A method for modeling bypass valve elements based on flowmaster

Abstract

The application provides a bypass valve element modeling method based on Flowmaster, which comprises the following steps: determining a bypass valve structure, which comprises a control cavity spring and a working cavity spring; obtaining displacement amounts of a control cavity valve and a working cavity valve when the bypass valve is in a working state; solving the displacement amounts to obtain a bypass valve opening degree; establishing a linear equation of a bypass valve interface element according to a general linear equation of a multi-interface element; obtaining the opening degree and pressure of the bypass valve according to physical and geometric characteristic parameters of the bypass valve, the valve interface linear equation and inlet and outlet geometric parameters; obtaining the opening degree and pressure of the bypass valve according to a characteristic relation curve of the opening degree and the difference between a valve control end and an inlet pressure, or a characteristic relation surface of the opening degree and the control end pressure and the inlet and outlet pressure difference, the bypass valve interface linear equation and the inlet and outlet geometric parameters; and carrying out bypass valve element opening degree test and flow characteristic test to verify the correctness of the bypass valve element.

Description

Technical Field

[0001] This application belongs to the field of aircraft fuel system pipeline design technology, and specifically relates to a method for modeling bypass valve components based on Flowmaster. Background Technology

[0002] In the engineering design of aircraft fuel systems, a special type of valve—the bypass valve—is often required based on mission needs and functional requirements. In some application scenarios, when the valve inlet pressure decreases, the fuel used for cooling after passing through all radiators is discharged into the fuel supply manifold; in other application scenarios, when the valve inlet pressure increases, some of the fuel used for cooling is returned to the fuel tank.

[0003] In simulating fuel system piping network performance using the fluid design software Flowmaster, the opening degree and pressure drop of the bypass valve are key parameters. However, Flowmaster's existing component library lacks a simulation model for this component, failing to meet engineering design requirements. Therefore, to ensure the accuracy of simulation calculations, it is necessary to establish a Flowmaster bypass valve component and its simulation model to meet the needs of fuel system simulation calculations. Summary of the Invention

[0004] The purpose of this application is to provide a method for modeling bypass valve components based on Flowmaster, in order to solve or mitigate at least one of the problems in the prior art.

[0005] The technical solution of this application is: a method for modeling bypass valve components based on Flowmaster, the method comprising:

[0006] The bypass valve structure is determined, which includes a control chamber spring and a working chamber spring. The displacement of the control chamber valve and the working chamber valve when the bypass valve is in the working state is obtained, and the opening degree of the bypass valve is obtained by solving the displacement.

[0007] The linear equation of the bypass valve interface element is established based on the general linear equation of the multi-interface element.

[0008] Based on the physical and geometric characteristics of the bypass valve, combined with the valve interface linear equation and inlet / outlet geometric parameters, the opening degree and pressure of the bypass valve are obtained; and

[0009] Based on the characteristic relationship curve between valve opening and the difference between valve control end and inlet pressure, or the characteristic relationship surface between valve opening and control end pressure and inlet / outlet pressure difference, the opening and pressure of the bypass valve are obtained by combining the linear equation of the bypass valve interface and the inlet / outlet geometric parameters.

[0010] Based on geometric parameters, characteristic relationship curves, and pressure boundary conditions, the Flowmaster bypass valve element's opening degree and flow characteristics were tested to verify the correctness of the bypass valve element.

[0011] Furthermore, the opening degree of the bypass valve satisfies:

[0012] (1)πR 2 >= 2πRL, that is At that time, the valve opening degree is

[0013] (2)πR 2 <2πRL, that is hour,

[0014] like Valve opening θ = 1;

[0015] like valve opening

[0016] In the formula, R is the radius of the valve inlet pipe, L is the maximum moving distance of the valve plate, and l is the displacement of the valve plate.

[0017] Furthermore, the general linear equation for multi-interface components is:

[0018] Furthermore, the linear equation of the bypass valve element is:

[0019]

[0020] The linear equation coefficients for the traffic at each interface are:

[0021]

[0022]

[0023]

[0024] Furthermore, the process for testing the opening degree of the bypass valve component is as follows:

[0025] Based on the known inlet and outlet pressure boundary conditions, and combined with the displacement equations of the control chamber valve and the working chamber valve, the displacement of the control chamber valve and the valve plate are obtained, thereby obtaining the bypass valve opening.

[0026] The theoretical calculation results of the bypass valve opening are compared with the pipeline test results from Flowmaster. If both errors are less than the predetermined value, the opening verification results of the bypass valve component are considered correct.

[0027] Furthermore, the process for testing the flow characteristics of the bypass valve element is as follows:

[0028] Based on the known characteristic curve of the opening degree with the working pressure difference of the bypass valve, and combined with the set pressure boundary conditions of the bypass valve inlet and outlet and the control end, the theoretical calculation value of the bypass valve opening degree is obtained.

[0029] Compare the theoretical calculation results of the bypass valve with the pipeline test results from Flowmaster. If both errors are less than the predetermined values, the opening degree verification result of the bypass valve component is correct.

[0030] The method provided in this application can effectively calculate the opening degree, inlet and outlet pressure and flow rate of the bypass valve model in Flowmaster software, enrich the component library of Flowmaster software, supplement the simulation model of fuel system accessories, and effectively support the engineering design needs of Flowmaster for simulation calculation of system pipelines and their performance. Attached Figure Description

[0031] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0032] Figure 1 A flowchart illustrating the bypass valve element modeling method of this application.

[0033] Figure 2 This is a schematic diagram of the bypass valve structure of this application.

[0034] Figure 3a and Figure 3b These are force analysis diagrams of the bypass valve in the non-operating and operating states of this application, respectively.

[0035] Figure 4a This is a schematic diagram of the component interface in this application.

[0036] Figure 4b This is a schematic diagram of the bypass valve in Flowmaster.

[0037] Figure 5 The diagram shows the input parameters and explanations of the bypass valve element in the Flowmaster of this application.

[0038] Figure 6 This is a schematic diagram of the pipeline network for bypass valve opening test and flow characteristic test in this application.

[0039] Figure 7a and Figure 7b These are schematic diagrams of the parameter setting interfaces for the bypass valve flow resistance coefficient and the three loss elements in the test pipeline network during the geometric parameter modeling and opening test of this application.

[0040] Figure 8a and Figure 8b These are the relationship between the loss coefficient and the opening change K0=f(θ) and the Reynolds number-related laminar flow correction coefficient C in this application. Re = the curve of g(Re).

[0041] Figure 9a A schematic diagram of the parameter setting interface for the characteristic curve modeling and opening test of this application.

[0042] Figure 9b This is the bypass valve opening characteristic curve of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0044] like Figure 1 As shown, the method for modeling bypass valve components based on Flowmaster provided in this application includes the following steps:

[0045] Step 1: Force analysis and state determination of the bypass valve.

[0046] The bypass valve structure contains two springs: a control chamber spring and a working chamber spring. The bypass valve is initially closed. To ensure a leak-free, airtight seal, both springs have an initial deformation X. 10 and X 20 When the bypass valve is in operation, the control chamber valve and the working chamber valve are subjected to pressure, and their displacements are X1 and l, respectively. By performing force analysis on the control chamber valve and the working chamber valve, and solving for their displacements, the opening degree of the bypass valve can be obtained.

[0047] like Figure 2 The diagram shows a bypass valve structure. The control oil circuit interface node is 1, the inlet and outlet oil circuit nodes of the working chamber are 2 and 3 respectively, and the effective area of ​​the control chamber valve is A. 1H The effective area of ​​the working chamber valve facing the inlet end is A. 2Hin The effective area facing the export end is A. 2Hout The control chamber valve moves a distance L from closed to its maximum opening. The pipe diameters of interface 2 and interface 3 are D2 and D3, respectively. The valve is initially closed. To ensure a tight seal, the control chamber spring and the working chamber spring have an initial deformation X. 10 and X 20 .

[0048] Figure 3 shows the force analysis diagram of the bypass valve in its non-operating and operating states. When the bypass valve is in the operating state, the inlet pressure of the control chamber is P1, the inlet pressure of the working chamber is P2, and the outlet pressure is P3. Let the displacement of the control chamber valve be X1, then X1 is the downward displacement of the control chamber valve. Let the displacement of the valve plate be l. From the connection relationship between the control chamber spring, the working chamber spring, and the control chamber valve and the working chamber valve, it can be seen that the deformation of the control chamber spring is X. 10 +X1, the deformation of the working chamber spring is X 20 -X1+l.

[0049] As can be seen from the valve structure, the control chamber valve and the connecting rod are rigidly connected. In operation, the working chamber valve is only subjected to the pressure at the inlet and outlet of the working chamber and the force of the working chamber spring. Force analysis of the control chamber valve and the working chamber valve separately yields the following results:

[0050] Force equation for the control chamber valve-connecting rod: P1A 1H -k1(X 10 +X1)-k2(X 20 +X1+l)=0 (1)

[0051] Force equation for the working chamber valve: P2A 2Hin -P3A 2Hout -k2(X 20 +X1+l)=0 (2)

[0052] Solving the two equations simultaneously, we obtain the solutions for the displacements of the control chamber valve and the working chamber valve as follows:

[0053]

[0054] If the solution is X1<0, it means that the displacement of the control cavity valve is zero. In this case, the displacement of the control cavity valve is taken as zero, that is, X1=0. Similarly, when l<0, it means that the displacement of the working cavity valve is zero. In this case, the displacement of the working cavity valve is taken as zero, that is, l=0, and l satisfies that it is not greater than the maximum movement range L.

[0055] When the maximum moving distance L of the valve plate and the radius R of the valve inlet pipe satisfy:

[0056] (1)πR 2 >= 2πRL, that is At that time, the valve opening degree is

[0057] (2)πR 2 <2πRL, that is hour,

[0058] like The valve opening θ = 1(5)

[0059] like valve opening

[0060] Step 2: Establish the linear equations for the bypass valve interface.

[0061] Flowmaster linearizes the flow equations of fluid components, solving a system of linear equations to determine parameters such as pressure, flow rate, and velocity. Based on the general linear equations for multi-interface components, it constructs linear equations for each interface of the bypass valve.

[0062] Based on the rules governing the construction of linear equations for multi-interface components, the linear equations for component nodes with any n interfaces can be derived, and these equations can be written as follows:

[0063] Interface No.1:

[0064] Interface No.2:

[0065] ...

[0066] No.n interface:

[0067] Therefore, its general linear equation format can be obtained as follows:

[0068] Therefore, the linear equation for the bypass valve element can be derived as follows:

[0069]

[0070] Since there is no loop at the valve control end, the flow rate at the control end... It is zero, that is:

[0071] When the valve has a certain opening, fluid flows through the inlet and outlet of the working chamber. Therefore, Bernoulli's equation for the main chamber of the valve is established:

[0072] After transformation, we get:

[0073] In the formula: ρ is the density of the fluid medium (kg / m³) 3 ;

[0074] Q is the flow rate m in the pump. 3 / s;

[0075] ξ is the flow modulus;

[0076] Flow modulus

[0077] Where K2 is the loss coefficient relative to the inlet velocity of the working cavity flow;

[0078] K3 is the loss coefficient relative to the outflow velocity of the main chamber;

[0079] A3 represents the export area. Unit m 2 ;

[0080] A2 represents the export area. Unit m 2 ;

[0081] Replacing Equation 10 with mass flow rate gives:

[0082] Based on the fact that inflow is negative and outflow is positive, the inlet flow rate of the working chamber is obtained respectively. and export flow They are respectively:

[0083]

[0084]

[0085] Comparing the above formula, the linear equation coefficients for the traffic at each interface can be obtained as follows:

[0086]

[0087]

[0088]

[0089] When the valve opening is zero, there is no flow at the inlet and outlet of the main chamber. At this time, the flow rate at the inlet and outlet of the main chamber is... All are zero. The flow rate is affected by the flow modulus ξ and the valve inlet / outlet loss coefficients K2 and K3. When the valve opening is zero, the flow modulus ξ and the valve inlet / outlet loss coefficients K2 and K3 are at their maximum values, thus achieving a minimum flow rate (approximately zero). Since the valve inlet / outlet loss coefficients K2 and K3 are obtained through curve interpolation corresponding to the valve opening, when the valve opening is less than or equal to 0.0001, K2 and K3 are both K values ​​when the valve opening is 0.0001.

[0090] Step 3: Establish a mathematical model for the bypass valve

[0091] (1) Modeling based on the geometric parameters of the bypass valve

[0092] Based on the physical and geometric characteristics of the bypass valve, the valve opening value is calculated after mechanical analysis. The loss coefficient K is then determined using the characteristic curve K=g(θ,Re) of the Reynolds number at different valve openings, or by using the laminar correction factor C related to the loss coefficient K at different valve openings with the Reynolds number. ReThe loss coefficient is obtained from the change curve; the bypass valve pressure and flow / opening are obtained from the linear equation of the bypass valve interface and the inlet and outlet geometric parameters.

[0093] (2) Modeling based on the flow resistance characteristic curve of the bypass valve

[0094] The valve opening value is calculated based on the curve of the valve opening versus the pressure difference at the valve control end and inlet, or the surface curve showing the relationship between the valve opening and the pressure difference at the control end and the inlet / outlet. The laminar flow correction factor C is then used to determine the characteristic curve of the loss coefficient K versus Reynolds number at different valve openings, or the relationship between the loss coefficient K and Reynolds number at different valve openings. Re The change curve is used to calculate the loss coefficient; based on the linear equation of the bypass valve interface and the inlet and outlet geometric parameters, the bypass valve pressure and flow rate / opening degree are obtained.

[0095] like Figure 4a The image shows a schematic diagram of the bypass valve's component interface in the Flowmaster software. Figure 4b This is a schematic diagram of the bypass valve in Flowmaster. The main chamber inlet diameter D2, main chamber outlet diameter D3, opening calculation method, geometric parameters, and flow resistance coefficient parameters are required component attributes. When the geometric algorithm is selected as the opening calculation method, the geometric parameters must be entered; when the characteristic curve algorithm is selected, the characteristic curve parameters must be entered.

[0096] like Figure 5 The diagram shows the input parameters for the bypass valve element. When selecting the geometric parameter modeling method, parameters 1, 2, 3, 4, and 6 are input parameters; when selecting the characteristic curve modeling method, parameters 1, 2, 3, 5, and 6 are input parameters. When using the opening surface calculation, parameter 5.1 is a required input parameter; when using the opening curve calculation, parameter 5.2 is a required input parameter. There are two methods for calculating the loss coefficient: when using the characteristic curve of the loss coefficient K varying with the Reynolds number at different valve openings, parameter 6.3 is a required input parameter; when using the laminar correction factor C related to the Reynolds number at different valve openings, the loss coefficient K can be calculated using... Re When calculating the change curve, parameters 6.4 and 6.5 are required input parameters.

[0097] Step 4: Bypass valve component testing.

[0098] The calculated valve opening results of Flowmaster under the geometric algorithm and the characteristic curve algorithm were compared with the theoretical calculation results. The valve opening was tested to verify the correctness of the calculated valve opening results.

[0099] By comparing the calculated pressure loss at the valve inlet and outlet with the theoretical calculation results using Flowmaster, valve flow characteristics were tested to verify the correctness of the valve inlet and outlet pressure calculations.

[0100] like Figure 6 The diagram shows the test network of the bypass valve element in Flowmaster. This test network is used to perform opening and flow characteristic tests on the developed bypass valve element.

[0101] 4.1) Opening test

[0102] a) Verify the correctness of the valve opening calculation results under the geometric algorithm.

[0103] When the inlet and outlet pressure boundary conditions are known, the control chamber valve displacement X1 and valve plate displacement l can be obtained through equation set 3, and the valve opening θ can be obtained. The theoretical calculation result of this valve opening is compared with the pipeline test results of Flowmaster to verify the correctness of the result.

[0104] The geometric parameters of the bypass valve are set as shown in Table 1, and the valve pressure boundary conditions are shown in Table 2. The valve control end pressure and valve outlet end pressure are set. By adjusting the valve inlet end pressure, the valve opening degree under different working pressure differentials is calculated.

[0105] Table 1. Bypass valve geometric parameter settings

[0106]

[0107]

[0108] Table 2. Valve Pressure Boundary Conditions

[0109] Case 1 1 1 0.5 0 0 Case 2 1 1.5 0.5 0.002 0.32 Case 3 1 5 0.5 0.009 1 Case 4 1 7 0.5 0.013 1 Case 5 1 10 0.5 0.019 1 Case 6 1 15 0.5 0.029 1

[0110] With the main chamber inlet diameter set at 0.025m, the valve inlet radius R = 0.0125m, and the maximum valve displacement L = 0.05m. Based on the geometric parameters and boundary conditions in Tables 1 and 2, the valve plate displacement and opening value can be obtained from Equation 3, and the calculation results are shown in Table 3.

[0111] Table 3. Theoretical calculation results of valve opening value under geometric parameter algorithm.

[0112] Case 1 1 1 0.5 0 0 Case 2 1 1.5 0.5 0.002 0.32 Case 3 1 5 0.5 0.009 1 Case 4 1 7 0.5 0.013 1 Case 5 1 10 0.5 0.019 1 Case 6 1 15 0.5 0.029 1

[0113] In Flowmaster software, select geometric parameters to calculate the valve opening. For valve flow resistance characteristic parameter settings, see [link to Flowmaster software]. Figure 7a and Figure 8a The parameter settings for the three loss elements in the test pipeline network are shown in [link to relevant documentation]. Figure 7bThe Flowmaster pipeline test results under various pressure boundary conditions of the valve are shown in Table 4.

[0114] Table 4 Flowmaster Pipeline Test Results

[0115]

[0116] The theoretical calculation results of valve displacement and opening are basically consistent with the Flowmaster pipeline test results.

[0117] b) Verify the correctness of the valve opening calculation results under the characteristic curve algorithm.

[0118] When the opening characteristic curve, i.e. the curve of opening change with the working pressure difference of the valve, is known, the theoretical calculation value of the valve opening can be obtained by curve interpolation by setting the pressure boundary conditions of the valve inlet, outlet and control end. The correctness of the result can be verified by comparing the theoretical calculation result with the pipeline test result of Flowmaster.

[0119] like Figure 9a and Figure 9b The table shows the parameter settings for the characteristic curve algorithm and the valve opening performance curve. The valve pressure boundary conditions are shown in Table 5, and the test results are shown in Table 6. Comparing the theoretical results of the curve difference with the Flowmaster pipeline test results, it can be seen that the valve opening characteristic curve algorithm results are correct.

[0120] Table 5. Pressure Boundary Conditions for Characteristic Curve Algorithm

[0121] Case 1 2.5 1.5 0.5 Case 2 2.5 2.05 0.5 Case 3 2.5 2.3 0.5

[0122] Table 6 Test Results of the Feature Curve Valve Opening Algorithm

[0123]

[0124]

[0125] 4.2) Flow characteristic test

[0126] Based on the valve opening degree and the valve resistance coefficient-opening degree curve, the valve resistance coefficient is obtained by interpolation, and the pressure loss at the valve inlet and outlet is calculated according to the valve flow equation. This calculated pressure loss result is then compared with the Flowmaster test results for verification.

[0127] Set the bypass valve component parameters according to Table 1, and then... Figures 7a-7b , Figures 8a-8bThe flow resistance coefficient characteristic curve was set. Interpolation was used to obtain the valve opening and flow resistance coefficient. The inlet and outlet pressure losses were obtained according to the Bernoulli equation for the valve inlet and outlet, as shown in Table 7. Comparison with the theoretical pressure difference and the Flowmaster test pressure difference shows that the bypass valve element can correctly calculate the valve inlet and outlet pressures.

[0128] Table 7. Test Results of Pressure Difference Between Valve Inlet and Outlet Table 7.

[0129]

[0130] The method provided in this application can effectively calculate the opening degree, inlet and outlet pressure and flow rate of the bypass valve model in Flowmaster software, enrich the component library of Flowmaster software, supplement the simulation model of fuel system accessories, and effectively support the engineering design needs of Flowmaster for simulation calculation of system pipelines and their performance.

[0131] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for modeling bypass valve components based on Flowmaster, characterized in that, The method includes: The bypass valve structure is determined, which includes a control chamber spring and a working chamber spring. The displacement of the control chamber valve and the working chamber valve when the bypass valve is in the working state is obtained, and the opening degree of the bypass valve is obtained by solving the displacement. The linear equation of the bypass valve interface element is established based on the general linear equation of the multi-interface element. Based on the physical and geometric characteristics of the bypass valve, combined with the valve interface linear equation and inlet / outlet geometric parameters, the opening degree and pressure of the bypass valve are obtained; and Based on the characteristic relationship curve between valve opening and the difference between valve control end and inlet pressure, or the characteristic relationship surface between valve opening and control end pressure and inlet / outlet pressure difference, the opening and pressure of the bypass valve are obtained by combining the linear equation of the bypass valve interface and the inlet / outlet geometric parameters. Based on geometric parameters, characteristic relationship curves, and pressure boundary conditions, the opening degree and flow characteristics of the bypass valve element Flowmaster were tested to verify the correctness of the bypass valve element.

2. The method for modeling bypass valve components based on Flowmaster as described in claim 1, characterized in that, The bypass valve opening satisfies: (1)πR 2 >= 2πRL, that is At that time, the valve opening degree is (2)πR 2 <2πRL, that is hour, like Valve opening θ = 1; like valve opening In the formula, R is the radius of the valve inlet pipe, L is the maximum moving distance of the valve plate, and l is the displacement of the valve plate.

3. The method for modeling bypass valve components based on Flowmaster as described in claim 2, characterized in that, The general linear equation for multi-interface components is:

4. The method for modeling bypass valve components based on Flowmaster as described in claim 3, characterized in that, The linear equation of the bypass valve element is: The linear equation coefficients for the traffic at each interface are:

5. The method for modeling bypass valve components based on Flowmaster as described in claim 4, characterized in that, The process of testing the opening degree of the bypass valve component is as follows: Based on the known inlet and outlet pressure boundary conditions, and combined with the displacement equations of the control chamber valve and the working chamber valve, the displacement of the control chamber valve and the valve plate are obtained, thereby obtaining the bypass valve opening. The theoretical calculation results of the bypass valve opening are compared with the pipeline test results from Flowmaster. If both errors are less than the predetermined value, the opening verification results of the bypass valve component are considered correct.

6. The method for modeling bypass valve components based on Flowmaster as described in claim 4, characterized in that, The process for testing the flow characteristics of bypass valve components is as follows: Based on the known characteristic curve of the opening degree with the working pressure difference of the bypass valve, and combined with the set pressure boundary conditions of the bypass valve inlet and outlet and the control end, the theoretical calculation value of the bypass valve opening degree is obtained. Compare the theoretical calculation results of the bypass valve with the pipeline test results from Flowmaster. If both errors are less than the predetermined values, the opening degree verification result of the bypass valve component is correct.

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