JP5501214B2 - Ultrasonic flowmeter verification system and verification method - Google Patents

Description

  The present invention relates to a verification system and a verification method for an ultrasonic flow meter, and more particularly to a verification system and a verification method for a propagation time difference type ultrasonic flow meter used for a feed water flow meter of a power plant such as a nuclear power plant.

  A nuclear power plant is operated under a certain reactor heat output (heat output rated value) determined by reactor safety design conditions. This reactor heat output is measured and calculated by the reactor heat output monitoring device, but the heat output calculation includes an error.

  For this reason, as the heat output target value when the nuclear power plant is actually operated, it is necessary to make the allowance corresponding to the calculation error into the heat output rated value. For example, if the calculation error of the reactor thermal power monitoring apparatus is 2%, the thermal power rating value is set to 102% and the power target value is set to 100%.

  This means that even though it is possible to output 102% of the thermal output of the reactor, the reactor must actually be operated at 100%. At the same time, if the calculation error of the reactor thermal power monitoring device can be reduced to 0.3%, it means that the operation can be performed at 101.7%, which can contribute to the improvement of the efficiency of the nuclear power plant.

  The calculation error in the reactor thermal power monitoring apparatus is largely due to the measurement accuracy of the feed water flow rate. The heat output calculation is a calculation in which the difference between the main steam enthalpy and the feed water enthalpy is multiplied by the feed water flow rate. Therefore, in the reliability of the heat output monitoring, the contribution of the measurement accuracy of the feed water flow rate is greater than the measurement accuracy of the main steam flow rate and the main steam temperature involved in enthalpy. That is, detecting the feed water flow rate with high accuracy directly leads to an improvement in the efficiency of the nuclear power plant.

  This will be described with reference to FIG. The graph of FIG. 2 represents the probability distribution of the heat output target value (heat output calculation value) when the flow meter is used, the horizontal axis is the heat output, and the vertical axis is the probability. Here, the flow nozzle (differential pressure type) flowmeter was used for the conventional water supply flowmeter. In the probability distribution 201 when this flow nozzle flow meter is used, since the heat output calculation accuracy is small, the standard deviation is large and the probability distribution is wide. Therefore, considering a probability of 97.7% as a safety standard, for example, up to 102% of the thermal output is included, so a safety analysis up to 102% of the thermal output is performed.

  On the other hand, for example, if a flow meter with a thermal output calculation accuracy of 0.3% is used, the probability distribution will be as shown in 202 of FIG. If the output does not exceed 102%, the heat output target value becomes 101.7%, and an increase of 1.7% is possible.

  Therefore, if the measurement accuracy of the feed water flow rate can be improved and the expected error in the heat output calculation can be reduced, the heat output target value can be increased from the current 100% to nearly 102% while ensuring safety. This indicates that the output can be improved and the operation efficiency of the plant can be improved only by changing the flow meter without changing the entire plant.

  There is an ultrasonic flow meter as a flow meter with high flow rate measurement accuracy that can satisfy the above-mentioned demand. There are various ultrasonic flowmeters such as Doppler type, propagation time difference type, correlation type, etc. Among them, the propagation time difference type flowmeter in which an ultrasonic sensor is inserted directly into the pipe measures the average flow velocity at multiple measurement lines simultaneously. It is known to have high measurement accuracy because it can be performed.

  For example, Non-Patent Document 1 describes a method of improving the measurement accuracy by using an ultrasonic flowmeter as a reactor water supply flowmeter, increasing the output accordingly, and improving the operation efficiency of the plant.

  Further, as a measure for improving the accuracy of the reactor water supply flow meter, for example, Patent Document 1 describes that the accuracy is improved by correcting a decrease in accuracy due to aged deterioration of the flow nozzle flow meter. In Patent Document 2, by using an ultrasonic flowmeter together with a flow nozzle flowmeter, a measurement accuracy state is determined, and a heat output target value corresponding to the determination result is selected. It is known to increase and improve the operation efficiency of the plant.

JP-A-1-221700 JP 2006-16413 A

“Results of Technical Review and Evaluation for Reactor Power Improvement”, Journal of Atomic Energy Society, vol. 50 No. 12 (2008)

  According to the patent document and the non-patent document described above, among the ultrasonic flowmeters, the measurement accuracy can be increased by using a highly accurate 8-line propagation time difference type ultrasonic flowmeter as a feed water flowmeter, Accordingly, it is known that the operation efficiency of the plant can be improved. In addition, it has been found that the advantage of using an ultrasonic flowmeter instead of a flow nozzle flowmeter, which causes structural deterioration and pressure loss, is great.

  Even when such an ultrasonic flowmeter is used, a thorough safety check is required for monitoring the reactor heat output. It is very important to verify and ensure that the safety design standards are sufficiently accurate. However, these patent documents and non-patent documents do not describe a method for verifying the ultrasonic water supply flowmeter.

  From the above, the object of the present invention is to improve the reliability of the measurement accuracy of the feed water flow rate by the propagation time difference type ultrasonic feed water flow meter, thereby making it possible to reduce the expected error in the heat output calculation, An object of the present invention is to provide a method for verifying an ultrasonic feed water flow meter that can improve the operation efficiency of a plant.

  In order to achieve the above object, in the propagation time difference type ultrasonic flowmeter verification system of the present invention, an analysis error setting means for setting an allowable error of ultrasonic flowmeter simulation by numerical analysis, an ultrasonic flowmeter spool, Numerical calculation mesh generating means for generating a numerical calculation mesh of a three-dimensional flow in the pipe before and after the fluid, fluid analysis means for calculating a flow velocity distribution in the pipe using the numerical calculation mesh, and fluid for calculating an error of the fluid analysis Analysis error calculation means, flow velocity vector acquisition means for assigning the result of fluid analysis to each mesh element of the ultrasonic flowmeter spool section of the numerical calculation mesh, ultrasonic flowmeter spool section and flow velocity vector of the numerical calculation mesh Integral average flow velocity calculation means for calculating the average flow velocity on the ultrasonic propagation path of each survey line, and ultrasonic flowmeter spool with numerical calculation mesh Compare the difference between the integrated average flow velocity and the propagation time difference average flow velocity, and the analysis error. Ultrasonic wave propagation analysis error determination means that determines whether the value is within the allowable range set by the setting means, and numerical calculation that corrects the numerical calculation mesh if the ultrasonic wave analysis error determination results in exceeding the allowable value A mesh correction means, a flow rate calculation means for analyzing the flow rate calculation result of the ultrasonic flowmeter from the propagation time difference average flow velocity, and an analysis result display means for displaying the flow rate calculation result, the fluid analysis error, and the ultrasonic propagation analysis error.

  Further, the numerical calculation mesh creating means sets so that the mesh width on the ultrasonic propagation path of the ultrasonic flowmeter spool section is subdivided from other portions.

  Further, the numerical calculation mesh creating means sets the mesh on the ultrasonic propagation path of the ultrasonic flowmeter spool unit so as to be orthogonal to the ultrasonic propagation direction.

  Further, the fluid analysis error calculation means calculates from the difference between the flow rate and the input flow rate in a plurality of cross sections perpendicular to the tube axis, using the flow velocity vector of the numerical calculation mesh ultrasonic flow meter spool.

  Moreover, the flow velocity vector acquisition means acquires only the flow velocity vector on the ultrasonic propagation path of each survey line necessary for the integral average flow velocity calculation means and the propagation time difference average flow velocity calculation means.

  The propagation time difference average flow velocity calculation means applies a ray tracing method for calculating the propagation path of the main sound ray to each element on the ultrasonic propagation path of the numerical calculation mesh.

  Further, the propagation time difference average flow velocity calculating means applies a ray tracing method for calculating a propagation path of a plurality of sound rays simulating the spread of ultrasonic sound to each element on the ultrasonic propagation path of the numerical calculation mesh.

  Further, the propagation time difference average flow velocity calculation means calculates a propagation path for each minute time as a ray tracing method.

  Further, the propagation time difference average flow velocity calculation means uses a flow velocity vector obtained by interpolation calculation from the flow velocity vector of each element or each node in the propagation path every minute time.

  Moreover, the finite element method or the finite volume method is applied to the propagation time difference average flow velocity calculation means.

  The numerical calculation mesh correction means sets so that the mesh width on the ultrasonic propagation path of the ultrasonic flowmeter spool section is subdivided from other portions.

  Further, the numerical calculation mesh correcting means sets the mesh on the ultrasonic propagation path of the ultrasonic flowmeter spool unit so as to be orthogonal to the ultrasonic propagation direction.

  In order to achieve the above object, in the propagation time difference type ultrasonic flowmeter verification method of the present invention, an analysis error setting step for setting an allowable error of an ultrasonic flowmeter simulation by numerical analysis, an ultrasonic flowmeter spool, and its A mesh creation process for creating a numerical calculation mesh for the three-dimensional flow in the front and rear pipes, a fluid analysis process for calculating the flow velocity distribution in the pipe using the mesh, and the result of the fluid analysis is the ultrasonic flowmeter spool of the mesh A flow velocity vector acquisition step to be assigned to each element of the section, an integral average flow velocity calculation step of calculating an average flow velocity on the ultrasonic propagation path of each measurement line using the mesh ultrasonic flowmeter spool portion and the flow velocity vector, Propagation time difference to calculate line average flow velocity of each survey line by conducting ultrasonic propagation analysis using ultrasonic flow meter spool and flow velocity vector Comparing the average flow velocity calculation step, the difference between the integrated average flow velocity and the propagation time difference average flow velocity, and determining whether it is within the allowable range set by the analysis error setting means, and the result of the analysis error determination If the allowable value is exceeded, the mesh correction process corrects the numerical calculation mesh, the flow calculation process that analyzes the flow rate calculation result of the ultrasonic flowmeter from the propagation time difference average flow velocity, and the analysis that displays the flow rate calculation result and analysis error And a result display step.

  In order to achieve the above object, in the method of verifying the propagation time difference type ultrasonic flowmeter of the present invention, the target pipe portion where the ultrasonic flowmeter is installed is divided into three-dimensional meshes, fluid analysis is performed, and ultrasonic waves are analyzed. Obtain the flow velocity of each mesh part including the propagation path part, and calculate the difference between the average flow speed obtained from the fluid analysis result in the ultrasonic propagation path part and the average flow speed obtained from the difference in ultrasonic propagation time in the ultrasonic propagation path part. The difference between the two average flow velocities is compared with the analysis allowable error as an ultrasonic propagation error. If the difference is within the analysis allowable error range, the mesh is refined and the difference between the average flow velocities is calculated again and the analysis allowable Evaluate the ultrasonic propagation error when it is within the error range.

  With the ultrasonic flow meter verification system of the present invention, it is possible to predict the measurement value of the flow rate with the propagation time difference type ultrasonic flow meter with high accuracy, and clarify the prediction accuracy with the numerical analysis of the propagation time difference type ultrasonic flow meter. Accordingly, it is possible to guarantee the accuracy of the propagation time difference type ultrasonic flowmeter with high reliability.

The schematic block diagram of the verification system of the ultrasonic flowmeter by the Example of this invention. The figure which shows the probability distribution of the heat output target value (heat output calculation value) when using a flowmeter. The figure which shows the flow direction cross section of the fluid of the piping which installed the ultrasonic flowmeter. The figure which shows a cross section perpendicular | vertical to the pipe-axis direction of piping which installed the ultrasonic flowmeter. The figure which shows the example of mesh creation of the fluid flow direction cross section of piping. The figure which shows the mesh creation example of a cross section perpendicular | vertical to the pipe-axis direction of piping. The figure which shows the fluid analysis result of the fluid flow direction cross section of piping. The figure which shows the fluid-analysis result of a cross section perpendicular | vertical to the pipe-axis direction of piping. The figure explaining the ray tracing method which calculates the propagation path of a main sound ray. The figure explaining the ray trace method which calculates the propagation path for every minute time. The figure explaining the ray tracing method which calculates the propagation path which simulated the spread of an ultrasonic wave. The figure which shows an example of the display screen of the verification system of an ultrasonic flowmeter. The flowchart of the verification method of the ultrasonic flowmeter by the Example of this invention. The figure which displayed and described the process performed in each part, and the result notionally and in time series.

  In an embodiment of the present invention, it is a propagation time difference type ultrasonic flow meter that is known to have high measurement accuracy among ultrasonic flow meters, and is used for measuring a feed water flow rate value used for heat output calculation of a nuclear power plant. The ultrasonic flowmeter with 8 measuring lines employed is in mind.

  For this reason, the structure and measurement principle of an eight-line propagation time difference type ultrasonic flowmeter will be described with reference to FIG. FIG. 3 a shows a cross section (cross section in the fluid flow direction) of the spool 300 that is a pipe provided with an ultrasonic flowmeter. 3b shows a cross section of the spool 300 that is also perpendicular to the tube axis direction.

  As shown in FIG. 3b, 16 branch pipes (bosses) into which an ultrasonic sensor (more precisely, a sensor housing in which the ultrasonic sensor is installed) are inserted are welded around the spool 300. . 2a to 17a indicated by solid lines are branch pipes (bosses), and 2b to 17b indicated by dotted lines are ultrasonic sensors inserted into the branch pipes (bosses). It should be noted that, as shown in FIG. 3a, the two numbers are assigned to one branch pipe (boss) or one ultrasonic sensor. This is because these are installed on the front side and the back side in FIG.

  FIG. 3A is a cross section of the spool 300 in the AA plane (cross section in the fluid flow direction), and each boss is arranged so that the inserted ultrasonic sensor faces the tube axis direction at an angle of 45 °. The For example, the ultrasonic sensor 2b inserted into the boss 2a faces the ultrasonic sensor 3b inserted into the boss 3a. Further, the ultrasonic sensor 4b inserted into the boss 4a faces the ultrasonic sensor 5b inserted into the boss 5a. In FIG. 3b, the front side and the back side have been described. In this case, the bosses 2b and 5b are the front side, and 3b and 4b are the back side. FIG. 3a shows only the cross section of the spool 300 on the AA plane (the cross section in the fluid flow direction), but the other arrangement cross sections parallel to the AA plane have the same arrangement as FIG. 3a. Yes.

  These two ultrasonic sensors facing each other form one survey line, and 16 ultrasonic sensors obtain eight pairs of survey lines. For each measurement line, the line average between the ultrasonic sensors is measured by measuring the difference in ultrasonic propagation time between the direction along the flow (hereinafter referred to as the downstream direction) and the direction against the flow (hereinafter referred to as the upstream direction). Calculate the flow rate.

  In FIG. 3a, for example, the flow direction of water is from the left to the right as shown in the flow velocity distribution 301 in the pipe spool, and the central portion has a high flow velocity and the peripheral portion (the wall surface side of the pipe spool) has a low flow velocity. The linear average flow velocity between the ultrasonic sensors 2b and 3b at this time is obtained. This is because the downstream propagation time Td is first measured when it is transmitted by the upstream ultrasonic sensor 2b and received by the downstream ultrasonic sensor 3b, and then transmitted by the downstream ultrasonic sensor 3b. The upstream propagation time Tu when received by the ultrasonic sensor 2b is measured.

  At this time, due to the influence of the flow velocity V in the flow direction, the apparent sound velocity in the ultrasonic propagation path direction is V ′ = Vsin45, which is faster in the downstream direction and slower in the upstream direction. Accordingly, the propagation time difference ΔT is calculated by ΔT = Tu−Td, and the linear average flow velocity V between the sensors is obtained from this value, the distance between the sensors, and the speed of sound. Note that the measurement is similarly performed on other survey lines.

  In FIG. 3b, as described in FIG. 3a, the ultrasonic sensor 2b and the ultrasonic sensor 3b are paired, and the ultrasonic sensor 4b and the ultrasonic sensor 5b are paired. Further, the ultrasonic sensor 6b and the ultrasonic sensor 7b are paired, and the ultrasonic sensor 8b and the ultrasonic sensor 9b are paired. Further, the ultrasonic sensor 10b and the ultrasonic sensor 11b are paired, and the ultrasonic sensor 12b and the ultrasonic sensor 13b are paired. Further, the ultrasonic sensor 14b and the ultrasonic sensor 15b are paired, and the ultrasonic sensor 16b and the ultrasonic sensor 17b are paired. As described above, the pairs of ultrasonic sensors are arranged so that four parallel pairs and four pairs are orthogonal to each other, and is an eight-track type.

  In the eight-line propagation time difference type ultrasonic flowmeter, the average flow rate in the pipe spool is calculated using the line average flow velocity obtained for each of the eight lines. For this, Gaussian integration that can be integrated with high accuracy from a finite discrete value is used. In Gaussian integration, the measurement position of the linear average flow velocity is determined in advance, and the measurement values at each position are weighted and integrated. In the eight-track type, Gauss integration is performed on each of four survey lines 2-3, 6-7, 10-11, 14-15 and four survey lines 4-5, 8-9, 12-13, 16-17. Measurement accuracy is improved by taking the average.

  In the embodiment of the present invention, the above-described eight-line propagation time difference type ultrasonic flowmeter will be described in mind. The contents of the ultrasonic flowmeter verification system according to an embodiment of the present invention will be described below.

  FIG. 1 is a configuration diagram of an ultrasonic flow meter verification system according to an embodiment of the present invention.

  As shown in FIG. 1, the ultrasonic flowmeter verification system 100 sets a calculation unit 120 configured by a computer, an analysis result display unit 111 configured by a monitor, and a calculation initial state of the calculation unit 120. It comprises analysis allowable error data input means 101 as an input unit.

  The calculation unit 120 includes a plurality of calculation means and a database that stores the results. In the figure, reference numerals 103 to 110 denote calculation means, and those symbols indicated by “a” are databases that store the calculation results. Specifically, each calculation means includes numerical calculation mesh creation means 102, fluid analysis means 103, fluid analysis error calculation means 104, flow velocity vector acquisition means 105, integral average flow velocity calculation means 106, and propagation time difference average. It comprises a flow velocity calculation means 107, an ultrasonic wave propagation analysis error determination means 108, a numerical calculation mesh correction means 109, and a flow rate calculation means 110.

  The database includes an analysis allowable error data storage device 101a, a numerical calculation mesh data storage device 102a, a fluid analysis result data storage device 103a, a fluid analysis result data storage device 104a, a flow velocity vector data storage device 105a, and an integral average flow velocity. It comprises a data storage device 106a, a propagation time difference average flow velocity data storage device 107a, an ultrasonic propagation analysis error data storage device 108a, and a flow rate calculation result data storage device 110a.

  In the initial state of the system 110, at least two initial states are set. First, using the analysis allowable error input device 101, an analysis allowable error is input to the analysis allowable error data storage device 101a. Here, the analysis allowable error input device 101 and the analysis allowable error data storage device 101a are, for example, a keyboard or an electronic storage device attached to a computer. The analysis allowable error is a value that is determined by an analysis accuracy requirement after a necessary condition is set based on an uncertainty analysis that determines the accuracy of the target ultrasonic flowmeter. Further, the analysis allowable error may be set for the entire analysis, or may be set for each of the fluid analysis and the ultrasonic propagation analysis.

  The initial state to be set next is a numerical calculation mesh, which is generated by the numerical calculation mesh generation means 102 and stored in the numerical calculation mesh data storage device 102a. The numerical calculation mesh data storage device 102a is created with a mesh accuracy such that the fluid analysis is performed with an accuracy equal to or less than the fluid analysis tolerance set by the analysis tolerance data storage device 101a.

  Specifically, the cross section of the fluid flow direction shown in FIG. 3 and the cross section perpendicular to the tube axis direction of the spool 300 are partitioned by a mesh. At this time, the vicinity of the wall surface of the spool 300 and the portion of the portion where the flow velocity distribution may be steep are refined, and the setting is made so that the distortion of the mesh does not increase. In addition, since the mesh corresponding to the ultrasonic propagation path of the ultrasonic flowmeter spool portion is also used for ultrasonic propagation analysis, it is also effective to make the ultrasonic propagation path part a more accurate mesh. An example in which the ultrasonic propagation path portion is a highly accurate mesh will be described with reference to FIG.

  FIG. 4 is a schematic diagram illustrating an example of a numerical calculation mesh of the ultrasonic flowmeter verification system according to the embodiment of the present invention. The mesh 400 shown in FIG. 4A corresponds to the cross section in the flow direction of FIG. 3A, and shows a mesh of a cross section including the ultrasonic wave propagation path of the flow meter spool section 300. The wall surface vicinity (upper and lower) of the mesh 400 is refined in consideration of fluid analysis accuracy. Furthermore, the ultrasonic wave propagation path 401 is made finer than the other parts, and is orthogonal to the ultrasonic wave propagation direction (a 45-degree oblique direction in the figure). Thereby, when using a fluid analysis result for ultrasonic wave propagation analysis, an error becomes small and the reliability of ultrasonic flowmeter simulation can be improved.

  Further, the mesh 400 shown in FIG. 4b corresponds to a cross section perpendicular to the tube axis direction of the spool 300 in FIG. 3b, and the vicinity of the wall surface (up, down, left and right) of the mesh 400 is considered in consideration of fluid analysis accuracy. It is miniaturized. Further, the ultrasonic wave propagation path portion 401 is made finer than other portions.

  For example, mesh data as shown in FIG. 4 created by the numerical computation mesh creation means 102 is stored in the numerical computation mesh data storage device 102a shown in FIG.

  Next, the verification system 100 of the ultrasonic flowmeter uses the numerical calculation mesh data storage device 102a to perform fluid analysis by the fluid analysis means 103, and stores the fluid analysis result in the fluid analysis result data storage device 103a.

  Although fluid analysis can be realized by a well-known method, for example, it has data such as the shape of the spool 300 that is a pipe to be analyzed, and the conditions of the fluid flowing through this pipe include the pipe inlet flow rate, the inlet and outlet fluids. Pressure, flow velocity distribution, etc. are preset. Here, as fluid analysis results, fluid data such as flow velocity vectors, pressures, densities, temperatures, and the like are obtained at portions corresponding to the mesh elements of the numerical calculation mesh data.

  FIG. 5 is a schematic diagram illustrating an example of a fluid analysis result. FIG. 5a shows a cross section (cross section in the fluid flow direction) of the spool 300, which is a pipe provided with an ultrasonic flowmeter. 5b shows a cross section of the spool 300 that is also perpendicular to the tube axis direction. In the cross section 500a perpendicular to the tube axis in FIG. 5b, portions 501a, 502a, 503a, and 504a indicated by dotted lines indicate the position of the survey line. Further, in a cross section 500b parallel to the tube axis in FIG. 5a, portions 502b and 505b indicated by dotted lines indicate the positions of the survey lines. 502a and 502b show the same survey line. The white line in the figure corresponds to the numerical calculation mesh, and the flow velocity in the tube axis direction is indicated by the shade of the color of each element in the mesh.

  From this fluid analysis result data, it can be seen that the flow velocity in the central portion of the spool 300 is fast and the peripheral portion (the flow velocity on the tube wall side is slow. The fluid analysis result data storage device 103a in FIG. The created fluid analysis result data as shown in FIG. 5 is stored.

  From this fluid analysis result data, the fluid analysis error calculation means 104 calculates a fluid analysis error. Here, the fluid analysis error calculation means 104 calculates the flow rate in a plurality of cross sections perpendicular to the tube axis in FIG. 5b as the sum of the products of the area of each mesh element in the cross section 500a and the flow velocity in the tube axis direction. On the other hand, a calculation is performed to take the difference in input flow rate as a set value as an analysis condition in the fluid analysis means 103. This flow rate difference should not occur originally, and this error becomes a fluid analysis error. The fluid analysis error calculated in this way is accumulated in the fluid analysis error data storage device 104a. Note that this fluid analysis error is not used in the subsequent calculation, but is used to be displayed on the analysis result output device 111.

  The fluid analysis result data obtained by the fluid analysis means 103 and stored in the fluid analysis result data storage device 103a is used by the flow velocity vector acquisition means 105 to acquire flow velocity vector data at each side line portion. That is, in the flow velocity vector acquisition means 105, the ultrasonic propagation path portion of each survey line indicated by 502b and 505b in the fluid flow direction cross section of FIG. 5b is selected from the flow velocity vectors stored in the fluid analysis result data storage device 103a. Extract the flow vector. The extracted velocity vector of the ultrasonic propagation path portion of each survey line is stored in the velocity vector data storage device 105a.

  Note that the flow velocity vector of the portion is used by an integral average flow velocity calculation means 106 and a propagation time difference average flow velocity calculation means 107 described later. By acquiring the velocity vector data prior to the ultrasonic propagation analysis, the ultrasonic propagation analysis time can be shortened, and if only the elements of the propagation path are acquired sequentially during the ultrasonic propagation analysis, the storage area of the computer is saved. Can be saved.

  The integrated average flow velocity calculation means 106 uses the numerical calculation mesh data stored in the numerical calculation mesh data storage device 102a and the flow velocity vector data stored in the flow velocity vector data storage device 105a to integrate integral average flow velocity data. Ask for. Here, the integrated average flow velocity is the sum of the products of the ultrasonic propagation path length and the pipe axial flow velocity in each mesh element within the dotted lines of the ultrasonic propagation paths 502b and 505b on each side line in FIG. This corresponds to the calculation divided by the length (ultrasonic propagation path length). By this calculation, the reference value of the line average flow velocity of each survey line when the flow velocity distribution of the fluid analysis result is positive can be obtained. That is, the average value of the fluid flow velocity in the area | region in the ultrasonic propagation path 502b of each side line of FIG. 5b and 505b is calculated | required. This result is stored in the integrated average flow velocity data storage device 106a.

  Next, the propagation time difference average flow velocity calculation means 107 uses the numerical calculation mesh data stored in the numerical calculation mesh data storage device 102a and the flow velocity vector data stored in the flow velocity vector data storage device 105a to propagate. Calculate the line average velocity of each survey line due to the time difference.

  Here, the propagation time difference average flow velocity calculation means 107 performs ultrasonic propagation analysis to simulate ultrasonic propagation in the fluid. The ultrasonic propagation analysis may be performed in detail using the finite element method or the finite volume method, or the ultrasonic propagation time can be calculated quickly and with high accuracy using a simple ray tracing method. it can.

  An example of propagation time difference average flow velocity calculation by the ray tracing method will be described with reference to FIG. FIG. 6 is a schematic diagram showing an ultrasonic propagation analysis method when the ray tracing method for calculating the propagation path of the main sound ray is applied to each mesh element on the ultrasonic propagation path of the numerical mesh. 6 (a), 6 (b), and 6 (C) each show the inside of the ultrasonic wave propagation paths 502b and 505b on the respective side lines in the longitudinal direction of the spool 300 in FIG. 5A. Specifically, the direction of fluid flow is taken in the horizontal direction of the figure, and here, a region 600 is formed by a horizontal 4 and vertical 3 mesh.

  In FIG. 6A, reference numeral 601a denotes a main sound ray from the ultrasonic sensor, which is irradiated at an angle of 45 degrees from the lower left to the upper right. On the other hand, the fluid flow velocity 605 is obtained for each mesh element and stored in the flow velocity vector data storage device 150a, and the flow velocity in the upper left portion is large in the example of the figure. As a result, the propagation direction and propagation velocity for each mesh element are set by the sum of the ultrasonic sound velocity vector 601a and the flow velocity vector 605, and the sum of the passage times of the mesh elements passing from transmission to reception is superfluous. Calculated as sound wave propagation time. Thereby, an ultrasonic propagation analysis result faithful to the fluid analysis result can be obtained.

  FIG. 6B is a schematic diagram showing an ultrasonic propagation analysis method when a ray tracing method for calculating a propagation path for every minute time is applied to the ultrasonic propagation path of the numerical calculation mesh. In this case, a flow velocity vector obtained by interpolation calculation from the flow velocity vectors of the mesh elements or nodes is used for the position 602 of the main sound ray 601b at each minute fixed period. In this method, the analysis accuracy can be improved by reducing the time step width, but errors due to interpolation are also included.

  FIG. 6C shows a case where a ray tracing method for calculating a propagation path of a plurality of sound rays simulating the spread of ultrasonic sound is applied to each element on the ultrasonic propagation path of the numerical calculation mesh. It is the schematic which shows a sound wave propagation analysis method. Similar to FIG. 6A, the main sound ray 601c is analyzed, and at the same time, the propagation analysis is also performed on the secondary sound rays 603 and 604 (which may be further increased) corresponding to the expansion of the ultrasonic beam. At this time, by setting values corresponding to the sound pressure of the ultrasonic wave to the main sound line and the sub sound line, the signal intensity can be predicted, and the reliability of the simulation can be improved.

  The propagation time difference average flow velocity calculation means 107 obtains the propagation time difference average flow velocity using the above-described method and stores it in the propagation time difference average flow velocity storage device 107a.

  Next, in the ultrasonic propagation analysis error determination means 108, the difference between the integrated average flow velocity data stored in the integrated average flow velocity data storage device 106a and the propagation time difference average flow velocity data stored in the propagation time difference average flow velocity storage device 107a. Is compared with the analysis allowable error data stored in the ultrasonic propagation analysis error data storage device 108a to obtain ultrasonic propagation analysis error data.

  Here, the meaning of obtaining the difference between the integrated average flow velocity data and the propagation time difference average flow velocity data will be described. Both are the average flow velocity at the side line portions 502b and 505b in the pipe longitudinal direction in FIG. However, the integrated average flow velocity data is the average flow velocity obtained from the fluid analysis result in the fluid analysis means 103, and the propagation time difference average flow velocity data is the average flow velocity obtained from the ultrasonic propagation time difference in the propagation time difference average flow velocity calculation means 107. is there. These average flow velocities are measured at the same place by different methods, and should be the same value.

  If there is a difference between these, it is considered that this is because the numerical mesh shown in FIG. 4 is coarse. If the mesh is sufficiently fine, the difference in average flow velocity data should be equal to or less than the analysis allowable error data stored in the ultrasonic wave propagation analysis error data storage device 108a.

  Therefore, in the present invention, when the analysis error exceeds the allowable value, the numerical calculation mesh correction means 109 corrects the numerical calculation mesh data. Then, the series of processes for obtaining the difference between the integrated average flow velocity data and the propagation time difference average flow velocity data described above is executed again. At this time, the mesh of the ultrasonic wave flow path spool portion corresponding to the ultrasonic wave propagation path has a smaller ultrasonic wave propagation analysis error by making the ultrasonic wave propagation path part as shown in FIG. can do.

  When the difference between the integrated average flow velocity data and the propagation time difference average flow velocity data falls within the range of the analysis permissible error data as a result of the recorrection, this result is stored in the ultrasonic propagation analysis error data storage device 108a.

  Finally, the flow rate calculation means 110 stores the flow rate calculation result data in which the measurement value of the ultrasonic flowmeter is predicted, and the flow rate calculation result data storage device 110a stores the flow rate calculation result data and the analysis allowable error. Data, fluid analysis error data, and ultrasonic propagation analysis error data are displayed on the display screen.

  FIG. 7 is a schematic diagram illustrating an example of a display screen of the analysis result output device 111. Here, the display screen 700 may be a screen of the apparatus or a document attached to the performance guarantee. The display screen 700 includes a flow rate measurement value simulation result display screen 701 and an analysis error evaluation result display screen 702.

  The flow rate measurement value simulation result display screen 701 displays simulation results of the input flow rate, the actual machine condition flow rate output value, and the flow rate correction coefficient. Moreover, you may display the result of the line average flow velocity and flow velocity distribution of each survey line. In addition, the accuracy of the flow meter can be guaranteed by displaying the simulation result for the accuracy of the flow meter in detail using a flow rate output value for the flow rate, a graph of the flow rate correction coefficient, or the like.

  The analysis error evaluation result display screen 702 includes an analysis allowable error setting value (analysis allowable error input data storage device 101a), fluid analysis error data (fluid analysis error data storage device 104a), and ultrasonic propagation analysis error data (ultrasonic propagation). Analysis error data storage device 108a), flow rate calculation error (fluid calculation result data storage device 110a), and the like are displayed. In particular, for the ultrasonic propagation error, the ultrasonic propagation error for each side line is displayed. Thereby, the error by analysis can be grasped | ascertained correctly and the reliability product of a flowmeter accuracy guarantee can be improved.

  With the ultrasonic flow meter verification system of the present invention, it is possible to predict the measurement value of the flow rate with the propagation time difference type ultrasonic flow meter with high accuracy, and clarify the prediction accuracy with the numerical analysis of the propagation time difference type ultrasonic flow meter. Accordingly, it is possible to guarantee the accuracy of the propagation time difference type ultrasonic flowmeter with high reliability.

  FIG. 8 is a flowchart showing a verification procedure of the verification method of the ultrasonic flowmeter according to the embodiment of the present invention.

  When verification of the ultrasonic flowmeter is started, an allowable error of the ultrasonic flowmeter simulation by numerical analysis is set in an analysis error setting step S101. Next, a numerical calculation mesh for a three-dimensional flow in the ultrasonic flowmeter spool and its front and rear pipes is generated in a numerical calculation mesh generation step S102. In the in-pipe fluid analysis step S103, the flow velocity distribution in the pipe is calculated using a numerical calculation mesh.

  Next, in the fluid analysis error determination step S104, it is determined whether or not the fluid analysis error is larger than the allowable value determined in the analysis error setting step S101. If the allowable value is exceeded, the numerical calculation mesh is corrected by the numerical calculation mesh correction step S105, and then the in-pipe fluid analysis step S103 is performed again.

  If the fluid analysis error is less than the allowable value, the result of the fluid analysis is assigned to each mesh element of the ultrasonic flowmeter spool section of the numerical calculation mesh in the flow velocity vector acquisition step S106, and the ultrasonic wave of the mesh is calculated in the integral average flow velocity calculation S107. The average flow velocity on the ultrasonic propagation path of each survey line is calculated using the flow meter spool section and the flow velocity vector. Further, in the propagation time difference average flow velocity calculation step S108, ultrasonic propagation analysis is performed using the ultrasonic flowmeter spool portion of the mesh and the flow velocity vector, and the line average flow velocity of each survey line due to the propagation time difference is calculated.

  In the ultrasonic wave propagation analysis error determination step S109, the difference between the integrated average flow velocity and the propagation time difference average flow velocity is compared, and it is determined whether the difference is within the allowable value range set by the analysis error setting means. If the ultrasonic wave propagation analysis error exceeds the allowable value, the numerical calculation mesh is corrected in the numerical calculation mesh correction step S105, and then the in-pipe fluid analysis step S103 is performed again.

  When the ultrasonic propagation analysis error is less than the allowable value, the flow rate calculation value of the ultrasonic flowmeter is calculated from the propagation time difference average flow velocity in the flow rate calculation step S110. Finally, the flow rate calculation result and the analysis error are displayed in the analysis result display step S110.

  FIG. 9 conceptually and chronologically displays and describes the processing performed by each unit or the result when the system configuration of FIG. 1 or the flowchart of FIG. 8 is executed.

  This flow is made up of AG, which will be explained briefly. First, in A, the target pipe portion is divided by a mesh. In B, fluid analysis is performed for each mesh portion to determine the fluid flow velocity. In C, the flow velocity vector of each mesh portion of the ultrasonic propagation path 401 is obtained.

  In D, the average flow velocity is obtained by two methods. The integrated average flow velocity data of D1 is the average flow velocity obtained from the fluid analysis result, and the propagation time difference average flow velocity data of D2 is the average flow velocity obtained from the ultrasonic propagation time difference.

  In E, the error of these two average flow velocities is compared with the analysis allowable error data given by F, and if it is within the error range, the analysis ends. If the error is equal to or greater than the error range, the process is re-executed after the mesh is refined in G.

  By the verification method of the present invention described in detail above, it is possible to predict the flow rate measurement value with a propagation time difference type ultrasonic flowmeter with high accuracy, and the prediction accuracy by numerical analysis of the propagation time difference type ultrasonic flowmeter is clarified. Accordingly, the reliability of verification of the measurement accuracy of the propagation time difference type ultrasonic flowmeter can be further improved.

  The present invention can be widely applied to flow measurement outside the nuclear field.

DESCRIPTION OF SYMBOLS 101 ... Analysis tolerance input device 102 ... Numerical calculation mesh preparation means 103 ... Fluid analysis means 104 ... Fluid analysis error calculation means 105 ... Flow velocity vector acquisition means 106 ... Integral average flow velocity calculation means 107 ... Propagation time difference average flow velocity calculation means 108 ... Super Sound wave propagation analysis error determination means 109 ... Numerical calculation mesh correction means 110 ... Flow rate calculation means 111 ... Analysis result display means 300 ... Ultrasonic flowmeter pipe spool 301 ... Pipe spool flow velocity distribution 302 to 317 ... Ultrasonic sensor 400 ... Numerical calculation Mesh 500 ... Fluid analysis result 600 ... Numerical calculation mesh element 700 ... Verification result display screen

Claims (14)

A verification system for a propagation time difference type ultrasonic flowmeter,
Analysis error setting means for setting the tolerance of the ultrasonic flowmeter simulation by numerical analysis;
A numerical calculation mesh creating means for creating a numerical calculation mesh of an ultrasonic flowmeter spool and a three-dimensional flow in the pipes before and after the spool;
Fluid analysis means for calculating a flow velocity distribution in the pipe using the numerical calculation mesh;
Fluid analysis error calculating means for calculating the error of the fluid analysis;
A flow velocity vector acquiring means for assigning the result of the fluid analysis to each mesh element of the ultrasonic flowmeter spool portion of the numerical mesh;
An integrated average flow velocity calculating means for calculating an average flow velocity on the ultrasonic propagation path of each measurement line using the ultrasonic flowmeter spool portion of the numerical calculation mesh and the flow velocity vector;
Propagation time difference average flow velocity calculating means for performing ultrasonic wave propagation analysis using the ultrasonic flowmeter spool portion of the numerical calculation mesh and the flow velocity vector, and calculating a line average flow velocity of each survey line by a propagation time difference;
Comparing the difference between the integral average flow velocity and the propagation time difference average flow velocity, and determining whether or not the ultrasonic propagation analysis error determination means determines whether it is within the allowable range set by the analysis error setting means;
As a result of the ultrasonic propagation analysis error determination, numerical calculation mesh correction means for correcting the numerical calculation mesh if the allowable value is exceeded,
A flow rate calculation means for analyzing a flow rate calculation result of an ultrasonic flowmeter from the propagation time difference average flow velocity;
Analysis result display means for displaying the flow rate calculation result, the fluid analysis error, and the ultrasonic propagation analysis error;
A verification system for a propagation time difference type ultrasonic flowmeter characterized by comprising: In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 1,
The numerical calculation mesh creating means sets the mesh width on the ultrasonic propagation path of the ultrasonic flow meter spool section so as to be subdivided from other parts, the propagation time difference type ultrasonic flow meter Verification system. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 1,
The numerical calculation mesh creating means sets the mesh on the ultrasonic propagation path of the ultrasonic flow meter spool section so as to be orthogonal to the ultrasonic propagation direction. Verification system. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 1,
The fluid analysis error calculating means calculates a difference in propagation time using a flow velocity vector of the numerical mesh ultrasonic flowmeter spool section and calculating from a difference between a flow rate and an input flow rate in a plurality of cross sections perpendicular to the tube axis. Type ultrasonic flowmeter verification system. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 1,
The flow velocity vector acquisition means acquires only a flow velocity vector on the ultrasonic propagation path of each measurement line necessary for the integral average flow velocity calculation means and the propagation time difference average flow velocity calculation means. Verification system. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 1,
The propagation time difference average flow velocity calculation means applies a ray tracing method for calculating a propagation path of a main sound ray for each element on the ultrasonic propagation path of the numerical calculation mesh, Verification system. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 1,
The propagation time difference average flow velocity calculating means applies a ray tracing method for calculating a propagation path of a plurality of sound rays simulating the spread of ultrasonic sound to each element on the ultrasonic propagation path of the numerical mesh. Propagation time difference type ultrasonic flowmeter verification system. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 6 or 7,
The propagation time difference average flow velocity calculating means calculates a propagation path for every minute time as the ray tracing method, and a verification system for a propagation time difference type ultrasonic flowmeter. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 8,
The propagation time difference average flow velocity calculating means uses a flow velocity vector obtained by interpolation calculation from a flow velocity vector of each element or each node in the propagation path for each minute time, and a propagation time difference ultrasonic flow meter Verification system. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 1,
The propagation time difference average flow velocity calculation means applies a finite element method or a finite volume method, a propagation time difference type ultrasonic flowmeter verification system. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 1,
The numerical calculation mesh correcting means is set so that the mesh width on the ultrasonic propagation path of the ultrasonic flow meter spool section is subdivided from other portions. Verification system. In the verification system of the propagation time difference type ultrasonic flowmeter according to claim 1,
The numerical calculation mesh correcting means sets the mesh on the ultrasonic propagation path of the ultrasonic flow meter spool section so as to be orthogonal to the ultrasonic propagation direction. Verification system. A verification method of a propagation time difference type ultrasonic flowmeter,
An analysis error setting process for setting an allowable error of the ultrasonic flowmeter simulation by numerical analysis,
A mesh creation process for creating a numerical calculation mesh of the ultrasonic flowmeter spool and the three-dimensional flow in the pipes before and after the spool;
A fluid analysis step of calculating a flow velocity distribution in the pipe using the mesh;
A flow velocity vector acquisition step of assigning the result of the fluid analysis to each element of the ultrasonic flowmeter spool portion of the mesh;
An integrated average flow velocity calculating step of calculating an average flow velocity on the ultrasonic propagation path of each measurement line using the ultrasonic flowmeter spool portion of the mesh and the flow velocity vector;
Ultrasonic propagation analysis using the ultrasonic flowmeter spool portion of the mesh and the flow velocity vector, and a propagation time difference average flow velocity calculation step of calculating a line average flow velocity of each measurement line by a propagation time difference;
An analysis error determination step of comparing the difference between the integrated average flow velocity and the propagation time difference average flow velocity, and determining whether the difference is within a tolerance range set by the analysis error setting means;
As a result of the analysis error determination, a mesh correction step of correcting the numerical calculation mesh if the allowable value is exceeded,
A flow rate calculation step of analyzing the flow rate calculation result of the ultrasonic flowmeter from the propagation time difference average flow velocity;
An analysis result display step for displaying the flow rate calculation result and the analysis error;
The verification method of the ultrasonic water supply flowmeter characterized by comprising. A verification method of a propagation time difference type ultrasonic flowmeter,
The target pipe part where the ultrasonic flowmeter is installed is divided into three-dimensional meshes,
Perform fluid analysis to find the flow velocity of each mesh part including the ultrasonic propagation path part,
Find the difference between the average flow velocity obtained from the fluid analysis result in the ultrasonic propagation path portion and the average flow velocity obtained from the ultrasonic propagation time difference in the ultrasonic propagation passage portion,
The difference between the two average flow velocities is compared with an analysis allowable error as an ultrasonic propagation error. If the difference is equal to or greater than the analysis allowable error range, the mesh is refined and the difference between the average flow velocities is obtained again, and the analysis allowable A method for verifying an ultrasonic water supply flowmeter, characterized by evaluating an ultrasonic propagation error within an error range.

Images