Multi-stage axial flow compressor stage flow coefficient design method based on inter-stage test data

Abstract

The present invention provides a design method for the stage flow coefficient of a multistage axial compressor based on inter-stage test data, comprising the following steps: Step 1, define the compressor stage and test parameters; Step 2, calculate the average static pressure P before the stator according to the static pressure on the outer wall measured in Step 1; Step 3, calculate the average total pressure before the stator according to the total pressures at multiple measurement points measured in Step 1; Step 4, calculate the average total temperature before the stator according to the total temperatures at multiple measurement points measured in Step 1; Step 5, determine the axial velocity correction coefficient at the inlet and outlet of the stator; Step 6, determine the stage flow coefficient according to Steps 2 to 5. Based on the basic equations of aerodynamics, through reasonable assumptions and curve fitting that conform to the basic principles of compressor aerodynamics, the present invention can significantly improve the ability to carry out the matching analysis of inter-stage parameters of the compressor based on inter-stage test data.

Description

Technical Field

[0001] The present invention relates to the technical field of aerodynamic design of multistage axial compressors, and particularly relates to a method for designing the stage flow coefficient of a multistage axial compressor based on inter-stage test data. Background Art

[0002] Good inter-stage parameter matching is an important factor determining the performance of a multistage fan / compressor (hereinafter referred to as: compressor). In engineering design, in order to further analyze the inter-stage parameter matching of the compressor, analyzing the matching between stages of a multistage compressor through carrying out inter-stage tests and test data analysis is an indispensable link in the independent development of modern aeroengine compressors. However, limited by test conditions, in most cases, the inter-stage measurement of a multistage compressor can only measure the total temperature, total pressure, and outer wall static pressure before each stator.

[0003] The dimensionless coefficient important for the analysis of compressor inter-stage matching, that is: the stage flow coefficient (this coefficient characterizes the flow capacity of the stage and is a coefficient for judging the flow matching of each stage), cannot be directly calculated from the inter-stage test data. As a result, the value of the previous inter-stage test data of multistage compressors has not been fully utilized. Summary of the Invention

[0004] In view of this, the present invention provides a method for designing the stage flow coefficient of a multistage axial compressor based on inter-stage test data, so as to achieve the purpose of improving the ability to carry out compressor inter-stage parameter matching analysis based on inter-stage test data.

[0005] The present invention provides the following technical solutions: A method for designing the stage flow coefficient of a multistage axial compressor based on inter-stage test data, comprising the following steps: Step 1, defining the compressor stage and test parameters; Step 2, calculating the average static pressure P before the stator according to the outer wall static pressure measured in Step 1; , calculating the average total pressure before the stator according to the total pressures at multiple measurement points measured in Step 1; Step 3, calculating the average total temperature before the stator according to the total temperatures at multiple measurement points measured in Step 1; Step 4, determining the axial velocity correction coefficient at the inlet and outlet of the stator; Step 5, determining the stage flow coefficient according to Steps 2 to 5.

[0006] Further, the average static pressure P before the stator is calculated by the formula .

[0007] Further, the average total pressure before the stator is calculated by the formula , where P1 - Pn is the total pressure measured at n total pressure measurement points before the stator, S is the annular area of the entire blade, , …… is the toroidal area between two measurement points or between a measurement point and the inner and outer walls.

[0008] Further, the average total temperature in front of the stator is calculated by the formula , where T1 - Tn are the total temperatures measured at n total temperature measurement points in front of the stator.

[0009] Further, the axial velocity correction coefficient at the stator inlet and outlet is determined by the formula , where is the toroidal area at the stator inlet, and is the toroidal area at the stator outlet.

[0010] Further, the stage flow coefficient is determined by the formula , where R is the gas constant; A is the toroidal area in front of the stage stator, with the unit ; ; is the tangential velocity at the middle of the rotor blade, with the unit , and k is the adiabatic index.

[0011] Further, by comparing the stage flow coefficient with the design target value, it is determined whether the flow capacity of the multi-stage axial compressor reaches the design target.

[0012] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the present invention at least include: Based on the basic equations of aerodynamics, through reasonable assumptions and curve fitting that conform to the basic principles of compressor aerodynamics, the present invention proposes a method for calculating the stage flow coefficient of a multi-stage axial compressor based on inter-stage test data. It can significantly improve the ability to carry out compressor inter-stage parameter matching analysis based on inter-stage test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0014] Figure 1 is the flow chart of the present invention;

[0015] Figure 2 is the schematic diagram of the definition of the compressor stage and the distribution of measurement points;

[0016] Figure 3For the calculation process of the compressor stage flow coefficient;

[0017] Figure 4 Schematic diagram of the total pressure measurement point in front of the compressor stator;

[0018] Figure 5 Schematic diagram of the total temperature measurement point in front of the compressor stator;

[0019] Figure 6 Schematic diagram of the definition and test measurement point distribution of the second stage of a certain compressor. Specific implementation mode

[0020] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0021] The following uses specific specific examples to illustrate the implementation mode of the present application. Those skilled in the art can easily understand other advantages and effects of the present application from the content 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 modes. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0022] As Figure 1 shown, the present invention provides a design method for the stage flow coefficient of a multi-stage axial compressor based on inter-stage test data, which specifically includes the following steps:

[0023] 1. Define the compressor stage and test parameters;

[0024] Since in the test, the inter-stage total temperature and total pressure measurement points can only be arranged on the stator blades, it is necessary to re-define the stage of the compressor. As Figure 2 shown, one stage of the compressor consists of a row of "stator + rotor" blades. The total temperature and total pressure measurement points are the circular points in the figure, in front of the stator blades, and the static pressure measurement point on the outer wall is the star point in the figure, on the outer casing of the compressor.

[0025] 2. Define the calculation method of the compressor stage flow coefficient;

[0026] The calculation process of the compressor stage flow coefficient is as Figure 3 shown. The designed calculation formula in the figure is as follows:

[0027] (1)

[0028] (2)

[0029] (3)

[0030] (4)

[0031] (5)

[0032] Equations (1)-(3) are the basic equations of aerodynamics. Equation (4) is the correction formula for calculating the axial velocity at the rotor inlet based on the axial velocity at the stator inlet. Equation (5) is the calculation formula for the stage flow coefficient.

[0033] The definitions of the parameters in the equations are as follows:

[0034] Table 1 Specific meaning description table of each parameter

[0035]

[0036] In Equations (1)-(5), the most critical parameters for solving the flow coefficient are: 、 、 、 These four parameters need to be fitted according to the test data or given based on design experience. Other parameters: the air flow rate m in front of the stage stator can be directly measured through experiments, the annulus area A in front of the stage stator can be calculated after the compressor design scheme is determined, the tangential velocity at the middle of the rotor blade can be calculated based on the test speed and the flow path size, and R and are usually constants. Therefore, the most critical part of calculating the flow coefficient lies in accurately giving the values of: 、 、 、 these four parameters.

[0037] 3. Calculate the average static pressure in front of the stator ;

[0038] For the determination of the average static pressure in front of the stage stator, it needs to be obtained based on the static pressure measured on the outer wall in Test 1 with correction:

[0039] (6)

[0040] In Equation 6, is the static pressure on the outer wall in front of the stage stator measured in the experiment.

[0041] 4. Calculate the average total pressure in front of the stator ;

[0042] The average total pressure in front of the stator The calculation of Figure 4 is obtained by area-weighted averaging the total pressure at n radial points measured in the experiment, as shown in

[0043] (7)

[0044] In formula (7), P1 - Pn are the total pressures measured at the first n total pressure measurement points in front of the stator, S is the toroidal area of the entire blade, and …… are the toroidal areas between two measurement points or between a measurement point and the inner and outer walls.

[0045] 5. Calculate the average total temperature in front of the stator ;

[0046] The average total pressure in front of the stator The calculation of Figure 5 is obtained by area-weighted averaging the total pressure at n radial points measured in the experiment, as shown in

[0047] (8)

[0048] In formula (8), T1 - Tn are the total temperatures measured at the first n total temperature measurement points in front of the stator, S is the toroidal area of the entire blade, and …… are the toroidal areas between two measurement points or between a measurement point and the inner and outer walls.

[0049] 6. Determine the axial velocity correction coefficient at the inlet and outlet of the stator ;

[0050] The calculation formula of the axial velocity correction coefficient is related to the ratio of the toroidal areas of the inlet and outlet channels of the compressor stator. Its calculation formula is as follows:

[0051] (9)

[0052] In formula (9), is the toroidal area at the inlet of the stator, is the toroidal area at the outlet of the stator.

[0053] 7. Calculate the stage flow coefficient ;

[0054] Substitute the above four key parameters obtained from the calculation into formulas (1) - (5), and the stage flow coefficient can be calculated.

[0055] Taking the second stage of a certain multistage axial compressor as an example, the following is a further detailed description:

[0056] 1. Define the second stage of the compressor and test parameters

[0057] As Figure 6 shown, define the combination of the first stage stator + the second stage rotor of the compressor as the "second stage". The measuring points between stages are the total temperature and total pressure at 5 radial points in front of the first stage stator, and the static pressure on the outer wall in front of the first stage stator.

[0058] 2. Define the calculation method of the compressor stage flow coefficient

[0059] Determine the basic equation for calculating the streamline coefficient.

[0060] 3. Calculate the average static pressure in front of the stator

[0061] Calculate the average static pressure in front of the first stage stator , and the calculated result is .

[0062] 4. Calculate the average total pressure in front of the stator

[0063] Calculate the average total pressure in front of the first stage stator , and the calculated result is .

[0064] 5. Calculate the average total temperature in front of the stator

[0065] Calculate the average total temperature in front of the first stage stator according to the method described in step 5 of the invention content , and the calculated result is .

[0066] 6. Determine the axial velocity correction coefficient at the inlet and outlet of the stator

[0067] Calculate the axial velocity correction coefficient at the inlet and outlet of the first stage stator , and the calculated result is

[0068] 7. Calculate the stage flow coefficient

[0069] Substitute the 4 key parameters obtained by calculation into formulas (1) - (5) to calculate the stage flow coefficient .

[0070] As described above, it is only the specific implementation manner 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 those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A design method for the stage flow coefficient of a multi-stage axial flow compressor based on inter-stage test data, characterized in that, It includes the following steps: Step 1, define the compressor stage and test parameters; Step 2. Calculate the average static pressure P in front of the stator according to the outer wall static pressure measured in Step 1 , and calculate the average static pressure P in front of the stator; Step 3: Calculate the average total pressure in front of the stator based on the total pressures of multiple measurement points measured in Step 1 ; Step 4: Calculate the average total temperature in front of the stator according to the total temperatures of multiple measuring points measured in Step 1 ; Step 5: Determine the axial velocity correction coefficient at the stator inlet and outlet ; Step VI. Determine the stage flow coefficient according to the aforesaid Step II to Step V ; Calculate the average static pressure P in front of the stator through the formula ​ Calculate the average total pressure in front of the stator through the formula where P1 - Pn are the total pressures measured at n total pressure measurement points in front of the stator, S is the toroidal area of the entire blade , and , ... are the toroidal areas between two measurement points or between a measurement point and the inner and outer walls; Through the formula calculate the average total temperature in front of the stator , where T1 - Tn are the total temperatures measured by n total temperature measuring points in front of the stator; Determine the stator inlet and outlet axial velocity correction coefficient through the formula , where is the stator inlet annulus area, and is the stator outlet annulus area. Determine the stage flow coefficient through the formula where R is the gas constant; A is the annulus area in front of the stage stator, with the unit ; ; is the tangential velocity at the middle of the rotor blade, with the unit , k is the adiabatic index, and m is the air flow rate in front of the stage stator.

2. The design method of the stage flow coefficient of a multistage axial flow compressor based on inter-stage test data according to claim 1, characterized in that Through-flow coefficient Compare with the design target value to determine whether the flow capacity of the multistage axial-flow compressor reaches the design target.

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