Simulation method for flow field of gas compressor

Abstract

The invention relates to the technical field of gas compressors, in particular to a simulation method for a flow field of a gas compressor, which is characterized in that on the basis of an AUSM + format, input three dimensions are projected to one dimension, output one dimension is reversely projected to three dimensions, the one-dimensional format is successfully popularized to a three-dimensional relative coordinate system, the cross section flux is solved, and the flow field of the gas compressor is simulated. And a simulation calculation result of the gas compressor is obtained through calculation. Through the method, the problem of inaccurate shock wave calculation of gas compressor flow field simulation in the prior art can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of compressors, and in particular to a simulation method for compressor flow fields. Background Art

[0002] In the aerodynamic design of subsonic compressors, in order to match the overall solution, the mass and size of the compressor are often limited. It is hoped that fewer compressor stages, a larger average stage load, and a smaller frontal area will be used. This requires increasing the airflow velocity of the compressor to increase the work added by the stage and improve the flow capacity. However, this method is limited by the relative Mach number of the airflow at the moving blade inlet must be less than 1.0, and when the flow rate is increased to a certain extent, as the flow rate is further increased, the stage efficiency will decrease. Therefore, in order to develop a high thrust-to-weight ratio and high-performance compressor, it is necessary to break through the limitation of the relative speed of the moving blade inlet being subsonic in the compressor aerodynamic design and develop supersonic and transonic compressors.

[0003] The biggest difficulty in developing supersonic and transonic compressors is that the design experience of many subsonic compressors is no longer applicable to transonic and supersonic compressors. Subsonic compressors are developed based on plane blade experiments. However, due to different mechanisms, the design experimental data of supersonic and transonic compressors cannot be obtained from supersonic and transonic plane blade experiments, but directly from supersonic and transonic single-rotor or single-stage compressor experiments, which consumes huge manpower, material and financial resources.

[0004] Through fluid simulation calculation, using computers instead of experimental devices for numerical simulation experiments can save development costs, shorten design time, and improve design level in the early stage of design. Correspondingly, as a direct physical simulation of the flow field, the role of the prototype experiment becomes just to verify and confirm the results of the fluid numerical simulation and to modify the methods and parameters of the calculation model.

[0005] Compressor CFD simulation is to calculate the density, velocity, pressure, and temperature distribution of the fluid in various parts under given geometric parameters, boundary conditions, and other related parameters, and then obtain the flow distribution, streamline distribution, pressure ratio, power, efficiency and other airflow parameters and performance distribution in the compressor. The use of these calculation results can provide qualitative and even quantitative guidance for blade optimization design, and provide sufficient theoretical support and numerical experimental verification for the design of compressors that meet high load, wide margin, safe and stable operation.

[0006] In the simulation calculation of transonic and supersonic compressor fluid, in order to accurately estimate the aerodynamic efficiency of the compressor, a key technology is the calculation of shock waves. Common shock wave solution methods include shock wave fitting method and shock wave capture method. However, the existing solution methods are based on ideal conditions and are suitable for simple static flow fields. The compressor is a three-dimensional coordinate system, and some numerical formats give scenes in a one-dimensional coordinate system. The one-dimensional format can only be used directly in a three-dimensional Cartesian coordinate system, and other three-dimensional coordinate systems need to be converted before they can be used.

[0007] It can be seen that the existing shock wave solution method is not completely applicable to compressors. Summary of the invention

[0008] In order to solve the above technical problems, the present invention proposes a simulation method for compressor flow field, which corrects and improves the compressor flow field simulation based on the AUSM+ format, and solves the problem of inaccurate shock wave calculation in compressor flow field simulation in the prior art.

[0009] The present invention is achieved by adopting the following technical solutions:

[0010] A simulation method for a compressor flow field comprises the following steps:

[0011] Step S1. Establishing a three-dimensional model of a compressor;

[0012] Step S2. Meshing the compressor three-dimensional model;

[0013] Step S3. Parameter solution, including using the improved AUSM+ format to solve the interface flux

[0014] In the formula, is the interface sound velocity, is the interface Mach number, is the left-conserved flux, is the right-hand conserved flux, is the interface pressure, n is the unit vector in the direction of the external normal at the midpoint of the interface, W is the three-dimensional cylindrical coordinate relative velocity, ρ is the density, u is the velocity, and H is the enthalpy;

[0015] Step S4: Calculate the simulation result according to the parameters solved in step S3.

[0016] When the calculated mesh surface is the mesh surface of the mover and the left value, right value, and interface are located at the same radius, or when the calculated mesh surface is the mesh surface of the stator, the interface sound velocity The calculation method is:

[0017]

[0018] In the formula, a * is the critical speed of sound of an ideal gas, u L is the interface left value of the normal component velocity, u R is the interface right value of the normal component velocity, γ is the specific heat ratio, H t is the total enthalpy;

[0019] When the calculated mesh surface is the mesh surface of the mover and the coordinate radii of the left value, right value, and interface positions are different, the interface sound velocity The calculation method is:

[0020]

[0021] In the formula, is the critical sound velocity of the interface, I is the rotor enthalpy, the subscript L represents the left value of the interface, and the subscript R represents the right value of the interface. is the velocity at the interface.

[0022] When it is a non-ideal gas, the calculation method of the specific heat ratio γ is:

[0023]

[0024] In the formula, a L is the left sound speed, a R is the right sound speed, H L is the left static enthalpy, H R is the right static enthalpy.

[0025] In the step S3, when calculating the interface flux, the input three-dimensional velocity is projected onto the interface normal, the component velocity in the interface normal direction is calculated, the one-dimensional interface flux is calculated for each interface, and the interface fluxes of all surfaces are added together to obtain the total interface flux of the entire control body; when outputting the three-dimensional interface flux, the velocity momentum flux of the interface flux and the pressure impulse flux of the interface flux are remapped from one dimension to three dimensions; wherein, the velocity is along the upstream velocity direction, and the velocity momentum flux value Pressure along the interface normal direction, pressure impulse flux value

[0026] Among them, ρ is density, u is velocity, W is the three-dimensional cylindrical coordinate relative velocity, the subscript L represents the left value of the interface, the subscript R represents the right value of the interface, 1 / 2 represents the interface value, P is pressure, and n is the unit vector in the direction of the external normal at the midpoint of the interface.

[0027] The step S3 of solving the interface flux specifically includes the following steps:

[0028] Step S 31 . Calculate the normal velocity on the left and right sides of the interface;

[0029] uL =W L ·n

[0030] u R =W R ·n

[0031] In the formula, u L is the interface left value of the normal component velocity, W L is the interface left value of the relative velocity, n is the unit vector in the direction of the external normal at the midpoint of the interface, u R is the interface right value of the normal component velocity, W R is the interface right value of relative velocity;

[0032] Step S 32 .Calculate the enthalpy of the left and right rotors;

[0033]

[0034] Where I is the rotor enthalpy, H s is the static enthalpy, U is the drag velocity, the subscript L indicates the left value of the interface, and the subscript R indicates the right value of the interface;

[0035] Step S 33 . Calculate the critical sound velocity at the interface

[0036]

[0037] Where γ is the specific heat ratio, is the involved velocity at the interface position;

[0038] Step S 34 . Calculate the interface sound velocity

[0039]

[0040] Step S 35 .Calculate other AUSM+ intermediate quantities, including interface Mach number and interface pressure;

[0041] Step S 36 . Calculate the interface flux:

[0042]

[0043] In the formula, is the interface Mach number, is the left-conserved flux, is the right-hand conserved flux, is the interface pressure.

[0044] When it is a non-ideal gas, the step S 33 Previously, the calculation of the specific heat ratio γ was also included.

[0045] The simulation calculation result obtained in step S4 specifically refers to: calculating the aerodynamic efficiency.

[0046] The step S4 specifically comprises the following steps:

[0047] Step S 41 .The initial flow field of all grids (i, j, k) is known Time step △t;

[0048] Step S 42 . Calculate the interface flux values ​​of all mesh surfaces passing through the mesh (i, j, k) using the calculation method in step S3, and calculate the mesh net flux;

[0049] Step S 43 .Use step S 42 The net flux of the grid calculated in the time marching format is used to calculate the flow field value at the next moment

[0050] Step S 44 .Traverse all grids and calculate the flow field values ​​of all grids at time t+△t;

[0051] Step S 45 .use As the initial condition, repeat step S 42 ~Step S 44 ,calculate Then calculate Until the time iteration converges;

[0052] Step S 46 . Calculate the aerodynamic efficiency using the flow field value at the end time.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] 1. In the present invention, by projecting the input three-dimensional into one-dimensional and reversely projecting the output one-dimensional back into three-dimensional, the one-dimensional format is successfully extended to the three-dimensional relative coordinate system, so that the fluid simulation in the three-dimensional compressor field can also use the AUSM+ format, making the shock wave calculation of the compressor flow field simulation more accurate.

[0055] 2. In the field of compressors, the moving blades of the compressor are moving grids, and the total enthalpy of isentropic flow is no longer a constant, so the theory on the stationary grid is no longer applicable. If the theory of the stationary grid is directly applied to the moving grid, it may cause unstable iterative calculations. When calculating the critical sound speed, the present invention uses rotor enthalpy instead of total enthalpy, which increases the stability of the solution in the rotor section, can suppress numerical oscillations, error convergence with iteration, iteration is not easy to diverge, and supports a larger iteration step; avoid using total enthalpy to calculate the critical sound speed in the conventional AUSM+ format, and use it directly in the field of compressors, which may cause numerical instability.

[0056] Specifically, the calculation method of the rotor enthalpy differs from the original AUSM+ format only when the left value, right value, and interface coordinate radius of the rotor segment are different. This is reflected in the result that the shock wave along the span direction can be calculated more stably. Considering that the shock wave is almost impossible to be strictly along the grid direction, most shock waves are oblique shock waves relative to the grid. The present invention can improve the stability of the calculation in these cases.

[0057] 3. The conventional AUSM+ format does not support non-ideal gas situations. For the flow field simulation of the compressor, fluid working fluids of non-ideal gas models such as superheat, saturation, water vapor, supercritical, and multiphase flow are often used. Therefore, this application uses the value of the equivalent specific heat ratio as the specific heat ratio and substitutes it into the conventional AUSM+ format for solution, thereby overcoming the problem that the AUSM+ format does not support non-ideal gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

[0059] Figure 1 The residual root mean square convergence curve diagram of solving the NASA Rotor37 transonic single rotor problem using different formats in the present invention;

[0060] Figure 2 This is a flow residual convergence curve diagram for solving the NASA Rotor37 transonic single rotor problem using different formats in the present invention. DETAILED DESCRIPTION

[0061] Example 1

[0062] As a basic embodiment of the present invention, the present invention includes a simulation method for a compressor flow field, comprising the following steps:

[0063] Step S1: Establish a three-dimensional model of the compressor.

[0064] Step S2: Meshing the compressor three-dimensional model.

[0065] Step S3. Parameter solution, including using the improved AUSM+ format to solve the interface flux

[0066] In the formula, is the interface sound velocity, is the interface Mach number, is the left-conserved flux, is the right-hand conserved flux, is the interface pressure, n is the unit vector in the direction of the external normal at the midpoint of the interface, W is the three-dimensional cylindrical coordinate relative velocity, ρ is the density, u is the velocity, and H is the enthalpy.

[0067] Through the above method, the input three-dimensional is projected into one dimension, and the output one-dimensional is reversely projected back into three dimensions, successfully generalizing the one-dimensional format to a three-dimensional relative coordinate system.

[0068] Step S4: Calculate the simulation result according to the parameters solved in step S3.

[0069] Example 2

[0070] As a preferred embodiment of the present invention, the present invention includes a simulation method for a compressor flow field, comprising the following steps:

[0071] Step S1: Establish a three-dimensional model of the compressor.

[0072] Step S2: Meshing the compressor three-dimensional model.

[0073] Step S3. Parameter solution, including using the improved AUSM+ format to solve the interface flux:

[0074]

[0075] In the formula, is the interface flux, is the interface sound velocity, is the interface Mach number, is the left-conserved flux, is the right-hand conserved flux, is the interface pressure, n is the unit vector in the direction of the external normal at the midpoint of the interface, W is the three-dimensional cylindrical coordinate relative velocity, ρ is the density, u is the velocity, and H is the enthalpy.

[0076] Through the above method, the input three-dimensional is projected into one dimension, and the output one-dimensional is reversely projected back into three dimensions, successfully generalizing the one-dimensional format to a three-dimensional relative coordinate system.

[0077] In the AUSM+ format, for isentropic flow, the total enthalpy of all particles remains unchanged, so using the total enthalpy to calculate the speed of sound can have good conservation and improve the stability of numerical calculations. * for:

[0078]

[0079] Where γ is the specific heat ratio, which is a constant set according to the fluid working medium. For example, the value of air is 1.4; H t is the total enthalpy, which is calculated from the basic flow parameters. For isentropic flow, the total enthalpy is equal at all locations.

[0080] So the critical sound velocity at the interface for:

[0081]

[0082] In the formula, u L is the interface left value of the normal component velocity, u R is the interface right value of the normal component velocity, which is calculated using the upwind scheme for the flow field velocity value at the grid around the interface.

[0083] In the compressor flow field, for the mover, since a non-inertial coordinate system is used, its relative total enthalpy or absolute total enthalpy does not remain constant. The present invention introduces the rotor enthalpy concept proposed by Professor Wu Zhonghua:

[0084]

[0085] Among them, H s is the static enthalpy, W is the relative velocity in three-dimensional cylindrical coordinates, U is the drag velocity caused by the compressor rotation, is the relative total enthalpy H of the mover t,rel It can be proved that for isentropic flow, the rotor enthalpy of all particles remains unchanged. In addition, for the stator, the relative velocity is equal to the absolute velocity, and the entrained velocity U is equal to 0, so it can be said that the rotor enthalpy of the stator is its absolute total enthalpy.

[0086] Based on this, in order to ensure conservation in the relative coordinate system, the total enthalpy is replaced by the rotor enthalpy, so:

[0087]

[0088] Considering that the actual flow is non-isentropic flow, it is necessary to use local values ​​to calculate the critical sound velocity, and different critical sound velocities are used at different locations. for:

[0089]

[0090] So the interface speed of sound The calculation method is:

[0091]

[0092] When the calculated mesh surface is the mesh surface of the mover and the left value, right value, and interface are located at the same radius, or when the calculated mesh surface is the mesh surface of the stator, the critical sound velocity of the interface is The calculation method is exactly the same as the original format of AUSM+.

[0093] Step S4: Calculate the simulation result according to the parameters solved in step S3.

[0094] Example 3

[0095] As another preferred embodiment of the present invention, the present invention includes further limiting the technical solution in the present invention on the basis of Example 1 or Example 2.

[0096] Calculating the critical sound velocity at the interface When the specific heat ratio γ is used, it is necessary to rely on the specific heat ratio γ. For an ideal gas, the specific heat ratio γ is a predetermined constant. For a non-ideal gas, there is no constant specific heat ratio γ, so the present invention is based on the relationship between the speed of sound a, the static enthalpy H, and the specific heat ratio γ:

[0097] a 2 =(γ-1)H

[0098] The calculation method of the equivalent specific heat ratio of non-ideal gas at the defined interface position is:

[0099]

[0100] In the formula, a L is the left sound speed, a R is the right sound speed, H L is the left static enthalpy, H R is the right static enthalpy.

[0101] Example 4

[0102] As another preferred embodiment of the present invention, the present invention includes further limiting the technical solution in the present invention on the basis of any one of Examples 1 to 3.

[0103] In the AUSM+ format, the flux formula of the one-dimensional Euler equation is given. However, the compressor is a three-dimensional relative cylindrical coordinate system, and the calculation method of momentum flux is different: the dimension of velocity increases from one dimension u to three dimensions [c r w θ c z ] T .

[0104] When calculating the interface flux, the input three-dimensional velocity is projected onto the interface normal. Since the component velocities in the other two directions will not affect the interface flux, only the component velocity in the interface normal direction needs to be considered. For the three-dimensional velocity, the magnitude of the component velocity in the interface normal direction can be calculated by vector dot multiplication of the interface normal vector. At this point, for one interface, the three-dimensional problem can be converted into a one-dimensional problem. For a three-dimensional mesh control volume, each interface needs to calculate the interface flux of the one-dimensional problem separately, and the interface fluxes of all faces added together is the total interface flux of the entire control volume.

[0105] The relative speed of three-dimensional cylindrical coordinates W = [c r w θ c z ] T , the unit vector of the external normal direction at the midpoint of the interface is n = [n r n θ n z ] T

[0106] The magnitude of the left and right velocity in the direction across the interface is

[0107] u L =W L ·n

[0108] u R =W R ·n

[0109] Since the interface flux includes the velocity momentum flux calculated from the interface velocity and the pressure impulse flux calculated from the interface pressure, when the three-dimensional flux needs to be output in the last step, the velocity momentum flux and the pressure impulse flux need to be remapped from one dimension to three dimensions. Among them, the velocity is along the upstream velocity direction, and the velocity momentum flux value Pressure is along the interface normal direction, flux value

[0110] Example 5

[0111] As the best embodiment of the present invention, the present invention includes a simulation method for a compressor flow field, comprising the following steps:

[0112] Step S1: Establish a three-dimensional model of the compressor.

[0113] Step S2: Meshing the compressor three-dimensional model.

[0114] Step S3. Parameter solution, including using the improved AUSM+ format to solve the interface flux. Specifically, it includes the following steps:

[0115] Step S31 . Calculate the normal velocity on the left and right sides of the interface;

[0116] u L =W L ·n

[0117] u R =W R ·n

[0118] In the formula, u L is the interface left value of the normal component velocity, W L is the interface left value of the relative velocity, n is the unit vector in the direction of the external normal at the midpoint of the interface, u R is the interface right value of the normal component velocity, W R is the interface right value of relative velocity.

[0119] Step S 32 .Calculate the enthalpy of the left and right rotors;

[0120]

[0121] Where I is the rotor enthalpy, H s is the static enthalpy, U is the drag velocity, the subscript L represents the left value of the interface, and the subscript R represents the right value of the interface.

[0122] Step S 33 . Calculate the critical sound velocity at the interface

[0123]

[0124] Where γ is the specific heat ratio, is the velocity at the interface.

[0125] In particular, if it is a non-ideal gas, the specific heat ratio γ is:

[0126]

[0127] In the formula, a L is the left sound speed, a R is the right sound speed, H L is the left static enthalpy, H R is the right static enthalpy.

[0128] Step S 34 .Calculate the interface sound velocity:

[0129]

[0130] Step S 35 .Calculate other AUSM+ intermediate quantities, including interface Mach number and interface pressure.

[0131] The calculation method of the interface Mach number is:

[0132]

[0133] Where M is the Mach number. L 、M R It is calculated by using the upwind scheme for the local Mach number of the flow field at the grid around the interface. + is the positive and negative Mach number flux, is the interface Mach number.

[0134] The calculation method of interface pressure is:

[0135]

[0136] Where p is the pressure. L , P R It is calculated by using the upwind method to calculate the flow field pressure value at the grid around the interface. + is the positive and negative pressure flux, is the interface pressure.

[0137] Among them, α and β are variable parameters, and their values ​​are:

[0138]

[0139] Step S 36 . Calculate the interface flux:

[0140]

[0141] In the formula, is the interface Mach number, is the left-conserved flux, is the right-hand conserved flux, is the interface pressure. The left and right conserved fluxes are calculated using the upwind scheme to calculate the conserved flux values ​​of the flow field at the mesh around the interface. The conserved fluxes include mass flux, momentum flux, and energy flux. The momentum flux includes velocity momentum flux and pressure impulse flux.

[0142] Step S4. According to the parameters solved in step S3, the simulation calculation results are calculated, that is, the aerodynamic efficiency is calculated. Specifically, the steps include:

[0143] Step S 41 .The initial flow field of all grids (i, j, k) is known Time step △t.

[0144] Step S 42. Use the calculation method in step S3 to calculate the interface flux values ​​of all mesh surfaces passing through the mesh (i, j, k) And calculate the mesh net flux:

[0145] Step S 43 .Use step S 42 The net flux of the grid calculated in the time marching format is used to calculate the flow field value at the next moment

[0146] Step S 44 .Traverse all grids and calculate the flow field values ​​of all grids at time t+△t;

[0147] Step S 45 .use As the initial condition, repeat step S 42 ~Step S 44 ,calculate Then calculate Until the time iteration converges;

[0148] Step S 46 . Calculate the aerodynamic efficiency using the flow field value at the end time.

[0149] The present invention adopts different technical solutions to solve the residual convergence curve of NASA Rotor37 transonic single rotor problem. The numerical format includes: center format, embodiment 1 and embodiment 2. Figure 1 And the instruction manual Figure 2 It can be seen that the iterative convergence speed of the improved AUSM+ format in Example 1 and Example 2 is significantly faster than that of the conventional center format. However, the curve using the center format has a slow convergence speed due to unstable calculation, and the numerical oscillation in space slows down the iterative convergence speed. The center format has artificial viscosity to suppress convergence, so even if there is a little numerical oscillation, the convergence speed is still very fast. However, due to the dissipative error caused by artificial viscosity, the flow residual of the import and export will no longer decrease after converging to a certain extent.

[0150] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical scheme and technical concept of the present invention without creative mental labor, which all fall within the scope of protection of the present invention.

Claims

1. A method for simulating a compressor flow field, characterized in that: The following steps are involved: Step S1. Establishing a three-dimensional model of a compressor; Step S2. Meshing the compressor three-dimensional model; Step S3. Parameter solution, including using the improved AUSM+ format to solve the interface flux In the formula, is the interface sound velocity, is the interface Mach number, is the left-conserved flux, is the right-hand conserved flux, is the interface pressure, n is the unit vector in the direction of the external normal at the midpoint of the interface, W is the three-dimensional cylindrical coordinate relative velocity, ρ is the density, u is the velocity, and H is the enthalpy; Step S4: Calculate the simulation result according to the parameters solved in step S3.

2. The method for simulating compressor flow field according to claim 1, characterized in that: When the calculated mesh surface is the mesh surface of the mover and the left value, right value, and interface are located at the same radius, or when the calculated mesh surface is the mesh surface of the stator, the interface sound velocity The calculation method is: In the formula, a * is the critical speed of sound of an ideal gas, u L is the interface left value of the normal component velocity, u R is the interface right value of the normal component velocity, γ is the specific heat ratio, H t is the total enthalpy; When the calculated mesh surface is the mesh surface of the mover and the coordinate radii of the left value, right value, and interface positions are different, the interface sound velocity The calculation method is: In the formula, is the critical sound velocity of the interface, I is the rotor enthalpy, the subscript L represents the left value of the interface, and the subscript R represents the right value of the interface. is the velocity at the interface.

3. A method for simulating compressor flow field according to claim 1 or 2, characterized in that: When it is a non-ideal gas, the calculation method of the specific heat ratio γ is: In the formula, a L is the left sound speed, a R is the right sound speed, H L is the left static enthalpy, H R is the right static enthalpy.

4. The method for simulating compressor flow field according to claim 3, characterized in that: In step S3, when calculating the interface flux, the input three-dimensional velocity is projected onto the interface normal, and the magnitude of the component velocity in the interface normal direction is calculated. The one-dimensional interface flux is calculated for each interface respectively, and the interface fluxes of all surfaces are added together to obtain the total interface flux of the entire control volume; When outputting the three-dimensional interface flux, the velocity momentum flux of the interface flux and the pressure impulse flux of the interface flux are remapped from one dimension to three dimensions; among them, the velocity is along the upstream velocity direction, and the velocity momentum flux value Pressure along the interface normal direction, pressure impulse flux value Among them, ρ is density, u is velocity, W is the three-dimensional cylindrical coordinate relative velocity, the subscript L represents the left value of the interface, the subscript R represents the right value of the interface, 1 / 2 represents the interface value, P is pressure, and n is the unit vector in the direction of the external normal at the midpoint of the interface.

5. The method for simulating compressor flow field according to claim 3, characterized in that: The step S3 of solving the interface flux specifically includes the following steps: Step S 31 . Calculate the normal velocity on the left and right sides of the interface; u L =W L ·n u R =W R ·n In the formula, u L is the interface left value of the normal component velocity, W L is the interface left value of the relative velocity, n is the unit vector in the direction of the external normal at the midpoint of the interface, u R is the right value of the interface normal component velocity, W R is the interface right value of relative velocity; Step S 32 .Calculate the enthalpy of the left and right rotors; Where I is the rotor enthalpy, H s is the static enthalpy, U is the drag velocity, the subscript L indicates the left value of the interface, and the subscript R indicates the right value of the interface; Step S 33 . Calculate the critical sound velocity at the interface Where γ is the specific heat ratio, is the involved velocity at the interface position; Step S 34 . Calculate the interface sound velocity Step S 35 .Calculate other AUSM+ intermediate quantities, including interface Mach number and interface pressure; Step S 36 . Calculate the interface flux: In the formula, is the interface Mach number, is the left-conserved flux, is the right-hand conserved flux, is the interface pressure.

6. The method for simulating compressor flow field according to claim 5, characterized in that: When it is a non-ideal gas, the step S 33 Previously, the calculation of the specific heat ratio γ was also included.

7. The method for simulating compressor flow field according to claim 3, characterized in that: The simulation calculation result obtained in step S4 specifically refers to: calculating the aerodynamic efficiency.

8. The method for simulating compressor flow field according to claim 7, characterized in that: The step S4 specifically comprises the following steps: Step S 41 .The initial flow field of all grids (i, j, k) is known Time step Δt; Step S 42 . Calculate the interface flux values ​​of all mesh surfaces passing through the mesh (i, j, k) using the calculation method in step S3, and calculate the mesh net flux; Step S 43 .Use step S 42 The net flux of the grid calculated in the time marching format is used to calculate the flow field value at the next moment Step S 44 .Traverse all grids and calculate the flow field values ​​of all grids at time t+Δt; Step S 45 .use As the initial condition, repeat step S 42 ~Step S 44 ,calculate Then calculate Until the time iteration converges; Step S 46 . Calculate the aerodynamic efficiency using the flow field value at the end time.

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