CN113591414B - Rectifying effect judging method suitable for flow valve - Google Patents

Abstract

The invention discloses a rectifying effect judging method suitable for a flow valve, which comprises the following steps: establishing a flow channel model; three-dimensional modeling is carried out on a valve and a rectifier under actual working conditions by utilizing Solidworks software, a rectifier model is assembled at an outlet of the valve, a model fluid domain is extracted, a flow channel model is obtained, and the flow channel model is characterized in that: the upstream of the flow channel model valve is five-pipe diameter, and the downstream of the rectifier is twelve-pipe diameter. The beneficial effects are that: the rectifying condition after the valve is reflected by a numerical simulation method, the speed eccentricity of the downstream cross section of the rectifier is utilized to judge whether the rectifying effect of the rectifier with different structures is good or not, and complex experiments are not needed to judge, so that manpower and material resources can be greatly reduced, and the method has practical significance in engineering.

Description

A method for determining the rectification effect suitable for process valves

Technical field

The present invention relates to the technical field of rectification effect determination, and specifically, to a rectification effect determination method suitable for process valves.

Background technique

Process valves play an increasingly important role in the fluid transmission process and are widely used in petrochemical, water conservancy and hydropower industries. It has functions such as adjustment, diversion, opening and closing under different working conditions. However, complex and unstable flows such as rapid flow changes and vortices caused by high shear flow inside the process valve will develop along the downstream pipeline, affecting the operational reliability of the process valve and the accurate measurement of pipeline fluids.

In engineering projects, rectifiers are often installed in front of pipeline fluid metering equipment to obtain a more stable metering signal. The rectifier is a device that accelerates the development of irregular fluids and mitigates the impact of flow field distortion on the flow meter. It can collect stable flow measurement signals in a small space and greatly improve the accuracy of flow measurement results. Installing a rectifier is an important way to optimize the current flow field and improve the performance of the flow meter.

However, in actual engineering, the rectification effect of the rectifier is usually judged based on the results obtained from experimental measurements, which consumes a lot of manpower and material resources, and the experimental results obtained still have errors and are not necessarily accurate.

No effective solutions have yet been proposed for the problems in related technologies.

Contents of the invention

In view of the problems in the related technology, the present invention proposes a rectification effect determination method suitable for process valves to overcome the above technical problems existing in the existing related technology.

To this end, the specific technical solutions adopted by the present invention are as follows:

A method for determining the rectification effect suitable for process valves, including the following steps:

S101. Establish a flow channel model; use Solidworks software to conduct three-dimensional modeling of the valve and rectifier under actual working conditions, assemble the rectifier model at the valve outlet, extract the model fluid domain, and obtain the flow channel model. The characteristics of the flow channel model are: : The upstream of the flow channel model valve is five times the pipe diameter, and the downstream of the rectifier is twelve times the pipe diameter;

S103. Mesh division; perform grid independence verification, select the number of meshes that meet the requirements, and mesh the flow channel model;

S105. Perform numerical calculations; import the flow channel grid into the ANASYS FLUENT software, set relevant parameters, and perform numerical calculations;

S107. Calculate the velocity eccentricity η of the downstream section; extract the maximum velocity on the cross-section of the pipeline downstream of the rectifier, and calculate the velocity eccentricity eta of each downstream cross-section according to the formula. The calculation formula is as follows:

Among them, Vmax represents the maximum velocity on the cross section of the downstream pipeline, in m/s; V0 represents the average velocity in the pipeline, in m/s.

S109, determine the rectification effect; based on the calculated speed eccentricity, use the Origin software to draw a curve chart of the speed eccentricity developing with the flow, and compare and analyze the rectification effects of rectifiers with different structures.

Preferably, the specific implementation of meshing includes the following steps:

S1031. In the Solidworks software, export each part of the flow channel model separately;

S1032. Use ANSYS ICEM CFD software to divide each part of the flow channel model into a structural mesh, and refine the mesh for the valve core and rectifier parts. Finally, use the Merge function of ANSYS ICEM CFD software to merge each part. The grids merge into a whole.

Preferably, the specific implementation of the grid independence verification includes the following steps:

S1033. For the flow channel model when the valve is fully open and a certain rectifier is installed, mesh it and divide it into multiple sets of flow channel mesh models with different mesh numbers;

S1034. Compare the flow coefficient and resistance coefficient under different grid numbers. When the flow coefficient and resistance coefficient remain basically unchanged as the number of grids increases, select the minimum number of grids where the flow coefficient and resistance coefficient remain basically unchanged.

Preferably, the specific implementation of setting relevant parameters in step S105 includes the following steps:

S1051. Define a solver in the General module. The solver type is a pressure-based solver, and the time type is set to the steady-state calculation method;

S1052. Select the calculation model in the Models module and select the Standard k-ε model for calculation;

S1053. Set the fluid medium in the Materials module, and select the fluid medium as water or gas according to the actual working conditions;

S1054. Set boundary conditions in the Boundary Conditions module. Select velocity-inlet for the inlet, pressure-outlet for the outlet, wall for the wall, and interface for the interface. When the actual working conditions are clear, set the boundary conditions according to the actual working conditions; when the actual working conditions When the conditions are unclear, set reasonable boundary conditions by yourself;

S1055. Define interface in the Mesh Interfaces module;

S1056. Set the convergence residual in the Residual module;

S1057. Click Hybrid Initialization in the Initialization module to initialize;

S1058. After setting the number of iteration steps in the Run Calculation module, click the Calculation module to start numerical calculations.

Preferably, the specific implementation of extracting the maximum speed on the cross-section of the pipeline downstream of the rectifier in step S107 includes the following steps:

S1071. Select Iso-Surface in the Surface module and create a cross section every 1D downstream of the rectifier, creating a total of 12 cross sections;

S1072. In the Surface Integrals module in the Reports module, select FacetMaximum for Report Type, select Velocity Magnitude for Field Variable, and select the cross section created downstream of the rectifier in step S1071 for Surfaces to get the maximum velocity on the cross section.

Preferably, the specific method for judging the rectification effect is: the smaller the velocity eccentricity of the cross-section, the more uniform the velocity distribution on the cross-section, the more stable the flow field, and the better the rectification effect of the rectifier. Drawing the curve of velocity eccentricity with flow development based on the Origin software can visually see the velocity eccentricity of the downstream cross-section of rectifiers with different structures, so as to determine the rectification effect of rectifiers with different structures.

The beneficial effects of the present invention are: through the method of numerical simulation, the rectification situation behind the valve is reflected, and the speed eccentricity of the downstream cross-section of the rectifier is used to determine the rectification effect of the rectifiers with different structures, without the need to conduct complex experiments to judge. , can greatly reduce manpower and material resources, and has practical significance in engineering.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the drawings of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a flow chart of a method for determining the rectification effect of a process valve according to an embodiment of the present invention;

Figure 2 is a two-dimensional structural diagram of the rectifier I in a method for determining the rectification effect of a process valve according to an embodiment of the present invention;

Figure 3 is a two-dimensional structural diagram of the rectifier II in a method for determining the rectification effect of a process valve according to an embodiment of the present invention;

Figure 4 is a model diagram of the ball valve and rectifier flow channel in a rectification effect determination method suitable for process valves according to an embodiment of the present invention;

Figure 5 is a grid diagram of the ball valve and rectifier flow channel model in a rectification effect determination method suitable for process valves according to an embodiment of the present invention;

Figure 6 is a grid-independent column chart of the flow coefficient and the resistance coefficient in a method for determining the rectification effect of a process valve according to an embodiment of the present invention;

Figure 7 is a graph showing the velocity eccentricity of the downstream sections of two rectifiers as the flow develops in a rectification effect determination method suitable for process valves according to an embodiment of the present invention.

Detailed ways

In order to further explain each embodiment, the present invention provides drawings. These drawings are part of the disclosure of the present invention. They are mainly used to illustrate the embodiments and can be used with the relevant descriptions in the specification to explain the operating principles of the embodiments. For reference From this, those of ordinary skill in the art will be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

According to an embodiment of the present invention, a method for determining the rectification effect suitable for process valves is provided.

Embodiment 1;

As shown in Figures 1-7, the rectification effect determination method suitable for process valves according to the embodiment of the present invention includes the following steps:

Step S101. Establish a flow channel model; use Solidworks software to conduct three-dimensional modeling of the valve and rectifier under actual working conditions, assemble the rectifier model at the valve outlet, extract the model fluid domain, and obtain the flow channel model and flow channel model characteristics. The method is: the upstream of the flow channel model valve is five times the pipe diameter, and the downstream of the rectifier is twelve times the pipe diameter;

Step S103: Mesh division; perform mesh independence verification, select the number of meshes that meet the requirements, and mesh the flow channel model;

Step S105: Perform numerical calculations; import the flow channel grid into the ANASYS FLUENT software, set relevant parameters, and perform numerical calculations;

Step S107: Calculate the velocity eccentricity η of the downstream section; extract the maximum velocity on the cross section of the pipeline downstream of the rectifier, and calculate the velocity eccentricity eta of each downstream cross section according to the formula. The calculation formula is as follows:

Among them, Vmax represents the maximum velocity on the cross section of the downstream pipeline, in m/s; V0 represents the average velocity in the pipeline, in m/s.

Step S109, determine the rectification effect; based on the calculated speed eccentricity, use the Origin software to draw a curve chart of the speed eccentricity developing with the flow, and compare and analyze the rectification effects of rectifiers with different structures.

The specific implementation of the meshing includes the following steps:

Step S1031. In the Solidworks software, export each part of the flow channel model separately;

Step S1032: Use ANSYS ICEM CFD software to divide each part of the flow channel model into a structural mesh, and perform mesh densification on the valve core and rectifier parts. Finally, use the Merge function of ANSYS ICEM CFD software to merge each part. The grids are merged into a whole.

The specific implementation of the grid independence verification includes the following steps:

Step S1033. For the flow channel model when the valve is fully open and a certain type of rectifier is installed, meshing is performed and divided into multiple sets of flow channel mesh models with different mesh numbers;

Step S1034: Compare the flow coefficient and resistance coefficient under different grid numbers. When the flow coefficient and resistance coefficient remain basically unchanged as the number of grids increases, select the minimum number of grids where the flow coefficient and resistance coefficient remain basically unchanged. .

The specific implementation of setting relevant parameters in step S105 includes the following steps:

Step S1051: Define a solver in the General module. The solver type is a pressure-based solver, and the time type is set to the steady-state calculation method;

Step S1052: Select the calculation model in the Models module and select the Standard k-ε model for calculation;

Step S1053: Set the fluid medium in the Materials module, and select the fluid medium as water or gas according to the actual working conditions;

Step S1054. Set boundary conditions in the Boundary Conditions module. Select velocity-inlet for the inlet, pressure-outlet for the outlet, wall for the wall, and interface for the interface. When the actual working conditions are clear, set the boundary conditions according to the actual working conditions. When working conditions are unclear, set reasonable boundary conditions by yourself;

Step S1055: Define interface in the Mesh Interfaces module;

Step S1056: Set the convergence residual in the Residual module;

Step S1057: Click Hybrid Initialization in the Initialization module to initialize;

Step S1058: Set the number of iteration steps in the Run Calculation module and click the Calculation module to start numerical calculation.

The specific implementation of extracting the maximum speed on the cross-section of the downstream pipe of the rectifier in step S107 includes the following steps:

Step S1071. Select Iso-Surface in the Surface module and create a cross section every 1D downstream of the rectifier, creating a total of 12 cross sections;

Step S1072. In the Surface Integrals module in the Reports module, select FacetMaximum for Report Type, select Velocity Magnitude for Field Variable, and select the cross section created downstream of the rectifier in Step S1071 for Surfaces to obtain the maximum velocity on the cross section.

The specific method for judging the rectification effect is: the smaller the velocity eccentricity of the cross section, the more uniform the velocity distribution on the cross section, the more stable the flow field, and the better the rectification effect of the rectifier. Drawing the curve of velocity eccentricity with flow development based on the Origin software can visually see the velocity eccentricity of the downstream cross-section of rectifiers with different structures, so as to determine the rectification effect of rectifiers with different structures.

Embodiment 2;

As shown in Figures 1-7, the rectification effect determination method suitable for process valves according to the embodiment of the present invention includes the following steps:

Step 1: Establish the flow channel model; select the ball valve as the spoiler element, use Solidworks software to conduct three-dimensional modeling of the valve and rectifier under actual working conditions, and assemble the rectifier I and rectifier II models at the outlet of the ball valve. Rectifier I and rectifier II The model is shown in Figures 2 and 3. The relative opening of the ball valve is set to 30%. The model fluid domain is extracted to obtain a flow channel model. The characteristics of the flow channel model are: the upstream of the valve in the flow channel model is five times the pipe diameter. , the downstream of the rectifier is twelve times the pipe diameter, and the flow channel model is shown in Figure 4;

Step 2: Divide the mesh; verify the grid independence, select the number of meshes that meet the requirements, and mesh the flow channel model;

The specific implementation of meshing includes the following steps:

In the Solidworks software, export each part of the flow channel model separately;

Use ANSYS ICEM CFD software to divide each part of the flow channel model into structural meshes, and refine the mesh for the valve core and rectifier parts. Finally, use the Merge function of ANSYS ICEM CFD software to merge the meshes of each part. Merged into a whole, the flow channel grid model is shown in Figure 5.

The specific implementation of the grid independence verification includes the following steps:

For the flow channel model when the valve is fully open and the rectifier I is installed, the mesh is divided into multiple sets of flow channel mesh models with different mesh numbers;

Compare the flow coefficient and resistance coefficient under different grid numbers. When the flow coefficient and resistance coefficient remain basically unchanged as the number of grids increases, select the minimum number of grids where the flow coefficient and resistance coefficient remain basically unchanged, as shown in the figure As shown in 6, select 3.5 million grid.

Step 3: Perform numerical calculations; import the flow channel grid into ANASYS FLUENT software, set relevant parameters, and perform numerical calculations;

The specific implementation of setting relevant parameters includes the following steps:

① Define the solver in the General module. The solver type is a pressure-based solver, and the time type is set to the steady-state calculation method;

②Select the calculation model in the Models module and select the Standard k-ε model for calculation;

③Set the fluid medium in the Materials module, and select water as the fluid medium according to the actual working conditions;

④Set boundary conditions in the Boundary Conditions module, select velocity-inlet for the inlet, pressure-outlet for the outlet, wall for the wall, and interface for the interface; set the boundary conditions according to the actual working conditions, set the inlet condition to 1m/s, and install the rectifier The outlet conditions of I and rectifier II are set to 17876.8Pa and 17880.9Pa respectively;

⑤Define interface in the Mesh Interfaces module;

⑥Set the convergence residual in the Residual module;

⑦Click Hybrid Initialization in the Solution Initialization module card to initialize;

⑧After setting the number of iteration steps in the Run Calculation module, click the Calculation module to start numerical calculations.

Step 4: Calculate the velocity eccentricity η of the downstream section; extract the maximum velocity on the cross-section of the pipeline downstream of the rectifier, and calculate the velocity eccentricity eta of each downstream cross-section according to the formula. The calculation formula is as follows:

Among them, Vmax represents the maximum velocity on the cross section of the downstream pipeline, in m/s; V0 represents the average velocity in the pipeline, in m/s.

The specific implementation of extracting the maximum velocity on the cross-section of the pipeline downstream of the rectifier includes the following steps:

① Select Iso-Surface in the Surface module and create a cross section every 1D downstream of the rectifier, creating a total of 12 cross sections;

② In the Surface Integrals module in the Reports module, select FacetMaximum for Report Type, select Velocity Magnitude for Field Variable, and select the cross section created downstream of the rectifier for Surfaces to get the maximum speed on the cross section, on the cross sections downstream of rectifier I and rectifier II. The maximum speed is as follows:

The calculation results of velocity eccentricity eta are as follows:

Step 5: Determine the rectification effect; based on the calculated speed eccentricity, use Origin software to draw a curve chart of the speed eccentricity developing with the flow, and compare and analyze the rectification effects of rectifiers with different structures.

The specific method for judging the rectification effect is: the smaller the velocity eccentricity of the cross section, the more uniform the velocity distribution on the cross section, the more stable the flow field, and the better the rectification effect of the rectifier. , as shown in Figure 7, the velocity eccentricity curve develops with the flow. It can be intuitively seen that the velocity eccentricity of the downstream section of rectifier I is greater than the velocity eccentricity of the downstream section of rectifier II. The flow field downstream of rectifier II is more uniform, so it can be determined , the rectification effect of rectifier II is better than that of rectifier I.

To sum up, with the help of the above technical solution of the present invention, the rectification situation behind the valve is reflected through the method of numerical simulation, and the speed eccentricity of the downstream cross section of the rectifier is used to determine the rectification effect of the rectifiers with different structures. Complex experiments are required to judge, which can greatly reduce manpower and material resources, and has practical significance in engineering.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (4)

1. The rectifying effect judging method suitable for the flow valve is characterized by comprising the following steps of:

s101, establishing a flow channel model; three-dimensional modeling is carried out on a valve and a rectifier under actual working conditions by utilizing Solidworks software, a rectifier model is assembled at an outlet of the valve, a model fluid domain is extracted, a flow channel model is obtained, and the flow channel model is characterized in that: the upstream of the flow channel model valve is five-pipe diameter, and the downstream of the rectifier is twelve-pipe diameter;

s103, dividing grids; performing grid independence verification, selecting grid numbers meeting requirements, and performing grid division on the flow model;

s105, performing numerical calculation; importing the runner grid into ANASYS FLUENT software, setting related parameters, and calculating a digital value;

s107, calculating the velocity eccentricity eta of the downstream section; the maximum speed on the cross section of the pipeline downstream of the rectifier is extracted, and the speed eccentricity eta of each cross section downstream is calculated according to the formula, wherein the calculation formula is as follows:the method comprises the steps of carrying out a first treatment on the surface of the Wherein Vmax represents the maximum velocity in m/s over the downstream pipe cross section; v0 represents the average velocity in the pipeline in m/s;

s109, judging the rectifying effect; drawing a graph of the speed eccentricity along with the flow development by using Origin software according to the calculated speed eccentricity, and comparing and analyzing the rectifying effects of rectifiers with different structures;

the implementation of extracting the maximum speed of the cross section of the pipeline at the downstream of the rectifier in the step S107 comprises the following steps:

s1071, selecting an Iso-Surface in a Surface module, and creating a cross section at intervals of 1D at the downstream of the rectifier to create 12 cross sections in total;

s1072, a Surface Integrals module in the Reports module, wherein the Report Type selects Facet Maximum, the Field Variable selects Velocity Magnitude, and the Surfaces select the cross section created at the downstream of the rectifier in the step S1071, so that the Maximum speed on the cross section can be obtained;

the specific method for judging the rectifying effect is as follows: the smaller the speed eccentricity of the cross section is, the more uniform the speed distribution on the cross section is, the more stable the flow field is, and the better the rectifying effect of the rectifier is; and drawing a graph of the speed eccentricity along with the flow development according to Origin software, and intuitively seeing the speed eccentricity of the downstream section of the rectifiers with different structures, so as to judge the rectifying effect of the rectifiers with different structures.

2. The rectifying effect determining method for a flow valve according to claim 1, wherein the meshing implementation comprises the steps of:

s1031, respectively exporting each part of the flow channel model in Solidworks software;

s1032, dividing each part of the flow model into structural grids by using ANSYS ICEM CFD software, encrypting the grids of the valve core and the rectifier part, and finally merging the grids of each part into a whole by using the Merge function of ANSYS ICEM CFD software.

3. The rectifying effect determining method for a flow valve according to claim 1, wherein the grid independence verification implementation comprises the following steps:

s1033, dividing grids aiming at the runner model when the valve is fully opened and a certain rectifier is installed, and dividing the runner model into a plurality of runner grid models with different grid numbers;

s1034, comparing the flow coefficient and the resistance coefficient under different grid numbers, and selecting the minimum grid number with the flow coefficient and the resistance coefficient unchanged when the flow coefficient and the resistance coefficient keep unchanged along with the increase of the grid number.

4. The rectifying effect determining method for a flow valve according to claim 1, wherein the setting of the relevant parameters in the step S105 comprises the following steps:

s1051, defining a solver in a General module, wherein the solver adopts a solver based on pressure, and the time type is set as a steady-state calculation mode;

s1052, selecting a calculation model in a Models module, and selecting a Standard k-epsilon model for calculation;

s1053, setting a fluid medium in the Materials module, and selecting the fluid medium as water or gas according to actual working conditions;

s1054, setting boundary conditions in a Boundary Conditions module, selecting a property-inlet as an inlet, selecting a pressure-outlet as an outlet, selecting wall surfaces, and selecting interfaces as interfaces; when the actual working conditions are clear, setting boundary conditions according to the actual working conditions; when the actual working condition is ambiguous, setting reasonable boundary conditions by oneself;

s1055, defining Interfaces in the Mesh Interfaces module;

s1056, setting convergence Residual in a Residual module;

s1057, clicking Hybrid Initialization in the Initialization module for Initialization;

s1058, after the number of iteration steps is set in the Run Calculation module, clicking the Calculation module to start numerical Calculation.