JP7797184B2 - Valve wall-thickness thinning prediction system and valve wall-thickness thinning prediction method - Google Patents

Description

This disclosure relates to a valve wall thinning prediction system and method.

It is important to predict changes in the flow characteristics and mechanical deterioration of valves used in piping within a plant and to replace valves and piping at the appropriate time.

Patent Document 1 discloses a control valve diagnostic device that provides a control valve located midway through a pipe through which a liquid flows with an opening indicator that detects the valve opening and a vibration accelerometer that detects vibration values, and a differential pressure gauge that measures the valve pressure difference between the upstream and downstream sides of the control valve. It diagnoses liquid leakage when the valve is closed based on the valve opening measured by the opening indicator and the vibration value measured by the vibration accelerometer, calculates a cavitation coefficient based on the valve pressure difference, and comprehensively evaluates the cavitation coefficient, vibration value, and valve opening value to determine whether mechanical deterioration has occurred during operation.

Patent Document 2 discloses a method for providing wall-thinning prediction information, in which wall-thickness data for piping components that specifies the wall thickness of the piping components is received from a customer, and wall-thickness data for piping components that is simulated based on the received wall-thickness data is provided to the customer. The method uses a computer to simulate the behavior of fluid flowing inside a piping line based on the wall-thickness data for the piping components and three-dimensional layout data for the piping line that includes the piping components, and determines the wall-thickness data for the piping components that make up the piping line from changes in the simulated behavior of the fluid.

Non-Patent Document 1 describes a simple method for predicting wall thinning, including the processes of fluid analysis, droplet trajectory analysis, and wall thinning evaluation. It describes how, by applying this method to a full-scale globe valve, the peak positions of the wall thinning rate correspond to the locations of holes in the actual valve, making it possible to predict locations of wall thinning. It also describes how, when this method was used to evaluate the distribution of wall thinning rates by changing the valve opening, it was found that the locations of wall thinning could change significantly depending on the valve opening.

Japanese Patent Application Publication No. 6-94160 Japanese Patent Application Laid-Open No. 2001-344295

Junya Watanabe et al., "Numerical Simulation of Droplet Impact Erosion in a Valve," Multiphase Flow, 2021, Vol. 35, No. 1, pp. 60-67

Generally, the internal shape of a valve is a complex three-dimensional shape. When a fluid flows through such a valve, flow separation and drift occur. As a result, high flow velocities and high pressures occur in certain parts of the valve's flow path area.

One indicator of the degree of valve deterioration is the amount of thinning on the valve's inner wall. When diagnosing thinning on the valve's inner wall, if the local flow inside the valve is not taken into account, there is a risk that thinning in areas where high flow velocities or high pressures occur will be underestimated. If thinning progresses locally on the valve's inner wall, it could lead to unexpected damage such as holes or accidents.

The control valve diagnostic device described in Patent Document 1 calculates the cavitation coefficient based on the valve differential pressure when the fluid flowing inside the control valve is liquid. Therefore, when dealing with cavitation issues under conditions where steam flows inside the valve and some of it condenses, there is room for improvement due to the difficulty of calculations using differential pressure and the different mechanisms of wall thinning. Furthermore, Patent Document 1 does not mention any simulations using data on the internal shape of the valve.

Furthermore, in the method of providing wall thinning prediction information described in Patent Document 2, the simulation is performed on the assumption that the internal shape of the piping component has a circular cross section. Therefore, the simulation does not take into account the complex internal shape of the valve, nor does it take cavitation into consideration.

The condition of the fluid inside the valve changes depending on the plant's usage conditions. Furthermore, when fluid flows through the valve, the shape of the flow path area formed inside the valve changes depending on the valve's opening angle.

The purpose of this disclosure is to accurately predict localized thinning inside a valve in order to perform appropriate maintenance on the valve.

The valve wall thinning prediction system disclosed herein comprises a measurement value storage unit that stores at least one measurement data measured by a fluid state sensor installed on at least one of the upstream and downstream sides of the valve; a flow characteristics storage unit that stores a valve flow calculation formula that calculates the flow rate of fluid passing through the inside of the valve; an inlet/outlet flow condition estimation unit that estimates and outputs valve inlet/outlet flow conditions for at least one valve opening; an inlet/outlet flow condition storage unit that stores the valve inlet/outlet flow conditions; a wall thinning rate database storage unit that stores the wall thinning rate distribution for each small region of the valve's inner wall surface for the valve inlet/outlet flow conditions; a wall thinning amount evaluation unit that calculates and outputs the cumulative wall thinning amount distribution for each small region for the valve opening; and a wall thinning amount storage unit that stores the cumulative wall thinning amount distribution for each small region for the valve opening, and predicts valve wall thinning.

The valve wall thinning prediction method disclosed herein stores at least one measurement data measured by a fluid state sensor installed on at least one of the upstream and downstream sides of the valve in a measurement value storage unit, stores a valve flow rate calculation formula for calculating the flow rate of fluid passing through the valve in a flow characteristics storage unit, estimates valve inlet and outlet flow conditions for at least one valve opening, stores the valve inlet and outlet flow conditions in an inlet and outlet flow condition storage unit, stores the wall thinning rate distribution for each small region of the valve inner wall surface for the valve inlet and outlet flow conditions in a wall thinning rate database storage unit, calculates the cumulative wall thinning amount distribution for each small region for the valve opening in a wall thinning amount evaluation unit, and predicts valve wall thinning.

According to the present disclosure, at least one measurement value is used to divide the flow path area inside the valve into multiple small areas, and by taking into account the local flow inside the valve, it is possible to predict thinning of the valve's inner wall for each small area and perform appropriate maintenance of the valve.

1 is a configuration diagram showing a wall-thinning prediction system according to a first embodiment. FIG. FIG. 10 is a diagram showing a specific example of the contents of the valve inlet/outlet flow conditions. 2 is a diagram showing a specific example of data stored in an inlet/outlet flow condition storage unit 104 in FIG. 1. FIG. FIG. 10 is a diagram showing a specific example of the contents of the wall-thinning rate distribution. FIG. 10 is a diagram showing a specific example of the content of the cumulative wall-thinning amount distribution. 2 is a diagram showing a specific example of data stored in a wall-thinning amount storage unit 107 in FIG. 1 . FIG. FIG. 10 is a diagram illustrating an example of an image on a display device. FIG. 1 is a flowchart showing a method for predicting metal thinning according to a first embodiment. FIG. 2 is a flowchart showing the process of estimating the flow conditions at the inlet and outlet of a valve when one type of measurement data is stored in the measurement value storage unit 101 of FIG. 1 . FIG. 2 is a flowchart showing the process of estimating valve inlet and outlet flow conditions when two types of measurement data including a valve inlet fluid pressure are stored in the measurement value storage unit 101 of FIG. 1 . FIG. 10 is a configuration diagram showing a metal-thickness reduction prediction system according to a second embodiment. FIG. 10 is a diagram showing an example of an image on a display device according to a second embodiment. FIG. 10 is a flowchart showing a method for predicting metal-thinning according to a second embodiment.

Embodiments of the present disclosure will be described below with reference to the drawings. In each embodiment, at least one measurement value is used to divide the flow path area inside the valve into multiple small areas, and thinning of the valve's inner wall is predicted for each small area, taking into account the local flow inside the valve. Note that common components in the following figures will be assigned the same reference numerals, and redundant explanations will be omitted.

First Embodiment
The first embodiment is an embodiment in which thinning of a valve is predicted without detecting the valve opening.

Figure 1 is a configuration diagram showing the wall-thinning prediction system according to this embodiment.

As shown in this diagram, the metal thinning prediction system 100 (valve metal thinning prediction system) includes a measurement value storage unit 101, a flow characteristics storage unit 102, an inlet/outlet flow condition estimation unit 103, an inlet/outlet flow condition storage unit 104, a metal thinning rate database storage unit 105, a metal thinning amount evaluation unit 106, a metal thinning amount storage unit 107, and a display unit 108.

The metal thinning prediction system 100 is a system that predicts metal thinning in valves. The inner walls of valves that come into contact with fluids undergo thinning due to erosion, corrosion, and other factors. When two-phase fluids such as wet steam flow through the valve, cavitation erosion and liquid droplet impingement (LDI) progress. The metal thinning prediction system 100 determines the rate and amount of thinning of the inner walls of the valve to enable quantitative evaluation of such thinning.

The metal-thinning prediction system 100 is composed of a computer equipped with, for example, an arithmetic unit such as a CPU (Central Processing Unit), storage devices such as ROM (Read Only Memory) and RAM (Random Access Memory), external storage devices such as magnetic disks, optical disks, and non-volatile memory, an input interface (input section), an output interface (output section), transmission and reception functions, etc. Some of the functions of the metal-thinning prediction system 100 may be executed by a program recorded on a computer-readable recording medium or by other hardware.

The measurement value storage unit 101 stores, as measurement data, the state quantities of the fluid measured by a sensor (fluid state sensor) installed at least on the upstream or downstream side of the valve. Specifically, the measurement data is any one of the valve inlet fluid pressure, valve inlet fluid temperature, valve outlet fluid pressure, valve outlet fluid temperature, and the flow rate of the fluid passing through the valve. The measurement value storage unit 101 stores at least one piece of measurement data. Note that in this specification, "storing" refers to recording data, programs, etc. on a computer-readable recording medium, storage device, etc.

The flow characteristics storage unit 102 stores a valve flow calculation formula that calculates the flow rate of fluid passing through a valve from the valve inlet fluid pressure, valve outlet fluid pressure, and valve opening.

Specifically, the valve flow rate calculation formula is defined by the following formulas (1) and (2).

where G is the flow rate of the fluid passing through the valve, _P1 is the fluid pressure at the valve inlet, _P2 is the fluid pressure at the valve outlet, _VA is the valve opening, _Cv is the flow coefficient, and α is the critical pressure ratio. Also, _Cv ( _VA ) indicates that the flow coefficient _Cv can be determined using the valve opening _VA as a variable.

Next, the relationship between the valve inlet fluid pressure P ₁ , the valve outlet fluid pressure P ₂ , and the flow rate G of the fluid passing through the valve will be described.

When _P1 and _P2 are equal, that is, when the pressure ratio _P2 / _P1 = 1, no flow occurs inside the valve, so G = 0. As _P2 / _P1 decreases from 1 and the difference between _P1 and _P2 increases, the flow velocity inside the valve increases and G increases. In this case, G is calculated using the above formula (1).

When _P2 / _P1 decreases to the critical pressure ratio α, the flow velocity becomes equal to the speed of sound, and even if _P2 / _P1 decreases below α, the flow velocity does not become faster than the speed of sound. In other words, when _P2 / _P1 <α, the flow velocity is always equal to the speed of sound, and in this case, G is calculated using the above formula (2).

The inlet/outlet flow condition estimation unit 103 takes as input the measurement data stored in the measurement value storage unit 101 and the valve flow calculation formula stored in the flow characteristics storage unit 102, and estimates and outputs the valve inlet/outlet flow conditions for one or more valve openings.

Figure 2 shows a specific example of the contents of the valve inlet and outlet flow conditions.

In this figure, the valve inlet/outlet flow conditions 110 consist of the valve opening, valve inlet flow velocity, valve inlet fluid temperature, and valve outlet fluid pressure, which are required to determine the flow within the valve.

The inlet/outlet flow condition storage unit 104 (Figure 1) stores the valve inlet/outlet flow conditions for at least one valve opening estimated and output by the inlet/outlet flow condition estimation unit 103.

Figure 3 shows a specific example of data stored in the inlet/outlet flow condition storage unit 104 in Figure 1.

In Figure 3, the valve inlet and outlet flow conditions 110 for a valve opening of 100% and a valve opening of 20% are stored.

The thinning rate database storage unit 105 (Figure 1) stores multiple thinning rate distributions on the inner wall surface of the valve for the valve inlet and outlet flow conditions 110.

Figure 4 shows a specific example of the thinning rate distribution.

In this figure, the metal thinning rate distribution 111 is composed of valve inlet/outlet flow conditions 110 and a region ID/coordinate/metal thinning rate table 112 for each small region of the valve inner wall (inner wall surface of the valve) for the flow within the valve calculated from the valve inlet/outlet flow conditions 110. Here, for example, the region ID "7" is assigned to "small region 7."

Here, the flow path area inside the valve is divided into multiple small areas based on the valve shape information, material information, and valve inlet/outlet flow conditions 110, and a numerical analysis simulation is performed that takes into account the local flow inside the valve, creating a table 112 of area IDs, coordinates, and thinning rate for each small area. It is desirable to calculate the data obtained from the simulation in advance and store it in a database, but it is also possible to perform the simulation and obtain the data in real time.

The metal-thinning amount evaluation unit 106 (Figure 1) receives as input the valve inlet/outlet flow conditions 110 for at least one valve opening stored in the inlet/outlet flow condition storage unit 104 and the metal-thinning rate distribution 111 stored in the metal-thinning rate database storage unit 105, and calculates and outputs the cumulative metal-thinning amount distribution for each small region of the valve inner wall for at least one valve opening.

Figure 5 shows a specific example of the cumulative wall-thinning distribution.

In this figure, the cumulative wall-thinning distribution 113 is composed of the valve opening and a region ID, coordinates, and cumulative wall-thinning table for each small region of the valve inner wall relative to the valve opening. The cumulative wall-thinning distribution 113 shows the cumulative wall-thinning distribution for each small region of the valve inner wall under conditions where the valve opening does not change over time and the valve opening is maintained.

The thinning amount storage unit 107 (Figure 1) stores the cumulative thinning amount distribution for at least one valve opening.

Figure 6 shows a specific example of data stored in the wall-thinning amount storage unit 107 in Figure 1.

In Figure 6, the cumulative thinning distribution 113 for a valve opening of 100% and a valve opening of 20% is stored.

The display unit 108 (Figure 1) has a display device. Examples of display devices include a liquid crystal display, plasma display, organic EL display, and cathode ray tube. The display unit 108 receives the cumulative wall-thinning amount distribution 113 for at least one valve opening stored in the wall-thinning amount storage unit 107 as input, and outputs the cumulative wall-thinning amount distribution for each small region of the valve inner wall for each valve opening.

Figure 7 shows an example of an image on the display device.

In this figure, a numerical image 114 and a shape image 115 are displayed on the display device 120. The numerical image 114 is the cumulative amount of thinning collected for each small area of the valve's inner wall for each valve opening. The shape image 115 is the shape of the flow path area or inner wall of the valve 1.

The numerical image 114 can be displayed as a table or the like, in association with the identifier (area ID) and coordinates assigned to each small area of the valve's inner wall. The shape image 115 can be displayed in two or three dimensions, in association with the cumulative metal loss results for each small area of the valve's inner wall. The shape image 115 can be created using image software or the like that models numerical data.

As shown in Figure 7, the identifiers (area IDs) displayed on the table can also be displayed in the corresponding areas of the shape image 115. Areas where the cumulative wall-thinning amount is greater than a predetermined threshold, locations where significant wall-thinning has occurred, and the risk of wall-thinning for each cell can be visually highlighted using color, texture, etc. Also, a map can be displayed with each cell separated by color or texture for each numerical range of the cumulative wall-thinning amount.

Alternatively, unlike Figure 7, the initial display can be such that only the shape image 115 is displayed, without the numerical image 114. In this initial display state, when any cell on the shape image 115 is designated by clicking or the like, the coordinates of that cell, the cumulative amount of thinning, etc. can be displayed in a pop-up or the like.

Next, we will explain in detail the process used by the wall-thickness reduction prediction system 100 to predict valve wall-thickness reduction.

Figure 8 is a flow diagram showing the metal-thickness reduction prediction method (valve metal-thickness reduction prediction method) according to this embodiment.

In this diagram, first, in step S151 (valve opening input process), at least one valve opening for predicting valve thinning is input from the input unit of the metal thinning prediction system 100. As a specific example, two valve openings are input: 100%, which is the maximum valve opening, and 20%, which is the minimum valve opening. Alternatively, three valve openings are input: the maximum and minimum valve openings of 100% and 20%, plus 50% as an intermediate valve opening. The valve opening is typically input by the user, but the valve opening determined by another automatic device, such as by detecting the passage of a predetermined time or by some kind of calculation, may be input to the input unit as an electrical signal.

In step S152 (measurement value acquisition process), the measurement value storage unit 101 acquires and stores measurement data measured by a sensor installed on at least one of the upstream and downstream sides of the valve.

In step S153 (inlet/outlet flow condition estimation process), the inlet/outlet flow condition estimation unit 103 receives the measurement data stored in the measurement value storage unit 101 and the valve flow calculation formula stored in the flow characteristics storage unit 102 as input, and estimates the valve inlet/outlet flow conditions 110 for the valve opening. The inlet/outlet flow condition storage unit 104 stores the valve inlet/outlet flow conditions 110.

In step S154 (metal thinning rate acquisition process), the metal thinning amount evaluation unit 106 inputs the valve inlet/outlet flow conditions 110 stored in the inlet/outlet flow condition storage unit 104 and the metal thinning rate distribution 111 stored in the metal thinning rate database storage unit 105, and selects one appropriate metal thinning rate distribution 111 from the multiple metal thinning rate distributions 111. This selection process is performed by selecting the valve inlet/outlet flow conditions 110 stored in the inlet/outlet flow condition storage unit 104 and the valve inlet/outlet flow conditions 110 described in the metal thinning rate distribution 111 that match. If no matching conditions exist, the closest conditions are selected.

In step S155 (metal thinning rate integration process), the metal thinning amount evaluation unit 106 uses the metal thinning rate distribution 111 selected in step S154 as input, time-integrates the metal thinning rate for each small region of the inner wall of the valve at the current time, and calculates the amount of change in metal thinning for each small region of the inner wall of the valve at the current time.

In step S156 (cumulative wall-thinning calculation process), the wall-thinning evaluation unit 106 reads the cumulative wall-thinning distribution 113 from the wall-thinning storage unit 107, and adds the change in wall-thinning for each small area of the valve at the current time calculated in step S155 to the cumulative wall-thinning for each small area of the valve's inner wall up to the previous measurement time included in the cumulative wall-thinning distribution 113 to calculate the cumulative wall-thinning for each small area of the valve's inner wall up to the current time, updates the cumulative wall-thinning distribution 113, and outputs it to the wall-thinning storage unit 107.

In step S157 (accumulated metal loss calculation completion determination process), the metal loss evaluation unit 106 determines whether the accumulated metal loss distribution 113 has been updated for all valve openings input in step S151. If the determination result is YES, the process proceeds to step S158 (display process); if the determination result is NO, the process proceeds to step S153 (inlet/outlet flow condition estimation process), and the subsequent processes are repeated.

In step S158 (display process), the display unit 108 receives the cumulative wall-thinning amount distribution 113 for at least one valve opening stored in the wall-thinning amount storage unit 107 as input, and displays the cumulative wall-thinning amount distribution for each small region of the valve inner wall for each valve opening on the display device 120.

In step S159 (thickness reduction prediction process end determination process), the thickness reduction prediction system 100 determines whether the process for predicting thickness reduction has reached the end time. If the determination result is NO, the system proceeds to step S152 (measurement value acquisition process) and repeats the subsequent processes. On the other hand, if the determination result is YES, the process for predicting valve thickness reduction ends.

Next, we will explain in detail the process used by the inlet/outlet flow condition estimation unit 103 to estimate the valve inlet/outlet flow conditions.

Figure 9 is a flow diagram showing the process of estimating valve inlet and outlet flow conditions when one type of measurement data is stored in the measurement value storage unit 101 of Figure 1.

9, first, in step S161 (valve inlet pressure storage determination step), it is determined whether or not the valve inlet fluid pressure _P1 is stored in the measurement value storage unit 101. If the determination result is YES, the process proceeds to step S162 (valve inlet temperature estimation step), and if the determination result is NO, the process proceeds to step S166 (valve inlet temperature storage determination step).

In step S162 (valve inlet temperature estimation step), the valve inlet fluid pressure _P1 is input and the valve inlet fluid temperature _T1 is estimated. Specifically, assuming that the fluid flowing into the valve is saturated, the saturation temperature _Tsat for _P1 is calculated, and the estimation is performed from the fact that _T1 is equal to _Tsat .

In step S163 (valve outlet pressure estimation step), _P1 is input and valve outlet fluid pressure _P2 is estimated. Specifically, assuming that _P2 / _P1 is equal to the critical pressure ratio α, _P2 is estimated from the fact that it is equal to α× _P1 .

In step S164 (valve passage flow rate calculation step), the valve openings V _A , P ₁ , and P ₂ are input, and the flow rate G of the fluid passing through the valve is calculated using the above equation (1).

In step S165 (valve inlet flow velocity calculation step), the valve inlet flow velocity _u1 is calculated using _P1 , _T1 , and G. Specifically, the valve inlet fluid density _ρ1 is calculated from _P1 and _T1 , and _u1 is calculated using the following equation (3).

Here, A is the cross-sectional area of the flow path at the valve inlet.

In step S166 (valve inlet temperature storage determination step), it is determined whether or not the valve inlet fluid temperature _T1 is stored in the measurement value storage unit 101. If the determination result is YES, the process proceeds to step S167 (valve inlet pressure estimation step), and if the determination result is NO, the process proceeds to step S168 (valve outlet pressure storage determination step).

In step S167 (valve inlet pressure estimation step), _T1 is input and _P1 is estimated. Specifically, assuming that the fluid flowing into the valve is saturated, the saturation pressure _Psat for _T1 is calculated, and estimation is performed from the fact that _P1 is equal to _Psat . After executing step S167, the process proceeds to step S163.

In step S168 (valve outlet pressure storage determination step), it is determined whether or not the valve outlet pressure _P2 is stored in the measurement value storage unit 101. If the determination result is YES, the process proceeds to step S169 (valve inlet pressure estimation step), and if the determination result is NO, the process proceeds to step S171 (valve outlet temperature storage determination step).

In step S169 (valve inlet pressure estimation step), _P2 is input and _P1 is estimated. Specifically, assuming that _P2 / _P1 is equal to the critical pressure ratio α, _P1 is estimated from the fact that it is equal to _P2 /α.

In step S170 (valve inlet temperature estimation step), _P1 is input and _T1 is estimated. The specific processing content is the same as that of step S162, so a description thereof will be omitted. After step S170 is executed, the process proceeds to step S164.

In step S171 (valve outlet temperature storage determination step), it is determined whether or not the valve outlet fluid temperature _T2 is stored in the measurement value storage unit 101. If the determination result is YES, the process proceeds to step S172 (valve outlet pressure estimation step), and if the determination result is NO, the process proceeds to step S173 (valve inlet pressure estimation step).

In step S172 (valve outlet pressure estimation step), _T2 is input and _P2 is estimated. Specifically, assuming that the fluid flowing out of the valve is saturated, the saturation pressure _Psat for _T2 is calculated, and _P2 is estimated from the fact that P2 is equal to _Psat . After executing step S172, the process proceeds to step S169.

In step S173 (valve inlet pressure estimation step), _P1 is estimated using V _A and G as inputs. Specifically, assuming that _P2 / _P1 is equal to the critical pressure ratio α, _P1 is calculated from the following equation (4), which is a modification of the above equation (2).

In step S174 (valve inlet temperature estimation step), _P1 is input and _T1 is estimated. The specific processing content is the same as in step S162, so a description thereof will be omitted.

In step S175 (valve outlet pressure estimation step), _P1 is input and _P2 is estimated. The specific processing content is the same as that of step S163, so a description thereof will be omitted. After step S175 is executed, the process proceeds to step S165.

When one piece of measurement data is stored in the measurement value storage unit 101 through the processing of steps S161 to S175, the valve opening V _A , valve inlet flow velocity u ₁ , valve inlet fluid temperature T ₁ , and valve outlet fluid pressure P ₂ required to determine the flow within the valve are all estimated, and then the processing for estimating the valve inlet and outlet flow conditions is terminated.

Figure 10 is a flow diagram showing the process of estimating valve inlet and outlet flow conditions when two types of measurement data, including valve inlet fluid pressure, are stored in the measurement value storage unit 101 of Figure 1.

10, first, in step S181 (valve outlet pressure storage determination step), it is determined whether or not _P1 and _P2 are stored in the measurement value storage unit 101. If the determination result is YES, the process proceeds to step S182 (valve inlet temperature estimation step), and if the determination result is NO, the process proceeds to step S185 (valve outlet temperature storage determination step).

In step S182 (valve inlet temperature estimation step), _T1 is estimated using _P1 as input. The specific processing content is the same as that of step S162, and therefore a description thereof will be omitted.

In step S183 (a process of calculating the flow rate through the valve), V _A , P ₁ , and P ₂ are input to calculate G. Specifically, if P ₂ /P ₁ is equal to or greater than α, G is calculated using the above formula (1), and if P ₂ /P ₁ is smaller than α, G is calculated using the above formula (2).

In step S184 (valve inlet flow velocity calculation step), the valve inlet flow velocity _u1 is calculated using _P1 , _T1 , and G. The specific processing content is the same as in step S165, and therefore will not be described here.

In step S185 (valve outlet temperature storage determination step), it is determined whether _P1 and _T2 are stored in the measurement value storage unit 101. If the determination result is YES, the process proceeds to step S186 (valve outlet pressure estimation step), and if the determination result is NO, the process proceeds to step S187 (valve inlet temperature storage determination step).

In step S186 (valve outlet pressure estimation step), _T2 is input and _P2 is estimated. The specific processing content is the same as that of step S172, so a description thereof will be omitted. After step S186 is executed, the process proceeds to step S182.

In step S187 (valve inlet temperature storage determination step), it is determined whether _P1 and _T1 are stored in the measurement value storage unit 101. If the determination result is YES, the process proceeds to step S188 (valve outlet pressure estimation step), and if the determination result is NO, the process proceeds to step S189 (valve outlet pressure calculation step).

In step S188 (valve outlet pressure estimation step), _P1 is input and _P2 is estimated. The specific processing content is the same as that of step S163, so a description thereof will be omitted. After step S188 is executed, the process proceeds to step S183.

In step S189 (valve outlet pressure calculation step), _P2 is calculated using V _A , P ₁ , and G. Specifically, _P2 is first calculated from the following equation (5), which is a modification of the above equation (1).

If _P2 / _P1 is equal to or greater than α, the application condition of the above formula (1) ( _P2 / _P1 ≥ α) is satisfied, so _P2 calculated by the above formula (5) is adopted. If _P2 / _P1 is less than α, the application condition of the above formula (1) is not satisfied, so _P2 is calculated assuming that _P2 / _P1 is equal to α, since _P2 is equal to α × _P1 .

In step S190 (valve inlet temperature estimation step), _P1 is input and _T1 is estimated. The specific processing content is the same as that of step S162, so a description thereof will be omitted. After step S190 is executed, the process proceeds to step S184.

When two measurement data sets including the valve inlet fluid pressure are stored through the processing of steps S181 to S190, the valve opening V _A , valve inlet flow velocity u ₁ , valve inlet fluid temperature T ₁ , and valve outlet fluid pressure P ₂ required to determine the flow within the valve are all estimated, and then the processing for estimating the valve inlet and outlet flow conditions is terminated.

Even when two measurement data sets excluding the valve inlet fluid pressure are stored, or when more than two measurement data sets are stored, the valve inlet and outlet flow conditions can be estimated using processing similar to that shown in Figure 9 or Figure 10, and detailed explanations will be omitted.

In this embodiment, at least one valve opening is specified, and at least one measurement value is used to estimate the flow conditions at the valve inlet and outlet for the specified valve opening. Furthermore, based on the estimated flow conditions at the valve inlet and outlet, the flow path area inside the valve is divided into multiple small areas, and the local flow inside the valve is taken into account to calculate the cumulative thinning distribution of the valve's inner wall for each small area. The cumulative thinning distribution is then displayed on the screen for each valve opening. In other words, if at least one measurement value is available, it is possible to predict thinning of the valve's inner wall for each small area.

In addition, in this embodiment, the specified valve opening does not change over time, and thinning of the valve inner wall is predicted under conditions where the valve opening is maintained. Because the location where thinning occurs varies depending on the valve opening, a representative valve opening is specified at the start of prediction, and thinning of the valve inner wall is predicted for each valve opening under conditions where the valve opening is maintained. This makes it possible to comprehensively identify locations where thinning is likely to occur, and to predict thinning of the valve inner wall safely.

As described above, in this embodiment, the flow path area inside the valve is divided into multiple small areas using at least one measurement value, and thinning of the valve's inner wall can be predicted for each small area, taking into account the local flow inside the valve.

Second Embodiment
The second embodiment is an embodiment of a wall-thinning prediction system capable of detecting a valve opening degree.

Figure 11 is a configuration diagram showing the wall-thinning prediction system according to this embodiment.

This embodiment differs from the first embodiment in that, as shown in this figure, a valve opening storage unit 201 is added to the wall-thinning prediction system 200, an inlet/outlet flow condition estimation unit 203 is provided instead of the inlet/outlet flow condition estimation unit 103, and a display unit 208 is provided instead of the display unit 108.

The valve opening storage unit 201 stores the valve opening obtained by a sensor installed in the valve body. This sensor (valve opening sensor) may be a potentiometer, positioner, pneumatic sensor, etc.

The inlet/outlet flow condition estimation unit 203 receives as input the valve opening stored in the valve opening storage unit 201, the measurement data stored in the measurement value storage unit 101, and the valve flow calculation formula stored in the flow characteristics storage unit 102, and estimates and outputs the valve inlet/outlet flow conditions for the valve opening stored in the valve opening storage unit 201.

The display unit 208 receives the cumulative wall-thinning amount distribution stored in the wall-thinning amount storage unit 107 as input and outputs the cumulative wall-thinning amount distribution for each small region of the valve inner wall.

Figure 12 shows an example of an image on the display device.

In this figure, a numerical image 114 and a shape image 115 are displayed on the display device 120. The numerical image 114 is the cumulative amount of thinning collected for each small area of the valve's inner wall. The shape image 115 is the shape of the flow path area or inner wall of the valve 1.

The above are the differences between this embodiment and the first embodiment; other points are the same as those of the first embodiment.

Next, we will explain in detail the process used by the wall-thickness reduction prediction system 200 to predict valve wall-thickness reduction.

Figure 13 is a flow diagram showing the metal-thickness reduction prediction method (valve metal-thickness reduction prediction method) according to this embodiment.

This embodiment differs from the first embodiment in that it includes processing steps of step S251 instead of step S151, step S253 instead of step S153, and step S258 instead of step S158. Step S157 is unnecessary and is therefore not included in the processing steps.

In step S251 (valve opening degree acquisition process), the valve opening degree storage unit 201 stores the valve opening degree acquired by a sensor installed in the valve body.

In step S253 (inlet/outlet flow condition estimation process), the inlet/outlet flow condition estimation unit 203 receives as input the valve opening stored in the valve opening storage unit 201, the measurement data stored in the measurement value storage unit 101, and the valve flow calculation formula stored in the flow characteristics storage unit 102, estimates the valve inlet/outlet flow conditions 110 for the valve opening, and stores them in the inlet/outlet flow condition storage unit 104.

In step S258 (display process), the display unit 208 receives the cumulative wall-thinning amount distribution 113 stored in the wall-thinning amount storage unit 107 as input and displays the cumulative wall-thinning amount distribution for each small region of the valve inner wall on the display device 120.

In this embodiment, the flow conditions at the valve inlet and outlet are estimated using the valve opening obtained by a sensor installed in the valve body and at least one measurement value. That is, in addition to the effects obtained in the first embodiment, this embodiment predicts thinning of the valve inner wall by taking into account the influence of the valve opening, making it possible to predict thinning of the valve inner wall with even greater accuracy.

In both the first and second embodiments, the valve may be manually operated or automatically operated.

Furthermore, the content described above as being displayed on the display device does not necessarily have to be actually displayed. For example, instead of displaying it, an audio warning of wall thinning may be issued, or the user may be notified by visual or audio warning only when a valve or other part needs to be replaced or repaired.

100, 200: Metal thinning prediction system, 101: Measurement value storage unit, 102: Flow characteristics storage unit, 103, 203: Inlet/outlet flow condition estimation unit, 104: Inlet/outlet flow condition storage unit, 105: Metal thinning rate database storage unit, 106: Metal thinning amount evaluation unit, 107: Metal thinning amount storage unit, 108, 208: Display unit, 110: Valve inlet/outlet flow conditions, 111: Metal thinning rate distribution, 112: Area ID/coordinate/metal thinning rate table, 113: Cumulative metal thinning amount distribution, 114: Numerical image, 115: Shape image, 120: Display device, 201: Valve opening storage unit.

Claims (10)

a measurement value storage unit that stores at least one measurement data measured by a fluid state sensor installed on at least one of the upstream side and downstream side of the valve;
a flow rate characteristics storage unit that stores a valve flow rate calculation formula for calculating the flow rate of a fluid passing through the inside of the valve;
an inlet/outlet flow condition estimation unit that receives the measurement data stored in the measurement value storage unit and the valve flow rate calculation formula stored in the flow characteristic storage unit as inputs and estimates and outputs valve inlet/outlet flow conditions for at least one valve opening;
an inlet/outlet flow condition storage unit for storing the valve inlet/outlet flow conditions;
a thinning rate database storage unit that stores a thinning rate distribution for each small region of the inner wall surface of the valve with respect to the valve inlet/outlet flow conditions;
a wall-thinning amount evaluation unit that receives as input the valve inlet/outlet flow conditions for the valve aperture stored in the inlet/outlet flow condition storage unit and the wall-thinning rate distribution stored in the wall-thinning rate database storage unit, calculates and outputs a cumulative wall-thinning amount distribution for each small region for the valve aperture;
a thinning amount storage unit that stores the cumulative thinning amount distribution for each small region with respect to the valve opening degree,
The valve flow rate calculation formula is defined by the following formulas (1) and (2):
(In the formula, G represents the flow rate of the fluid passing through the valve, P1 represents _the fluid pressure at the valve inlet, P2 _represents the fluid pressure at the valve outlet, VA _represents the valve opening, Cv _represents the flow coefficient, and α represents the critical pressure ratio. Also, Cv ₍ VA ₎ indicates that the flow coefficient Cv can be determined using the valve opening VA as a _variable . ₎
A valve wall thinning prediction system that predicts wall thinning of the valve. The valve wall-thinning prediction system of claim 1 further comprises a display unit that displays the cumulative wall-thinning amount distribution for each small region relative to the valve opening. further comprising an input unit for inputting the valve opening degree;
The valve wall thinning prediction system according to claim 1 , wherein the inlet/outlet flow condition estimation unit estimates the valve inlet/outlet flow conditions using the input valve opening. a valve opening storage unit that stores the valve opening acquired by a valve opening sensor installed in the valve;
The valve wall-thickness thinning prediction system according to claim 1 , wherein the inlet/outlet flow condition estimation unit estimates the valve inlet/outlet flow conditions using the acquired valve opening. The valve wall thinning prediction system of claim 1, wherein the fluid state sensor measures the temperature or pressure of the fluid. storing at least one measurement data measured by a fluid state sensor installed on at least one of the upstream side and downstream side of the valve in a measurement value storage unit;
a valve flow rate calculation formula for calculating the flow rate of a fluid passing through the inside of the valve is stored in a flow rate characteristics storage unit;
an inlet/outlet flow condition estimation unit estimates valve inlet/outlet flow conditions for at least one valve opening using the measurement data stored in the measurement value storage unit and the valve flow rate calculation formula stored in the flow characteristics storage unit as inputs ;
storing the valve inlet/outlet flow conditions in an inlet/outlet flow condition storage unit;
storing a wall thinning rate distribution for each small region of the inner wall surface of the valve corresponding to the valve inlet/outlet flow conditions in a wall thinning rate database storage unit;
a metal-thinning amount evaluation unit receives as input the valve inlet/outlet flow conditions for the valve opening stored in the inlet/outlet flow condition storage unit and the metal-thinning rate distribution stored in the metal-thinning rate database storage unit, calculates a cumulative metal-thinning amount distribution for each small region for the valve opening, and predicts metal-thinning of the valve,
The valve wall thinning prediction method , wherein the valve flow rate calculation formula is defined by the following formulas (1) and (2) :
(In the formula, G represents the flow rate of the fluid passing through the valve, P1 represents _the fluid pressure at the valve inlet, P2 _represents the fluid pressure at the valve outlet, VA _represents the valve opening, Cv _represents the flow coefficient, and α represents the critical pressure ratio. Also, Cv ₍ VA ₎ indicates that the flow coefficient Cv can be determined using the valve opening VA as a _variable . ₎ The valve wall-thinning prediction method according to claim 6, wherein the cumulative wall-thinning amount distribution for each small region relative to the calculated valve opening is displayed on a display unit. The valve wall thinning prediction method according to claim 6, wherein the inlet and outlet flow conditions are estimated using the valve opening input from an input unit. The valve wall thinning prediction method according to claim 6, wherein the inlet and outlet flow conditions are estimated using the valve opening acquired by a valve opening sensor installed in the valve. The valve wall thinning prediction method according to claim 6, wherein the measurement data is the temperature or pressure of the fluid.