A rapid prediction method for aerodynamic / structural coupled thermal environment along the flight envelope

Abstract

The present invention provides a rapid prediction method for the aerodynamic / structural coupled thermal environment along the flight envelope, belonging to the technical field of coupled thermal environment prediction. It includes: S1. Discretize the flight envelope of the aircraft to obtain a dataset of flight envelope state points; S2. Obtain the thermal flux distribution data of the aircraft structure skin; S3. Obtain the temperature distribution data of the aircraft structure at the state points; S4. Feed back the temperature distribution data of the aircraft structure at the state points into the prediction of the aerodynamic thermal environment as the wall temperature boundary condition for aerodynamic heat calculation; S5. Perform calculations along the flight envelope; S6. Repeat steps S2 to S5 until the calculations for all flight envelope state points are completed to obtain the aerodynamic / structural coupled thermal environment database of the whole aircraft. It solves the technical problem in the prior art that the calculation cost and efficiency are low when performing high-precision coupled numerical simulations for the entire flight envelope.

Description

Technical Field

[0001] The present application relates to a method for rapidly predicting the aerodynamic / structural coupled thermal environment along the flight envelope, and belongs to the technical field of coupled thermal environment prediction. Background Art

[0002] Near-space hypersonic vehicles have received extensive attention from major aerospace countries around the world due to their huge technical advantages and application values in the flight environment of wide speed ranges and large airspaces. During the long-term cross-domain high-speed dynamic flight of the vehicle, the vehicle generates aerodynamic heating due to the intense friction with the air, resulting in the vehicle being in a high-temperature environment for a long time during high-speed flight, which has a series of impacts on the skin, structure, thermal protection, infrared stealth, and thermal management. The accurate prediction of the aerodynamic heating phenomenon has become the most urgent technical problem to be solved in the development of the vehicle.

[0003] With the development of aviation technology, the design of aircraft is developing towards precision, refinement, and rapid iteration. The aerodynamic shape design of the aircraft no longer only considers the aerodynamic characteristics themselves. Aerodynamic thermal design has become the key to the success or failure of the development. Moreover, the thermal environment is generated by the intense friction between the aircraft skin and the air and acts on the skin structure and conducts inward, which is a comprehensive prediction involving multiple disciplines and physical fields such as aerodynamics, structure, and thermal management. This puts forward higher requirements for the highly accurate prediction of the aerodynamic / structural coupled thermal environment in the design and development of hypersonic vehicles, and thus more complex problems and solutions need to be faced.

[0004] In engineering, usually the aerodynamic thermal environment and the structural thermal environment are considered separately or a high-precision numerical simulation of aerodynamic heat / structural heat conduction coupling is established. First, the temperature or heat flux distribution under a single flight state in the flight envelope is obtained using isothermal wall or adiabatic wall conditions. The structural thermal environment takes the heat flux or temperature distribution of the aerodynamic thermal environment under typical working conditions or typical heating states as input to predict the structural temperature field. Usually, only one iteration is performed, ignoring the dynamic changes in the aerodynamic thermal environment caused by the change of flight conditions during the dynamic flight of the vehicle and the different heat distribution on the vehicle skin surface. The structural thermal environment prediction also selects the most severe point during the flight as input for assessment, and the calculation accuracy often cannot meet the requirements for high-precision data in aircraft design, and the resulting design margin is often too large. Conducting a high-precision coupled numerical simulation of aerodynamic heat / structural heat conduction often calculates for a single-point state under severe working conditions. If a high-precision coupled numerical simulation is performed for the entire flight envelope, it often takes weeks or even months, and the calculation cost and efficiency cannot meet the requirements of rapid design prediction. Summary of the Invention

[0005] A brief summary of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this summary is not an exhaustive summary of the present invention. It is not intended to identify the key or important parts of the present invention, nor is it intended to limit the scope of the present invention. Its purpose is only to present certain concepts in a simplified form as a prelude to the more detailed description discussed later.

[0006] In view of this, to solve the technical problems of high computational cost and low efficiency in the prior art when performing high-precision coupled numerical simulation of the entire flight envelope, the present invention provides a method for rapidly predicting the aerodynamic / structural coupled thermal environment along the flight envelope. This method is applied to the aerodynamic heat design stage of hypersonic vehicles and is a method for multi-field coupling of the aerodynamic heat environment and the structural heat environment. By using simplified models or rapid prediction algorithms, the efficiency of the design stage is improved on the premise of ensuring a certain accuracy.

[0007] Solution 1: A method for rapidly predicting the aerodynamic / structural coupled thermal environment along the flight envelope, comprising the following steps:

[0008] S1. Discretize the flight envelope of the aircraft to obtain a dataset of flight envelope state points (P1, P2, P3......P N ), and form the calculation control condition data for predicting the thermal environment of the flight envelope.

[0009] Discretize the flight envelope of the aircraft by using the method of equal distance or equal time step. The specific implementation method is as follows:

[0010] Method of equal distance step: The method of equal distance step is to discretize the flight envelope at equal distances according to the flight distance, that is, to equally divide the flight envelope distance, is a constant value, S represents the flight distance, n is the number of discrete points, is the length of the equal-distance envelope for advancing the calculation. According to the equally divided points of the flight envelope distance, obtain the flight states of each flight envelope distance point, and form a dataset of flight envelope state points.

[0011] Method of equal time step: The method of equal time step is to discretize the flight envelope at equal time steps according to the flight time, that is, to equally divide the flight time of the envelope, is a constant value, where t represents the flight time, n is the number of discrete points, is the time interval for advancing the calculation, obtain the flight states of each flight envelope time point, and form a dataset of flight envelope state points.

[0012] The flight envelope state points include flight time t, altitude H, Mach number Ma, angle of attack , pressure P, density and temperature T;

[0013] S2. Predict the aerodynamic heat environment of the entire aircraft at the flight envelope state point P1 to obtain the data of the heat flux distribution on the skin of the aircraft structure;

[0014] S3. Input the data of the heat flux distribution on the skin of the entire aircraft as the boundary condition into the prediction of the structural heat environment, and perform quasi-one-dimensional heat conduction iterative calculations. After convergence and equilibrium, obtain the data of the temperature distribution of the aircraft structure at the state point;

[0015] S4. Feed back the data of the temperature distribution of the aircraft structure at the state point P1 into the prediction of the aerodynamic heat environment as the wall temperature boundary condition for the aerodynamic heat calculation;

[0016] S5. Advance the calculation along the flight envelope until the aerodynamic heat environment calculation at the state point P2 converges to equilibrium, and obtain the data of the heat flux distribution on the skin at the P2 state;

[0017] S6. Repeat steps S2 - S5 until the advancement calculations for all flight envelope state points are completed to obtain the aerodynamic / structural coupled heat environment database of the entire aircraft.

[0018] Preferably, the data of the heat flux distribution on the skin of the aircraft structure is obtained by numerical solution. The specific implementation method is:

[0019] For the stagnation point region, the following formula is used:

[0020] ;

[0021] For the large area of the surface, the following formula is used:

[0022] ;

[0023] where s represents the stagnation point parameter, w represents the wall parameter, e represents the outer edge parameter of the boundary layer, represents the parameter obtained by using the reference enthalpy relation, represents the heat flux, Re represents the Reynolds number, Pr represents the Prandtl number, represents the viscosity coefficient, and h represents the enthalpy value.

[0024] Preferably, the quasi-one-dimensional heat conduction iterative calculation method is:

[0025] ;

[0026] where , , and k respectively represent the density, specific heat capacity, and thermal conductivity of the structural material, and n represents the normal direction.

[0027] Solution 2: An electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the method for rapidly predicting the aerodynamic / structural coupled thermal environment along the flight envelope described in Solution 1 are implemented.

[0028] Solution 3: A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for rapidly predicting the aerodynamic / structural coupled thermal environment along the flight envelope described in Solution 1 is implemented.

[0029] The beneficial effects of the present invention are as follows: The present invention realizes the rapid prediction of the aerodynamic / structural coupled thermal environment, completes the coupling effect between multiple physical fields, and improves the accuracy of prediction data; in the process of calculating the aerodynamic thermal environment, the temperature field distribution data fed back by the structure is used as the boundary condition, and compared with the traditional isothermal wall with a fixed temperature, the aerodynamic thermal data is closer to the real flight condition; based on the simplified model assumption, the calculation efficiency can be rapidly improved, and the thermal environment prediction of the entire flight envelope can be realized in a short time, greatly shortening the thermal environment prediction time of the aircraft.

[0030] The present invention is applied to the prediction requirements of the aerodynamic thermal environment and the structural thermal environment in the design and development of hypersonic aircraft. It can be completed by a single machine working alone or a single machine combined with a supercomputing platform, realizing the rapid prediction of the thermal environment in the aerodynamic / structural coupled state along the flight envelope, and greatly improving the calculation efficiency and accuracy under the condition of ensuring a certain calculation accuracy. Description of the Drawings

[0031] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0032] Figure 1 It is a schematic flow chart of a method for rapidly predicting the aerodynamic / structural coupled thermal environment along the flight envelope. Detailed Embodiments

[0033] In order to make the technical solutions and advantages in the embodiments of the present application clearer and more understandable, the following further details the exemplary embodiments of the present application with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0034] Embodiment 1: Refer to Figure 1 To illustrate this embodiment, a method for rapidly predicting the aerodynamic / structural coupled thermal environment along the flight envelope includes the following steps:

[0035] S1. Discretize the flight envelope of the aircraft to obtain a dataset of flight envelope state points (P1, P2, P3......P N ), forming the data for the control conditions of the flight envelope thermal environment prediction calculation;

[0036] Equal - distance step method: The equal - distance step method discretizes the flight envelope at equal distances according to the flight distance, that is, divides the flight envelope distance equally. is a constant value, S represents the flight distance, and n is the number of discrete points. is the length of the equal - distance envelope for propulsion calculation. According to the equally - spaced discrete points of the flight envelope, the flight states at each flight envelope distance point are obtained, forming a dataset of flight envelope state points.

[0037] Equal - time step method: The equal - time step method discretizes the flight envelope at equal time steps according to the flight time, that is, divides the flight time of the envelope equally. is a constant value, where t represents the flight time and n is the number of discrete points. is the time interval for propulsion calculation. The flight states at each flight envelope time point are obtained, forming a dataset of flight envelope state points.

[0038] The flight envelope state points include flight time t, altitude H, Mach number Ma, angle of attack , pressure P, density and temperature T;

[0039] For the key - concern area of the flight envelope, this area can be further discretized to increase the state - point density, thereby further improving the calculation accuracy.

[0040] S2. Predict the aerothermal environment of the whole aircraft for the flight envelope state point P1 to obtain the data of the heat - flux distribution on the skin of the aircraft structure;

[0041] The data of the heat - flux distribution on the skin of the aircraft structure is obtained by numerical solution. The specific implementation method is as follows:

[0042] For the stagnation - point region, the following formula is used:

[0043] ;

[0044] For the large - area surface region, the following formula is used:

[0045] ;

[0046] Among them, the subscript s represents the stagnation - point parameters, the subscript w represents the wall - surface parameters, the subscript e represents the boundary - layer outer - edge parameters, and the superscript represents the parameters obtained by using the reference - enthalpy relationship. represents the heat flux, Re represents the Reynolds number, and Pr represents the Prandtl number. μ represents the viscosity coefficient, and h represents the enthalpy value.

[0047] S3. Input the heat flux distribution data of the whole aircraft's surface skin as the boundary condition into the structural thermal environment prediction, and perform one-dimensional heat conduction iterative calculation. After convergence and equilibrium, obtain the structural temperature distribution data of the state point aircraft.

[0048] The method of one-dimensional heat conduction iterative calculation is as follows:

[0049] ;

[0050] where , , and k represent the density, specific heat capacity, and thermal conductivity of the structural material respectively, and n represents the normal direction.

[0051] During the process of predicting the whole aircraft's structural thermal environment, as a fast prediction method, usually only consider the heat transfer process in the normal direction gradient of the structure temperature, and ignore the influence of the small temperature gradient in the circumferential direction on the structural temperature transfer process.

[0052] S4. Feed back the structural temperature distribution data of the state point P1 aircraft into the aerodynamic thermal environment prediction as the wall temperature boundary condition for aerodynamic heat calculation.

[0053] After the structural thermal environment prediction is completed, that is, obtain the temperature distribution data of the structural part (including the coupling boundary). By extracting the coupling boundary temperature data, directly assign this point data to the aerodynamic thermal environment prediction to complete the update of the coupling boundary temperature boundary condition and realize the aerodynamic / structural coupling.

[0054] S5. Advance the calculation along the flight envelope until the aerodynamic thermal environment calculation of the state point P2 converges to equilibrium, and obtain the heat flux distribution data of the surface skin under the P2 state.

[0055] S6. Repeat steps S2 - S5 until the advancement calculation of all flight envelope state points is completed to obtain the whole aircraft's aerodynamic / structural coupled thermal environment database.

[0056] During the process of predicting the aerodynamic / structural coupled thermal environment of the flight envelope state point data set, for each flight state data point, obtain the aerodynamic and structural thermal environment distribution data under this state. After the advancement calculation of all the flight envelope state points is completed, obtain the thermal environment data at each state point, thereby forming the thermal environment database.

[0057] Embodiment 2. The computer device of the present invention may be a device including a processor and a memory, such as a single-chip microcomputer including a central processing unit. Moreover, when the processor is used to execute the computer program stored in the memory, the steps of the above-mentioned method for rapidly predicting the aerodynamic / structural coupling thermal environment along the flight envelope are implemented.

[0058] The so-called processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0059] The memory may mainly include a program storage area and a data storage area. Among them, the program storage area may store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area may store data created according to the use of the mobile phone (such as audio data, phone book, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0060] Embodiment 3. Embodiment of the computer-readable storage medium

[0061] The computer-readable storage medium of the present invention may be any form of storage medium readable by the processor of the computer device, including but not limited to non-volatile memory, volatile memory, ferroelectric memory, etc. A computer program is stored on the computer-readable storage medium. When the processor of the computer device reads and executes the computer program stored in the memory, the steps of the above-mentioned method for rapidly predicting the aerodynamic / structural coupling thermal environment along the flight envelope can be implemented.

[0062] The computer program includes computer program code, which may be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, removable hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice within the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0063] Although the present invention has been described based on a limited number of embodiments, those skilled in the art in this technical field will understand that other embodiments can be envisioned within the scope of the present invention thus described. In addition, it should be noted that the language used in this specification is mainly selected for readability and teaching purposes, rather than for the purpose of explaining or limiting the subject matter of the present invention. Therefore, many modifications and changes are obvious to those of ordinary skill in the art in this technical field without departing from the scope and spirit of the appended claims. For the scope of the present invention, the disclosure made of the present invention is illustrative rather than restrictive, and the scope of the present invention is defined by the appended claims.

Claims

1. A rapid prediction method for the aerodynamic / structural coupled thermal environment along the flight envelope, characterized in that Including the following steps: S1. Discretize the flight envelope of the aircraft to obtain a dataset of flight envelope state points (P1, P2, P3......P n ), and form the data of the control conditions for the prediction and calculation of the thermal environment of the flight envelope; Discretize the flight envelope of the aircraft using the method of equal distance or equal time step. The specific implementation method is: Method of equal interval step: The method of equal interval step is to discretize the flight envelope at equal distances according to the flight distance, that is, to equally divide the flight envelope distance. is a fixed value, S represents the flight distance, and n is the number of discrete points. is the length of the equal interval envelope for propulsion calculation. According to the equally spaced points of the flight envelope, the flight states at each flight envelope distance point are obtained, forming a dataset of flight envelope state points. Equal time step method: The equal time step method discretizes the flight envelope at equal time steps according to the flight time, that is, divides the flight time of the envelope equally. is a fixed value, where t represents the flight time and n is the number of discrete points. is the time interval for advancing the calculation, obtaining the flight states at each flight envelope time point, and forming a flight envelope state point data set. The flight envelope state points include flight time t, altitude H, Mach number Ma, angle of attack , pressure P, density and temperature T; S2. Predict the aerodynamic heat environment of the whole aircraft for the flight envelope state point P i and obtain the skin heat flux distribution data on the aircraft structure surface; S3. Input the skin heat flux distribution data of the whole aircraft surface as the boundary condition into the structural thermal environment prediction, and perform quasi-one-dimensional heat conduction iterative calculation. After convergence and equilibrium, obtain the structural temperature distribution data of the state point aircraft; S4. Feed the structural temperature distribution data of the state point P i back into the prediction of the aerodynamic heat environment and use it as the wall temperature boundary condition for aerodynamic heat calculation; S5. Advance the calculation along the flight envelope until the state point P i+1 The aerothermal environment calculation converges to equilibrium to obtain P i+1 The surface skin heat flux distribution data under the state; S6. Repeat steps S2 to S5 until the propulsion calculation of all flight envelope state points is completed, and obtain the aerodynamic / structural coupled thermal environment database of the whole aircraft.

2. The rapid prediction method for the aerodynamic / structural coupling thermal environment along the flight envelope according to claim 1, wherein Obtain the skin heat flux distribution data of the aircraft structure surface by numerical solution. The specific implementation method is: The stagnation point region adopts the following formula: ； The large surface area region adopts the following formula: ； Among them, s represents the stagnation point parameter, w represents the wall parameter, and e represents the boundary layer outer edge parameter. represents the parameter obtained by using the reference enthalpy relation. represents the heat flux, Re represents the Reynolds number, and Pr represents the Prandtl number. represents the viscosity coefficient, and h represents the enthalpy value.

3. A rapid prediction method for the aerodynamic / structural coupled thermal environment along the flight envelope according to claim 2, characterized in that The quasi-one-dimensional heat conduction iterative calculation method is: ； Among them, , , k respectively represent the density, specific heat capacity and thermal conductivity of the structural material, and n represents the normal direction.

4. An electronic device, characterized in that, Including a memory and a processor. The memory stores a computer program. When the processor executes the computer program, it implements the steps of a method for rapid prediction of aerodynamic / structural coupled thermal environment along the flight envelope according to any one of claims 1-3.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements a method for rapid prediction of aerodynamic / structural coupled thermal environment along the flight envelope according to any one of claims 1-3.

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