from the temperature distribution of the pipe 10, the relationship between the temperature distribution and the flow velocity is obtained in advance, and the temperature is used using the obtained relationship. A method of converting the distribution into a flow velocity is used. In this case, in order to obtain the flow velocity accurately, the relationship between the temperature distribution and the flow velocity is obtained accurately.

Here, in the present embodiment, in the pipe 10, the heating unit 2 and the temperature measuring unit 3 (each temperature sensor 3a) are covered with the heat insulating material 12 as an example, but the present invention is not limited to this. .. For example, if the control unit 4 corrects the measurement data (temperature distribution) sent from the temperature measuring unit 3 in consideration of heat dissipation from the surface 10a of the pipe 10, the surface 10a of the pipe 10 is covered with the heat insulating material 12. You don't have to. Alternatively, only a part of the surface 10a (the installation portion of the temperature measuring unit 3) may be covered with the heat insulating material 12.

Further, the fluid flowing in the pipe 10 is not limited to steam or air. For example, the configuration according to the present embodiment can be applied even when measuring the flow velocity of hot water flowing in the pipe 10. Further, the fluid flowing in the pipe 10 may be Freon, ammonia, LNG (Liquefied Natural Gas) or the like, and the configuration according to the present embodiment can be applied when measuring the flow velocity of these fluids. is there.

Further, in the present embodiment, the heating unit 2 is exemplified as a heat exchanger that exchanges heat with the pipe 10, but the present invention is not limited to this. For example, as the heat exchanger, a cooler that cools the surface 10a of the pipe 10 may be used, and the flow velocity of steam flowing in the pipe 10 based on the temperature distribution generated in the pipe axis direction of the pipe 10 by cooling. May be measured. In this case, when the steam is saturated steam or superheated steam close to it, condensation may occur, so it is necessary to take this into consideration when calculating the heat transfer coefficient.

Further, in the flow velocity measurement system 100 (FIG. 1), the preheater 2b is not an essential configuration. The configuration of the flow velocity measurement system 100 may be a configuration that does not include the preheater 2b.

[Explanation of analysis processing using fitting]
FIG. 5 is a diagram showing an example of the relationship between the axial distance of the pipe 10 and the temperature of the surface 10a of the pipe 10 (when the flow velocity is 5 m / s).
FIG. 6 is a diagram showing an example of the relationship between the axial distance of the pipe 10 and the temperature of the surface 10a of the pipe 10 (when the flow velocity is 20 m / s).
FIG. 7 is a diagram showing an example of the relationship between the axial distance of the pipe 10 and the temperature of the surface 10a of the pipe 10 (when the flow velocity is 35 m / s).

In the graphs shown in FIGS. 5 to 7, the horizontal axis represents the distance [m] in the axial direction of the pipe 10, and the vertical axis represents the temperature [° C.] of the surface 10a of the pipe 10. In each of FIGS. 5 to 7, the characteristics of the relationship between the axial distance of the pipe 10 and the temperature of the surface 10a of the pipe 10 (characteristic 201 of temperature distribution when the flow velocity is 5 m / s, temperature when the flow velocity is 20 m / s). An example of the distribution characteristic 202 and the temperature distribution characteristic 203) at a flow velocity of 35 m / s is shown.
Each characteristic 2001-203 has a symmetrical shape (or a shape close to left-right symmetry) with respect to the horizontal axis, and the position of the center of the left-right symmetric horizontal axis (or a position close to the center of the horizontal axis). ) Corresponds to the position of the heating unit 2.

FIG. 8 is a diagram showing an example of the full width at half maximum P1 in the characteristic 201 of the temperature distribution.
FIG. 9 is a diagram showing an example of the maximum temperature P2 in the characteristic 201 of the temperature distribution. The maximum temperature P2 indicates, for example, the peak temperature.
FIG. 10 is a diagram showing an example of the area P3 of the temperature distribution waveform in the characteristic 201 of the temperature distribution.
In the present embodiment, the area P3 of the temperature distribution waveform is the area of the region surrounded by the temperature baseline 251 and the temperature distribution waveform (mountain-shaped line). In this case, the area P3 is not affected by the temperature of the baseline 251 and has good sensitivity. In the example of FIG. 10, as the temperature baseline 251, a point on the left baseline (for example, the point on the right end) and a point on the right baseline (for example, the point on the left end) are connected. The baseline is used.
As another configuration example, another area may be used as the area P3 of the temperature distribution waveform. As a specific example, as the area P3 of the temperature distribution waveform, the area of the region surrounded by the horizontal axis (value on the vertical axis is 0) and the temperature distribution waveform (mountain-shaped line) may be used, or the horizontal axis may be used. A line whose vertical axis value is not 0 (a line parallel to or non-parallel to the horizontal axis) may be used instead of the axis, and the minimum value of the horizontal axis value that divides the area for which the area is to be obtained. Alternatively, one or both of the maximum values may be set.
Here, FIGS. 8 to 10 are diagrams showing an example corresponding to the graph shown in FIG.
Normally, as the flow velocity increases, the full width at half maximum P1 decreases, the maximum temperature P2 decreases, and the area P3 of the temperature distribution waveform decreases.

Here, as described above, the parameters (features of the temperature distribution) that can be used in the analysis include the full width at half maximum, the maximum temperature, and the area of the temperature distribution waveform.
In the present embodiment, the case where the full width at half maximum is used as the parameter of the analysis is shown, but as another configuration example, the maximum temperature may be used, or the area of the temperature distribution waveform may be used, or , Half width, maximum temperature, and area of temperature distribution waveform may be combined in combination of two or more.

FIG. 11 is a diagram showing an example of the relationship between the flow velocity and the half width.
In the graph shown in FIG. 11, the horizontal axis represents the flow velocity [m / s], and the vertical axis represents the half width. The graph shows an example of the measured value 301 and an example of the analysis value 311 regarding the relationship between the flow velocity and the full width at half maximum. Here, the analysis value 311 is, for example, a characteristic (characteristic of the relationship between the flow velocity and the half width) obtained as a result of performing fitting processing on a plurality of actually measured values 301. In this example, the analysis value of the quadratic function is used in the fitting for obtaining the analysis value 311.

FIG. 12 is a diagram showing an example of the relationship between the measured value 401 of the temperature distribution and the analysis value 411 of the temperature distribution.
In the graph shown in FIG. 12, the horizontal axis represents the axial distance (distance in the flow direction) [m] of the pipe 10, and the vertical axis represents the temperature [° C.].
For example, at each point of the plurality of measured values 401, the difference between the measured value 401 and the analysis value 411 becomes an error. Further, the squared error of the squared error (difference between the measured value 401 and the analysis value 411) at each point of the plurality of measured values 401 is summed with respect to the points of the plurality of measured values 401 to obtain a squared error. In this example, the analysis value of the quadratic function is used in the fitting for obtaining the analysis value 411.

FIG. 13 is a diagram showing an example of the relationship between the flow velocity and the squared error (square error between the measured value of the temperature distribution and the analyzed value of the temperature distribution).
In the graph shown in FIG. 13, the horizontal axis represents the flow velocity [m / s], and the vertical axis represents the square error. The graph shows an example of the measured value 501 and an example of the analysis value 511 regarding the relationship between the flow velocity and the squared error. Here, the analysis value 511 is, for example, a characteristic (characteristic of the relationship between the flow velocity and the square error) obtained as a result of performing fitting processing on a plurality of actually measured values 501. In this example, the analysis value of the quadratic function is used in the fitting for obtaining the analysis value 511.

<First example of analysis processing using fitting>
A first example of an analysis process using fitting will be described with reference to FIGS. 14-17.
In the present embodiment, for convenience of explanation, the entire processing group will be divided into a first processing group and a second processing group, but the first processing group and the second processing group may be integrated. Good. After the processing of the first processing group is performed, the processing of the second processing group is performed. In the present embodiment, in the control unit 4, the CPU 62 of the computing device 50 executes each process included in the entire processing group by using the memory 63 or the like.

FIG. 14 is a diagram showing an example of the first processing group.
FIG. 15 is a diagram showing an example of the flow velocity setting process in the first process group.
FIG. 16 is a diagram showing a first example of the second processing group.
FIG. 17 is a diagram showing an example of the relationship between the flow velocity and the square error (square error between the measured value of the temperature distribution and the analysis value of the temperature distribution).

The first processing group will be described with reference to FIG.
(Step S1)
In the control unit 4, a predetermined measured value (measured value) is input. This measured value is, for example, a measured value of the temperature of a fluid (for example, steam or the like) in the pipe 10, and a measured value of the pressure of the fluid. The fluid is, for example, the one before being heated by the heating unit 2.

(Step S2)
In the control unit 4, a predetermined parameter is input. This parameter is, for example, a parameter such as the inner diameter, wall thickness, material, thermal conductivity, and thickness of the heat insulating material of the pipe 10. Here, in the present embodiment, the parameter is input from the input device 60, but as another configuration example, a part or all of the parameter may be stored in the memory 63 in advance and used. ..
The process of (step S1) and the process of (step S2) may be performed in the reverse order. Further, at the stage of the process of (step S1) and the process of (step S2), a specific flow velocity is not assumed.

(Step S3)
In the control unit 4, the flow velocity at three points is set.
Here, in the present embodiment, the flow velocities at three points are set, but as another configuration example, the flow velocities at four points or more may be set. That is, an arbitrary number of flow velocities of 3 points or more may be set.

An example of the flow velocity setting process (process in step S3) in the first process group shown in FIG. 14 will be described with reference to FIG.
(Step S21)
First, in the control unit 4, the flow velocity at one point is set.

(Step S22)
Next, in the control unit 4, the half width is calculated at the set flow velocity. Specifically, in the control unit 4, the analysis value (theoretical value) of the temperature distribution is calculated by using the finite element method at the set flow velocity, and the analysis value of the half width (theoretical value) is calculated based on the calculated analysis value of the temperature distribution. Value) is calculated.

(Step S23)
Next, in the control unit 4, the flow velocity at one point (the flow velocity at the second point in the first loop of steps S22 to S24) is set based on the measured value of the half width. Specifically, in the control unit 4, a flow velocity at one point is newly set based on the analysis value of the half-value width at the already set flow velocity and the measured value of the measured half-value width.

(Step S24)
Next, the control unit 4 determines whether or not to finish setting the flow velocity. When the control unit 4 determines that the setting of the flow velocity is completed, this process is terminated. On the other hand, when the control unit 4 determines that the setting of the flow velocity is not completed, the process proceeds to step S22.
Here, as a condition for ending the setting of the flow velocity, for example, a condition of ending when a predetermined number of flow velocities are set may be used. As the predetermined number, for example, any number of 3 or more may be used. In the present embodiment, 3 is set as a predetermined number.

A specific example of the flow velocity setting process (processes of steps S21 to S24) shown in FIG. 15 is shown.
A specific example with respect to FIG. 15 is shown.
For example, when setting the flow velocity of three points or more in the control unit 4, first, the analysis value of the half width of the temperature distribution is calculated at the flow velocity of one point or more. Next, in the control unit 4, the measured value of the measured half-value width is acquired. Then, in the control unit 4, a new flow velocity (flow velocity at the next point) is determined based on the analysis value and the actual measurement value.
In addition, the process of determining the flow velocity in this way may be further repeated once or more.
Further, the flow velocities at these three points or more can be regarded as, for example, tentatively set flow velocities (dummy flow velocities) for performing the subsequent processing.

A detailed concrete example with respect to FIG. 15 is shown.
First, in the control unit 4, the flow velocity at the midpoint within the range of the assumed flow velocity is set as the flow velocity at the first point. As an example, when the assumed flow velocity range is 0 to 40 [m / s], the midpoint flow velocity is 20 [m / s]. Next, in the control unit 4, the analysis value of the half-value width at the set midpoint flow velocity is calculated, and the measured value of the measured half-value width is acquired.
As a result, when the measured value of the half width is smaller than the analysis value, the control unit 4 determines and sets a flow velocity larger than the flow velocity at the midpoint as the flow velocity at the second point. In the above example, any flow velocity of 20 to 40 is set as the flow velocity, and for example, a flow velocity of 30 which is the midpoint of 20 to 40 may be set.
On the other hand, when the measured value of the half width is larger than the analysis value, the control unit 4 determines and sets a flow velocity smaller than the flow velocity at the midpoint as the flow velocity at the second point. In the above example, any flow velocity of 0 to 20 is set as the flow velocity, and for example, a flow velocity of 10 which is a midpoint of 0 to 20 may be set.

In the present embodiment, in order to simplify the explanation, as an example, the assumed flow velocity range is 0 to 40 [m / s], but 0 [m / s] is not realistic and is actually used. For example, the flow velocity of steam or the like in the pipe 10 is considered to be about 2 to 40 [m / s].

A continuation of a detailed specific example with respect to FIG. 15 is shown.
Further, in the control unit 4, the flow velocity at the third point is set.
Specifically, in the control unit 4, when the measured value of the half price width is located between the analysis value of the half price width at the first point flow velocity and the analysis value of the half price width at the second point flow velocity, 1 The flow velocity located between the flow velocity of the second point and the flow velocity of the second point is determined and set as the flow velocity of the third point. As the flow velocity located between the flow velocity of the first point and the flow velocity of the second point, as an example, the flow velocity at the midpoint between the flow velocity of the first point and the flow velocity of the second point may be used.
On the other hand, in the control unit 4, when the measured value of the half price width is not located between the analysis value of the half price width at the first point flow velocity and the analysis value of the half price width at the second point flow velocity, the first point The flow velocity at a position exceeding the flow velocity at the second point when viewed from the flow velocity is determined and set as the flow velocity at the third point. As an example, the flow velocity at a position exceeding the flow velocity of the second point when viewed from the flow velocity of the first point is 1.5 times the distance to the flow velocity of the second point when viewed from the flow velocity of the first point. A certain flow rate may be used. In this case, for example, the range of the flow velocity (maximum value and minimum value) may be assumed and set. Then, when the flow velocity at the second point is larger than the flow velocity at the first point and the flow velocity at the 1.5 times position exceeds the assumed range, the maximum flow velocity within the assumed range is It may be used. On the contrary, when the flow velocity of the second point is smaller than the flow velocity of the first point and the flow velocity at the 1.5 times position is less than the assumed range, the minimum flow velocity in the assumed range is It may be used.
In the same way, the control unit 4 may set the flow velocity after the fourth point.

Here, as another configuration example, another method may be used as a method of setting the flow velocity of three or more points in the processes shown in FIGS. 14 and 15. As an example, a method of selecting (determining) and setting a flow velocity of any three or more points within an assumed flow velocity range (for example, 0 to 40 [m / s]) may be used. Specifically, for example, such as a combination of flow velocities of 5 [m / s], 20 [m / s], and 35 [m / s], the flow rate is distributed evenly over the entire flow rate range. A method of selecting (determining) and setting the flow rate above the point may be used.

A first example of the second processing group will be described with reference to FIG. The processing of the second processing group shown in FIG. 16 is performed after the processing of the first processing group shown in FIG.
(Step S41)
First, in the control unit 4, the analysis value (theoretical value) of the temperature distribution obtained by using the finite element method and the actually measured value of the measured temperature distribution at each flow velocity among the three or more set flow velocities. , Calculate the squared error of both.

(Step S42)
Next, in the control unit 4, the relationship (analyzed value) between the flow velocity and the square error is obtained by fitting. In fitting, for example, a quadratic function is used.
(Step S43)
Next, in the control unit 4, a candidate for the flow velocity is determined based on the fitting result (analyzed value).
As an example, in the control unit 4, the flow velocity having the smallest square error in the fitting result (analyzed value) is determined as a flow velocity candidate.
Here, FIG. 17 shows the flow velocity Q1 having the minimum square error in the same graph as in FIG. In the graph shown in FIG. 17, the horizontal axis represents the flow velocity [m / s], and the vertical axis represents the square error. The graph shows an example of the measured value 601 and an example of the analysis value 611 regarding the relationship between the flow velocity and the squared error.

(Step S44)
Next, in the control unit 4, the squared error between the analysis value (theoretical value) of the temperature distribution obtained by using the finite element method and the measured value of the measured temperature distribution in the determined flow velocity candidates. To calculate. Then, the control unit 4 determines whether or not the calculated squared error is equal to or less than a predetermined specified value. As the default value, any value may be used, and for example, it may be set in advance.

(Step S45)
When the control unit 4 determines that the square error is equal to or less than a predetermined specified value as a result of the determination in (step S44) described above, the candidate flow velocity is formally determined. Then, the control unit 4 ends this process.

(Step S46)
On the other hand, when the control unit 4 determines that the square error exceeds a predetermined specified value as a result of the determination in (step S44) described above, the flow velocity (combination of flow velocities of 3 points or more) is changed. The process proceeds to the above-mentioned (step S41).
Here, as a method of changing the flow velocity (combination of flow velocities of 3 points or more), as an example, one point as a candidate instead of the flow velocity of one point out of the original flow velocities of three points or more. The method of adding the flow velocity of the above may be used. As an example, as the flow velocity of one point to be excluded, the flow velocity of the point having the largest square error among the flow velocities of these plurality of points may be used.
Further, the loop of the processes of (step S41) to (step S44) and (step S46) may be performed any number of times, but usually, for example, when the square error becomes equal to or less than the specified value in about 1 to 5 times. is expected.

Here, in the present embodiment, the flow velocity used for setting the flow velocity of the new point in the process shown in FIG. 15 (for example, when setting the flow velocity of three points, the flow velocity of the first point and 2 The flow velocity at the point) is included in the flow velocities at three or more points in the process shown in FIG. 16 (step S41). As a result, the flow velocity set in the process shown in FIG. 15 can be effectively used in the process shown in FIG. 16 (step S41).
As another configuration example, a part of the flow velocity used for setting the flow velocity of a new point in the process shown in FIG. 15 (for example, when setting a flow velocity of 4 points or more, the first point). The flow velocity of 3 points or more in the process shown in FIG. 16 (step S41) may be set by excluding the flow velocity of the above. For example, when the flow velocities of 4 or more Z (Z is an integer of 4 or more) points are set in the process shown in FIG. 15, the flow velocities of the points of (Z-3) or less are excluded. The process shown in FIG. 16 (step S41) may be performed.

As described above, in the first example of the analysis process using the fittings shown in FIGS. 14 to 16, the time required for the evaluation of the flow velocity can be shortened. Moreover, it is possible to improve the accuracy of the evaluation of the flow velocity.
For example, regarding the fitting of the relationship between the flow velocity and the square error shown in FIG. 13, it is possible to improve the accuracy and the processing speed.
Although the square error is used in this embodiment, another error may be used as another configuration example.

<Second example of analysis processing using fitting>
A second example of an analysis process using fitting will be described with reference to FIGS. 14, 15, and 18.
In the present embodiment, for convenience of explanation, the entire processing group will be divided into a first processing group and a second processing group, but the first processing group and the second processing group may be integrated. Good. After the processing of the first processing group is performed, the processing of the second processing group is performed. In the present embodiment, in the control unit 4, the CPU 62 of the computing device 50 executes each process included in the entire processing group by using the memory 63 or the like.

Here, the processing shown in FIGS. 14 and 15 (processing of the first processing group) is the same as in the case of the above-mentioned <first example of analysis processing using fitting>.
First, the control unit 4 performs the processes shown in FIGS. 14 and 15 (processes of the first process group).

FIG. 18 is a diagram showing a second example of the second processing group.
A second example of the second processing group will be described with reference to FIG. The processing of the second processing group shown in FIG. 18 is performed after the processing of the first processing group shown in FIG.
(Step S61)
First, in the control unit 4, the analysis value (theoretical value) of the temperature distribution is calculated by using the finite element method at each flow velocity among the three or more set flow velocities, and the half-value width (analysis value) of the flow velocity and the temperature distribution is calculated. ) Is calculated by fitting. In fitting, for example, a quadratic function is used.

(Step S62)
Next, in the control unit 4, the half-value width in the fitting result is based on the fitting result (analyzed value) of the relationship between the flow velocity and the half-value width of the temperature distribution and the measured value of the measured half-value width of the temperature distribution. The flow velocity corresponding to the measured value of is obtained, and the flow velocity is determined as a candidate for the flow velocity.

(Step S63)
Next, in the control unit 4, the squared error between the analysis value (theoretical value) of the temperature distribution obtained by using the finite element method and the measured value of the measured temperature distribution in the determined flow velocity candidates. To calculate. Then, the control unit 4 determines whether or not the calculated squared error is equal to or less than a predetermined specified value. As the default value, any value may be used, and for example, it may be set in advance.

(Step S64)
When the control unit 4 determines that the square error is equal to or less than a predetermined specified value as a result of the determination in (step S63) described above, the candidate flow velocity is formally determined. Then, the control unit 4 ends this process.
On the other hand, when the control unit 4 determines that the square error exceeds a predetermined specified value as a result of the determination in (step S63) described above, the process proceeds to the process in (step S61) described above. At this time, when the process of (step S61) is performed in the control unit 4, the combination of the flow velocities of three points or more is changed to a combination of the flow velocities already used. The process of changing the flow velocity may be performed by an arbitrary method, and as an example, a predetermined value (for example, a positive value, etc.) is applied to a predetermined one or more flow velocities among three or more points. Alternatively, a method using the value obtained by adding (negative value) may be used.

Here, in the present embodiment, the flow velocity used for setting the flow velocity of the new point in the process shown in FIG. 15 (for example, when setting the flow velocity of three points, the flow velocity of the first point and 2 The flow velocity of the point) is included in the flow velocity of three or more points in the process shown in FIG. 18 (step S61). As a result, the flow velocity set in the process shown in FIG. 15 can be effectively used in the process shown in FIG. 18 (step S61).
As another configuration example, a part of the flow velocity used for setting the flow velocity of a new point in the process shown in FIG. 15 (for example, when setting a flow velocity of 4 points or more, the first point). The flow velocity of 3 points or more in the process shown in FIG. 18 (step S61) may be set by excluding the flow velocity of the above. For example, when the flow velocities of 4 or more Z (Z is an integer of 4 or more) points are set in the process shown in FIG. 15, the flow velocities of the points of (Z-3) or less are excluded. The process shown in FIG. 18 (step S61) may be performed.

As described above, in the second example of the analysis process using the fittings shown in FIGS. 14, 15 and 18, it is possible to shorten the time required for the evaluation of the flow velocity. Moreover, it is possible to improve the accuracy of the evaluation of the flow velocity.
For example, it is possible to improve the accuracy and the processing speed of the fitting of the relationship between the flow velocity and the full width at half maximum shown in FIG.
Although the square error is used in this embodiment, another error may be used as another configuration example.

[Summary of the above embodiments]
As a configuration example, it is an evaluation method for evaluating the flow velocity of the fluid flowing inside the pipe 10, and the flow velocity is determined for the flow velocity of one or more points based on the analysis value (theoretical value) of the feature amount of the temperature distribution. This is a method for evaluating the flow velocity.
As a configuration example, in the flow velocity evaluation method, the feature amount of the temperature distribution is a feature amount that decreases as the flow velocity increases.
As a configuration example, in the flow velocity evaluation method, the feature amount of the temperature distribution is one or more of the half width, the maximum temperature, or the area of the temperature distribution waveform.
As a configuration example, in the flow velocity evaluation method, a heat exchange step of heat exchange at a predetermined portion of the surface 10a of the pipe 10 and a calculation of calculating the analysis value of the characteristic amount of the temperature distribution for the flow velocity of one or more points. The flow velocity was set by the flow velocity setting step and the flow velocity setting step based on the step, the analysis value calculated by the calculation step, and the measured value of the characteristic amount of the temperature distribution measured with respect to the piping. The flow velocity determination step of determining the flow velocity using the flow velocity is included.
As a configuration example, in the flow velocity evaluation method, in the flow velocity setting step, the analysis value calculated by the calculation step for the flow velocity at the midpoint of the assumed flow velocity range and the feature amount of the measured temperature distribution are used. The flow velocity at a new point is set according to the magnitude relationship with the measured value (step S23).
As a configuration example, in the flow velocity evaluation method, the flow velocity setting step sets a flow velocity of three points or more, and the flow velocity determination step uses the flow velocity of the three points or more set by the flow velocity setting step. Determine the flow velocity.
As a configuration example, in the flow velocity evaluation method, the flow velocity determination step uses a part or all of the flow velocity used in the flow velocity setting step.
As a configuration example, in the flow velocity evaluation method, the flow velocity determination step is performed with the analysis value of the temperature distribution (obtained by using the finite element method) and (measured) at each of the flow paths set by the flow velocity setting step. The first step (step S41) of calculating the squared error with the measured value (of the temperature distribution) and the 1-2 step (step S42) of obtaining the relationship between the flow velocity and the squared error (by fitting). ), Step 1-3 (step S43) for determining the flow velocity candidate, and the squared error between the analysis value of the temperature distribution and the measured value (of the measured temperature distribution) in the determined flow velocity candidate. Steps 1-4 (step S44) for determining whether or not the value is equal to or less than the predetermined specified value, and when it is determined that the square error is equal to or less than the predetermined specified value, the candidate for the flow velocity is officially selected. 1-5 steps (step S45) determined to be, and when it is determined that the square error exceeds the predetermined specified value, the flow velocity is changed and the process proceeds to the 1-1 step again. 1-6 steps (step S46) and.
As a configuration example, in the flow velocity evaluation method, the flow velocity determination step includes the flow velocity and the characteristic amount of the temperature distribution (obtained by using the finite element method) at each of the flow velocities set by the flow velocity setting step. Step 2-1 (step S61) for calculating the analysis value of the relationship, and step 2-2 for determining the candidate flow velocity based on the calculated analysis value and the measured characteristic amount of the temperature distribution. First, it is determined whether or not the square error between the analysis value of the temperature distribution and the measured value (of the measured temperature distribution) is equal to or less than a predetermined specified value in the determined flow velocity candidates in step S62. In step 2-3 (step S63), when it is determined that the square error is equal to or less than the predetermined specified value, the candidate for the flow velocity is formally determined, and in other cases, the flow velocity is changed. Then, the steps 2-4 (step S63, step S64) of shifting to the second step 2-1 again are included.

As a configuration example, it is an evaluation system that evaluates the flow velocity of the fluid flowing inside the pipe 10, and determines the flow velocity for one or more points of flow velocity based on the analysis value (theoretical value) of the characteristic amount of the temperature distribution. It is a flow velocity evaluation system (in the embodiment, a flow velocity measurement system 100).
As a configuration example, in the flow velocity evaluation system, the feature amount of the temperature distribution is a feature amount that decreases as the flow velocity increases.
As a configuration example, in the flow velocity evaluation system, the feature amount of the temperature distribution is one or more of the half width, the maximum temperature, or the area of the temperature distribution waveform.
As a configuration example, in a flow velocity evaluation system, a heat exchanger (heating unit 2 in the embodiment) that exchanges heat at a predetermined portion of the surface 10a of the pipe 10 and a characteristic of temperature distribution for a flow velocity of one or more points. The calculation unit (in the embodiment, the function of the control unit 4) that calculates the analysis value of the quantity, the analysis value calculated by the calculation unit, and the measured value of the characteristic amount of the temperature distribution measured with respect to the piping. Based on this, a flow velocity setting unit that sets the flow velocity (in the embodiment, the function of the control unit 4) and a flow velocity determination unit that determines the flow velocity using the flow velocity set by the flow velocity setting unit (in the embodiment, the control unit). 4 functions) and.
As a configuration example, in the flow velocity evaluation system, the flow velocity setting unit determines the analysis value calculated by the calculation unit for the flow velocity at the midpoint of the assumed flow velocity range, and the feature amount of the measured temperature distribution. The flow velocity at a new point is set according to the magnitude relationship with the measured value.
As a configuration example, in the flow velocity evaluation system, the flow velocity setting unit sets a flow velocity of three points or more, and the flow velocity determination unit uses the flow velocity of the three points or more set by the flow velocity setting unit. Determine the flow velocity.
As a configuration example, in the flow velocity evaluation system, the flow velocity determination unit uses a part or all of the flow velocity used in the flow velocity setting unit.
As a configuration example, in the flow velocity evaluation system, the flow velocity determination unit is measured with the analysis value of the temperature distribution (obtained by using the finite element method) at each of the flow paths set by the flow velocity setting unit. The 1-1 step of calculating the squared error with the measured value (of the temperature distribution), the 1-2 step of finding the relationship between the flow velocity and the squared error (by fitting), and the candidate of the flow velocity are determined. It is determined whether or not the squared error between the analysis value of the temperature distribution and the measured value (of the measured temperature distribution) is less than or equal to the predetermined specified value in the first to third steps to be performed and the determined candidate flow velocity. The first to fourth steps to be performed, the first to fifth steps for formally determining the candidate for the flow velocity when it is determined that the squared error is equal to or less than the predetermined specified value, and the squared error are the above. If it is determined that the value exceeds a predetermined value, the flow velocity is changed and the steps 1 to 6 for shifting to the first step 1-1 are executed again.
As a configuration example, in the flow velocity evaluation system, the flow velocity determination unit determines the flow velocity and the characteristic quantity of the temperature distribution (obtained by using the finite element method) at each of the flow velocities set by the flow velocity setting unit. The second step is to calculate the analysis value of the relationship, and the second step is to determine the candidate flow velocity based on the calculated analysis value and the characteristic amount of the measured temperature distribution. In the candidate flow velocity, the second and third steps of determining whether or not the square error between the analysis value of the temperature distribution and the measured value (of the measured temperature distribution) is equal to or less than a predetermined specified value, and the above 2 When it is determined that the multiplication error is equal to or less than the predetermined specified value, the candidate for the flow velocity is formally determined, while in other cases, the flow velocity is changed and the process proceeds to the second step 2-1 again. Perform steps 2-4 and.

In this embodiment, the following configuration may be used.
As a configuration example, it is a relational information setting method for obtaining relational information indicating a relation between a flow velocity of a fluid flowing inside a pipe and a temperature distribution on the surface of the pipe, and heat exchange is performed at a predetermined portion of the surface of the pipe. A temperature boundary clerk that acquires a value of a temperature boundary coefficient indicating a quantitative ratio of a fluid that contributes to heat transfer by heat exchange performed in a predetermined portion of the surface of the pipe in the heat exchange step and the fluid flowing through the pipe. A relation information setting method including a numerical value acquisition step and a relation information setting step of obtaining the relation information based on the value of the temperature boundary coefficient acquired in the temperature boundary coefficient value acquisition step may be used.
As an example of the configuration, in the relationship information setting method, in the temperature boundary coefficient value acquisition step, a configuration in which the value of the temperature boundary coefficient is acquired for each flow velocity of the fluid may be used.
As a configuration example, in the relationship information setting method, a temperature measurement step of measuring the temperature distribution on the surface of the pipe in the pipe axis direction of the pipe in which heat exchange is performed in the predetermined portion, and a flow velocity of the fluid are measured. In the temperature boundary coefficient value acquisition step including the flow velocity measurement step, the value of the temperature boundary coefficient is set based on the temperature distribution measured in the temperature measurement step and the flow velocity measured in the flow velocity measurement step. , Configuration may be used.
As a configuration example, a flow velocity measurement heat exchange step in which heat is exchanged at a predetermined portion of the surface of the pipe in a state where the flow velocity of the fluid flowing inside the pipe is the flow velocity to be measured, and the flow velocity measurement heat. The temperature distribution measurement step at the time of flow velocity measurement for measuring the temperature distribution of the surface in the pipe axis direction of the pipe in which heat exchange was performed at the predetermined portion in the exchange step, and the temperature distribution measurement step at the time of flow velocity measurement. A flow velocity measuring method including a flow velocity acquisition step of obtaining a flow velocity of the fluid flowing inside the pipe based on the temperature distribution and the relational information obtained by the relational information setting method may be used.

As a configuration example, a relationship information setting system that obtains relationship information indicating the relationship between the flow velocity of a fluid flowing inside a pipe and the temperature distribution on the surface of the pipe, and heat exchange is performed at a predetermined portion of the surface of the pipe. A temperature boundary clerk that acquires a value of a temperature boundary coefficient indicating a quantitative ratio of a heat exchanger and a fluid that contributes to heat transfer by heat exchange performed on a predetermined portion of the surface of the pipe among the fluids flowing through the pipe. A relationship information setting system including a numerical value acquisition unit and a relationship information setting unit that obtains the relationship information based on the value of the temperature boundary coefficient acquired by the temperature boundary coefficient value acquisition unit may be used.
As a configuration example, in the relational information setting system, the configuration in which the temperature boundary coefficient value acquisition unit acquires the value of the temperature boundary coefficient for each flow velocity of the fluid may be used.
As a configuration example, in the relationship information setting system, a temperature measuring unit that measures the temperature distribution on the surface of the pipe in the pipe axis direction of the pipe that has undergone heat exchange at the predetermined portion, and a flow velocity of the fluid are measured. A flow velocity measuring unit is provided, and the temperature boundary coefficient value acquisition unit sets a value of the temperature boundary coefficient based on the temperature distribution measured by the temperature measuring unit and the flow velocity measured by the flow velocity measuring unit. , Configuration may be used.
As a configuration example, a storage unit that stores the relationship information set by the relationship information setting unit of the relationship information setting system and a state in which the flow velocity of the fluid flowing inside the pipe is the flow velocity of the measurement target, the pipe A heat exchanger that exchanges heat at a predetermined portion of the surface, a temperature measuring unit that measures the temperature distribution on the surface of the pipe in the pipe axial direction of the pipe that has undergone heat exchange at the predetermined portion, and the temperature measuring unit. A flow velocity measurement system including a flow velocity calculation unit that calculates the flow velocity of the fluid based on the temperature distribution measured by the storage unit and the relational information stored in the storage unit may be used.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within a range not deviating from the gist of the present invention are also included.

Further, as in the present embodiment, a program for realizing the function of the device (for example, the calculation device 50) according to the above-described embodiment is recorded on a computer-readable recording medium and recorded on the recording medium. The processing may be performed by loading the executed program into a computer system and executing it.
The term "computer system" as used herein may include hardware such as an operating system (OS: Operating System) and peripheral devices.
The "computer-readable recording medium" includes a flexible disk, a photomagnetic disk, a ROM (Read Only Memory), a writable non-volatile memory such as a flash memory, and a portable medium such as a DVD (Digital Versaille Disk). A storage device such as a hard disk built into a computer system.
Further, the "computer-readable recording medium" is a volatile memory (for example, DRAM (for example, DRAM) inside a computer system that serves as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. It also includes those that hold the program for a certain period of time, such as Dynamic Random Access Memory)).
Further, the above program may be transmitted from a computer system in which this program is stored in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting a program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
Further, the above program may be for realizing a part of the above-mentioned functions. Further, the above program may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

2 ... heating unit, 2b ... preheater, 3 ... temperature measuring unit, 3a ... temperature sensor, 3A ... temperature sensor group, 4 ... control unit, 5 ... flow meter, 10 ... piping, 10a ... surface, 11 ... installation part, 12 ... Insulation material, 20 ... Steam production device, 30 ... Load equipment, 50 ... Calculation device, 60 ... Input device, 61 ... Converter, 62 ... CPU, 63 ... Memory, 64 ... Display device, 100 ... Flow velocity measurement system, 201-203 ... Characteristics, 251 ... Baseline, 301, 401, 501, 601 ... Measured values, 311, 411, 511, 611 ... Analytical values

Claims (16)

It is an evaluation method that evaluates the flow velocity of the fluid flowing inside the pipe.
The analysis value of the half width of the temperature distribution in the pipe axis direction when heat exchange is performed at a predetermined portion of the surface of the pipe is calculated for a plurality of flow velocities.
Heat exchange is performed at a predetermined portion on the surface of the pipe to measure the measured value of the half width of the temperature distribution in the pipe axis direction.
The analysis value of the half width closest to the measured value of the measured half width is selected, and the flow velocity corresponding to the analysis value of the selected half width is determined as the flow velocity of the fluid flowing inside the pipe.
Evaluation method of flow velocity. The half width of the temperature distribution in the tube axis direction is a feature amount that decreases as the flow velocity increases.
The method for evaluating a flow velocity according to claim 1. A heat exchange step in which heat is exchanged at the predetermined portion of the surface of the pipe,
A measurement step of performing the heat exchange in the heat exchange step to measure the measured value of the half width of the temperature distribution in the pipe axis direction, and a measurement step.
A calculation step of calculating the analysis value of the half width of the temperature distribution in the pipe axis direction when heat exchange is performed on the predetermined portion of the surface of the pipe for the plurality of flow paths.
By comparing the magnitude relationship between the analysis value calculated by the calculation step and the measured value of the half width of the temperature distribution in the pipe axis direction measured for the pipe, a plurality of flow velocities corresponding to the measured value are obtained. The flow velocity setting process to be set and
The flow velocity having the smallest error between the analysis value of the temperature distribution in the tube axis direction and the measured value of the temperature distribution in the tube axis direction for a plurality of flow velocities set by the flow velocity setting step is determined for the pipe. A flow velocity determination step that determines the flow velocity of the fluid flowing inside, and
The method for evaluating a flow velocity according to any one of claims 1 and 2, comprising the above. In the flow velocity setting step, the magnitude of the analysis value calculated by the calculation step for the flow velocity at the midpoint of the assumed flow velocity range and the measured value of the half width of the measured temperature distribution in the pipe axis direction. Set the flow velocity at the new point according to the relationship,
The method for evaluating a flow velocity according to claim 3. In the flow velocity setting step, a flow velocity of three or more points is set.
In the flow velocity determination step, the flow velocity is determined using the flow velocities of the three points or more set by the flow velocity setting step.
The method for evaluating a flow velocity according to any one of claims 3 and 4. The flow velocity determination step uses a part or all of the flow velocity set in the flow velocity setting step.
The method for evaluating a flow velocity according to any one of claims 3 to 5. The flow velocity determination step is
In each of the flow velocities set by the flow velocity setting step, the 1-1 step of calculating the squared error between the analysis value and the actually measured value of the temperature distribution in the tube axis direction, and
The first and second steps for obtaining the relationship between the flow velocity and the squared error, and
Steps 1-3 to determine the flow velocity with the smallest square error as a candidate for the flow velocity, and
In the determined flow velocity candidates, the first to fourth steps of determining whether or not the squared error between the analysis value and the actually measured value of the temperature distribution in the tube axis direction is equal to or less than a predetermined specified value, and
When it is determined that the square error is equal to or less than the predetermined specified value, the steps 1 to 5 for formally determining the candidate for the flow velocity and
When it is determined that the square error exceeds the predetermined specified value, the flow velocity is changed, and the steps 1 to 6 for shifting to the first step again are performed.
including,
The method for evaluating a flow velocity according to any one of claims 3 to 6. The flow velocity determination step is
The second step of calculating the analysis value of the relationship between the flow velocity and the half width of the temperature distribution in the tube axis direction at each of the flow velocities set by the flow velocity setting step, and the second step.
The second and second steps of selecting the analysis value of the half width that is closest to the measured value of the measured half width and determining the flow velocity corresponding to the selected analysis value as a candidate for the flow velocity.
In the determined flow velocity candidates, the second and third steps of determining whether or not the squared error between the analysis value and the actually measured value of the temperature distribution in the tube axis direction is equal to or less than a predetermined specified value, and
When it is determined that the square error is equal to or less than the predetermined specified value, the candidate for the flow velocity is formally determined, while in other cases, the flow velocity is changed and the step 2-1 is performed again. Steps 2-4 and
including,
The method for evaluating a flow velocity according to any one of claims 3 to 6. An evaluation system that evaluates the flow velocity of the fluid flowing inside the pipe.
The analysis value of the half width of the temperature distribution in the pipe axis direction when heat exchange is performed at a predetermined portion of the surface of the pipe is calculated for a plurality of flow velocities.
Heat exchange is performed at a predetermined portion on the surface of the pipe to measure the measured value of the half width of the temperature distribution in the pipe axis direction.
The analysis value of the half width closest to the measured value of the measured half width is selected, and the flow velocity corresponding to the analysis value of the selected half width is determined as the flow velocity of the fluid flowing inside the pipe.
Flow velocity evaluation system. The half width of the temperature distribution in the tube axis direction is a feature amount that decreases as the flow velocity increases.
The flow velocity evaluation system according to claim 9. A heat exchanger that exchanges heat at the predetermined portion of the surface of the pipe,
A measuring unit that performs the heat exchange and measures the measured value of the half width of the temperature distribution in the pipe axis direction.
A calculation unit that calculates the analysis value of the half width of the temperature distribution in the pipe axis direction when heat exchange is performed on the predetermined portion of the surface of the pipe for the plurality of flow paths.
By comparing the magnitude relationship between the analysis value calculated by the calculation unit and the measured value of the half width of the temperature distribution in the pipe axis direction measured for the pipe, a plurality of flow velocities corresponding to the measured value are obtained. The flow velocity setting unit to be set and
The flow velocity having the smallest error between the analysis value of the temperature distribution in the tube axis direction and the measured value of the temperature distribution in the tube axis direction for a plurality of flow velocities set by the flow velocity setting unit is determined for the pipe. A flow velocity determining unit that determines the flow velocity of the fluid flowing inside,
9. The flow velocity evaluation system according to any one of claims 9 or 10. The flow velocity setting unit has a magnitude of the analysis value calculated by the calculation unit for the flow velocity at the midpoint of the assumed flow velocity range and the measured value having a half width of the measured temperature distribution in the pipe axis direction. Set the flow velocity at the new point according to the relationship,
The flow velocity evaluation system according to claim 11. The flow velocity setting unit sets the flow velocity at three or more points,
The flow velocity determining unit determines the flow velocity using the flow velocities of the three points or more set by the flow velocity setting unit.
The flow velocity evaluation system according to any one of claims 11 and 12. The flow velocity determining unit uses a part or all of the flow velocity set by the flow velocity setting unit.
The flow velocity evaluation system according to any one of claims 11 to 13. The flow velocity determining unit
The 1-1 step of calculating the squared error between the analyzed value and the measured value of the temperature distribution in the tube axis direction at each of the flow velocities set by the flow velocity setting unit.
The first and second steps for obtaining the relationship between the flow velocity and the squared error, and
Steps 1-3 to determine the flow velocity with the smallest square error as a candidate for the flow velocity, and
In the determined flow velocity candidates, the first to fourth steps of determining whether or not the squared error between the analysis value and the actually measured value of the temperature distribution in the tube axis direction is equal to or less than a predetermined specified value, and
When it is determined that the square error is equal to or less than the predetermined specified value, the steps 1 to 5 for formally determining the candidate for the flow velocity and
When it is determined that the square error exceeds the predetermined specified value, the flow velocity is changed, and the steps 1 to 6 for shifting to the first step again are performed.
To execute,
The flow velocity evaluation system according to any one of claims 11 to 14. The flow velocity determining unit
The first step of calculating the analysis value of the relationship between the flow velocity and the half width of the temperature distribution in the tube axis direction at each of the flow velocities set by the flow velocity setting unit, and the second step.
The second and second steps of selecting the analysis value of the half width that is closest to the measured value of the measured half width and determining the flow velocity corresponding to the selected analysis value as a candidate for the flow velocity.
In the determined flow velocity candidates, the second and third steps of determining whether or not the squared error between the analysis value and the actually measured value of the temperature distribution in the tube axis direction is equal to or less than a predetermined specified value, and
When it is determined that the square error is equal to or less than the predetermined specified value, the candidate for the flow velocity is formally determined, while in other cases, the flow velocity is changed and the step 2-1 is performed again. Steps 2-4 and
To execute,
The flow velocity evaluation system according to any one of claims 11 to 14.

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