Performance prediction method of axial flow compressor with back pressure boundary condition

Abstract

The application relates to a kind of axial flow compressor performance prediction method using back pressure boundary condition, which is to replace the flow rate at the outlet static pressure of axial flow compressor as the input parameter of low-dimensional analysis program, and then analyze the performance level of axial flow compressor, through the means of combining least square method and variable optimization formula, the calculation mode of back pressure boundary condition of axial flow compressor low-dimensional analysis program is applied, and the calculation content and process of axial flow compressor low-dimensional analysis program under the calculation mode of back pressure boundary condition are planned simultaneously;So that the axial flow compressor low-dimensional analysis program has the ability to predict the performance of axial flow compressor in the state of blockage, and the performance prediction integrity and reliability of one-dimensional design stage and two-dimensional design stage in the design system of axial flow compressor are also enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluid machinery design, and particularly relates to a performance prediction method of an axial flow compressor. BACKGROUND

[0002] With the development of the times and the progress of science and technology, the industrial level is continuously improved. At the same time, the technical level and design index of an aero-engine and a gas turbine are also higher and higher. As a core component, the design capability and involvement level of an axial flow compressor are directly related to the performance level of the aero-engine and the gas turbine. The axial flow compressor has two operating conditions in the running process, namely, a design condition and a non-design condition. And in the actual working state of the axial flow compressor, most of the conditions are non-design conditions. There are two relatively "dangerous" states in the non-design condition, which are a stall state and a choked state. The present application mainly discusses the choked state of the axial flow compressor in the non-design condition.

[0003] Earlier designers of the axial flow compressor believed that the choked state of the axial flow compressor is extremely detrimental to the performance of the axial flow compressor, and the loss caused by the high Mach number and the shock wave is relatively severe, so the axial flow compressor is generally designed to avoid working in the choked state. With continuous in-depth research, researchers have found that not all choked states are undesirable.

[0004] Taking a supersonic inlet flow cascade angle-loss characteristic curve as an example, under a certain inlet Mach number (greater than 1), as the attack angle continuously decreases, the total pressure loss coefficient continuously decreases; until the attack angle decreases to a certain angle, the attack angle no longer decreases, and there is a normal shock wave in the axial flow compressor cascade passage, at this time, the cascade passage is in a choked state of supersonic inlet flow, also known as a start-up state. In this state, the inlet flow attack angle no longer changes, which means that the cascade inlet flow angle and the flow rate in the axial flow compressor are fixed, and at this time, the loss coefficient of the cascade is related to the outlet static pressure (outlet static pressure is also called back pressure) of the cascade. The smaller the outlet static pressure, the greater the loss coefficient, and the lower the pressure ratio of the compressor. It corresponds to the "vertical section" in the flow rate-pressure ratio characteristic diagram of the axial flow compressor. However, in the choked state of the supersonic cascade, within a certain range of outlet static pressure, the loss coefficient of the cascade can be controlled in an acceptable range in design and application. In addition, the axial flow compressor in the gas turbine also has engineering needs to run in the choked condition.

[0005] At the same time, the performance prediction and analysis of the axial flow compressor in the blocked state at present mainly relies on full three-dimensional numerical simulation calculation, which is an extremely time-consuming and high-cost prediction means. Since the design process of the axial flow compressor needs to be iterated constantly, the full three-dimensional numerical simulation means cannot be relied on for the design and analysis of the axial flow compressor. In the existing technical axial flow compressor aerodynamic design system, the main tools used are one-dimensional design and analysis programs and two-dimensional design and analysis programs, wherein the design program is used for scheme design and geometry generation, and the analysis program is used for rapid inspection of the performance indicators of the design scheme.

[0006] However, at present, there is no low-dimensional (one-dimensional or two-dimensional) analysis program that can predict the performance of the compressor in the blocked state. The main reasons are as follows: first, since the flow does not change in the blocked state of the compressor, the performance points corresponding to multiple blocked states of the compressor at this flow, therefore, a single flow input cannot accurately predict the performance of the axial flow compressor at this flow; second, the performance of the axial flow compressor in the blocked state is determined by the flow and the outlet static pressure of the working condition point, and the calculation of the key parameters "loss coefficient" and "lag angle" in the performance calculation needs a semi-empirical model with flow and outlet static pressure as input. The model has not been published due to the lack of a supporting one-dimensional or two-dimensional analysis program of the axial flow compressor.

[0007] In summary, in the design process of the axial flow compressor, the prediction and analysis of the performance in the blocked state are crucial, and therefore, it is urgent to provide a method for predicting the performance of the axial flow compressor. SUMMARY

[0008] The purpose of the present application is to avoid the shortcomings of the prior art by using an optimization method to impose a calculation mode of the back pressure boundary condition of the low-dimensional analysis program of the axial flow compressor, so as to make it have the basic conditions for predicting the performance of the axial flow compressor in the blocked state, and to plan the calculation content and process of the low-dimensional analysis program of the axial flow compressor under the calculation mode of the back pressure boundary condition, solve the problem that the low-dimensional analysis program cannot predict the performance of the axial flow compressor in the blocked state in the existing axial flow compressor design system.

[0009] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a performance prediction method of an axial flow compressor using a back pressure boundary condition, comprising the following steps:

[0010] Step one, give a boundary condition of an axial flow compressor element in the performance analysis of the axial flow compressor, the boundary condition includes: absolute flow angle , total temperature , total pressure , pressure ratio , static pressure of the static blade outlet calculation station , the rotational speed of the axial compressor and the geometric parameters of the axial compressor elementary stage;

[0011] Step two, calculating the pressure ratio of the rotor inlet calculation station determining the static pressure of the rotor inlet calculation station , combining the static pressure of the stator outlet calculation station , so as to initialize the static pressure of the rotor outlet calculation station is:

[0012] ,

[0013] Step three, based on the performance analysis calculation model of the axial compressor and the number of axial compressor elementary stages, the performance parameters of the rotor inlet calculation station, the rotor outlet calculation station, the stator inlet calculation station and the stator outlet calculation station of the axial compressor are calculated in the direction of airflow of the axial compressor, and the calculation process of each axial compressor elementary stage is as follows:

[0014] First, according to the boundary conditions, the flow rate of the rotor inlet calculation station of the axial compressor elementary stage is solved ; according to the static pressure of the rotor outlet calculation station , the flow rate of the rotor outlet calculation station is solved ;

[0015] Next, according to the flow rate of the rotor outlet calculation station , the performance parameters of the stator inlet calculation station are solved

[0016] Among them, the performance parameters include the total temperature , total pressure , absolute tangential velocity , axial velocity , absolute velocity , static temperature , static pressure of the stator inlet calculation station;

[0017] Finally, according to the performance parameters of the stator inlet calculation station and the static pressure of the stator outlet calculation station , the flow rate of the stator outlet calculation station is calculated , that is, the calculation of the performance parameters of the axial compressor elementary stage is completed;

[0018] After the calculation of the performance parameters of each elementary stage is completed, it is judged whether the current elementary stage is the last axial compressor elementary stage in the axial compressor, that is, the flow rate of the rotor outlet calculation station and the flow rate of the stator outlet calculation station in each elementary stage of the axial compressor are obtained;

[0019] Step four, based on the least square method, the flow rate of the rotor inlet calculation station the flow rate of the moving blade outlet calculation station the flow rate of the stationary blade outlet calculation station establishing a target function for measuring the flow rate difference of the axial compressor elementary stage

[0020] Step five, based on the target function, the static pressure of the moving blade inlet calculation station the static pressure of the moving blade outlet calculation station for the optimization variable, according to the law of conservation of mass, using the variable optimization formula to update the optimization variable continuously until the value of the target function is less than 10 -8 , that is, the updated performance parameters of the axial compressor are obtained.

[0021] Further, in step three, the flow rate of the moving blade inlet calculation station is equal to the flow rate of the inlet guide vane outlet calculation station of the axial compressor.

[0022] Further, in step three, in the calculation of each elementary stage, the absolute flow angle, total temperature and total pressure of the moving blade inlet calculation station of the next axial compressor elementary stage are the same as those of the stationary blade outlet calculation station of the previous axial compressor elementary stage.

[0023] Further, the flow rate of the moving blade inlet calculation station in step three is solved as follows:

[0024] First, according to the total temperature , total pressure and static pressure of the moving blade inlet calculation station, the static temperature of the moving blade inlet calculation station is determined as follows:

[0025] ,

[0026] In the formula, is equal to 1.4, which is the specific heat ratio constant;

[0027] Next, according to the isentropic relationship, the absolute speed of the moving blade inlet calculation station is determined as follows:

[0028] ,

[0029] In the formula, is equal to 1004.0, which is the constant pressure specific heat capacity;

[0030] Further, in turn, according to the absolute flow angle of the moving blade inlet calculation station, and the axial speed of the moving blade inlet calculation station determined according to the speed triangle relationship; according to the rotational speed and the centerline radius of the rotor blade inlet calculation station , determine the circumferential velocity of the rotor blade inlet calculation station , absolute circumferential speed , relative circumferential speed and relative speed , the specific formulas include:

[0031] ,

[0032] ,

[0033] ,

[0034] ,

[0035] ,

[0036] Next, according to the thermodynamic relationship, determine the relative total temperature of the blade inlet calculation station. , relative total pressure , the specific formula is:

[0037] ,

[0038] ,

[0039] Then, based on the known geometric parameters of the axial flow compressor elementary stage and the static pressure of the moving blade inlet, the static pressure of the station is calculated. , static temperature , determine the airflow density at the rotor blade inlet calculation station and traffic , the specific formula is:

[0040] ,

[0041] ,

[0042] Where, Equal to 287.03, is the gas state constant, at this time, the output of the blade inlet calculation station flow .

[0043] Furthermore, the flow rate of the moving blade outlet calculation station in step 3 The calculation process is:

[0044] According to the conservation relationship of transfer enthalpy, the static pressure of the station is calculated based on the moving blade outlet. , circumferential speed and the relative total temperature of the blade inlet calculation station , circumferential speed Then, the relative total temperature at the blade exit calculation station is determined is determined as

[0045] ,

[0046] wherein is equal to 1004.0, the constant pressure specific heat capacity;

[0047] Based on the blade loss coefficient ,

[0048] ,

[0049] Thus, according to the isentropic relation, the ideal relative total pressure at the blade exit calculation station is determined is determined as

[0050] ,

[0051] wherein is equal to 1.4, the specific heat ratio constant;

[0052] Since the blade loss coefficient is calculated by the loss model in the axial compressor performance analysis and calculation model, the relative total pressure at the blade exit calculation station is determined is determined as

[0053] ,

[0054] Further, according to the static pressure at the blade exit calculation station which has been allocated , the relative total temperature at the blade exit calculation station , and the relative total pressure at the blade exit calculation station , according to the isentropic relation, the static temperature at the blade exit calculation station is determined is determined as

[0055] ,

[0056] According to the relation between the relative total temperature at the blade exit calculation station and the static temperature at the blade exit calculation station , the relative velocity at the blade exit calculation station is determined is determined as

[0057] ,

[0058] Continuously, according to the velocity triangle relation, the outlet circumferential velocity at the blade exit calculation station , the relative circumferential velocity at the blade exit calculation station , the absolute circumferential velocity at the blade exit calculation station , and the absolute velocity at the blade exit calculation station are determined, and the specific formula is

[0059] ,

[0060] ,

[0061] ,

[0062] ,

[0063] wherein, is the relative flow angle of the moving blade outlet calculation station, which is calculated by the lag angle model in the axial compressor performance analysis and calculation model;

[0064] Further, according to the stagnation state concept, the absolute velocity of the moving blade outlet calculation station is known, and the total temperature of the moving blade outlet calculation station is determined as:

[0065] ,

[0066] According to the isentropic relationship, and the static temperature , the total temperature , and the static pressure of the moving blade outlet calculation station, the total pressure of the moving blade outlet calculation station is determined as:

[0067] ,

[0068] The air flow density and the flow rate of the moving blade outlet calculation station are:

[0069] ,

[0070] ,

[0071] At this time, the flow rate of the moving blade outlet calculation station is obtained.

[0072] Further, the specific calculation process of the flow rate of the stator outlet calculation station in step three is as follows:

[0073] According to the static pressure of the stator outlet calculation station, the total pressure of the stator inlet calculation station, and the static running characteristics of the stator in the axial compressor elementary stage, the air flow in the stator belongs to absolute non-isentropic flow, so that the total temperature of the stator outlet calculation station is equal to the total temperature of the stator inlet calculation station;

[0074] Then, the total pressure of the stator blade outlet calculation station is determined is:

[0075] ,

[0076] wherein, is the stator blade loss coefficient, which is calculated by the loss model in the axial flow compressor performance analysis and calculation model;

[0077] Then, the static pressure of the stator blade outlet calculation station is determined , the total temperature , the total pressure , the static temperature of the stator blade outlet calculation station is determined is:

[0078] ,

[0079] Then, the absolute speed , the axial speed of the stator blade outlet calculation station are determined according to the isentropic relationship, combined with the known total temperature and static temperature of the stator blade outlet calculation station, and the absolute flow angle of the stator blade outlet calculation station determined by the lag angle model in the axial flow compressor performance analysis and calculation model, and the specific values are:

[0080] ,

[0081] , wherein,

[0082] is equal to 1004.0, which is the constant pressure specific heat capacity; At the same time, the flow density

[0083] and the flow rate of the stator blade outlet calculation station are determined, and the specific values are:

[0084] ,

[0085] , wherein,

[0086] is equal to 287.03, which is the gas state constant; At this time, the flow rate

[0087] of the stator blade outlet calculation station is obtained.

[0088] Further, the objective function established in step four is:

[0089] ,​

[0090] wherein, , , is the rotor inlet calculated station flow rate , the rotor outlet calculated station flow rate , the stator outlet calculated station flow rate .

[0091] Further, the variable optimization formula in step five is:

[0092] ,

[0093] wherein, is the updated input variable, is the input variable before updating, is the learning rate, representing the size of the parameter adjustment in the optimization process, is the is the corresponding output variable when the input variable is, corresponding to the output variable of the axial compressor outlet; comprises , , , and , , is the rotor inlet calculated station flow rate , the rotor outlet calculated station flow rate , the stator outlet calculated station flow rate .

[0094] The beneficial effects of the present application are: the present application provides an axial flow compressor performance prediction method using back pressure boundary conditions, which proposes a method and calculation process for applying back pressure boundary conditions by optimization means, and simultaneously plans the calculation content and process of the axial flow compressor low-dimensional analysis program under the calculation mode of the back pressure boundary condition by using the optimization means to apply the calculation mode of the back pressure boundary condition of the axial flow compressor low-dimensional analysis program; so that the axial flow compressor low-dimensional analysis program has the ability to predict the performance of the axial flow compressor in the blocked state; also enhances the performance prediction integrity and reliability of the axial flow compressor in the one-dimensional design stage and two-dimensional design stage of the axial flow compressor design system. BRIEF DESCRIPTION OF DRAWINGS

[0095] Figure 1 is the flow chart of the present application;

[0096] Figure 2 is the schematic diagram of the axial flow compressor element level structure described in the present application;

[0097] Figure 3is a schematic diagram of a three-stage axial flow compressor PW3S1 in specific example 1 of the present application;

[0098] Figure 4 is a schematic diagram of a velocity triangle principle in specific example 1 of the present application;

[0099] Figure 5 is a total pressure and static pressure distribution diagram of each calculation station obtained by using a flow boundary condition in specific example 1 of the present application;

[0100] Figure 6 is an axial velocity distribution diagram of each calculation station obtained by using a flow boundary condition in specific example 1 of the present application;

[0101] Figure 7 is a comparison diagram of total pressure and static pressure distribution of each calculation station obtained by using a flow boundary condition and using a back pressure boundary condition respectively in three-stage axial flow compressor PW3S1 in specific example 1 of the present application;

[0102] Figure 8 is a comparison diagram of axial velocity distribution of each calculation station obtained by using a flow boundary condition and using a back pressure boundary condition respectively in three-stage axial flow compressor PW3S1 in specific example 1 of the present application;

[0103] Figure 9 is a convergence history diagram of the calculation process in specific example 1 of the present application;

[0104] Figure 10 is a schematic diagram of a structure principle of a Laval nozzle in specific example 2 of the present application;

[0105] Figure 11 is an outlet static pressure flow characteristic diagram obtained in specific example 2 of the present application;

[0106] Figure 12 is a comparison diagram of a calculation result and an analytical solution by using a back pressure boundary condition in a blocked state of the Laval nozzle in specific example 2 of the present application;

[0107] Figure 13 is a convergence history diagram of the calculation process in specific example 2 of the present application. DETAILED DESCRIPTION

[0108] The principles and features of the present application are described below in conjunction with the drawings, and the examples are only used to explain the present application and are not used to limit the scope of the present application.

[0109] Example 1: As shown in the present application, a kind of axial flow compressor performance prediction method using back pressure boundary condition includes the following steps: Figure 1

[0110] ​S01. Given the boundary conditions of an axial flow compressor elementary stage in the axial flow compressor performance analysis, the boundary conditions include: the absolute airflow angle of the rotor blade inlet calculation station , total temperature , total pressure , pressure ratio ; Static pressure at the stationary blade outlet , axial compressor speed and the geometrical parameters of the elementary stage of the axial flow compressor;

[0111] S02. Calculate the pressure ratio of the station based on the moving blade inlet Determine the static pressure at the rotor blade inlet calculation station , combined with the static pressure of the stationary blade outlet calculation station , thereby initializing the static pressure distribution of the blade outlet calculation station for:

[0112] ;

[0113] S03. Calculate the performance parameters of the first axial flow compressor elementary stage rotor blade inlet, rotor blade outlet calculation station, stator blade inlet, and stator blade outlet calculation station:

[0114] Calculate the total temperature of the station based on the blade inlet , total pressure , static pressure , determine the static temperature of the blade inlet calculation station for:

[0115] ,

[0116] Where, is equal to 1.4, which is the specific heat constant;

[0117] Then, according to the isentropic relationship, the absolute speed of the rotor blade inlet calculation station is determined for:

[0118] ,

[0119] Where, is equal to 1004.0, which is the specific heat capacity at constant pressure;

[0120] Then, according to the absolute airflow angle of the rotor blade inlet, , and the axial velocity of the rotor blade inlet calculation station determined according to the velocity triangle relationship ; According to the speed of the axial compressor and the centerline radius of the rotor blade inlet calculation station , determine the circumferential velocity of the rotor blade inlet calculation station , absolute circumferential speed Relative tangential velocity and relative velocity , the specific formulae include:

[0121] ,

[0122] ,

[0123] ,

[0124] ,

[0125] ,

[0126] S04, according to the thermodynamic relation, the relative total temperature of the rotor inlet calculation station is determined , the relative total pressure , the specific formulae are:

[0127] ,

[0128] ,

[0129] S05, according to the known geometric parameters of the axial compressor elementary stage, and the static pressure , the static temperature of the rotor inlet calculation station, the air flow density and the flow rate of the rotor inlet calculation station are determined, the specific formulae are:

[0130] ,

[0131] ,

[0132] In the formula, is equal to 287.03, which is the gas state constant, at this time, the flow rate of the rotor inlet calculation station of the output first axial compressor elementary stage , the flow rate of the rotor inlet calculation station at this time is equal to the flow rate of the inlet guide vane outlet calculation station of the axial compressor;

[0133] S06, according to the rotational enthalpy conservation relation, based on the static pressure , the tangential velocity of the rotor outlet calculation station, and the relative total temperature , the tangential velocity of the rotor inlet calculation station, the relative total temperature of the rotor outlet calculation station is determined as:

[0134] ,

[0135] wherein, is equal to 1004.0, is the specific heat at constant pressure;

[0136] Based on the blade loss coefficient :

[0137] ,

[0138] Thus, according to the isentropic relation, the ideal relative total pressure at the blade outlet calculation station is determined as :

[0139] ,

[0140] wherein, is equal to 1.4, is the specific heat ratio constant;

[0141] Since the blade loss coefficient is calculated by the loss model in the axial flow compressor performance analysis and calculation model, the relative total pressure at the blade outlet calculation station is determined as :

[0142] ,

[0143] Further, according to the assigned static pressure at the blade outlet calculation station , the relative total temperature at the blade outlet calculation station , and the relative total pressure at the blade outlet calculation station , according to the isentropic relation, the static temperature at the blade outlet calculation station is determined as :

[0144] ,

[0145] S07, according to the relation between the relative total temperature at the blade outlet calculation station and the static temperature at the blade outlet calculation station , the relative velocity at the blade outlet calculation station is determined as :

[0146] ,

[0147] Continuously, according to the velocity triangle relation, the outlet circumferential velocity at the blade outlet calculation station , the relative circumferential velocity at the blade outlet calculation station , the absolute circumferential velocity at the blade outlet calculation station , and the absolute velocity at the blade outlet calculation station are determined, and the specific formula is:

[0148] ,

[0149] ,

[0150] ,

[0151] ,

[0152] where, is the relative flow angle at the rotor outlet calculation station, which is calculated from the lag angle model in the axial compressor performance analysis and calculation model;

[0153] S08, according to the stagnation state concept, the absolute velocity and the static temperature at the rotor outlet calculation station are known, and the total temperature at the rotor outlet calculation station is determined as:

[0154] ,

[0155] S09, according to the isentropic relationship, and the static temperature , the total temperature , and the static pressure at the rotor outlet calculation station, the total pressure at the rotor outlet calculation station is determined as:

[0156] ,

[0157] The air flow density and the flow rate at the rotor outlet calculation station are:

[0158] ,

[0159] ,

[0160] At this time, the flow rate at the rotor outlet calculation station of the first axial compressor elementary stage is obtained.

[0161] S10, according to the static pressure at the stator outlet calculation station, the total pressure at the stator inlet calculation station, and the static running characteristics of the stator in the axial compressor elementary stage, the air flow in the stator belongs to absolute non-isentropic flow, so the total temperature at the stator outlet calculation station is equal to the total temperature at the stator inlet calculation station;

[0162] S11, the total pressure at the stator outlet calculation station is determined as:

[0163] ,

[0164] where, is the loss coefficient of the stator blade, which is calculated by the loss model in the performance analysis and calculation model of the axial flow compressor;

[0165] Then, the static pressure , total temperature , and total pressure at the stator blade outlet calculation station are determined, and the static temperature at the stator blade outlet calculation station is determined as follows:

[0166] ,

[0167] S12, the absolute speed , axial speed , and absolute flow angle at the stator blade outlet calculation station are determined according to the isentropic relationship, in combination with the total temperature , static temperature at the stator blade outlet calculation station, and the absolute flow angle at the stator blade outlet calculation station determined by the lag angle model in the performance analysis and calculation model of the axial flow compressor, and the specific values are as follows:

[0168] ,

[0169] ,

[0170] In the formula, is equal to 1004.0, which is the constant-pressure specific heat capacity;

[0171] At the same time, the air flow density and flow rate at the stator blade outlet calculation station are determined, and the specific values are as follows:

[0172] ,

[0173] ,

[0174] In the formula, is equal to 287.03, which is the gas state constant;

[0175] At this time, the flow rate at the stator blade outlet calculation station is obtained, and in this embodiment, the calculation of the performance parameters of the first axial flow compressor elementary stage is completed;

[0176] S13, according to the principle that the absolute flow angle, total temperature, total pressure of the next axial flow compressor elementary stage rotor inlet calculation station are the same as the absolute flow angle, total temperature, total pressure of the last axial flow compressor elementary stage stator outlet calculation station, the performance parameters of each elementary stage are calculated according to the calculation method of steps S03 to S12, and it is judged that the current elementary stage is the last axial flow compressor elementary stage in the axial flow compressor, that is, the flow rate of the rotor outlet calculation station and the flow rate of the stator outlet calculation station of all elementary stages included in the axial flow compressor are obtained;

[0177] S14, based on the least square method, the flow rate of the rotor inlet calculation station , the flow rate of the rotor outlet calculation station , and the flow rate of the stator outlet calculation station , the objective function for measuring the flow rate difference of the axial flow compressor elementary stage is established as:

[0178] ,

[0179] In the formula, , , The flow rate of the rotor inlet calculation station is , the flow rate of the rotor outlet calculation station is , and the flow rate of the stator outlet calculation station is .

[0180] Step five, based on the objective function, the static pressure of the rotor inlet calculation station , the static pressure of the rotor outlet calculation station are used as optimization variables, and the variable optimization formula is used to update the optimization variables according to the law of conservation of flow rate until the value of the objective function is less than 10 -8 , and the variable optimization formula is:

[0181] ,

[0182] In the formula, is the updated input variable, is the input variable before updating, is the learning rate, which represents the size of the parameter adjustment in the optimization process, is is the output variable corresponding to the input variable, is the output variable corresponding to the input variable; includes , , , and , , The flow rate of the rotor inlet calculation station is , the flow rate of the rotor outlet calculation station is , the static blade outlet calculation station flow ;

[0183] At this time, the updated axial compressor performance parameters are obtained.

[0184] As Figures 2-13 indicated, in order to further illustrate the technical solutions and technical effects of the present application, the following specific examples are provided:

[0185] Specific Example 1: As Figures 2-9 indicated, taking a three-stage axial compressor PW3S1 as an example, as Figure 2 indicated, an axial compressor elementary stage structure diagram, wherein R represents a moving blade, and S represents a static blade; the axial compressor elementary stage is composed of one row of moving blades and one row of static blades, and the stage number of the axial compressor is determined by the number of elementary stages contained in the axial compressor;

[0186] The calculation stations in the axial compressor elementary stage are defined, including the moving blade inlet calculation station, the moving blade outlet calculation station, the static blade inlet calculation station, and the static blade outlet calculation station; the airflow in the axial compressor elementary stage flows in along the axial direction from the moving blade inlet calculation station, passes through the moving blade outlet calculation station, the static blade inlet calculation station in sequence, and flows out from the static blade outlet calculation station;

[0187] The calculation stations in the axial compressor elementary stage are defined, including the moving blade inlet calculation station, the moving blade outlet calculation station, the static blade inlet calculation station, and the static blade outlet calculation station; the airflow in the axial compressor elementary stage flows in along the axial direction from the moving blade inlet calculation station, passes through the moving blade outlet calculation station, the static blade inlet calculation station in sequence, and flows out from the static blade outlet calculation station; , the axial compressor calculation station ring area , the axial compressor calculation station centerline radius , the axial compressor rotational speed , the absolute airflow angle , wherein the number of calculation stations in the axial compressor elementary stage is represented by n, wherein the guide vane inlet calculation station , the guide vane outlet calculation station , the first-stage moving blade outlet calculation station , the first-stage moving blade outlet calculation station , the first-stage static blade inlet calculation station , the first-stage static blade outlet calculation station , the second-stage moving blade inlet calculation station , the second-stage moving blade outlet calculation station , the second-stage static blade inlet calculation station , the second-stage static blade outlet calculation station , the third-stage moving blade inlet calculation station , the third-stage moving blade outlet calculation station , the third-stage static blade inlet calculation station , the third-stage static blade outlet calculation station ; wherein the centerline position is also shown in Figure 2 ;

[0188] As Figure 3The three-stage axial flow compressor PW3S1 shown in the figure is composed of a first row of inlet guide vanes and three sequentially arranged elementary stages. The airflow in the three-stage axial flow compressor PW3S1 flows in the axial direction from the guide vane inlet calculation station, passes through the guide vane outlet calculation station, the first-stage moving blade outlet calculation station, the first-stage moving blade outlet calculation station, the first-stage stator blade inlet calculation station, the first-stage stator blade outlet calculation station, the second-stage moving blade inlet calculation station, the second-stage moving blade outlet calculation station, the second-stage stator blade inlet calculation station, the second-stage stator blade outlet calculation station, the third-stage moving blade inlet calculation station, the third-stage moving blade outlet calculation station, the third-stage stator blade inlet calculation station, and flows out from the third-stage stator blade outlet calculation station. Specific calculation example 1 of the present invention is Figure 3 The three-stage axial compressor PW3S1 is shown;

[0189] The specific method steps of the present invention are:

[0190] Step 1: Given the boundary conditions of the three-stage axial flow compressor PW3S1 in the axial flow compressor performance analysis calculation model;

[0191] The boundary conditions for the performance analysis of the axial flow compressor elementary stage include: the absolute airflow angle at the rotor blade inlet calculation station , total temperature of the rotor blade inlet calculation station , total pressure of the rotor blade inlet calculation station , geometric parameters of each calculation station in the axial flow compressor elementary stage, static pressure of the stationary blade outlet calculation station And the static pressure of the blade inlet calculation station Total pressure of the rotor blade inlet calculation station Compare ;

[0192] Among them, in the boundary conditions, the absolute airflow angle of the inlet guide vane inlet calculation station given in the example is , total temperature , total pressure , the static pressure of the station outlet of the last elementary stage , axial compressor speed and the geometrical parameters of each computing station in the elementary stage of the axial flow compressor;

[0193] In addition, it should be noted that if the axial flow compressor includes inlet guide vanes, the absolute flow angle, total temperature, and total pressure mentioned in the boundary conditions are the parameters at the inlet guide vane inlet calculation station; the parameters at the inlet in the boundary conditions refer to the parameters at the inlet calculation station of the first blade row in the axial flow compressor;

[0194] Step 2: Calculate the station pressure ratio based on the inlet of the first row of inlet guide vanes , determine the static pressure of the first elementary stage inlet guide vane inlet calculation station , combined with the last elementary level station blade outlet calculation station static pressure Thus, the static pressure of the other blade stage outlet calculation station is initialized to be:

[0195]

[0196]

[0197]

[0198]

[0199]

[0200]

[0201] In addition, the three-stage axial compressor PW3S1 contains inlet guide vanes, and the parameter calculation of the inlet guide vane inlet calculation station and the inlet guide vane outlet calculation station is the same as that of the stator blade inlet calculation station and the stator blade outlet calculation station. The following steps are performed in the order of the element stages, starting from the first-stage blade inlet calculation station.

[0202] Step three, blade inlet calculation station parameter solving:

[0203] According to the boundary conditions given in step three and the static pressure of the blade stator outlet calculation station assigned in step four According to the order of the element stages from the blade inlet calculation station, the blade outlet calculation station, the stator blade inlet calculation station, and the stator blade outlet calculation station in sequence, each calculation station is solved for the three-stage axial compressor PW3S1:

[0204] First, the parameter calculation is performed for the first-stage blade inlet calculation station. According to the total temperature of the first-stage blade inlet calculation station , the total pressure of the first-stage blade inlet calculation station , and the static pressure of the first-stage blade inlet calculation station , the static temperature of the first-stage blade inlet calculation station is determined :

[0205]

[0206] wherein is the specific heat ratio, a constant, approximately 1.4;

[0207] Further, the absolute velocity of the first-stage blade inlet calculation station is determined according to the stagnation state concept :

[0208] ​​​​​​​​​​​​​ ,

[0209] where, is the specific heat at constant pressure, a constant, approximately 1004.0;

[0210] Further, the absolute flow angle at the first stage blade inlet calculation station is determined according to the first stage blade inlet calculation station absolute flow angle and Figure 4 the velocity triangle relationship , the first stage blade inlet calculation station peripheral velocity is determined according to the rotational speed of the axial compressor and the first stage blade inlet calculation station mean radius , the first stage blade inlet calculation station absolute peripheral velocity , the first stage blade inlet calculation station relative peripheral velocity and the first stage blade inlet calculation station relative velocity :

[0211] ,

[0212] ,

[0213] ,

[0214] ,

[0215] ,

[0216] The first stage blade inlet calculation station relative total temperature , the first stage blade inlet calculation station relative total pressure are determined according to the thermodynamic relationship

[0217] ,

[0218] ,

[0219] Further, the first stage blade inlet calculation station air density and the first stage blade inlet calculation station flow rate are determined according to the known geometric parameters and the first stage blade inlet calculation station static pressure , the first stage blade inlet calculation station static temperature :

[0220] ,

[0221] ,

[0222] ​Furthermore, according to the law of flow conservation, the flow rate of the first stage rotor blade inlet calculation station is determined Is it equal to the flow rate of the inlet guide vane outlet calculation station? , iteratively adjust the axial speed of the first stage rotor blade inlet calculation station according to the difference between the two Flow rate to the first stage rotor blade inlet calculation station Calculate the flow rate of the outlet of the inlet guide vane Keep consistent; at the same time, the thermal parameters of the first-stage rotor blade inlet calculation station are kept updated during the iteration process;

[0223] Step 6: Solve the parameters of the rotor blade outlet calculation station:

[0224] The static pressure of the first stage moving blade outlet is calculated based on the static pressure of the first stage moving blade outlet determined in step 4. , and the conservation relationship of transfer enthalpy, the relative total temperature of the blade outlet calculation station Calculate the relative total temperature of the station through the blade inlet And the circumferential speed of the blade outlet calculation station Sure:

[0225] ,

[0226] Furthermore, the blade loss coefficient Calculated by the following formula:

[0227] ,

[0228] Determine the ideal relative total pressure at the first stage moving blade outlet calculation station based on the isentropic relationship :

[0229] ,

[0230] Due to the blade loss coefficient The relative total pressure at the first stage moving blade outlet calculation station can be determined by calculating the loss model in the performance prediction program. :

[0231] ,

[0232] Furthermore, the station static pressure is calculated based on the allocated first stage moving blade outlet , and the relative total temperature of the first stage moving blade outlet calculation station and the relative total pressure at the first stage rotor blade outlet calculation station , according to the isentropic relationship, the static temperature of the first stage moving blade outlet calculation station is determined :

[0233] ,

[0234] Furthermore, the relative airflow angle of the first stage rotor blade outlet is calculated Calculated by the lag angle model in the performance prediction program;

[0235] Furthermore, the relative total temperature of the station is calculated based on the first stage moving blade outlet. and static temperature of the first stage rotor blade outlet calculation station The relationship between the first stage rotor blade outlet calculation station relative speed is determined :

[0236] ,

[0237] Furthermore, according to the velocity triangle relationship, the circumferential velocity of the first stage rotor blade outlet calculation station is determined. , Relative circumferential velocity of the first stage rotor blade outlet calculation station , Absolute circumferential velocity of the first stage rotor blade outlet calculation station And the absolute speed of the first stage rotor blade outlet calculation station :

[0238] ,

[0239] ,

[0240] ,

[0241] ,

[0242] Furthermore, according to the concept of stagnation state, the absolute velocity of the calculation station at the outlet of the first stage rotor blade is known to be and static temperature of the first stage rotor blade outlet calculation station , determine the total temperature of the first stage moving blade outlet calculation station for:

[0243] ,

[0244] Furthermore, according to the isentropic relationship and the static temperature of the first stage moving blade outlet, , the total temperature of the first stage moving blade outlet calculation station , Static pressure of the first stage moving blade outlet calculation station , determine the total pressure of the first stage moving blade outlet calculation station for:

[0245] ,

[0246] Further, a method similar to step 5 is used to determine the airflow density at the first stage rotor blade outlet calculation station. And the flow rate of the first stage moving blade outlet calculation station :

[0247] ,

[0248] ,

[0249] Complete the parameter calculation of the first-stage moving blade outlet calculation station and output the flow rate of the first-stage moving blade outlet calculation station ;

[0250] Step 7: Solve the parameters of the stationary blade inlet calculation station:

[0251] The airflow flows out from the first stage moving blade outlet calculation station and directly enters the first stage stationary blade inlet calculation station. According to the flow conservation law, the flow rate of the first stage stationary blade inlet calculation station is determined. Calculate the station flow rate at the first stage rotor blade outlet ;

[0252] Furthermore, according to the absolute isentropic flow characteristics, the total temperature of the calculation station at the first-stage stator inlet is determined. Equal to the total temperature of the first stage moving blade outlet calculation station , total pressure at the first stage station blade inlet calculation station Equal to the total pressure at the first stage rotor blade outlet calculation station ;

[0253] Furthermore, the absolute circumferential velocity of the first-stage stator blade inlet calculation station is determined by equal annular volume calculation. :

[0254]

[0255] Furthermore, assuming that the axial velocity of the first-stage stator blade inlet is , calculated based on the absolute circumferential velocity of the first stage stator inlet 、Total temperature of the first stage stator blade inlet calculation station , determine the absolute speed of the first stage stator blade inlet calculation station and the static temperature of the first stage stator blade inlet calculation station :

[0256] ,

[0257] ,

[0258] Furthermore, according to the isentropic relationship and the total temperature of the first stage stator inlet, 、The static temperature of the first stage stator blade inlet calculation station 、Total pressure at the first stage station blade inlet calculation station Determine the static pressure at the first stage stator inlet calculation station :

[0259] ,

[0260] Furthermore, the static pressure of the station is calculated based on the first stage stator inlet. 、The static temperature of the first stage stator blade inlet calculation station , determine the airflow density at the first stage stator inlet calculation station , the flow rate of the first stage stator inlet calculation station :

[0261] ,

[0262] ,

[0263] Furthermore, according to the law of flow conservation, the flow rate of the first-stage stator inlet calculation station is determined Is it equal to the flow rate of the first stage moving blade outlet calculation station? , iteratively adjust the axial speed of the first stage stator blade inlet calculation station according to the difference between the two Flow rate to the first stage stator inlet calculation station Calculate the flow rate at the outlet of the first stage rotor blade Keep consistent; at the same time, the thermal parameters of the calculation station of the first-stage stator inlet are kept updated during the iteration process;

[0264] Step 8. Solve the parameters of the stationary blade outlet calculation station:

[0265] Static pressure of the first stage stator outlet calculation station In step 3, it has been determined that according to the operating characteristics of the static stator blades in the elementary stage of the axial flow compressor, the air flow in the stator blades belongs to absolute energy non-isentropic flow, and the total temperature of the calculation station at the outlet of the first stage stator blade is determined. Equal to the total temperature of the first stage stator inlet calculation station ;

[0266] Furthermore, the stator loss coefficient Calculated by the following formula:

[0267] ,

[0268] Furthermore, the stator loss coefficient The total pressure at the first stage station blade outlet is determined by the loss model in the performance prediction program. :

[0269] ,

[0270] Furthermore, the static pressure at the first stage stator outlet is calculated , total pressure at the first stage station blade inlet calculation station 、Total temperature of the first stage stator blade inlet calculation station , determine the static temperature of the first stage stator blade outlet calculation station :

[0271] ,

[0272] Further, according to the stagnation state concept, the absolute velocity at the first stage stator exit calculation station is determined by the known first stage stator exit calculation station total temperature and the first stage stator exit calculation station static temperature and the first stage stator exit calculation station absolute flow angle determined by the lag angle model in the performance prediction program

[0273] ,

[0274] ,

[0275] Further, the first stage stator exit calculation station air density and the first stage stator exit calculation station flow rate are determined according to a method similar to the step five:

[0276] ,

[0277] ,

[0278] The first stage stator exit calculation station parameter solving is completed, and the first stage stator exit calculation station flow rate is outputted;

[0279] Step nine, axial compressor outlet determination:

[0280] The axial compressor outlet is the stator exit calculation station of the last elementary stage of the axial compressor; it is determined whether the stator exit calculation station in the step eight is the axial compressor outlet, for the three-stage axial compressor PW3S1, the stator exit calculation station in the step eight is the first stage outlet of the axial compressor, and the three-stage axial compressor PW3S1 contains three elementary stages, so the parameter calculation of the next elementary stage is continued, and the steps four to eight are repeated;

[0281] Step ten, for the three-stage axial compressor PW3S1, the absolute velocity at the second stage stator exit calculation station is determined according to the initialized and allocated calculation station static pressure , , , , , , , ​​​, the inlet guide vane inlet calculation station, the inlet guide vane outlet calculation station, the first stage moving blade outlet calculation station, the first stage static blade outlet calculation station, the second stage moving blade outlet calculation station, the second stage static blade outlet calculation station, the third stage moving blade outlet calculation station, the third stage static blade outlet calculation station, corresponding flow rates 、 、 、 、 、 、 、 ; in this step, for the convenience of expression , , , , , , , are respectively denoted as , , , , , , , 、 、 、 、 、 、 、 are respectively denoted as , , , , , , , as the output of the steps five to eight. According to the law of conservation of flow rate, i.e. ;

[0282] Therefore, using the least square method, the output variables are constructed as the objective function of the optimization problem :

[0283] ,

[0284] Step five, based on the objective function, the inlet guide vane inlet calculation station static pressure , the inlet guide vane inlet calculation station static pressure , the first stage moving blade outlet calculation station static pressure , the first stage static blade outlet calculation station static pressure , the second stage moving blade outlet calculation station static pressure​ , second stage vane exit calculation station static pressure , third stage blade exit calculation station static pressure For optimization variables, according to the law of flow conservation, the optimization variables are constantly updated using the variable optimization formula until the value of the objective function is less than 10 -8 , that is, the updated axial flow compressor performance parameters are obtained;

[0285] The variable optimization formula is:

[0286] ,

[0287] Wherein, is the updated input variable, is the input variable before updating, is the learning rate, which represents the size of the parameter adjustment amplitude in the optimization process, is is the corresponding output variable when the input variable is, the output variable corresponding to the outlet of the axial flow compressor; subscript represents the input, ;

[0288] After determining the direction of updating the input static pressure, the size of the updating step is determined; according to the situation that the input static pressure of each calculation station in the axial flow compressor is inconsistent, the learning rate and are combined to determine the step size of updating the input static pressure of each calculation station and to keep it matched;

[0289] At the same time, the value of the input variable , , , , , , is constantly adjusted in the optimization process to ensure that the output flow of each calculation station tends to be constant, the value of the objective function tends to 0, and the calculation is completed and the axial flow compressor performance parameters are obtained after reaching the convergence standard.

[0290] Finally, the optimization obtained three-stage axial flow compressor PW3S1 simulation parameters include:

[0291] The total pressure of the inlet is 101325pa, the total temperature of the inlet is 288.15k, the rotating speed is 5455RPM, the flow rate is 4.29kg / s, and there are seven rows of blades and 14 calculation stations.

[0292] Three-stage axial flow compressor PW3S1 simulation result verification:

[0293] In the first step, the one-dimensional analysis program of the axial flow compressor with flow rate as the boundary condition is used to calculate the above working conditions. The total pressure and static pressure distribution of each calculation station are as follows: Figure 5 As shown, the horizontal axis is the number of each calculation station, and the vertical axis is the pressure;

[0294] The axial velocity distribution of each calculation station is obtained as follows Figure 6 As shown, the horizontal axis is the number of each calculation station, the vertical axis is the speed, and under the design point working condition, the static pressure at the calculation station of the third-stage stator outlet of the three-stage axial compressor PW3S1 is 14430.5 Pa;

[0295] In the second step, the static pressure and boundary condition parameters of the calculation station at the third-stage stator outlet of the three-stage axial flow compressor PW3S1 obtained in the first step are used as input and calculation is performed according to the steps described in the present invention.

[0296] Compare the calculation results with the results obtained in the first step. Figure 7 As shown, the horizontal axis is the number of each computing station, and the vertical axis is the pressure; the circle line is the calculation result of the one-dimensional analysis program of the axial flow compressor with flow rate as the boundary condition, and the cross line is the calculation result of the one-dimensional analysis program of the axial flow compressor with pressure as the boundary condition.

[0297] The comparison results of the axial velocity of each calculation station are as follows: Figure 8 As shown, the horizontal axis is the number of each computing station, and the vertical axis is the speed; the circle line is the calculation result of the one-dimensional analysis program of the axial flow compressor with flow as the boundary condition, and the cross line is the calculation result of the one-dimensional analysis program of the axial flow compressor with pressure as the boundary condition.

[0298] The flow convergence history in the final optimization process of the present invention is as follows Figure 9 As shown; Simulation results analysis of three-stage axial compressor PW3S1:

[0299] Conclusion 1: Figure 7 Comparison results of total pressure and static pressure in Figure 8 The comparison results of axial velocity show that the calculation results obtained by the method of the present invention are completely consistent with the calculation results obtained by using the one-dimensional analysis program of flow boundary conditions, which proves that the method of the present invention has the ability to predict the performance parameters of each calculation station of the compressor;

[0300] Conclusion 2: From Figure 9 The convergence history of the flow rate shows that the inlet and outlet flows gradually become consistent during the program calculation process and converge to the flow rate corresponding to the working condition;

[0301] Conclusion 3: Simulation data demonstrates that the method described in this patent can replace the traditional one-dimensional analysis program for axial flow compressors that uses flow as a boundary condition for compressor performance prediction. The feasibility and effectiveness of the theory and method proposed in this patent have been verified.

[0302] Specific example 2: Figures 10-13 As shown in Figure 2, this specific example primarily analyzes and calculates the performance parameters of an axial compressor in a blocked state. Since the flow rate remains constant in a blocked state, the performance of an axial compressor is related to the loss and trailing angle of the blocked blade row. In this case, the loss or trailing angle is related to the static pressure at the blade outlet and the blocked flow rate.

[0303] The method provided in this application also provides basic conditions for the axial flow compressor performance analysis calculation model to predict the performance of the axial flow compressor under the blocked state. Due to the lack of a supporting model for predicting loss and lagging angle, the verification of the axial flow compressor blocked state in this invention is relatively difficult.

[0304] However, the flow path of the blocked exhaust flow of the axial compressor is similar to that of the Laval nozzle, and the flow state of the airflow is similar to the supercritical state of the Laval nozzle with a subsonic outlet. Therefore, the second example of the present invention is the calculation of the flow from the inlet to the throat to the outlet of a symmetrical Laval nozzle, as shown in FIG. Figure 10 As shown in the figure, there are three calculation stations, namely inlet calculation station 1, throat calculation station 2, and outlet calculation station 3. The static pressures of the three calculation stations are given during initialization, and the calculation is performed using the following steps:

[0305] Step 1: Given the boundary conditions for the Laval nozzle when calculating with back pressure boundary conditions:

[0306] The boundary conditions include: absolute airflow angle at the inlet calculation station , total temperature , total pressure , static pressure of the export calculation station ,Here the static pressure of the outlet calculation station is not limited to a single value, and the static pressures of multiple outlet calculation stations will be given for calculation;

[0307] Step 2: Calculate the station pressure ratio based on the inlet Determine the static pressure at the inlet calculation station , combined with the static pressure of the outlet calculation station , thereby initializing the static pressure of the distribution throat calculation station :

[0308] ,

[0309] Step 3: Calculate the inlet calculation station, throat calculation station, and outlet calculation station in sequence, and solve the flow rate of the inlet calculation station according to the boundary conditions. , throat calculated station flow rate , exit calculated station flow rate :

[0310] Step four, based on the least square method, the inlet calculated station flow rate , throat calculated station flow rate , exit calculated station flow rate , a target function for measuring the flow rate difference of the inlet calculated station, throat calculated station and exit calculated station of the Laval nozzle is established;

[0311] Step five, based on the target function, the inlet calculated station static pressure , throat calculated station static pressure is taken as the optimization variable, the optimization variable is constantly updated according to the flow conservation law using the variable optimization formula until the value of the target function is less than 10 -8 , and the performance parameters of the updated Laval nozzle are obtained.

[0312] Laval nozzle simulation results:

[0313] With the continuous decrease of the Laval nozzle exit calculated station static pressure, the Laval nozzle enters a supercritical state, which corresponds to the choked state in the axial flow compressor. At this time, the Laval nozzle throat is choked, and the flow rate of the entire nozzle no longer changes, as shown in Figure 11 , wherein the horizontal coordinate is the flow rate, and the vertical coordinate is the Laval nozzle exit static pressure;

[0314] When the nozzle is in a supercritical state, the outlet Mach number calculated by the method described in the present application is compared with the analytical solution obtained by theoretical calculation, and the comparison results are shown in Figure 12 , wherein the horizontal coordinate is the outlet Mach number, and the vertical coordinate is the ratio of the Laval nozzle exit calculated station static pressure to the Laval nozzle inlet calculated station total pressure; the circle point is the theoretical calculation result, and the solid line is the calculation result of the method described in the present application;

[0315] Under a certain supercritical condition of the Laval nozzle, the convergence history of the Laval nozzle inlet calculated station flow rate, the Laval nozzle throat calculated station flow rate and the Laval nozzle exit calculated station flow rate is shown in Figure 13 , wherein the horizontal coordinate is the iteration step number, and the vertical coordinate is the flow rate; the solid line, the dashed line and the dot-dashed line respectively represent the Laval nozzle inlet calculated station flow rate, the exit calculated station flow rate and the throat calculated station flow rate change;

[0316] Laval nozzle simulation result analysis:

[0317] Conclusion one: from Figure 11It can be seen that with the continuous decrease of the static pressure of the exit calculation station of the Laval nozzle, the Laval nozzle gradually enters the supercritical state, at this time, the flow in the nozzle changes constantly, and the trend of the flow change in the Laval nozzle is successfully predicted;

[0318] Conclusion two: from Figure 12 From the comparison between the calculation results of the method and the theoretical calculation, it can be seen that the method can accurately predict the change of the exit Mach number after the Laval nozzle is blocked, and since the nozzle enters the supercritical state, there are shock waves and losses in the nozzle expansion section, and the size of the loss directly affects the size of the exit Mach number, therefore, the successful prediction of the exit Mach number can represent the effectiveness of the method;

[0319] Conclusion three: from Figure 13 It can be seen that the flow of the three calculation stations in the Laval nozzle converges to the expected flow with the increase of the iteration number.

[0320] Conclusion four: the simulation data show that the method has the ability to capture the flow size and the performance level of the blocked state of the Laval nozzle, and it is proved that the method provides a basic condition for the one-dimensional and two-dimensional analysis programs of the axial flow compressor to predict the performance of the blocked state of the axial flow compressor.

[0321] The above only describes the preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for predicting axial flow compressor performance using back pressure boundary conditions, characterized in that: The following steps are involved: Step 1: Given the boundary conditions of an axial flow compressor elementary stage in the axial flow compressor performance analysis, the boundary conditions include: the absolute airflow angle of the blade inlet calculation station , total temperature , total pressure , pressure ratio ; Static pressure at the stationary blade outlet , axial compressor speed and the geometrical parameters of the elementary stage of the axial flow compressor; Step 2: Calculate the pressure ratio of the station based on the moving blade inlet Determine the static pressure at the rotor blade inlet calculation station , combined with the static pressure of the stationary blade outlet calculation station , thereby initializing the static pressure distribution of the blade outlet calculation station for: ， Step 3: Based on the axial flow compressor performance analysis calculation model and the number of axial flow compressor elementary stages, the performance parameters of the axial flow compressor's moving blade inlet, moving blade outlet calculation stations, stator blade inlet, and stator blade outlet calculation stations are calculated elementary stage by elementary stage in the airflow direction of the axial flow compressor. The calculation process for each axial flow compressor elementary stage is as follows: First, according to the boundary conditions, the flow rate of the rotor blade inlet calculation station of the axial flow compressor primitive stage is solved. ;Calculate the static pressure of the station according to the blade outlet , solve the flow rate of the rotor blade outlet calculation station ; Next, calculate the flow rate of the station according to the rotor blade outlet , solve the performance parameters of the stationary blade inlet calculation station; Among them, the performance parameters include the total temperature of the stationary blade inlet calculation station , total pressure , absolute circumferential speed , axial speed , absolute speed , static temperature , static pressure ; Finally, according to the performance parameters of the stationary blade inlet calculation station and the static pressure of the stationary blade outlet calculation station , calculate the flow rate of the stationary blade outlet calculation station , that is, completing the calculation of the performance parameters of the elementary stage of the axial flow compressor; After the performance parameters of each elementary stage are calculated, it is determined that the current elementary stage is the last axial flow compressor elementary stage in the axial flow compressor, that is, the flow rate of the moving blade outlet calculation station and the flow rate of the stationary blade outlet calculation station in each elementary stage of the axial flow compressor are obtained; Step 4: Calculate the flow rate of the station through the rotor blade inlet based on the least squares method , flow rate of the rotor blade outlet calculation station , flow rate of the stationary blade outlet calculation station , establish the objective function for measuring the flow rate difference of the elementary stage of the axial flow compressor; Step 5: Based on the objective function, calculate the static pressure of the station at the rotor blade inlet , static pressure at the blade outlet calculation station To optimize the variables, according to the law of conservation of flow, the variable optimization formula is used to continuously update the optimization variables until the value of the objective function is less than 10 -8 , that is, the updated axial flow compressor performance parameters are obtained.

2. The axial flow compressor performance prediction method using back pressure boundary conditions according to claim 1, characterized in that: In step 3, the flow rate of the rotor blade inlet is calculated Equal to the calculated station flow rate at the inlet guide vane outlet of the axial flow compressor.

3. The axial flow compressor performance prediction method using back pressure boundary conditions according to claim 1, characterized in that: In step three, in the elementary level calculation, the absolute airflow angle, total temperature, and total pressure of the moving blade inlet calculation station of the next axial flow compressor elementary level are the same as the absolute airflow angle, total temperature, and total pressure of the stationary blade outlet calculation station of the previous axial flow compressor elementary level.

4. The method for predicting axial flow compressor performance using back pressure boundary conditions according to claim 1, wherein: The flow rate of the rotor blade inlet calculation station described in step 3 The solution process is: First, calculate the total temperature of the station based on the blade inlet , total pressure , static pressure , determine the static temperature of the blade inlet calculation station for: ， Where, is equal to 1.4, which is the specific heat constant; Then, according to the isentropic relationship, the absolute speed of the rotor blade inlet calculation station is determined for: ， Where, is equal to 1004.0, which is the specific heat capacity at constant pressure; Then, according to the absolute airflow angle of the rotor blade inlet calculation station , and the axial velocity of the rotor blade inlet calculation station determined according to the velocity triangle relationship ; According to the speed of the axial compressor and the centerline radius of the rotor blade inlet calculation station , determine the circumferential velocity of the rotor blade inlet calculation station , absolute circumferential speed , relative circumferential speed and relative speed , the specific formulas include: ， ， ， ， ， Next, according to the thermodynamic relationship, determine the relative total temperature of the blade inlet calculation station. , relative total pressure , the specific formula is: ， ， Then, based on the known geometric parameters of the axial flow compressor elementary stage and the static pressure of the moving blade inlet, the static pressure of the station is calculated. , static temperature , determine the airflow density at the rotor blade inlet calculation station and traffic , the specific formula is: ， ， Where, Equal to 287.03, is the gas state constant, at this time, the output of the blade inlet calculation station flow .

5. The method for predicting axial flow compressor performance using back pressure boundary conditions according to claim 1, wherein: The flow rate of the moving blade outlet calculation station described in step 3 The calculation process is: According to the conservation relationship of transfer enthalpy, the static pressure of the station is calculated based on the moving blade outlet. , circumferential speed and the relative total temperature of the blade inlet calculation station , circumferential speed , then, the relative total temperature of the blade outlet calculation station is Determined as: ， Where, is equal to 1004.0, which is the specific heat capacity at constant pressure; Based on the rotor blade loss coefficient : ， Thus, according to the isentropic relationship, the ideal relative total pressure at the blade outlet calculation station is determined for: ， Where, is equal to 1.4, which is the specific heat constant; Because the moving blade loss coefficient It is calculated by the loss model in the axial flow compressor performance analysis calculation model, and then the relative total pressure at the moving blade outlet calculation station is determined. for: ， Then, the static pressure of the station is calculated based on the assigned moving blade outlet. , and the relative total temperature of the blade outlet calculation station and relative total pressure According to the isentropic relationship, the static temperature of the blade outlet calculation station is determined for: ， Then calculate the relative total temperature of the station according to the blade outlet and Jingwen The relationship between the blade outlet and the calculation station is used to determine the relative speed of the blade outlet. for: ， Next, according to the velocity triangle relationship, determine the outlet circumferential velocity of the rotor blade outlet calculation station , relative circumferential speed , absolute circumferential speed and absolute speed , the specific formula is: ， ， ， ， Where, is the relative airflow angle at the blade outlet calculation station, which is calculated by the lagging angle model in the axial flow compressor performance analysis calculation model; Furthermore, according to the concept of stagnation state, the absolute velocity of the rotor blade outlet calculation station is known to be and Jingwen , determine the total temperature of the blade outlet calculation station for: ， According to the isentropic relationship and the static temperature of the blade outlet calculation station , total temperature , static pressure , determine the total pressure at the rotor blade outlet calculation station for: ， Airflow density at the rotor blade outlet calculation station and traffic for: ， ， At this time, the flow rate of the moving blade outlet calculation station is obtained .

6. The method for predicting axial flow compressor performance using back pressure boundary conditions according to claim 1, wherein: The flow rate of the stationary blade outlet calculation station described in step 3 The specific calculation process is: Calculate the static pressure of the station according to the stator outlet , total pressure of the stationary blade inlet calculation station The operating characteristics of the static stator blades in the elementary stage of the axial compressor are that the airflow in the stator blades belongs to absolute energy non-isentropic flow, so the total temperature of the stator blade outlet calculation station is determined. Equal to the total temperature of the stationary blade inlet calculation station ; Next, determine the total pressure at the stationary blade outlet calculation station. for: ， Where, is the stator blade loss coefficient, which is calculated by the loss model in the axial compressor performance analysis and calculation model; Then, the static pressure at the station is calculated based on the stator outlet , total temperature , total pressure , determine the static temperature of the stationary blade outlet calculation station for: ， Next, continue to calculate the total temperature of the station at the known stator outlet based on the isentropic relationship. and Jingwen , and the absolute airflow angle at the stator blade outlet calculation station determined by the lagging angle model in the axial flow compressor performance analysis calculation model , determine the absolute speed of the stationary blade exit calculation station , axial speed The size is: ， ， Where, is equal to 1004.0, which is the specific heat capacity at constant pressure; At the same time, determine the airflow density at the stationary blade outlet calculation station and traffic , specifically: ， ， Where, Equal to 287.03, which is the gas state constant; At this time, the flow rate of the stationary blade outlet calculation station is obtained .

7. The method for predicting axial flow compressor performance using back pressure boundary conditions according to claim 1, wherein: The objective function established in step 4 for: ， Where, 、 、 The flow rate of the rotor blade inlet calculation station , flow rate of rotor blade outlet calculation station , flow rate of stationary blade outlet calculation station .

8. The method for predicting axial flow compressor performance using back pressure boundary conditions according to any one of claims 1 to 7, wherein: The variable optimization formula in step 5 is: ， Where, is the updated input variable, is the input variable before updating, Is the learning rate, which represents the magnitude of parameter adjustment during the optimization process. yes The corresponding output variable is the input variable. Output variable corresponding to the outlet of the axial compressor; Including 、 、 ,and 、 、 The flow rate of the rotor blade inlet calculation station , flow rate of rotor blade outlet calculation station , flow rate of stationary blade outlet calculation station .

Images