Model calculation method for simulating small-scale flow of flow channel in aircraft engine

Abstract

The invention provides a model calculation method for simulating small-scale flow of a flow channel in an aircraft engine. The model calculation method for simulating the small-scale flow of the internal flow channel of the aircraft engine comprises the following steps: establishing an internal and external flow coupling aircraft main flow field structure grid; performing structure grid division on the aircraft main flow field at a non-small-scale flow position; on the wall surface of the small-scale flow position, the small-scale flow problem is modeled through a wall surface permeation model; calculating fluid attributes at the wall surface permeation model according to the wall surface permeation model; adding a small-scale flow source item in the flow equation; and carrying out aircraft flow field iterative calculation to obtain the aerodynamic performance of the aircraft when small-scale flow exists in the flow channel in the engine of the aircraft. By applying the technical scheme of the invention, the technical problem that the aerodynamic performance of the aircraft cannot be effectively simulated when small-scale flow exists in the flow channel in the engine of the aircraft in the prior art can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of computational fluid dynamics, and in particular relates to a model calculation method for simulating small-scale flow in a flow channel of an aircraft engine. Background Art

[0002] In view of the flight engineering problems of large airspace and wide speed range of internal and external flow coupling aircraft, leakage holes and leakage cavities are designed in the engine inlet duct during aircraft design to effectively reduce the adverse effects of shock wave / boundary layer interference and improve the aerodynamic performance of the engine. In addition, the fuel injection holes inside the aircraft engine are used to inject fuel into the main combustion area inside the combustion chamber, which has an important impact on the engine combustion process. The leakage process of the leakage hole is that a part of the fluid flows out from the mainstream area into the leakage cavity, and the fuel injection process of the fuel injection hole requires the injection of a certain mass flow rate of fluid into the mainstream area to participate in the subsequent combustion reaction. Flow processes such as leakage holes and fuel injection holes are small-scale flows relative to the mainstream field of the aircraft. There is a problem of flow scale mismatch with the mainstream field, which is easy to cause computational convergence problems. At the same time, if the mainstream area, leakage holes, leakage cavities, fuel injection holes, etc. are generated together to generate structural grids for flow field calculation, it is very difficult to generate grids, and the computational efficiency will decrease as the grid size increases.

[0003] In order to improve the aerodynamic performance of the aircraft when small-scale flow exists in the flow channel of the simulated aircraft engine, it is necessary to develop a wall penetration model. By adding small-scale flow source terms to the flow equation, the influence of small-scale flow on the mainstream field is considered, thereby avoiding drawing grids in places where small-scale flow exists, such as leakage holes, leakage cavities, and injection holes. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] The present invention provides a model calculation method for simulating small-scale flow in a flow channel of an aircraft engine. The model calculation method for simulating small-scale flow in a flow channel of an aircraft engine comprises:

[0006] Establish the structural grid of the mainstream field of the aircraft with internal and external flow coupling: divide the structural grid of the mainstream field of the aircraft at the non-small-scale flow position;

[0007] On the wall where the small-scale flow occurs, the small-scale flow problem is simulated by the wall penetration model.

[0008] Calculate the fluid properties at the wall penetration model according to the wall penetration model;

[0009] Add source terms for small-scale flows to the flow equations;

[0010] The aircraft flow field is iteratively calculated to obtain the aircraft aerodynamic performance when small-scale flow exists in the flow channel of the aircraft engine.

[0011] Furthermore, multiple structural grids are generated by structural grid division software and output in CGNS format to form the input files required for the structural flow field solver.

[0012] Furthermore, for the leakage hole flow, the wall penetration model is based on the mass flow outflow, given the mass flow rate and porosity of the outflowing fluid; for the injection hole flow, the wall penetration model is based on the mass flow inflow, given the mass flow rate, components and component mass fractions, total temperature and porosity of the inflowing fluid.

[0013] Furthermore, calculating the fluid properties at the wall permeability model specifically includes: back-calculating the main variables of pressure, temperature, density and velocity according to the given small-scale flow information.

[0014] Furthermore, for the mass flow inflow: T 0_bleed =T 0_input

[0015] Y k_bleed =Y k_input

[0016] p bleed =p in

[0017] Among them, T 0_bleed Refers to the total temperature at the penetration hole, T 0_input Refers to the input of the specified total temperature, k represents the specific component number, Y k_bleed represents the mass fraction of the component at the permeation pore, Y k_input Represents the mass fraction of the component specified by the input, p bleed Refers to the pressure at the penetration hole, p in Refers to the pressure in the flow field near the permeation hole;

[0018] For mass flow outflow: T 0_bleed =T 0_in

[0019] Y k_bleed =Y k_in

[0020] p bleed =p in

[0021] Among them, T 0_in Refers to the total temperature in the flow field near the penetration hole, Y k_in Represents the mass fraction of this component in the flow field near the permeation pore.

[0022] Further, according to

[0023]

[0024] Get the total enthalpy, where nspecies represents the total number of components and R mix_bleed The gas constant, R, represents the gas constant of the mixed heat of the perfect gas at the permeation pore. k represents the gas constant for each component, H mix_bleed represents the total enthalpy of the mixed heat of the complete gas at the permeation pore, H k represents the total enthalpy of each component, a 1k ~a 6k All are fitting parameters of the gas component thermophysical property database;

[0025] according to

[0026] Cp k =a 1k +a 2k T bleed +a 3k T bleed 2 +a 4k T bleed 3 +a 5k T bleed 4

[0027]

[0028] Get the specific heat at constant pressure, where Cp mix_bleed Represents the constant pressure specific heat of the perfect gas at the permeation pore, Cp k represents the specific heat at constant pressure of each component, T bleed Represents the static temperature at the penetration hole.

[0029] Further, according to

[0030]

[0031]

[0032] V x_bleed =V bleed *Nx

[0033] V y_bleed =V bleed *Ny

[0034] V z_bleed =V bleed *Nz

[0035]

[0036] Get speed and energy information, where Rho bleed represents the density at the penetration pore, V bleed represents the velocity at the penetration wall, Area represents the penetration area, is the mass flow rate of the fluid, Nx, Ny and Nz are the surface normals in the x, y and z directions respectively, V x_bleed 、V y_bleed and V z_bleed are the velocity components in the x, y and z directions respectively, and E bleed Represents the energy at the penetration wall.

[0037] Further, according to Get the mass flow rate through the permeation hole, where represents the mass flow rate through the permeable pore after considering the porosity, and λ is the porosity.

[0038] Furthermore, the weight factor of the source term of each unit is considered according to the unit volume, and the corresponding source term is added to the NS equation and component equation in each unit.

[0039] For the NS equation,

[0040]

[0041] For the component equation,

[0042]

[0043] Where w represents the weight factor, ΔS rho represents the source term of the density equation, ΔS u represents the source term of the velocity equation in the x direction, ΔS v represents the source term of the velocity equation in the y direction, ΔS w represents the source term of the velocity equation in the z direction, ΔS E represents the source term of the energy equation, ΔS k Represents the source term of the component equation.

[0044] Furthermore, the structural solver is used to perform implicit iterative calculations of the steady-state flow field of the aircraft to obtain the aerodynamic performance when small-scale flow exists in the flow channel of the aircraft engine.

[0045] By applying the technical solution of the present invention, a model calculation method for simulating small-scale flow in the flow channel of an aircraft engine is provided. The method divides the main flow field of the aircraft into structural grids at non-small-scale flow positions, models the small-scale flow problem at the wall surface of the small-scale flow position through a wall permeability model, calculates the fluid properties at the wall permeability model according to the wall permeability model, adds the source term of the small-scale flow to the flow equation, performs iterative calculation of the aircraft flow field, and obtains the aerodynamic performance of the aircraft when small-scale flow exists in the flow channel of the aircraft engine. The present invention is suitable for solving the aerodynamic performance of an aircraft when small-scale flow exists in the flow channel of an aircraft engine. Compared with the prior art, the technical solution of the present invention can solve the technical problem that the prior art cannot effectively simulate the aerodynamic performance of an aircraft when small-scale flow exists in the flow channel of an aircraft engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A schematic flow chart of a model calculation method for simulating small-scale flow in an aircraft engine internal flow channel provided according to a specific embodiment of the present invention is shown. DETAILED DESCRIPTION

[0048] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values.

[0051] like Figure 1 As shown, according to a specific embodiment of the present invention, a model calculation method for simulating small-scale flow in a flow channel of an aircraft engine is provided, the method comprising:

[0052] Establish the structural grid of the mainstream field of the aircraft with internal and external flow coupling: divide the structural grid of the mainstream field of the aircraft at the non-small-scale flow position;

[0053] On the wall where the small-scale flow occurs, the small-scale flow problem is simulated by the wall penetration model.

[0054] Calculate the fluid properties at the wall penetration model according to the wall penetration model;

[0055] Add source terms for small-scale flows to the flow equations;

[0056] The aircraft flow field is iteratively calculated to obtain the aircraft aerodynamic performance when small-scale flow exists in the flow channel of the aircraft engine.

[0057] By applying this configuration, a model calculation method for simulating small-scale flow in the flow channel of an aircraft engine is provided. The method divides the aircraft mainstream field into structural grids at non-small-scale flow positions, models the small-scale flow problem at the wall surface at the small-scale flow position through a wall permeability model, calculates the fluid properties at the wall permeability model according to the wall permeability model, adds the source term of the small-scale flow to the flow equation, performs iterative calculation of the aircraft flow field, and obtains the aerodynamic performance of the aircraft when small-scale flow exists in the flow channel of the aircraft engine. The present invention is suitable for solving the aerodynamic performance of an aircraft when small-scale flow exists in the flow channel of an aircraft engine. Compared with the prior art, the technical solution of the present invention can solve the technical problem that the prior art cannot effectively simulate the aerodynamic performance of an aircraft when small-scale flow exists in the flow channel of an aircraft engine.

[0058] First, in the present invention, the structural grid of the mainstream field of the aircraft coupled with internal and external flows is established: the mainstream field of the aircraft is structurally gridded at non-small-scale flow positions. In the present invention, it is not necessary to generate grids at places where small-scale flows exist, such as leak holes and fuel injection holes.

[0059] As a specific embodiment of the present invention, multiple structural grids are generated by structural grid division software such as Gridgen and Pointwise, and are output in CGNS format to form the input files required by the structural flow field solver.

[0060] Furthermore, after establishing the internal and external flow coupling aircraft mainstream field structure grid, the small-scale flow problem is simulated by the wall penetration model on the wall surface at the small-scale flow position. In the present invention, the small-scale flow problem is simulated by the wall penetration model on the wall surface where the leakage holes, injection holes, etc. should exist.

[0061] As a specific embodiment of the present invention, for the flow through the leak hole, the wall permeability model needs to consider the mass flow rate outflow. At this time, the wall permeability model needs to give the mass flow rate of the outflow fluid and porosity λ; for the flow through the injection hole, the mass flow inflow must be considered, and the wall penetration model needs to give the mass flow of the inflow fluid Component k and component mass fraction Y k_bleed , total temperature T 0_bleed and the porosity λ.

[0062] Furthermore, after simulating the small-scale flow problem through the wall permeability model, the fluid properties at the wall permeability model are calculated according to the wall permeability model.

[0063] As a specific embodiment of the present invention, calculating the fluid properties at the wall permeability model specifically includes: back-calculating the main variables such as pressure, temperature, density and velocity according to the given information such as the mass flow rate of the fluid flowing at a small scale.

[0064] Specifically, the calculation of the fluid properties at the wall permeability model distinguishes between mass flow inflow and mass flow outflow. For mass flow inflow, the total temperature, components and component mass fractions of the incoming fluid need to be specified; for mass flow outflow, the temperature on the permeation wall is considered to be the total temperature of the outflowing fluid, and the components and component mass fractions are the same as the gas components in the flow field near the wall. Regardless of whether it is mass flow inflow or outflow, the pressure of the permeation zone uses the pressure of the flow field near the wall.

[0065] That is, for mass flow inflow: T 0_bleed =T 0_input

[0066] Y k_bleed =Y k_input

[0067] p bleed =p in

[0068] Among them, T 0_bleed Refers to the total temperature at the penetration hole, T 0_input Refers to the input of the specified total temperature, k represents the specific component number, Y k_bleed represents the mass fraction of the component at the permeation pore, Y k_input Represents the mass fraction of the component specified by the input, p bleed Refers to the pressure at the penetration hole, p in Refers to the pressure in the flow field near the permeation hole.

[0069] For mass flow outflow: T 0_bleed =T 0_in

[0070] Y k_bleed =Y k_in

[0071] p bleed =p in

[0072] Among them, T 0_in Refers to the total temperature in the flow field near the penetration hole, Y k_in Represents the mass fraction of this component in the flow field near the permeation pore.

[0073] Then, the gas constant of the mixed heat complete gas is calculated based on the mass fraction of the components. The total enthalpy is then calculated using the total temperature, and then the static temperature of the fluid on the permeable wall is obtained using the Newton iteration method, thereby obtaining information including the fluid specific heat ratio and enthalpy value. Then, based on the pressure, static temperature and mass flow rate, the density and velocity information, as well as the energy information, are obtained. Finally, the porosity is considered to obtain the mass flow rate flowing through the permeable pore. Specifically:

[0074]

[0075] Among them, nspecies represents the total number of components, R mix_bleed The gas constant, R, represents the gas constant of the mixed heat of the perfect gas at the permeation pore. k represents the gas constant for each component, H mix_bleed represents the total enthalpy of the mixed heat of the complete gas at the permeation pore, H k represents the total enthalpy of each component, a 1k ~a 6k All are fitting parameters of the gas component thermophysical properties database.

[0076] Assuming that an initial value of static temperature is given, the constant pressure specific heat is calculated, and then the static temperature is calculated using the total enthalpy and the constant pressure specific heat. The error with the initial value is obtained, and the static temperature of the fluid on the permeable wall is obtained through the Newton iteration method.

[0077] Cp k =a 1k +a 2k T bleed +a 3k T bleed 2 +a 4k T bleed 3 +a 5k T bleed 4

[0078]

[0079] Among them, Cp mix_bleed Represents the constant pressure specific heat of the perfect gas at the permeation pore, Cp k represents the specific heat at constant pressure of each component, T bleed Represents the static temperature at the penetration hole.

[0080]

[0081] V x_bleed =V bleed *Nx

[0082] V y_bleed =V bleed *Ny

[0083] V z_bleed =V bleed *Nz

[0084]

[0085] Among them, Rho bleed represents the density at the penetration pore, V bleed represents the velocity magnitude at the penetration wall, Area represents the penetration area, Nx, Ny and Nz are the surface normals in the x, y and z directions respectively, V x_bleed 、V y_bleed and V z_bleed are the velocity components in the x, y and z directions respectively, and E bleed Represents the energy at the penetration wall.

[0086]

[0087] in, Represents the mass flow rate through the permeable pore after taking the porosity into account.

[0088] If the Mach number of the fluid at the wall penetration model calculated by the given parameters reaches or exceeds 1, it means that the flow is blocked and the program will give an alarm. Whether the calculation of the property information of the fluid at the penetration wall is reasonable is the key to simulating small-scale flow.

[0089] Furthermore, after calculating the fluid properties at the wall permeability model, the source term of the small-scale flow is added to the flow equation. The present invention considers the influence of the small-scale flow on the mainstream field by adding the small-scale flow source term to the source term of the NS flow equation.

[0090] As a specific embodiment of the present invention, based on the calculated information such as the fluid density, pressure, temperature and velocity at the permeation wall, the influence of the fluid flowing in or out of the wall permeation model needs to be considered in the mass equation, momentum equation and energy equation. In addition, if it is a mixed hot perfect gas, the source term of the fluid at the permeation wall in the component continuity equation also needs to be considered.

[0091] The weight factor of the source term of each unit is considered according to the unit volume, so that the corresponding source term is added to the NS equations and component equations in each unit.

[0092] For the NS equation,

[0093]

[0094] For the component equation,

[0095]

[0096] Where w represents the weight factor, ΔS rho represents the source term of the density equation, ΔS u represents the source term of the velocity equation in the x direction, ΔS v represents the source term of the velocity equation in the y direction, ΔS w represents the source term of the velocity equation in the z direction, ΔS E represents the source term of the energy equation, ΔS k Represents the source term of the component equation.

[0097] Furthermore, after adding the source term of small-scale flow to the flow equation, the aircraft flow field is iteratively calculated to obtain the aerodynamic performance of the aircraft when small-scale flow exists in the flow channel of the aircraft engine.

[0098] As a specific embodiment of the present invention, the present invention uses a structural solver to perform iterative calculation of a steady-state flow field. Specifically, the aircraft flow field structure grid in CGNS format and a control script with set solution equations, boundary conditions, wall permeability model, space discretization, time advancement and other control parameters are used to perform implicit iterative calculation of the aircraft steady-state flow field using a structural solver to obtain the aerodynamic performance when there is a small-scale flow in the flow channel of the aircraft engine.

[0099] The present invention provides a model calculation method for simulating small-scale flow in an aircraft engine inner flow channel. First, the aircraft mainstream field is structurally gridded, and there is no need to generate grids at places where small-scale flow exists, such as leak holes and fuel injection holes. On the wall surface where the leak holes and fuel injection holes should exist, the small-scale flow problem is simulated by a wall permeability model. For the leak hole flow, the mass flow outflow needs to be considered, and the mass flow rate and porosity of the outflowing fluid are required at this time. For the fuel injection hole flow, the mass flow inflow needs to be considered, and the mass flow rate, components and component mass fractions, total temperature and porosity of the inflowing fluid need to be given at this time. According to the specified small-scale flow fluid mass flow rate and other information, the main variables such as pressure, temperature, density and velocity are back-calculated, and added to the source term of the flow equation, so as to consider the influence of the small-scale flow on the mainstream field. The structural solver is used to perform iterative calculation of the steady-state flow field to obtain the aerodynamic performance of the aircraft when the small-scale flow exists in the inner flow channel of the aircraft engine.

[0100] The method of the present invention improves engineering applicability and facilitates solving the aerodynamic performance of an aircraft when small-scale flow exists in the flow passage of an aircraft engine.

[0101] In order to have a further understanding of the present invention, the model calculation method for simulating small-scale flow in the flow channel of an aircraft engine of the present invention is described in detail below in conjunction with specific embodiments.

[0102] like Figure 1 As shown, according to a specific embodiment of the present invention, a model calculation method for simulating small-scale flow in an aircraft engine internal flow channel is provided, which specifically includes the following steps.

[0103] Step 1: Perform structural meshing on the mainstream field of the aircraft. There is no need to generate meshes in places where small-scale flows exist, such as leak holes and fuel injection holes. Export them to the structured CGNS mesh format.

[0104] Step 2: In addition to setting the control parameters of the incoming flow parameters, control equations, boundary conditions, time discretization, and space discretization, it is also necessary to simulate the small-scale flow problem through the wall penetration model on the wall where leakage holes, oil injection holes, etc. should exist.

[0105] There are two main applications of the wall permeability model. One is for the flow of leak holes. The wall permeability model needs to consider the mass flow outflow. At this time, the mass flow rate and porosity of the outflowing fluid need to be set; the other is for the flow of injection holes. The mass flow inflow needs to be considered. At this time, the wall permeability model needs to give the mass flow rate, components and component mass fractions, total temperature and porosity of the inflowing fluid.

[0106] Step three, in the structured grid flow field solver, according to the given wall penetration model parameters, calculate the fluid properties at the penetration wall. Specifically, for mass flow inflow, it is necessary to specify the total temperature, components and component mass fractions of the incoming fluid; for mass flow outflow, the temperature on the penetration wall is considered to be the total temperature of the outflow fluid, and the components and component mass fractions are the same as the gas components of the flow field near the wall. Regardless of whether the mass flow is inflow or outflow, the pressure of the penetration zone uses the pressure of the flow field near the wall. Then, the total enthalpy is calculated based on the total temperature, and then the Newton iteration method is used to obtain the static temperature of the fluid on the penetration wall, thereby obtaining information including the specific heat ratio of the fluid and the enthalpy value. Then, based on the pressure, static temperature, and mass flow rate, the density and velocity information, as well as the total energy information, are obtained. Finally, the porosity is considered to obtain the mass flow rate of small holes such as leak holes. If the Mach number of the fluid at the wall penetration model calculated by the given parameters reaches or exceeds 1, it means that the flow is congested and the program will give an alarm. Whether the calculation of fluid property information at the penetration wall is reasonable is the key to simulating small-scale flow.

[0107] Step 4: Based on the calculated fluid density, pressure, temperature, velocity and other information at the permeation wall, the influence of the fluid flowing in or out of the wall permeation model needs to be considered in the mass equation, momentum equation and energy equation. In addition, if it is a mixed hot perfect gas, the source term of the fluid at the permeation wall in the component continuity equation also needs to be considered.

[0108] Step 5: Use the structured grid flow field solver that considers the influence of the permeable wall to calculate the aircraft flow field. This method does not require drawing grids for the leakage holes, leakage cavities, injection holes, etc. Only the grids for the mainstream field are needed, which solves the problem of flow scale mismatch in large airspace and wide speed domains, obtains the aerodynamic characteristics of the flow channel in the aircraft engine when there is a small-scale flow, and guides the aerodynamic design of the aircraft.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A model calculation method for simulating small-scale flow in an aircraft engine flow channel, characterized in that: The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine comprises: Establish the structural grid of the mainstream field of the aircraft with internal and external flow coupling: divide the structural grid of the mainstream field of the aircraft at the non-small-scale flow position; On the wall where the small-scale flow occurs, the small-scale flow problem is simulated by the wall penetration model. Calculate the fluid properties at the wall penetration model according to the wall penetration model; Add source terms for small-scale flows to the flow equations; The aircraft flow field is iteratively calculated to obtain the aircraft aerodynamic performance when small-scale flow exists in the flow channel of the aircraft engine.

2. The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine according to claim 1, characterized in that: Multiple structural grids are generated by structural grid generation software and output in CGNS format to form the input files required for the structural flow field solver.

3. The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine according to claim 1, characterized in that: For leaky hole flow, the wall penetration model is based on mass flow rate outflow, given the mass flow rate of the outflowing fluid and the porosity; For orifice flow, the wall penetration model is based on mass flow inflow, given the mass flow rate, species and species mass fractions, total temperature, and porosity of the inflowing fluid.

4. The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine according to claim 3, characterized in that: Calculating the fluid properties at the wall permeability model specifically includes: back-calculating the main variables of pressure, temperature, density and velocity based on the given small-scale flow information.

5. The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine according to claim 4, characterized in that: For mass flow inflow: T 0_bleed =T 0_input AND k_bleed =And k_input p bleed =p in Among them, T 0_bleed Refers to the total temperature at the penetration hole, T 0_input Refers to the input of the specified total temperature, k represents the specific component number, Y k_bleed represents the mass fraction of the component at the permeation pore, Y k_input Represents the mass fraction of the component specified by the input, p bleed Refers to the pressure at the penetration hole, p in Refers to the pressure in the flow field near the permeation hole; For mass flow outflow: T 0_bleed =T 0_in AND k_bleed =And k_in p bleed =p in Among them, T 0_in Refers to the total temperature in the flow field near the penetration hole, Y k_in Represents the mass fraction of this component in the flow field near the permeation pore.

6. The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine according to claim 5, characterized in that: according to Get the total enthalpy, where nspecies represents the total number of components and R mix_bleed The gas constant, R, represents the gas constant of the mixed heat of the perfect gas at the permeation pore. k represents the gas constant for each component, H mix_bleed represents the total enthalpy of the mixed heat of the complete gas at the permeation pore, H k represents the total enthalpy of each component, a 1k ~a 6k All are fitting parameters of the gas component thermophysical property database; according to Cp k =a 1k +a 2k T bleed +a 3k T bleed 2 +a 4k T bleed 3 +a 5k T bleed 4 Get the specific heat at constant pressure, where Cp mix_bleed Represents the constant pressure specific heat of the perfect gas at the permeation pore, Cp k represents the specific heat at constant pressure of each component, T bleed Represents the static temperature at the penetration hole.

7. The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine according to claim 6, characterized in that: according to V x_bleed =V bleed *Nx V y_bleed =V bleed *The V z_bleed =V bleed *Nz Get speed and energy information, where Rho bleed represents the density at the penetration pore, V bleed represents the velocity at the penetration wall, Area represents the penetration area, is the mass flow rate of the fluid, Nx, Ny and Nz are the surface normals in the x, y and z directions respectively, V x_bleed 、V y_bleed and V z_bleed are the velocity components in the x, y and z directions respectively, E bleed Represents the energy at the penetration wall.

8. The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine according to claim 7, characterized in that: according to Get the mass flow rate through the permeation hole, where represents the mass flow rate through the permeable pore after considering the porosity, and λ is the porosity.

9. The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine according to claim 1, characterized in that: Consider the weight factor of the source term of each unit according to the unit volume, and add the corresponding source term to the NS equation and component equation in each unit. For the NS equation, For the component equation, Where w represents the weight factor, ΔS rho represents the source term of the density equation, ΔS u represents the source term of the velocity equation in the x direction, ΔS v represents the source term of the velocity equation in the y direction, ΔS w represents the source term of the velocity equation in the z direction, ΔS E represents the source term of the energy equation, ΔS k Represents the source term of the component equation.

10. The model calculation method for simulating small-scale flow in the flow channel of an aircraft engine according to claim 1, characterized in that: The structural solver is used to perform implicit iterative calculations of the steady-state flow field of the aircraft to obtain the aerodynamic performance when small-scale flow exists in the flow channel of the aircraft engine.

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