A test device for regulating valve flow characteristics

Abstract

The present invention relates to a testing device for regulating valve flow characteristics, comprising: an actuator, a connecting rod, a valve core seat, a valve core, a valve cover, an upper valve body, a lower valve body, a valve seat, and a water outlet pipe; the actuator rod of the actuator is connected to one end of the connecting rod, the other end of the connecting rod is connected to one end of the valve core seat, the valve core is sleeved on the other end of the valve core seat, and the outer wall profile of the valve core is wide at the top and narrow at the bottom; one end of the valve cover is connected to the housing of the actuator, and the other end is detachably connected to the top end of the upper valve body, the lower end of the upper valve body abuts against the upper end of the lower valve body, and the lower end of the lower valve body Abutting against the upper end of the valve seat; the connecting rod, valve core seat and valve core are arranged in the chamber formed by the valve cover, upper valve body, lower valve body and valve seat, and the inner diameter of the valve seat is equal to the outer diameter of the upper part of the valve core; the valve seat is the inlet; the outlet pipe is detachably connected to the side wall of the lower valve body, and the outlet pipe is connected to the chamber through the first through hole on the side wall of the lower valve body; when working, the height of the valve core is adjusted by the actuator to change the gap between the valve core and the valve seat; by replacing the upper valve body, lower valve body, valve seat and valve core, it can adapt to the flow characteristic test of valves of different specifications. This device has a short production cycle and flexible assembly, which can greatly reduce the test cost.

Description

Technical Field

[0001] The invention relates to the technical field of flow testing, and in particular to a testing device for flow characteristics of a regulating valve. Background Art

[0002] Pneumatic low temperature (normal temperature) control valve is the most commonly used equipment in large cryogenic equipment, and its flow characteristics are directly related to the stability and accuracy of the control process. In actual engineering applications, the requirements for flow control of control valves are getting higher and higher. Flow characteristics are very important performance parameters of control valves, and flow characteristic testing is also an important item in the type test of control valves. Therefore, it is necessary to carry out flow control characteristic testing on the manufactured control valve samples on the flow test platform.

[0003] At present, the relevant technology mainly uses real valve samples for flow characteristic testing. On the one hand, the valve sample preparation cycle is long, and valve samples of different specifications need to be made separately, and the utilization rate of valve samples is extremely low; on the other hand, because the valve flow characteristic test uses water as the medium, after the valve sample test is completed, even after cleaning and drying, it can no longer be used in liquid helium, liquid nitrogen and other media scenarios, resulting in valve waste. Therefore, the existing testing device is time-consuming, labor-intensive, and costly. Based on this, there is an urgent need for a test device and test method for the flow characteristics of regulating valves with a short production cycle, flexible assembly, and suitable for multiple specifications and calibers to solve the above problems. Summary of the invention

[0004] The embodiment of the present invention provides a testing device for regulating valve flow characteristics, which has a short production cycle, flexible assembly, and is reusable, and can significantly reduce testing costs.

[0005] An embodiment of the present invention provides a testing device for regulating valve flow characteristics, comprising: an actuator, a connecting rod, a valve core seat, a valve core, a valve cover, an upper valve body, a lower valve body, a valve seat, and a water outlet pipe;

[0006] The actuator rod of the actuator is connected to one end of the connecting rod, the other end of the connecting rod is connected to one end of the valve core seat, the valve core is sleeved on the other end of the valve core seat, and the outer wall profile of the valve core is an arc line that is wide at the top and narrow at the bottom;

[0007] One end of the valve cover is connected to the housing of the actuator, and the other end is detachably connected to the top end of the upper valve body, the lower end of the upper valve body abuts against the upper end of the lower valve body, and the lower end of the lower valve body abuts against the upper end of the valve seat; the connecting rod, the valve core seat and the valve core are sequentially arranged in a chamber formed by the valve cover, the upper valve body, the lower valve body and the valve seat, the inner diameter of the valve seat is equal to the outer diameter of the upper part of the valve core; the valve seat is an inlet; the water outlet pipe is detachably connected to the side wall of the lower valve body, and the water outlet pipe is communicated with the chamber through a first through hole on the side wall of the lower valve body;

[0008] During operation, the heights of the connecting rod, the valve core seat and the valve core are adjusted through the actuator to change the gap between the valve core and the valve seat; and the flow characteristic tests of regulating valves of different specifications are adapted by replacing the sizes of the upper valve body, the lower valve body, the valve seat and the valve core.

[0009] An embodiment of the present invention provides a testing device for the flow characteristics of a regulating valve. First, the height of the valve core can be changed by driving the connecting rod, the valve core seat and the valve core to move up and down axially through the actuator. By changing the height of the valve core, the gap between the valve core and the valve seat can be changed, thereby changing the opening of the regulating valve. By changing the opening of the regulating valve, flow characteristic tests at different openings can be completed. Secondly, since the valve cover is detachably connected to the upper valve body, when regulating valves of different sizes need to be tested, it is only necessary to select the corresponding sizes of the upper valve body, lower valve body, valve seat and valve core according to the size of the regulating valve and reinstall them. In this way, the production cycle is short, the assembly is flexible, and it can be reused, which can greatly reduce the testing cost. It can be seen that the present application has a simple structure and strong versatility, and can be applied to flow characteristic tests of valves of various sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0011] Figure 1 A schematic diagram of the structure of a testing device provided by an embodiment of the present invention at a certain angle;

[0012] Figure 2 A schematic diagram of the structure of a testing device provided by an embodiment of the present invention from another angle;

[0013] Figure 3 is a schematic diagram of different grid shapes provided by an embodiment of the present invention;

[0014] Figure 4 is a schematic diagram of a local structure of a sub-region provided by an embodiment of the present invention;

[0015] Figure 5 is a schematic diagram of a grid before optimization provided by an embodiment of the present invention;

[0016] Figure 6 is a schematic diagram of an optimized grid provided by an embodiment of the present invention;

[0017] Figure 7 is a velocity cloud map before optimization provided by an embodiment of the present invention;

[0018] Figure 8 is an optimized velocity cloud map provided by an embodiment of the present invention;

[0019] Fig. 9 is a residual curve diagram provided by an embodiment of the present invention;

[0020] Fig.10 is an outlet mass flow curve diagram provided by an embodiment of the present invention;

[0021] Fig.11 is an inlet and outlet mass flow curve diagram provided by an embodiment of the present invention;

[0022] Fig.12 is an outlet volume flow curve diagram provided by an embodiment of the present invention;

[0023] Fig.13 is a velocity field distribution cloud map provided by an embodiment of the present invention;

[0024] Fig.14 is a flow chart provided by an embodiment of the present invention;

[0025] Fig.15 is a pressure field distribution cloud map provided by an embodiment of the present invention;

[0026] Fig.16 It is a comparison chart of calculation results of the present application method and the existing method according to an embodiment of the present invention.

[0027] Reference numerals:

[0028] 1-actuator; 2-connecting rod; 3-valve core seat; 4-valve core; 5-valve cover; 6-upper valve body; 7-lower valve body; 8-valve seat; 9-water outlet pipe; 10-laser rangefinder; 11-positioner; 12-positioning plate; 13-fixed flange; 14-pull rod; 15-first sealing ring; 16-second sealing ring; 17-sealing gasket. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a testing device for regulating valve flow characteristics, including: an actuator 1, a connecting rod 2, a valve core seat 3, a valve core 4, a valve cover 5, an upper valve body 6, a lower valve body 7, a valve seat 8, and a water outlet pipe 9;

[0031] The actuator rod of the actuator 1 is connected to one end of the connecting rod 2, the other end of the connecting rod 2 is connected to one end of the valve core seat 3, the valve core 4 is sleeved on the other end of the valve core seat 3, and the outer wall profile of the valve core 4 is an arc line that is wide at the top and narrow at the bottom;

[0032] One end of the valve cover 5 is connected to the housing of the actuator 1, and the other end is detachably connected to the top end of the upper valve body 6. The lower end of the upper valve body 6 abuts against the upper end of the lower valve body 7, and the lower end of the lower valve body 7 abuts against the upper end of the valve seat 8. The connecting rod 2, the valve core seat 3 and the valve core 4 are sequentially arranged in the chamber formed by the valve cover 5, the upper valve body 6, the lower valve body 7 and the valve seat 8. The inner diameter of the valve seat 8 is equal to the outer diameter of the upper part of the valve core 4. The valve seat 8 is the inlet. The water outlet pipe 9 is detachably connected to the side wall of the lower valve body 7, and the water outlet pipe 9 is connected to the chamber through the first through hole on the side wall of the lower valve body 7.

[0033] During operation, the heights of the connecting rod 2, the valve core seat 3 and the valve core 4 are adjusted through the actuator 1 to change the gap between the valve core 4 and the valve seat 8; the sizes of the upper valve body 6, the lower valve body 7, the valve seat 8 and the valve core 4 are replaced to adapt to the flow characteristic test of regulating valves of different specifications.

[0034] In this embodiment, first, the height of the valve core 4 can be changed by driving the connecting rod 2, the valve core seat 3 and the valve core 4 to move up and down axially through the actuator 1. By changing the height of the valve core 4, the gap between the valve core 4 and the valve seat 8 can be changed, thereby changing the opening of the regulating valve. By changing the opening of the regulating valve, flow characteristic tests at different openings can be completed. Secondly, since the valve cover 5 is detachably connected to the upper valve body 6, when it is necessary to test regulating valves of different sizes, it is only necessary to select the corresponding upper valve body 6, lower valve body 7, valve seat 8 and valve core 4 according to the size of the regulating valve and reinstall them. In this way, the production cycle is short, the assembly is flexible, and it can be reused, which can greatly reduce the testing cost. It can be seen that the present application has a simple structure and strong versatility, and can be applied to flow characteristic tests of valves of various sizes.

[0035] It should also be noted that the existing regulating valve test device uses real valve samples, which include CNC instruments, elastic connectors, etc. Since CNC instruments and elastic connectors will affect the stroke height, it is impossible to confirm whether the flow characteristics of the matching size of the valve core 4 and the valve seat 8 meet the design requirements, and it is impossible to determine the optimization direction. However, this application simplifies the CNC instruments and elastic connectors, and the valve opening is only related to the matching of the valve core 4 and the valve seat 8, which can more accurately test the influence of the valve core 4 profile on the flow characteristics.

[0036] In addition, in order to ensure the sealing performance of the valve, a first sealing ring 15 is provided on the connection surface between the valve cover 5 and the upper valve body 6. A second sealing ring 16 is provided on the connection surface between the lower valve body 7 and the valve seat 8. A sealing gasket 17 is provided on the connection surface between the valve seat 8 and the valve core seat 3.

[0037] In addition, for the convenience of control, the actuator 1 adopts a pneumatic actuator, and of course it can also be an electric actuator 1, which is not specifically limited in this application.

[0038] In some embodiments, it further includes a laser rangefinder 10, a positioner 11 and a positioning piece 12; the positioner 11 is arranged on the actuator 1, the positioning piece 12 is arranged on the connecting rod 2, and the laser rangefinder 10 is fixed at a preset position of the test bench;

[0039] The positioner 11 is used to send an adjustment instruction to the actuator 1 based on the test opening; the actuator 1 drives the connecting rod 2, the valve core seat 3, the valve core 4 and the positioning piece 12 to move based on the adjustment instruction; the laser rangefinder 10 is used to emit a laser signal to the positioning piece 12, and determine the actual distance moved by the positioning piece 12 based on the laser signal reflected by the positioning piece 12, so as to judge whether the valve reaches the test opening based on the actual distance.

[0040] In this embodiment, after the actuator 1 inputs a signal as required, it drives the connecting rod 2, the valve core seat 3, the sealing gasket 17 and the valve core 4 to rise and fall synchronously. During the lifting process, the gap area between the valve seat 8 and the valve core 4 (i.e., the flow area of ​​the fluid) increases or decreases, thereby realizing the effective flow regulation function of the valve. In addition, the positioning piece 12 receives the laser signal emitted by the laser rangefinder 10, and the actuator 1 rotates to drive the connecting rod 2 to move, and monitors the height change of the positioning piece 12 fed back by the laser rangefinder 10. Based on the height change, the height of the valve core 4 rising with the connecting rod 2 is obtained, thereby quantitatively determining the opening of each test condition.

[0041] In some embodiments, the testing device further includes a fixing flange 13 and a pull rod 14;

[0042] The lower inner wall of the upper valve body 6 is provided with a first annular groove, and the upper end of the lower valve body 7 is clamped in the first annular groove; the lower inner wall of the lower valve body 7 is provided with a second annular groove, and the upper end of the valve seat 8 is clamped in the second annular groove; the outer diameter of the upper end of the valve seat 8 is greater than the outer diameter of the lower end thereof; the center of the fixed flange 13 is provided with a second through hole matching the outer diameter of the lower end of the valve seat 8;

[0043] After the upper valve body 6 , the lower valve body 7 and the valve seat 8 are abutted in sequence, the lower end of the valve seat 8 is passed through the second through hole to bolt the fixed flange 13 and the flange of the upper valve body 6 through the pull rod 14 .

[0044] In this embodiment, in order to complete the flow characteristic test of valves of various specifications and sizes, the upper valve body 6, the lower valve body 7, and the valve seat 8 are detachably connected, and the corresponding size specifications are selected for assembly test. In addition, the connection surfaces of the upper valve body 6, the lower valve body 7, and the valve seat 8 are preferably bolted flange connections. On the one hand, it is convenient to flexibly adjust the specifications of the test valve; on the other hand, since there is no welding, the flow characteristic will not change due to welding deformation. In addition, each connection surface is sealed with a sealing ring to prevent water leakage.

[0045] The test device of the present application is simple to manufacture and has a short delivery cycle. After the test, it only needs to be disassembled and replaced with parts of the next specification, while the rest remain unchanged. There is no need for purification treatment such as drying, which greatly shortens the replacement time of the test object and improves the test efficiency.

[0046] In some implementations, for each specification of the regulating valve, the profile of the valve core 4 is designed in advance. The present application designs the profile of the valve core 4 through the following steps:

[0047] Step 100, based on the application scenario of the regulating valve, determine the main parameters for calculating the valve core of the regulating valve; the main parameters include: flow characteristic type, caliber, flow pattern type, calculation boundary and boundary layer processing method;

[0048] Step 102, based on the type of flow characteristics, select a theoretical calculation mathematical model for valve core design, and calculate the theoretical profile of the valve core and the theoretical value of the flow characteristics of the regulating valve at different openings based on the mathematical model and main parameters;

[0049] Step 104, constructing a three-dimensional model of the regulating valve at different openings based on the caliber of the regulating valve and the theoretical profile of the valve core;

[0050] Step 106, for each three-dimensional model of the regulating valve at each opening, the following steps are performed: extracting a three-dimensional model of the fluid domain at the opening from the three-dimensional model of the regulating valve, and meshing the three-dimensional model of the fluid domain; performing simulation calculation on the meshed three-dimensional model of the fluid domain based on CFD simulation technology to obtain a simulation value of the flow characteristic of the regulating valve at the theoretical profile and the opening;

[0051] Step 108 , based on the difference between the theoretical value and the simulation value at each opening, the theoretical profile of the valve core 4 is corrected until a corrected valve core profile is obtained.

[0052] In this embodiment, firstly, a theoretical calculation mathematical model is determined based on the type of flow characteristic, so as to calculate the theoretical profile of the valve core 4 and the theoretical value of the flow characteristic under each opening based on the mathematical model. Then, on the basis of the valve core theoretical profile, a three-dimensional model of the regulating valve is constructed, and the three-dimensional model of the fluid domain under different openings is extracted, and then the extracted fluid domain is meshed, so as to simulate and calculate the meshed fluid domain based on the CFD simulation technology, and obtain the simulation value of the flow characteristic of the regulating valve. Since the simulation value can characterize the flow characteristic of the valve core theoretical profile in actual application, the merits of the valve core theoretical profile can be judged based on the difference between the simulation value and the theoretical value, so as to correct the theoretical profile of the valve core 4 based on the difference between the two, until the profile of the valve core 4 has a good effect in both the theoretical value and the simulation value, and the corrected valve core profile is obtained. It can be seen from this that the method of the present application does not need to make a real prototype, but only needs to obtain the valve core 4 that meets the flow characteristic requirements through multiple theoretical calculations and multiple simulations, so that the design cycle of the valve core 4 can be greatly shortened, and the designed valve core 4 has a good flow characteristic.

[0053] The specific implementation method of each step is described below.

[0054] First, with respect to step 100 , based on the application scenario of the regulating valve, main parameters for calculating the valve core of the regulating valve are determined.

[0055] In this step, the types of flow characteristics mainly include: linear flow characteristics, equal percentage flow characteristics and quick opening flow characteristics; different flow characteristics correspond to different theoretical calculation mathematical models.

[0056] For example, when the flow rate of the control valve changes slightly, that is, less than the flow threshold, select the linear flow characteristic; when the flow rate of the control valve changes significantly, that is, greater than the flow threshold, select the equal percentage flow characteristic; when the response speed of the control valve is required to be greater than the preset speed, that is, the control valve needs to meet the working condition of fast response, select the fast opening flow characteristic. Users can select the appropriate flow characteristic type according to the actual application scenario of the control valve.

[0057] In addition, the caliber of the regulating valve is determined based on the pipeline resistance of the regulating valve and the maximum flow rate that needs to be controlled. In addition, the calculation boundary includes the inlet, outlet and wall of the medium. When the regulating valve is a symmetrical structure, the symmetry surface is also included.

[0058] It should also be noted that the flow states include laminar flow and turbulent flow. Due to the throttling characteristics of the regulating valve, the turbulent flow state is selected here. The boundary layer processing method corresponds to the turbulent flow state and will not be repeated here.

[0059] For step 102, this step uses an equal percentage flow characteristic and a theoretical calculation mathematical model corresponding to the equal percentage flow characteristic, such as a curve envelope calculation method, to derive a mathematical model of the valve core profile curve. This mathematical model is a commonly used model in this field and will not be described in detail here. The valve core theoretical profile calculated by the mathematical model serves as the basis for subsequent simulation calculations, and the calculated theoretical value of the flow characteristic serves as a comparison of the simulation calculation results.

[0060] In addition, the number of openings can be determined according to user needs, such as 3%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% and other 12 kinds of openings. It can be understood that the more the number of openings, the more accurate the calculation results, but the amount of calculation also increases significantly.

[0061] With respect to step 104 , a three-dimensional model of the regulating valve at different openings is constructed based on the caliber of the regulating valve and the theoretical profile of the valve core 4 .

[0062] In this step, the three-dimensional model of the regulating valve is composed of a valve core model and a valve body model. Therefore, after the theoretical profile of the valve core 4 is designed, the three-dimensional model of the valve core 4 can be generated and assembled into the designed three-dimensional model of the valve body to form a complete three-dimensional model of the regulating valve. After the three-dimensional model of the regulating valve is built, the three-dimensional model of the regulating valve is adjusted to the required opening by adjusting the opening height of the valve core 4.

[0063] With respect to step 106 , the concept of a fluid domain is first introduced: the fluid domain is the area through which the medium flows inside the valve when the valve core is opened.

[0064] In some embodiments, the fluid domain range at each opening is determined by:

[0065] The fluid domain has clear boundaries, and each boundary has physical parameters that meet the requirements; the physical parameters include mass flow, pressure and velocity;

[0066] There is no backflow at the flow field outlet of the fluid domain and the fluid domain meets the boundary stability requirements.

[0067] In this step, the fluid domain has a clear starting position and end position, and when determining the scope of the fluid domain, it is necessary to analyze whether there is reasonable boundary condition information on the boundary, whether the boundary condition can match the physical problem to be analyzed, and determine the boundary of the calculation domain at a location with reasonable data. Secondly, analyze whether the problem can be simplified into a two-dimensional problem or an axisymmetric problem. In order to ensure that the fluid mechanics calculation and analysis results of the medium in the regulating valve are correct and have reference value, the fluid boundary stability requirements must also be met when determining the calculation range of the fluid domain. The flow of fluid in a pipeline is generally referred to as pipeline flow. The flow field gradually transitions from the initial stage of the inlet to a relatively stable fully developed stage as the flow state changes. Therefore, the intercepted fluid domain needs to ensure that the medium is in the fully developed stage, that is, the fluid domain includes not only the internal cavity of the valve, but also the water inlet and outlet pipes of the valve. For example, the length of the water inlet pipe is 10 times the length of the valve pipe diameter, and the length of the water outlet pipe is 5 times the length of the pipe diameter. After obtaining the flow field calculation results, observe whether there is backflow at the flow field outlet. It is reasonable if there is no backflow, and the flow field is complete. If there is backflow, adjust the inlet and outlet pipe lengths step by step to the appropriate length.

[0068] In some embodiments, meshing the fluid domain three-dimensional model includes:

[0069] Step A1, based on the flow direction and flow characteristics of the medium in the fluid domain, the fluid domain is divided into a plurality of continuous sub-regions; the sub-regions at least include an inlet pipe region, an outlet pipe region, and an inlet and outlet pipe intersection region;

[0070] Step A2, for each sub-region, determining the grid size and grid shape based on the severity of the change of the flow field parameters in the sub-region and its geometric shape;

[0071] Step A3, meshing the sub-area based on the mesh size and mesh shape.

[0072] In this step, the process of discretizing the fluid domain requires specific analysis of specific locations. For example, locations where geometric parameters or physical parameters change sharply need to be encrypted, while locations where physical parameters or geometric parameters are relatively flat can use a slightly sparse grid.

[0073] Based on the above principles, this application first divides the fluid domain into multiple sub-areas, and adopts different grid shapes and grid numbers based on the geometric dimensions and medium flow characteristics of each sub-area, so as to maximize the reasonable allocation of computing resources, obtain reasonable calculation results, and promote the rapid development of control valve flow characteristics.

[0074] The implementation process of step A2 is described in detail below.

[0075] In some embodiments, for each sub-region, the grid size and grid shape are determined based on the severity of the change in flow field parameters in the sub-region and its geometric shape, including:

[0076] B1, based on the severity of the change in flow field parameters in each sub-area, the size of the grid is reduced in order from small to large;

[0077] B2, for the sub-regions where the drastic degree of flow field parameter change exceeds the first preset value, and the sub-regions where the grid lines are consistent with the medium flow direction, a quadrilateral grid or a hexahedral grid is used;

[0078] B3, for the grids where the drastic degree of flow field parameter change is less than the second preset value, and the sub-regions where the grid lines are inconsistent with the medium flow direction, a tetrahedral grid is used; the second preset value is less than the first preset value;

[0079] B4, hexahedral mesh is used for the inlet and outlet pipe areas;

[0080] B5, tetrahedral mesh is used for the intersection area of ​​inlet and outlet pipes;

[0081] B6, a pyramidal pentahedral mesh is used for the sub-region where the mesh transitions from hexahedral to tetrahedral.

[0082] In this step, the grid generation technology is a very critical step. The quality of the grid has a direct impact on the calculation accuracy and efficiency. For the calculation of complex problems, grid division is extremely time-consuming and error-prone, and may even take up 80% of the total time of the entire calculation process. Therefore, it is necessary to reasonably design and generate the grid to ensure the calculation accuracy requirements while using the computing power in the key positions.

[0083] Based on the above reasons, step B1 can save computing power by using the densest grid for the sub-region where the flow field parameters change more dramatically, and the sparsest grid for the sub-region where the flow field parameters change most slowly.

[0084] In addition, different mesh shapes also directly affect the calculation results. Figure 3 The commonly used grid shapes are shown in FIG. 1 , and different grid shapes have different effects on computing power. This embodiment can effectively reduce the dissipation in the computing process and improve the adaptability of the model to complex geometry through the grid division form of steps B2 to B6.

[0085] In addition, for areas where the difference in geometric dimensions between two continuous sub-areas exceeds a preset order of magnitude, discontinuous grids can also be used. Each sub-area generates a grid according to its own scale, and then the two areas are connected with a discontinuous grid interface. The physical quantities will be interpolated on this interface during calculation. Figure 4As shown in the figure, it is a certain opening condition of a certain specification of control valve, and the throttling surface width d 1 It is only at the 10e-2mm level, and its downstream d 2 The size is 10e2mm level, from d 1 to d 2 , in the area with a height h of about 1mm, the geometric size differs by 4 orders of magnitude. For such problems with large local size spans, discontinuous grids can be used, starting from the local area, and increasing the size of the grid according to the appropriate gradient outward. The grid should be changed from dense to sparse as slowly as possible to ensure that the flow field details can be fully and correctly captured, such as the pressure gradient, velocity gradient, and the integrity of the velocity direction change trend, etc. Otherwise, the calculation is very likely to diverge.

[0086] It should also be noted that for the mesh of the boundary layer, due to the reduction in velocity caused by the throttling surface, the Reynolds number Re of the medium flow state will usually decrease sharply here, closer to the laminar state, and the wall effect caused by the fluid viscosity will also be amplified accordingly. Therefore, in the direction away from the wall, the density of the mesh is reduced in sequence, and the meshes before and after optimization are as follows: Figure 5 and Figure 6 As shown in the figure, the speed cloud diagrams before and after optimization are as follows: Figure 7 and Figure 8 As shown in the figure, it can be seen that the flow field velocity obtained by using the grid division method of the present application is more accurate.

[0087] In addition, in step 106, the three-dimensional model of the fluid domain after meshing is simulated and calculated based on the CFD simulation technology to obtain the simulation value of the flow characteristic of the regulating valve under the theoretical profile and the opening, including:

[0088] S1, determine the input parameters of CFD simulation calculation; the input parameters include the time state of the three-dimensional model of the fluid domain, the type of flow state, the fluid medium parameters, the physical parameters of the flow field that need to be calculated and monitored, the inlet boundary conditions and the outlet boundary conditions;

[0089] S2, determining the initial value of the current physical parameter of the current calculation round;

[0090] S3, based on the input parameters and the initial value of the current physical parameter, iteratively calculate each grid in the three-dimensional model of the fluid domain according to the NS equation along the flow direction of the medium until the last grid is traversed to obtain the new physical parameter value of the current calculation round;

[0091] S4, calculating the first absolute residual between the new physical parameter value and the current initial value of the physical parameter;

[0092] S5, determining whether the first absolute residual is not greater than the first residual threshold; if so, executing S6; if not, taking the sum of the new physical parameter value and the set step length as the initial value of the next calculation round, and returning to execute S3 to S5, until the calculated first absolute residual is not greater than the first residual threshold, and executing S6;

[0093] S6, using the new physical parameter value as a simulation value of the flow characteristic of the regulating valve under the theoretical profile and the opening.

[0094] In this embodiment, by analyzing the dimensionless parameter Re of the fluid medium flow in the regulating valve, it is determined whether the working condition that needs CFD calculation is turbulent or laminar, and the corresponding flow state calculation model, wall function model, etc. are input. The physical property parameters of the fluid medium include density, viscosity, temperature, etc. The boundary conditions determine whether the calculation results are reasonable and correct, and analyze the physical problems of the working condition. The inlet boundary conditions include: at least one of the inlet pressure, inlet velocity and inlet mass flow rate; the outlet boundary conditions include: at least one of the outlet pressure, outlet velocity, outlet mass flow rate and free outlet. The wall conditions include moving without slip and slip. When uncertain, the calculation results of several groups of schemes can be compared to determine the most reasonable scheme.

[0095] In addition, for each opening, steps S1 to S6 can be used until the calculation converges to obtain the simulation result of the flow characteristics under the opening. The calculation formula of the first absolute residual is |Q 1 -Q 0 |, where Q 0 is the initial value of the physical parameters at the beginning of this round of calculation, Q 1 is the new physical parameter value obtained in this round of calculation. When the absolute residual is less than the set first residual threshold, it means that the calculation has converged. The first residual threshold can be 1e-3. Of course, the relative residual can also be used as a criterion for convergence. The calculation formula of the relative residual is: |Q 1 -Q 0 | / Q 1 In addition, even if the residual does not reach the set value, as long as the physical quantity of interest (such as temperature, mass flow, speed, etc.) is stable, it can be considered converged, such as Figure 9-12 As shown, the obtained residual curve, outlet mass flow curve, inlet and outlet mass flow curves and outlet volume flow curve can be used as the judgment criteria for convergence.

[0096] It should also be noted that the simulation results output by CFD calculation mainly include the following:

[0097] 1. Speed ​​related: velocity field distribution cloud map, velocity size cloud map, vector streamline map, streamline map, contour map, etc.;

[0098] 2. Pressure related: pressure field distribution cloud map, pressure distribution contour map, etc.;

[0099] 3. Flow related: average import mass flow, average export mass flow, etc.

[0100] The schematic diagrams of velocity field distribution cloud map, streamline map and pressure field distribution cloud map are as follows: Figure 13-15 shown.

[0101] Finally, for step 108, by sorting and analyzing the simulation results at each opening, data can generally be extracted through color cloud maps, contour maps, streamline maps and numerical reports of specific physical quantities, such as inlet and outlet mass flow rates, average velocity, inlet and outlet pressures, etc. The extracted data can show whether the global flow state is reasonable, whether there is separation in certain areas, and whether the key flow characteristics are accurately calculated. When performing specific analysis, it is necessary to be based on the basic knowledge of fluid mechanics, and specific physical quantities also require quantitative analysis. The calculation model of the present invention can extract parameters such as outlet mass flow rate and inlet and outlet average pressure, summarize and draw the flow characteristic curve of the regulating valve, and compare it with the theoretical value. When the second absolute residual at all openings is less than the second residual threshold (such as ±5%), the corrected theoretical valve core profile can be used as the corrected valve core profile.

[0102] It should be noted that after a certain simulation calculation, if the simulation results at an opening of 40% to 100% meet the deviation requirements from the theoretical simulation results. Then the valve core profile can be corrected based on the simulation results of a small opening of 30%, and the theoretical calculation and simulation calculation of the 0-30% opening are re-performed for the corrected valve core until each opening meets the requirements. This is because the valve core profile has little effect on the total throttling surface of the fluid domain. After adjusting the valve core profile, the effect on the flow characteristics at a large opening is small, so it can be ignored. This optimization method can greatly improve the correction speed while ensuring the calculation accuracy. Of course, the user can also recalculate all openings, and this application does not make specific restrictions.

[0103] In order to verify the effect of the method of the present application, the inventors compared the deviations of the calculation results of the method of the present application and the calculation results of the existing method with the theoretical results at various openings of the regulating valve (0-100%). Fig.16 As shown in the figure, it can be seen that the deviation between the calculation results of the existing method and the theoretical results is 5% to 28%, while the deviation between the calculation results of the method of the present application and the theoretical results is ±5%.

[0104] After the valve core profile is obtained through the above theoretical calculation and CFD simulation calculation, it can be installed in the above test device for flow characteristic test. If the test results do not meet the requirements, the theoretical calculation and CFD calculation are re-performed by the method of this application to obtain a new valve core profile until the test results meet the requirements and the final valve core profile is obtained. In this way, a valve core profile with more accurate control accuracy can be obtained, the design goal of the flow characteristic of the regulating valve can be achieved, the qualified rate of prototype verification can be improved, and the development cost can be reduced.

[0105] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the statement "comprise one..." do not exclude the existence of other identical factors in the process, method, article or equipment including the elements.

[0106] Finally, it should be noted that the above is only a preferred embodiment of the present invention, which is only used to illustrate the technical solution of the present invention, and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A test device for regulating valve flow characteristics, characterized in that: include: Actuator (1), connecting rod (2), valve core seat (3), valve core (4), valve cover (5), upper valve body (6), lower valve body (7), valve seat (8), and water outlet pipe (9); The actuator rod of the actuator (1) is connected to one end of the connecting rod (2), the other end of the connecting rod (2) is connected to one end of the valve core seat (3), the valve core (4) is sleeved on the other end of the valve core seat (3), and the outer wall profile of the valve core (4) is an arc line that is wide at the top and narrow at the bottom; One end of the valve cover (5) is connected to the housing of the actuator (1), and the other end is detachably connected to the top end of the upper valve body (6); the lower end of the upper valve body (6) abuts against the upper end of the lower valve body (7), and the lower end of the lower valve body (7) abuts against the upper end of the valve seat (8); the connecting rod (2), the valve core seat (3) and the valve core (4) are sequentially arranged in a chamber formed by the valve cover (5), the upper valve body (6), the lower valve body (7) and the valve seat (8); the inner diameter of the valve seat (8) is equal to the outer diameter of the upper part of the valve core (4); the valve seat (8) is an inlet; the water outlet pipe (9) is detachably connected to the side wall of the lower valve body (7), and the water outlet pipe (9) is connected to the chamber through a first through hole on the side wall of the lower valve body (7); When in operation, the heights of the connecting rod (2), the valve core seat (3) and the valve core (4) are adjusted through the actuator (1) to change the gap between the valve core (4) and the valve seat (8); and the sizes of the upper valve body (6), the lower valve body (7), the valve seat (8) and the valve core (4) are replaced to adapt to flow characteristic tests of regulating valves of different specifications.

2. The device according to claim 1, characterized in that It also comprises a laser rangefinder (10), a positioner (11) and a positioning plate (12); the positioner (11) is arranged on the actuator (1), the positioning plate (12) is arranged on the connecting rod (2), and the laser rangefinder (10) is fixed at a preset position of the test bench; The positioner (11) is used to send an adjustment instruction to the actuator (1) based on the test opening; the actuator (1) drives the connecting rod (2), the valve core seat (3), the valve core (4) and the positioning plate (12) to move based on the adjustment instruction; the laser rangefinder (10) is used to emit a laser signal to the positioning plate (12), and determine the actual distance moved by the positioning plate (12) based on the laser signal reflected by the positioning plate (12), so as to judge whether the valve has reached the test opening based on the actual distance.

3. The device according to claim 1, characterized in that It also includes a fixing flange (13) and a pull rod (14); The lower inner wall of the upper valve body (6) is provided with a first annular groove, and the upper end of the lower valve body (7) is clamped in the first annular groove; the lower inner wall of the lower valve body (7) is provided with a second annular groove, and the upper end of the valve seat (8) is clamped in the second annular groove; the outer diameter of the upper end of the valve seat (8) is greater than the outer diameter of the lower end; the center of the fixed flange (13) is provided with a second through hole matching the outer diameter of the lower end of the valve seat (8); After the upper valve body (6), the lower valve body (7) and the valve seat (8) are abutted in sequence, the lower end of the valve seat (8) is passed through the second through hole to bolt the fixed flange (13) and the flange of the upper valve body (6) through the pull rod (14).

4. The device according to claim 1, characterized in that A first sealing ring (15) is provided on the connection surface between the valve cover (5) and the upper valve body (6).

5. The device according to claim 1, characterized in that A second sealing ring (16) is provided on the connection surface between the lower valve body (7) and the valve seat (8).

6. The device according to claim 1, characterized in that A sealing gasket (17) is provided on the connection surface between the valve seat (8) and the valve core seat (3).

7. The device according to claim 1, characterized in that The actuator (1) is a pneumatic actuator.

8. The device according to claim 1, characterized in that The profile of the valve core (4) is determined by the following method: Based on the application scenario of the regulating valve, determine the main parameters for calculating the regulating valve core; the main parameters include: flow characteristic type, caliber, flow pattern type, calculation boundary and boundary layer processing method; Based on the type of flow characteristics, a theoretical calculation mathematical model for valve core design is selected, and based on the mathematical model and the main parameters, a theoretical profile of the valve core (4) and theoretical values ​​of the flow characteristics of the regulating valve at different openings are calculated; Based on the caliber of the regulating valve and the theoretical profile of the valve core (4), constructing a three-dimensional model of the regulating valve at different openings; For each three-dimensional model of the regulating valve at each opening, the following steps are performed: extracting a three-dimensional model of the fluid domain at the opening from the three-dimensional model of the regulating valve, and meshing the three-dimensional model of the fluid domain; performing simulation calculation on the meshed three-dimensional model of the fluid domain based on CFD simulation technology to obtain a simulation value of the flow characteristic of the regulating valve at the theoretical profile and the opening; Based on the difference between the theoretical value and the simulation value at each opening, the theoretical profile of the valve core (4) is corrected until a corrected valve core profile is obtained.

9. The device according to claim 8, characterized in that Meshing of the 3D model of the fluid domain, including: Based on the flow direction and flow characteristics of the medium in the fluid domain, the fluid domain is divided into a plurality of continuous sub-regions; the sub-regions at least include an inlet pipe region, an outlet pipe region, and an inlet and outlet pipe intersection region; For each of the sub-regions, the grid size and grid shape are determined based on the severity of the change in the flow field parameters in the sub-region and its geometric shape; The sub-region is meshed based on the mesh size and the mesh shape.

10. The device according to claim 9, characterized in that For each of the sub-regions, the grid size and grid shape are determined based on the severity of the change in the flow field parameters in the sub-region and its geometric shape, including: Based on the severity of the change in flow field parameters in each sub-area, the size of the grid is reduced in order from small to large; For the sub-regions where the drastic degree of change of the flow field parameters exceeds the first preset value, and the sub-regions where the grid lines are consistent with the medium flow direction, a quadrilateral grid or a hexahedral grid is used; For the grids whose flow field parameter variation is less than the second preset value and the sub-regions whose grid lines are inconsistent with the medium flow direction, a tetrahedral grid is used; the second preset value is less than the first preset value; For the water inlet pipe area and the water outlet pipe area, a hexahedral grid is used; For the intersection area of ​​the inlet and outlet pipes, a tetrahedral grid is used; For the sub-region where the mesh transitions from hexahedral to tetrahedral, a pyramid-shaped pentahedral mesh is used.

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