A method, device, equipment and storage medium for aerodynamic performance analysis based on engine outlet boundary conditions

Abstract

The present application discloses an aerodynamic performance analysis method, apparatus, device, and storage medium based on engine outlet boundary conditions, which relates to the field of fluid mechanics technology and includes: simulating the engine outlet flow field of a target engine to obtain a target flow field; determining the target flow rate, total temperature, and gas flow direction of the engine outlet boundary in the target flow field, and determining the actual flow rate of the engine outlet boundary based on the body center value of the unit to which each boundary surface of the engine outlet boundary belongs; determining the total pressure of the engine outlet boundary based on the target flow rate and the actual flow rate; determining the boundary conditions of the engine outlet boundary based on the total pressure, total temperature, and gas flow direction, so as to perform numerical simulation of the target engine according to the boundary conditions and analyze the aerodynamic performance of the target engine. The total pressure of the boundary surface is adjusted according to the fixed target flow rate so that the flow rate of the boundary surface meets the target value, thereby improving the accuracy of the boundary conditions and the effect of the engine aerodynamic performance analysis.

Description

Technical Field

[0001] The present invention relates to the field of fluid mechanics technology, and in particular to an aerodynamic performance analysis method, device, equipment and storage medium based on engine outlet boundary conditions. Background Art

[0002] In CFD (Computational Fluid Dynamics) numerical simulations, the calculated flow field can only encompass a portion of the actual physical domain. This truncation of the physical domain creates an artificial boundary, at which appropriate values ​​for flow field quantities must be specified. These are known as boundary conditions. Improper implementation of boundary conditions can lead to inaccurate simulations of real physics and adversely affect the stability and convergence of the flow field solution. Therefore, how to properly set boundary conditions for flow fields remains an unresolved issue in this field. Summary of the Invention

[0003] In light of this, the present invention aims to provide an aerodynamic performance analysis method, apparatus, device, and storage medium based on engine outlet boundary conditions. These methods adjust the total pressure at the boundary surface based on a fixed target flow rate, ensuring that the flow rate at the boundary surface meets a given target value. This improves the accuracy of the boundary conditions and the effectiveness of the aerodynamic performance analysis of the target engine. The specific implementation is as follows:

[0004] In a first aspect, the present application provides an aerodynamic performance analysis method based on engine outlet boundary conditions, comprising:

[0005] Simulating the engine outlet flow field of the target engine to obtain the target flow field;

[0006] determining a target flow rate, a total temperature, and a gas flow direction at an engine outlet boundary in the target flow field, and determining a current actual flow rate at the engine outlet boundary based on a body center value of a cell to which each boundary surface at the engine outlet boundary belongs;

[0007] determining a total pressure at the engine outlet boundary according to the target flow rate and the actual flow rate;

[0008] The boundary conditions of the engine outlet boundary are determined based on the total pressure, the total temperature and the gas flow direction, so as to perform a numerical simulation of the target engine according to the boundary conditions and analyze the aerodynamic performance of the target engine based on the simulation results.

[0009] Optionally, determining the current actual flow rate of the engine outlet boundary based on the body center value of the unit to which each boundary surface of the engine outlet boundary belongs includes:

[0010] Determining the body center value of the unit to which each boundary surface of the engine outlet boundary belongs; the body center value includes the flow field density, flow field pressure and the first velocity component in each preset direction at the body center of the boundary surface;

[0011] determining a second velocity component along the normal direction of each of the boundary surfaces based on the first velocity component;

[0012] Determining the boundary surface area of ​​each boundary surface and the number of boundary surfaces of the engine outlet boundary;

[0013] The gas flow rate of each boundary surface is determined according to the product of the second velocity component, the boundary surface area and the flow field density, and the gas flow rates are summed according to the number of boundary surfaces to obtain the actual flow rate at the engine outlet boundary.

[0014] Optionally, determining the total pressure at the engine outlet boundary according to the target flow rate and the actual flow rate includes:

[0015] determining a ratio between the target flow rate and the actual flow rate to obtain a flow rate ratio at the engine outlet boundary;

[0016] determining a corresponding normal velocity based on a product of the flow ratio and the second velocity component of each of the boundary surfaces;

[0017] The total pressure at the engine outlet boundary is determined based on the normal velocity.

[0018] Optionally, determining the total pressure at the engine outlet boundary according to the normal velocity includes:

[0019] Determining a third velocity component in each of the preset directions based on the second velocity component; the third velocity component is a velocity component corresponding to the gas flow direction;

[0020] Determining a corresponding third velocity component based on the normal velocity and a target value; the target value being a dot product of a unit vector in each of the preset directions and a unit normal vector of the boundary surface;

[0021] The total pressure at the engine outlet boundary is determined based on the third velocity component and the flow field pressure.

[0022] Optionally, before determining the total pressure at the engine outlet boundary based on the third velocity component and the flow field pressure, the method further includes:

[0023] determining a stagnation speed of sound at the engine outlet boundary based on the total temperature, a preset air specific heat ratio, and a preset gas constant;

[0024] Determining a critical speed of the corresponding engine outlet boundary according to the stagnation sound speed and the preset air specific heat ratio;

[0025] Accordingly, determining the total pressure at the engine outlet boundary according to the third velocity component and the flow field pressure includes:

[0026] determining a current Laval number based on the third velocity component and the critical velocity;

[0027] The current total pressure at the engine outlet boundary is determined according to the Laval number, the flow field pressure, and a preset air specific heat ratio.

[0028] Optionally, the process of determining the current Laval number based on the third velocity component and the critical velocity further includes:

[0029] Presetting the gas flow rate at the engine outlet boundary to be subsonic, and setting the maximum threshold of the Laval number to 1 based on the subsonic speed;

[0030] The minimum value between the Laval number and the maximum threshold is used as the current Laval number.

[0031] Optionally, determining the boundary condition of the engine outlet boundary based on the total pressure, the total temperature, and the gas flow direction includes:

[0032] determining a Mach number corresponding to the body center of each of the boundary surfaces based on the preset air specific heat ratio, the flow field pressure, the flow field density, and the first velocity component in each preset direction;

[0033] determining an average total pressure at the engine outlet boundary based on the total pressure and the boundary surface area of ​​each boundary surface;

[0034] The boundary condition of the engine outlet boundary is determined according to the total pressure average value, the Mach number, and the preset air specific heat ratio.

[0035] In a second aspect, the present application provides an aerodynamic performance analysis device based on engine outlet boundary conditions, comprising:

[0036] The flow field simulation module simulates the engine outlet flow field of the target engine to obtain the target flow field;

[0037] a flow determination module, configured to determine a target flow rate, a total temperature, and a gas flow direction at an engine outlet boundary in the target flow field, and determine a current actual flow rate at the engine outlet boundary based on a body center value of a cell to which each boundary surface at the engine outlet boundary belongs;

[0038] a total pressure determination module, configured to determine the total pressure at the engine outlet boundary according to the target flow rate and the actual flow rate;

[0039] A condition determination module is used to determine the boundary conditions of the engine outlet boundary based on the total pressure, the total temperature and the gas flow direction, so as to perform numerical simulation of the target engine according to the boundary conditions and analyze the aerodynamic performance of the target engine based on the simulation results.

[0040] In a third aspect, the present application provides an electronic device comprising a processor and a memory; wherein the memory is used to store a computer program, and the computer program is loaded and executed by the processor to implement the aforementioned aerodynamic performance analysis method based on engine outlet boundary conditions.

[0041] In a fourth aspect, the present application provides a computer-readable storage medium for storing a computer program, which, when executed by a processor, implements the aforementioned aerodynamic performance analysis method based on engine outlet boundary conditions.

[0042] In this application, after simulating the engine outlet flow field of the target engine to obtain the target flow field, the target flow rate, total temperature and gas flow direction of the engine outlet boundary in the target flow field are determined, and based on the body center value of the unit to which each boundary surface of the engine outlet boundary belongs, the current actual flow rate of the engine outlet boundary is determined, and the total pressure of the engine outlet boundary is determined based on the target flow rate and the actual flow rate. Then, the boundary conditions of the engine outlet boundary can be determined based on the total pressure, total temperature and gas flow direction, so as to perform numerical simulation of the target engine according to the boundary conditions and analyze the aerodynamic performance of the target engine based on the simulation results. Through the above technical solution, the present application can first set a fixed target flow rate of the engine outlet boundary in the target flow field, and then detect the actual flow rate of the engine outlet boundary, determine the total pressure of the engine outlet boundary through the target flow rate and the actual flow rate, so as to make the flow rate of the boundary surface meet the given target value by adjusting the total pressure of the boundary surface, effectively improving the accuracy when setting the boundary conditions, and improving the stability of the flow field solution, thereby improving the effect of the aerodynamic performance analysis of the target engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0044] Figure 1A flow chart of an aerodynamic performance analysis method based on engine outlet boundary conditions provided in this application;

[0045] Figure 2 A schematic diagram of a computational flow field including an engine inlet boundary provided for this application;

[0046] Figure 3 A schematic cross-sectional view of a boundary unit provided in this application;

[0047] Figure 4 A schematic diagram of the structure of an aerodynamic performance analysis device based on engine outlet boundary conditions provided in this application;

[0048] Figure 5 This is a structural diagram of an electronic device provided in this application. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] In CFD numerical simulation, it is necessary to specify appropriate values ​​of flow field physical quantities on the boundary, that is, boundary conditions. When setting boundary conditions, inappropriate implementation may lead to inaccurate simulation of real physics, and will also have an adverse effect on the stability and convergence of the flow field solution. In this application, the target flow rate and the current actual flow rate at the engine outlet boundary in the target flow field can be first determined, and the total pressure at the engine outlet boundary can be adjusted to make the flow rate on the boundary surface meet the given target value, thereby effectively improving the accuracy of setting boundary conditions.

[0051] See also Figure 1 As shown, an embodiment of the present invention discloses an aerodynamic performance analysis method based on engine outlet boundary conditions, comprising:

[0052] Step S11: Simulate the engine outlet flow field of the target engine to obtain the target flow field.

[0053] First, it's important to note that the engine outlet refers to the interface where the high-temperature, high-pressure combustion gases from the engine are discharged into the external environment. For example, a turbofan engine typically has two outlets: the inner duct outlet, which is the high-temperature gas outlet of the core engine (after the combustion chamber); and the outer duct outlet, which is the fan-driven, low-temperature airflow outlet (usually a mixed inner and outer duct exhaust). In flow field simulation, the "engine outlet" is defined as an artificial cutoff boundary. The engine outlet boundary condition is a type of boundary condition in CFD simulations and is typically used for flow field calculations involving aircraft engine outlets (such as integrated internal and external flow field simulations of powered aircraft). It is used to simulate the engine outlet flow field conditions to avoid the difficulties associated with directly simulating the engine itself.

[0054] In this embodiment, it is first necessary to determine the outlet flow field of the target engine of the current aircraft, and then simulate the engine outlet flow field of the target engine to obtain the target flow field. Figure 2 Figure 1 shows a schematic cross-section of the calculated flow field for a transport aircraft engine nacelle. The grid lines within the dashed boxes labeled "bypass" and "inner duct" on the right side of the figure represent the engine outlet boundary surfaces where conditions must be specified. Typical engine outlet boundary conditions include fixed total state variables (total pressure and temperature, velocity direction), fixed velocity and density, or fixed flow rate (flow rate and total temperature, velocity direction).

[0055] Step S12: determining the target flow rate, total temperature, and gas flow direction of the engine outlet boundary in the target flow field, and determining the current actual flow rate of the engine outlet boundary based on the body center value of the unit to which each boundary surface of the engine outlet boundary belongs.

[0056] It is understandable that in aerodynamic calculations involving internal flow, mass flow rate Q is a very important parameter. Compared to total state parameters (total pressure, total temperature, total density), mass flow rate is usually a known parameter, specified by the user or provided by wind tunnel tests. Other aerodynamic characteristics need to be solved as a function of mass flow rate. In this embodiment, a fixed flow rate is first set, that is, the target flow rate Q at the engine outlet boundary in the target flow field is determined. t, as well as the total temperature T0 of the engine outlet boundary and the gas flow direction, and based on the body center value of the unit to which each boundary surface of the engine outlet boundary belongs, the current actual flow rate of the engine outlet boundary is determined. And when determining the actual flow rate based on the body center value of the unit to which each boundary surface of the engine outlet boundary belongs, the body center value of the unit to which each boundary surface of the engine outlet boundary belongs is first determined, wherein the body center value includes the flow field density, flow field pressure and first velocity component of each preset direction at the body center of the boundary surface; then, based on the first velocity component, the second velocity component of the unit normal vector of each boundary surface is determined, the boundary surface area of ​​each boundary surface and the number of boundary surfaces of the engine outlet boundary are determined, and then the gas flow rate of each boundary surface is determined based on the product of the second velocity component, the boundary surface area and the flow field density, and the gas flow rates are summed according to the number of boundary surfaces to obtain the actual flow rate of the engine outlet boundary.

[0057] That is to say, after each numerical iteration step of CFD is completed, the center value of the flow field unit can be obtained, that is, Figure 3 The flow field density ρ, pressure p and the first velocity component in each preset direction at the center C: the velocity component u in the x direction, the velocity component v in the y direction and the velocity component w in the z direction. It can be understood that Figure 3 The "×" in the figure marks the center of the body C, and B is a grid node on the boundary. The air flow rate can then be collected for each grid face on the engine inlet boundary to obtain the current actual flow rate (Qa) at the engine outlet. The specific calculation formula is as follows:

[0058] ;

[0059] In the above formula, i represents each boundary surface, The number of faces representing all boundary surfaces of the engine inlet boundary, is the density, is the velocity perpendicular to the boundary surface, is the area of ​​the boundary surface. and The calculation is performed by taking the value of the cell center of the cell C to which the boundary surface i belongs.

[0060] Step S13: determining the total pressure at the engine outlet boundary according to the target flow rate and the actual flow rate.

[0061] In this embodiment, the total pressure at the engine outlet boundary can be determined based on the target flow rate and the actual flow rate. Specifically, the ratio between the target flow rate and the actual flow rate can be determined to obtain the flow ratio at the engine outlet boundary, and the corresponding normal velocity can be determined based on the product of the flow ratio and the second velocity component of each boundary surface. The total pressure at the engine outlet boundary can then be determined based on the normal velocity. and actual traffic , calculate the flow ratio The specific calculation formula is as follows:

[0062] ;

[0063] Then, the flow ratio is used to adjust the normal velocity Vn of each boundary surface i. The adjusted normal velocity is for:

[0064] ;

[0065] The total pressure at the engine outlet boundary is then determined based on the normal velocity. Specifically, the third velocity component in each preset direction can be determined based on the second velocity component, where the third velocity component corresponds to the gas flow direction. The corresponding third velocity component is then determined based on the normal velocity and a target value, where the target value is the dot product of the unit vector in each preset direction and the unit normal vector of the surface. The total pressure at the engine outlet boundary is then determined based on the third velocity component and the flow field pressure. The third velocity component, that is, the velocity component along the specified flow direction, is:

[0066] ;

[0067] in, 、 、 are the unit normal vector components of the boundary surface on the x, y, and z coordinate axes respectively; 、 、 It is the component of the vector in the predetermined fluid flow direction on the x, y, and z coordinate axes respectively.

[0068] Furthermore, in this embodiment, before determining the total pressure at the engine outlet boundary based on the third velocity component and the flow field pressure, it is necessary to determine the stagnation velocity of sound at the engine outlet boundary based on the total temperature, the preset air specific heat ratio, and the preset gas constant. Furthermore, the critical velocity at the corresponding engine outlet boundary is determined based on the stagnation velocity of sound and the preset air specific heat ratio. In other words, first, using the given total temperature T0, the stagnation velocity of sound c0 and the critical velocity c* must be calculated:

[0069] ;

[0070] in, is the specific heat ratio of air (air = 1.4), is the gas constant (air = 287 J / (kg·K)).

[0071] Accordingly, when determining the total pressure at the engine outlet boundary based on the third velocity component and the flow field pressure, the current Laval number can be determined based on the third velocity component and the critical speed, and the current total pressure at the engine outlet boundary can be determined based on the Laval number, the flow field pressure, and the preset air specific heat ratio. First, calculate the local Laval number :

[0072] ;

[0073] It should also be noted that in determining the current Laval number, the gas flow velocity at the engine outlet boundary is pre-set to subsonic, so that the maximum threshold of the Laval number is set to 1 based on the subsonic speed, and the minimum of the Laval number and the maximum threshold is used as the current Laval number. In other words, in this embodiment, because the boundary condition is subsonic flow, the Laval number is limited to no greater than 1, that is:

[0074] ;

[0075] Since the Laval number is the ratio of the velocity to the critical speed of sound, limiting it to no more than 1 can effectively avoid computational instability caused by supersonic flow.

[0076] Step S14: determining the boundary conditions of the engine outlet boundary based on the total pressure, the total temperature, and the gas flow direction, so as to perform a numerical simulation of the target engine according to the boundary conditions, and analyzing the aerodynamic performance of the target engine based on the simulation results.

[0077] In this embodiment, the boundary conditions of the engine outlet boundary can be determined based on the total pressure, total temperature and gas flow direction, so that a numerical simulation of the target engine can be performed according to the boundary conditions, and the aerodynamic performance of the target engine can be analyzed based on the simulation results.

[0078] Determine the boundary conditions of the engine outlet boundary. Specifically, the Mach number corresponding to the center of each boundary surface can be determined based on the preset air specific heat ratio, flow field pressure, flow field density and the first velocity component in each preset direction. Based on the total pressure and the boundary surface area of ​​each boundary surface, the average total pressure of the engine outlet boundary is determined. Then, the boundary conditions of the engine outlet boundary are determined based on the average total pressure, Mach number and the preset air specific heat ratio. First, according to the Laval number and static pressure pc, calculate the local total pressure , in this way, the total pressure can be reversed based on the corrected velocity and static pressure, which helps to update the subsequent boundary conditions:

[0079] ;

[0080] Then calculate the average value of the total pressure , through averaging, the local fluctuation of the total pressure at the boundary is reduced and the calculation stability is improved:

[0081] ;

[0082] in, is the area of ​​the i-th boundary surface, is the total pressure on the i-th boundary surface;

[0083] And calculate the Mach number at the cell center C :

[0084] ;

[0085] In the above formula, u c 、v c 、w c That is, the first velocity component at the body center C, is the flow field density at the body center C; then, the flow field variables on the boundary surface can be calculated based on the total pressure, total temperature, unit velocity direction vector, and Mach number at the unit center C, and the corresponding boundary conditions can be constructed, including:

[0086] ;

[0087] in, is the static pressure on the boundary surface B, is the static temperature of the boundary surface B, is the gas density at the boundary surface B, is the speed of sound at the boundary surface B, is the gas flow velocity at the boundary surface B, 、 、 are the velocity components in each direction of the boundary surface B.

[0088] Through the above technical solution, this embodiment can set the mass flow rate, total temperature, and flow direction of the boundary surface at the engine outlet boundary in the target flow field. The actual flow rate at the engine outlet boundary is then detected, and the total pressure at the engine outlet boundary is determined based on the target flow rate and the actual flow rate. The total pressure of the boundary surface is then adjusted to make the flow rate at the boundary surface meet the given target value. Based on the adjusted total pressure, total temperature, and velocity direction, other flow field variables can be calculated, and complete boundary flow field parameters (density, velocity, pressure, etc.) can be derived, providing complete boundary conditions for the next CFD iteration. At the same time, it also takes into account abnormal conditions such as local congestion and supersonic flow that may occur during the calculation process. It has the advantages of balancing accuracy and robustness, effectively improving the accuracy of boundary condition setting and the stability of flow field solution. Through the "flow rate-velocity-total pressure" adjustment, efficient and accurate setting of engine outlet boundary conditions is achieved. This is particularly suitable for CFD simulations that require precise control of mass flow rate, and improves the aerodynamic performance analysis of the target engine.

[0089] See also Figure 4 As shown, the embodiment of the present application further discloses an aerodynamic performance analysis device based on engine outlet boundary conditions, comprising:

[0090] The flow field simulation module 11 simulates the engine outlet flow field of the target engine to obtain the target flow field;

[0091] a flow determination module 12 for determining a target flow rate, a total temperature, and a gas flow direction at an engine outlet boundary in the target flow field, and determining a current actual flow rate at the engine outlet boundary based on a body center value of a cell to which each boundary surface of the engine outlet boundary belongs;

[0092] a total pressure determination module 13, configured to determine the total pressure at the engine outlet boundary according to the target flow rate and the actual flow rate;

[0093] The condition determination module 14 is used to determine the boundary conditions of the engine outlet boundary based on the total pressure, the total temperature and the gas flow direction, so as to perform numerical simulation of the target engine according to the boundary conditions and analyze the aerodynamic performance of the target engine based on the simulation results.

[0094] This embodiment first simulates the engine outlet flow field of a target engine to obtain the target flow field. The target flow rate, total temperature, and gas flow direction at the engine outlet boundary in the target flow field are then determined. Based on the body center values ​​of the cells to which each boundary surface of the engine outlet boundary belongs, the current actual flow rate at the engine outlet boundary is determined. The total pressure at the engine outlet boundary is then determined based on the target flow rate and the actual flow rate. Boundary conditions at the engine outlet boundary are then determined based on the total pressure, total temperature, and gas flow direction. Numerical simulation of the target engine is then performed based on these boundary conditions, and the aerodynamic performance of the target engine is analyzed based on the simulation results. In this manner, by setting a fixed target flow rate at the engine outlet boundary in the target flow field, detecting the actual flow rate at the engine outlet boundary, and then determining the total pressure at the engine outlet boundary based on the target flow rate and the actual flow rate, the total pressure at the boundary surface is adjusted to ensure that the flow rate at the boundary surface meets the given target value. This effectively improves the accuracy of setting boundary conditions and the stability of the flow field solution, thereby enhancing the aerodynamic performance analysis of the target engine.

[0095] In some specific embodiments, the flow determination module 12 specifically includes:

[0096] a body center value determination unit, configured to determine the body center value of a unit to which each boundary surface of the engine outlet boundary belongs; the body center value includes the flow field density, flow field pressure, and first velocity component in each preset direction at the body center of the boundary surface;

[0097] a first velocity component determining unit, configured to determine a second velocity component along the normal direction of each of the boundary surfaces based on the first velocity component;

[0098] a boundary surface determination unit, configured to determine the boundary surface area of ​​each boundary surface and the number of boundary surfaces of the engine outlet boundary;

[0099] An actual flow determination unit is used to determine the gas flow rate of each boundary surface according to the product of the second velocity component, the boundary surface area and the flow field density, and sum the gas flow rates according to the number of boundary surfaces to obtain the actual flow rate at the engine outlet boundary.

[0100] In some specific embodiments, the total pressure determination module 13 specifically includes:

[0101] a flow ratio determination submodule, configured to determine a ratio between the target flow and the actual flow, and obtain the flow ratio of the engine outlet boundary;

[0102] a velocity determination submodule, configured to determine a corresponding normal velocity based on the product of the flow ratio and the second velocity component of each of the boundary surfaces;

[0103] A total pressure determination submodule is configured to determine the total pressure at the engine outlet boundary according to the normal velocity.

[0104] In some specific embodiments, the total pressure determination submodule specifically includes:

[0105] a second velocity component determining unit, configured to determine a third velocity component in each of the preset directions based on the second velocity component; the third velocity component being a velocity component corresponding to the gas flow direction;

[0106] a velocity correction unit, configured to determine a corresponding third velocity component based on the normal velocity and a target value, wherein the target value is a dot product of a unit vector in each of the preset directions and a unit normal vector of the boundary surface;

[0107] The first total pressure determining unit is configured to determine the total pressure at the engine outlet boundary according to the third velocity component and the flow field pressure.

[0108] In some specific embodiments, the total pressure determination submodule further includes:

[0109] a sound speed determining unit, configured to determine a stagnation sound speed at the engine outlet boundary based on the total temperature, a preset air specific heat ratio, and a preset gas constant;

[0110] a critical speed determining unit, configured to determine a critical speed of the corresponding engine outlet boundary according to the stagnation sound speed and the preset air specific heat ratio;

[0111] Correspondingly, the total pressure determination submodule specifically includes:

[0112] a first parameter determination unit, configured to determine a current Laval number based on the third velocity component and the critical velocity;

[0113] The second total pressure determination unit is configured to determine the current total pressure at the engine outlet boundary according to the Laval number, the flow field pressure, and a preset air specific heat ratio.

[0114] In some specific embodiments, the total pressure determination submodule further includes:

[0115] a threshold setting unit, configured to pre-set the gas flow velocity at the engine outlet boundary to be subsonic, so as to set the maximum threshold of the Laval number to 1 based on the subsonic speed;

[0116] The second parameter determination unit is configured to use the minimum value between the Laval number and the maximum threshold as the current Laval number.

[0117] In some specific embodiments, the condition determination module 14 specifically includes:

[0118] A Mach number determination unit, configured to determine the Mach number corresponding to the body center of each of the boundary surfaces based on the preset air specific heat ratio, the flow field pressure, the flow field density, and the first velocity component in each preset direction;

[0119] an average value determining unit, configured to determine an average value of the total pressure at the engine outlet boundary based on the total pressure and the boundary surface area of ​​each of the boundary surfaces;

[0120] A boundary condition determination unit is used to determine the boundary condition of the engine outlet boundary according to the total pressure average value, the Mach number and the preset air specific heat ratio.

[0121] Furthermore, the embodiment of the present application also discloses an electronic device, Figure 5 This is a structural diagram of an electronic device 20 according to an exemplary embodiment. The content in the diagram should not be considered as any limitation to the scope of application of the present application.

[0122] Figure 5 This is a schematic diagram of the structure of an electronic device 20 provided in an embodiment of the present application. The electronic device 20 may specifically include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. The memory 22 is used to store a computer program, which is loaded and executed by the processor 21 to implement the relevant steps of the aerodynamic performance analysis method based on engine outlet boundary conditions disclosed in any of the aforementioned embodiments. Furthermore, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0123] In this embodiment, the power supply 23 is used to provide operating voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and the external device. The communication protocol it follows is any communication protocol that can be applied to the technical solution of this application and is not specifically limited here; the input and output interface 25 is used to obtain external input data or output data to the outside world. Its specific interface type can be selected according to specific application needs and is not specifically limited here.

[0124] In addition, the memory 22, as a carrier for resource storage, can be a read-only memory, random access memory, disk or CD, etc. The resources stored thereon can include an operating system 221, a computer program 222, etc., and the storage method can be temporary storage or permanent storage.

[0125] The operating system 221 is used to manage and control the hardware devices and computer program 222 on the electronic device 20, and can be Windows Server, Netware, Unix, Linux, etc. In addition to including a computer program capable of implementing the aerodynamic performance analysis method based on engine outlet boundary conditions performed by the electronic device 20 as disclosed in any of the aforementioned embodiments, the computer program 222 may further include computer programs capable of implementing other specific tasks.

[0126] Furthermore, this application discloses a computer-readable storage medium for storing a computer program. When executed by a processor, the computer program implements the aforementioned aerodynamic performance analysis method based on engine outlet boundary conditions. The specific steps of this method can be found in the corresponding contents disclosed in the aforementioned embodiments and will not be further elaborated here.

[0127] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Reference can be made to the descriptions of the identical or similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the methods.

[0128] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0129] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0130] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0131] The above is a detailed introduction to the technical solution provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for analyzing aerodynamic performance based on engine outlet boundary conditions, characterized in that: include: Simulating the engine outlet flow field of the target engine to obtain the target flow field; determining a target flow rate, a total temperature, and a gas flow direction at an engine outlet boundary in the target flow field, and determining a current actual flow rate at the engine outlet boundary based on a body center value of a cell to which each boundary surface at the engine outlet boundary belongs; determining a total pressure at the engine outlet boundary according to the target flow rate and the actual flow rate; determining a boundary condition of the engine outlet boundary based on the total pressure, the total temperature, and the gas flow direction, so as to perform a numerical simulation of the target engine according to the boundary condition, and analyzing the aerodynamic performance of the target engine based on the simulation result; The determining of the current actual flow rate of the engine outlet boundary based on the body center value of the unit to which each boundary surface of the engine outlet boundary belongs includes: Determining the body center value of the unit to which each boundary surface of the engine outlet boundary belongs; the body center value includes the flow field density, flow field pressure and the first velocity component in each preset direction at the body center of the boundary surface; determining a second velocity component along the normal direction of each of the boundary surfaces based on the first velocity component; Determining the boundary surface area of ​​each boundary surface and the number of boundary surfaces of the engine outlet boundary; determining the gas flow rate of each boundary surface according to the product of the second velocity component, the boundary surface area, and the flow field density, and summing the gas flow rates according to the number of boundary surfaces to obtain the actual flow rate at the engine outlet boundary; Accordingly, the boundary condition of the engine outlet boundary is determined based on the total pressure, the total temperature and the gas flow direction, including: determining a Mach number corresponding to the body center of each of the boundary surfaces based on a preset air specific heat ratio, the flow field pressure, the flow field density, and the first velocity component in each preset direction; determining an average total pressure at the engine outlet boundary based on the total pressure and the boundary surface area of ​​each boundary surface; The boundary condition of the engine outlet boundary is determined according to the total pressure average value, the Mach number, and the preset air specific heat ratio.

2. The aerodynamic performance analysis method based on engine outlet boundary conditions according to claim 1, characterized in that: The determining the total pressure at the engine outlet boundary according to the target flow rate and the actual flow rate includes: determining a ratio between the target flow rate and the actual flow rate to obtain a flow rate ratio at the engine outlet boundary; determining a corresponding normal velocity based on a product of the flow ratio and the second velocity component of each of the boundary surfaces; The total pressure at the engine outlet boundary is determined based on the normal velocity.

3. The aerodynamic performance analysis method based on engine outlet boundary conditions according to claim 2, characterized in that: Determining the total pressure at the engine outlet boundary according to the normal velocity includes: Determining a third velocity component in each of the preset directions based on the second velocity component; the third velocity component is a velocity component corresponding to the gas flow direction; Determining a corresponding third velocity component based on the normal velocity and a target value; the target value being a dot product of a unit vector in each of the preset directions and a unit normal vector of the boundary surface; The total pressure at the engine outlet boundary is determined based on the third velocity component and the flow field pressure.

4. The aerodynamic performance analysis method based on engine outlet boundary conditions according to claim 3, characterized in that: Before determining the total pressure at the engine outlet boundary according to the third velocity component and the flow field pressure, the method further includes: determining a stagnation speed of sound at the engine outlet boundary based on the total temperature, a preset air specific heat ratio, and a preset gas constant; Determining a critical speed of the corresponding engine outlet boundary according to the stagnation sound speed and the preset air specific heat ratio; Accordingly, determining the total pressure at the engine outlet boundary according to the third velocity component and the flow field pressure includes: determining a current Laval number based on the third velocity component and the critical velocity; The current total pressure at the engine outlet boundary is determined according to the Laval number, the flow field pressure, and a preset air specific heat ratio.

5. The aerodynamic performance analysis method based on engine outlet boundary conditions according to claim 4, characterized in that: The process of determining the current Laval number based on the third velocity component and the critical velocity further includes: Presetting the gas flow rate at the engine outlet boundary to be subsonic, and setting the maximum threshold of the Laval number to 1 based on the subsonic speed; The minimum value between the Laval number and the maximum threshold is used as the current Laval number.

6. An aerodynamic performance analysis device based on engine outlet boundary conditions, characterized in that: include: The flow field simulation module simulates the engine outlet flow field of the target engine to obtain the target flow field; a flow determination module, configured to determine a target flow rate, a total temperature, and a gas flow direction at an engine outlet boundary in the target flow field, and determine a current actual flow rate at the engine outlet boundary based on a body center value of a cell to which each boundary surface at the engine outlet boundary belongs; a total pressure determination module, configured to determine the total pressure at the engine outlet boundary according to the target flow rate and the actual flow rate; a condition determination module, configured to determine a boundary condition of the engine outlet boundary based on the total pressure, the total temperature, and the gas flow direction, so as to perform a numerical simulation of the target engine according to the boundary condition, and analyze the aerodynamic performance of the target engine based on the simulation result; Wherein, the flow determination module includes: a body center value determination unit, configured to determine the body center value of a unit to which each boundary surface of the engine outlet boundary belongs; the body center value includes the flow field density, flow field pressure, and first velocity component in each preset direction at the body center of the boundary surface; a first velocity component determining unit, configured to determine a second velocity component along the normal direction of each of the boundary surfaces based on the first velocity component; a boundary surface determination unit, configured to determine the boundary surface area of ​​each boundary surface and the number of boundary surfaces of the engine outlet boundary; an actual flow rate determining unit, configured to determine the gas flow rate of each boundary surface according to the product of the second velocity component, the boundary surface area, and the flow field density, and sum the gas flow rates according to the number of boundary surfaces to obtain the actual flow rate at the engine outlet boundary; Accordingly, the condition determination module includes: A Mach number determination unit is configured to determine the Mach number corresponding to the body center of each of the boundary surfaces based on a preset air specific heat ratio, the flow field pressure, the flow field density, and the first velocity component in each preset direction; an average value determining unit, configured to determine an average value of the total pressure at the engine outlet boundary based on the total pressure and the boundary surface area of ​​each of the boundary surfaces; A boundary condition determination unit is used to determine the boundary condition of the engine outlet boundary according to the total pressure average value, the Mach number and the preset air specific heat ratio.

7. An electronic device, characterized in that: The electronic device includes a processor and a memory; wherein the memory is used to store a computer program, and the computer program is loaded and executed by the processor to implement the aerodynamic performance analysis method based on engine outlet boundary conditions as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that Used to store a computer program, which, when executed by a processor, implements the aerodynamic performance analysis method based on engine outlet boundary conditions as described in any one of claims 1 to 5.

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