Design method of flow area of ​​disc exhaust throttle for compression component testing

Abstract

The present invention provides a method for designing the flow area of ​​a disc-type exhaust throttle for a compression component test, comprising the following steps: S1: using simulation software to calculate the physical flow of the exhaust throttle under fully open conditions; S2: constructing a pressure drop ratio-flow coefficient model based on the physical flow; S3: repeating steps S1 and S2 to construct a pressure drop ratio-flow coefficient model for exhaust throttles of different areas; S4: calculating the flow area of ​​the exhaust throttle based on the pressure drop ratio-flow coefficient model for exhaust throttles of different areas and the test state. By means of numerical simulation, combined with the exhaust parameters of the compression component test piece, the area of ​​the exhaust throttle required for the test can be effectively estimated, which solves the problem that the test cannot be carried out due to insufficient exhaust throttle area in the large flow and low pressure ratio compression component test, and also provides a method for designing the flow area of ​​the disc-type exhaust throttle of the compression component tester.

Description

Technical Field

[0001] The invention relates to the technical field of aero-engine compression component testing, and in particular to a method for designing a flow area of ​​a disc-type exhaust throttle valve for compression component testing. Background Art

[0002] At present, most of the domestic axial flow compression component testers use a disc exhaust valve to adjust the exhaust area to achieve the purpose of changing the test state. However, when the flow rate required by the test piece exceeds the design flow rate of the tester, it is necessary to evaluate the flow capacity of the tester's exhaust system. If the evaluation fails, the exhaust throttle needs to be modified. Currently, there is a lack of more accurate evaluation methods, and there is also a lack of corresponding area calculation methods for the modification. During the compression component test, for a new test piece that is tested for the first time, it is impossible to accurately give the initial position of the exhaust throttle, and the possible position can only be given through experience or analogy. Therefore, the present invention proposes a method for calculating the flow area of ​​a disc exhaust throttle for compression component testing based on numerical simulation. Summary of the invention

[0003] In view of this, the present invention provides a method for designing the flow area of ​​a disc-type exhaust throttle for a compression component test, so as to achieve the purpose of accurately estimating the exhaust throttle area under different working conditions of different compression components through the model.

[0004] The present invention provides the following technical solution: a method for designing the flow area of ​​a disc-type exhaust throttle for a compression component test, comprising the following steps:

[0005] S1: Use simulation software to calculate the physical flow of the exhaust throttle under fully open conditions;

[0006] S2: constructing a pressure drop ratio-flow coefficient model based on the physical flow;

[0007] S3: repeating step S1 and step S2 to construct a pressure drop ratio-flow coefficient model for exhaust throttles with different areas;

[0008] S4: Calculate the flow area of ​​the exhaust throttle based on the pressure drop ratio-flow coefficient model of exhaust throttles with different areas and the test state.

[0009] Furthermore, the step S1 comprises:

[0010] S1.1. Construct a numerical calculation model under the condition of full opening of exhaust throttle;

[0011] S1.2, set the calculation boundary conditions;

[0012] S1.3. Calculate the physical flow of the exhaust throttle under different boundary conditions based on the numerical calculation model.

[0013] Further, step S1.1 is specifically as follows: the numerical calculation model includes an exhaust section, an exhaust throttle, an exhaust volute and an exhaust duct of the compression component test piece;

[0014] Step S1.2 is as follows: Boundary conditions include the exhaust throttle fully open flow area A 0 , inlet boundary pressure P 1 , Temperature T 1 and the outlet boundary pressure P 2 .

[0015] Furthermore, step S1.3 is specifically as follows:

[0016] Change the inlet boundary pressure P 1 , calculate and extract each set of inlet boundary pressure P 1 The physical flow Mi.

[0017] Furthermore, step S2 is specifically as follows:

[0018] S2.1. Calculate the inlet boundary pressure P for each group 1 The flow coefficient q(λ) under

[0019] S2.2, draw a curve of pressure drop ratio π and flow coefficient q(λ) and determine the critical pressure drop ratio π0;

[0020] S2.3. By fitting the drop pressure ratio π and the flow coefficient q(λ) curve, the drop pressure ratio-flow coefficient model is obtained.

[0021] Further, step S2.1 is specifically: by formula Calculate the inlet boundary pressure P for each group 1 The flow coefficient q(λ) under the condition where m is a constant.

[0022] Furthermore, the fitting method in step S2.3 includes:

[0023] When the pressure drop ratio is less than the critical pressure drop ratio, a third-order polynomial fitting is used;

[0024] When the pressure drop ratio is greater than the critical pressure drop ratio, the flow coefficient q(λ) is a constant.

[0025] Furthermore, the step S3 specifically includes: changing the flow area of ​​the exhaust throttle valve, repeating the steps S1 and S2, and constructing a pressure drop ratio-flow coefficient model of exhaust throttle valves with different areas.

[0026] Further, step S4 includes:

[0027] S4.1. Calculate the pressure drop ratio π according to the exhaust pressure P of the compression component test, and then use the pressure drop ratio-flow coefficient model under the condition of the exhaust throttle fully open flow area A0 to obtain the flow coefficient q(λ);

[0028] S4.2. According to the exhaust pressure P, temperature T and physical flow M required for the test of the compression component f And the flow coefficient q(λ), calculate the flow area A of the exhaust throttle required for the test f ;

[0029] S4.3. Based on the calculated flow area A of the exhaust throttle required for the test f , redefine the pressure drop ratio-flow coefficient model, and select the exhaust throttle flow area A required for the test f The pressure drop ratio-flow coefficient model with the smallest difference is used and steps S4.1 and S4.2 are repeated to calculate the flow area of ​​the exhaust throttle valve.

[0030] Further, step S4.2 is specifically to use the formula , calculate the flow area A of the exhaust throttle required for the test f .

[0031] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted in the present invention include at least: through the means of numerical simulation, combined with the exhaust parameters of the compression component test piece, the area of ​​the exhaust throttle required for the test can be effectively estimated, which solves the problem that the test cannot be carried out due to insufficient exhaust throttle area in the test of large-flow and low-pressure ratio compression components, and also provides a method for the design of the flow area of ​​the disc-type exhaust throttle of the compression component tester. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 is a schematic diagram of a flow chart of an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of an exhaust throttle valve of the present invention;

[0035] Figure 3 It is the pressure drop ratio-flow coefficient curve;

[0036] Figure 4 It is a curve of pressure drop ratio-flow coefficient under different areas. DETAILED DESCRIPTION

[0037] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0038] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0039] like Figure 1 As shown, an embodiment of the present invention provides a method for designing the flow area of ​​a disc-type exhaust throttle for a compression component test, the method comprising the following steps:

[0040] S1: CAE software is used to calculate the aerodynamic flow field of the exhaust throttle;

[0041] S2: Construct a pressure drop ratio-discharge coefficient model based on the calculation results;

[0042] S3: Construct the pressure drop ratio-flow coefficient model of exhaust throttles with different areas;

[0043] S4: Calculate the exhaust throttle flow area based on the model and test conditions.

[0044] Through numerical simulation and combined with the exhaust parameters of the compression component test piece, the area of ​​the exhaust throttle required for the test can be effectively estimated, which solves the problem of the inability to conduct the test due to insufficient exhaust throttle area in the large flow and low pressure ratio compression component test. It also provides a method for the design of the flow area of ​​the disc exhaust throttle of the compression component tester.

[0045] The disc exhaust throttle is mainly composed of a dynamic ring and a static ring. During use, the circumferential position of the dynamic ring is changed to achieve different flow areas. The specific structure is as follows: Figure 2 shown.

[0046] The S1 comprises the following steps:

[0047] S1.1: Construct a numerical simulation calculation model under the condition of fully open disc exhaust throttle valve. Create a calculation model based on the geometric structure of the test disc exhaust valve. The calculation model includes the exhaust section of the compression component test piece, the exhaust throttle valve, the exhaust volute and the exhaust duct;

[0048] S1.2: Set the calculation boundary conditions, exhaust throttle fully open flow area A 0 , inlet boundary pressure P1 , Temperature T 1 is the standard atmospheric temperature and the outlet boundary pressure P 2 is the local atmospheric pressure;

[0049] S1.3: Calculate the physical flow rate under different inlet boundary pressure conditions and extract the flow rate, changing the inlet boundary pressure P 1 , calculate and extract each group P 1 The physical flow Mi, P 1 Range: 1.02P 2 ~2.5 P 2 , P 1 The larger the number, the higher the calculation accuracy. It is recommended to use P 1 No less than 10 groups.

[0050] The S2 comprises the following steps:

[0051] S2.1: Exhaust throttle flow area A calculated by CAE software 0 The physical flow rate Mi under the inlet boundary pressure P 1 and temperature T1 to calculate the inlet boundary pressure P for each group 1 The flow coefficient q(λ) under the above parameters is as follows: , where m=0.04042;

[0052] S2.2: Draw the curve of pressure drop ratio π and flow coefficient q(λ), where pressure drop ratio π is the inlet boundary pressure P 1 The local atmospheric pressure P 2 The ratio between them is used to draw a curve with the pressure drop ratio π as the X coordinate and the flow coefficient q(λ) as the Y coordinate, as shown in Figure 3 As shown;

[0053] S2.3: Determine the critical pressure drop ratio π0. When the pressure drop ratio π reaches the critical pressure drop ratio π0, the flow coefficient remains basically unchanged as the pressure drop ratio changes.

[0054] S2.4: Construct the exhaust throttle flow area A 0 The pressure drop ratio-flow coefficient model under the condition of pressure drop ratio π and flow coefficient q(λ) is obtained by fitting the pressure drop ratio π and flow coefficient q(λ) curve. The specific fitting method is as follows:

[0055] 1) When the pressure drop ratio is less than the critical pressure drop ratio, a third-order polynomial fitting is used. , where a, b, c, d are fitting coefficients;

[0056] 2) When the pressure drop ratio is greater than the critical pressure drop ratio, the flow coefficient q(λ) is a constant value, which is the maximum flow coefficient q under the exhaust throttle flow area Ai. max (λ).

[0057] The S3 comprises the following steps:

[0058] S3.1: Change the exhaust throttle flow area to A n , repeat steps S1 and S2 to construct pressure drop ratio-flow coefficient models under different flow areas, such as Figure 4 shown.

[0059] The S4 comprises the following steps:

[0060] S4.1: Calculate the pressure drop ratio π=P / P based on the exhaust pressure P of the compression component test 2 , and then use the circulation area A 0 The discharge coefficient q(λ) is obtained from the pressure drop ratio-discharge coefficient model under the conditions;

[0061] S4.2: Based on the exhaust pressure P, temperature T and physical flow rate M of the compression component test piece f And q(λ), using the formula Calculate the flow area of ​​the exhaust throttle required for the test, where m=0.04042;

[0062] S4.3: Based on the calculated flow area Ai, redetermine the pressure drop ratio-flow coefficient model, select the pressure drop ratio-flow coefficient model with the smallest difference from An, and repeat steps S4.1 and S4.2 to calculate the flow area of ​​the exhaust throttle.

[0063] In S2.2: When calculating the pressure drop ratio π, if the pressure loss of the exhaust volute and the exhaust duct is taken into account, the calculated value can be corrected to 1.01π.

[0064] In the above embodiment, the accuracy of the pressure drop ratio-flow coefficient model can be effectively improved by modifying the test data. It is particularly noted that this method does not take into account the leakage area of ​​the exhaust throttle. If the maximum flow calculation is performed, the flow can be appropriately enlarged based on the calculation result.

[0065] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for designing the flow area of ​​a disc exhaust throttle for a compression component test, characterized in that: The following steps are involved: S1: Use simulation software to calculate the physical flow of the exhaust throttle under fully open conditions; S2: Step S2.1, by formula Calculate the flow coefficient q(λ) under each group of inlet boundary pressures P1, where m is a constant; Step S2.2, draw a curve of the pressure drop ratio π and the flow coefficient q(λ) and determine the critical pressure drop ratio π0; Step S2.3, fit the pressure drop ratio π and the flow coefficient q(λ) curve to obtain a pressure drop ratio-flow coefficient model, wherein the fitting method includes: when the pressure drop ratio is less than the critical pressure drop ratio, a third-order polynomial fitting is used; when the pressure drop ratio is greater than the critical pressure drop ratio, the flow coefficient q(λ) is a constant; S3: repeating step S1 and step S2 to construct a pressure drop ratio-flow coefficient model for exhaust throttles with different areas; S4: S4.

1. Calculate the pressure drop ratio π according to the compression component test exhaust pressure P, and then use the pressure drop ratio-flow coefficient model under the condition of exhaust throttle fully open flow area A0 to obtain the flow coefficient q(λ); S4.

2. Calculate the pressure drop ratio π according to the compression component test exhaust pressure P, temperature T and the physical flow M required for the experiment f And the flow coefficient q(λ), using the formula , calculate the flow area A of the exhaust throttle required for the test f ; S4.3, according to the calculated flow area A of the exhaust throttle required for the test f , redefine the pressure drop ratio-flow coefficient model, and select the exhaust throttle flow area A required for the test f The pressure drop ratio-flow coefficient model with the smallest difference is used and steps S4.1 and S4.2 are repeated to calculate the flow area of ​​the exhaust throttle valve.

2. The method for designing the flow area of ​​a disc-type exhaust throttle for a compression component test according to claim 1, characterized in that: The step S1 comprises: S1.

1. Construct a numerical calculation model under the condition of full opening of exhaust throttle valve; S1.2, set the calculation boundary conditions; S1.

3. Calculate the physical flow of the exhaust throttle under different boundary conditions based on the numerical calculation model.

3. The method for designing the flow area of ​​a disc-type exhaust throttle for compression component testing according to claim 2, characterized in that: Step S1.1 is specifically as follows: the numerical calculation model includes the exhaust section, exhaust throttle, exhaust volute and exhaust duct of the compression component test piece; Step S1.2 is specifically as follows: the boundary conditions include the exhaust throttle fully open flow area A0, the inlet boundary pressure P1, the temperature T1 and the outlet boundary pressure P2.

4. The method for designing the flow area of ​​a disc exhaust throttle for compression component testing according to claim 3, characterized in that: Step S1.3 is specifically: The inlet boundary pressure P1 is changed, and the physical flow Mi of each set of inlet boundary pressure P1 is calculated and extracted.

5. The method for designing the flow area of ​​a disc exhaust throttle for compression component testing according to claim 1, characterized in that: The step S3 specifically includes: changing the flow area of ​​the exhaust throttle valve, repeating the steps S1 and S2, and constructing a pressure drop ratio-flow coefficient model for exhaust throttle valves with different areas.

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