CN-121980985-A - Multi-body separation rapid simulation method based on unsteady pneumatic modeling

CN121980985ACN 121980985 ACN121980985 ACN 121980985ACN-121980985-A

Abstract

The invention provides a multi-body separation rapid simulation method based on unsteady aerodynamic modeling, which comprises the steps of firstly obtaining a static aerodynamic database and unsteady aerodynamic data of a single typical state through CFD calculation; and then the two types of data are fused and modeled, and a high-precision proxy model capable of predicting aerodynamic force of the dynamic process is constructed. During simulation, the real-time position and the gesture of the separator are input into the model, the current aerodynamic force is rapidly predicted, the motion state is updated by solving a rigid six-degree-of-freedom motion equation, the surface grid motion is driven to realize visualization, and the iteration is circulated until the separation is finished. The invention combines static and unsteady aerodynamic forces, improves the simulation efficiency by several orders of magnitude compared with the traditional method while ensuring the accuracy of capturing dynamic aerodynamic effects, and can be widely applied to the design and analysis of the aerospace and weapon engineering fields such as aircraft separation, ammunition throwing and the like.

Inventors

Meng Xufei
ZHAO HONGRUI
LI PENGFEI
LIU ZHOU
YANG YUNJUN

Assignees

中国航天空气动力技术研究院

Dates

Publication Date: 20260505
Application Date: 20251215

Claims (10)

1. A multi-body separation rapid simulation method based on unsteady pneumatic modeling is characterized by comprising the following steps: s1, acquiring static aerodynamic force data of a separator in different states through a computational fluid dynamics CFD method, and constructing a static aerodynamic force database; S2, carrying out fusion modeling on the static aerodynamic data and the unsteady aerodynamic data obtained in the step S1, and constructing an aerodynamic prediction model which can predict aerodynamic force at corresponding time or position in the separation process according to the position and posture information of the separation body; S3, setting an initial time t 0 of multi-body separation simulation, acquiring position information and attitude information of a separation body at time t 0 , and inputting the position information and the attitude information into the aerodynamic force prediction model constructed in the step S2 to obtain aerodynamic force corresponding to time t 0 ; S4, substituting aerodynamic force at the moment t 0 obtained in the step S3 into a rigid body six-degree-of-freedom motion equation, and obtaining position information and posture information of a separator at the next moment t 1 through numerical solution, wherein t 1 =t 0 +deltat, deltat is a set time step; S5, moving and rotating the surface grid of the separator according to the position information and the posture information of the separator at the time t 1 obtained in the step S4, so that the actual positions and the postures of the surface grid and the separator are kept consistent, and the visualization of the separation process is realized; And S6, judging whether the set separation duration is reached, if not, taking the position and posture information at the moment t 1 as new input, repeating the steps S3-S5, and if so, stopping simulation, and outputting separation track data and posture change data of the separation body in the whole separation process.
2. The method for rapidly simulating multi-body separation based on unsteady aerodynamic modeling according to claim 1, wherein in step S1, the different states comprise different angles of attack, sideslip angles, mach numbers and flying heights of the separation bodies, and the static aerodynamic data comprise axial force, normal force, lateral force, rolling moment, yaw moment and pitching moment.
3. The method for rapidly simulating multi-body separation based on unsteady aerodynamic modeling according to claim 1, wherein in step S1, when calculating an unsteady motion process in a single typical motion state, an unsteady CFD solving method is adopted, and a solving time step is set according to an actual calculation state, so that time resolution of unsteady aerodynamic data is ensured.
4. The method for rapidly simulating multi-body separation based on unsteady aerodynamic modeling according to claim 1, wherein in step S2, a weighted fusion algorithm is adopted in data fusion modeling, and the weight coefficient of static aerodynamic data and the weight coefficient of unsteady aerodynamic data are adaptively adjusted according to dynamic characteristics of a separation process, wherein the dynamic characteristics include motion acceleration, angular velocity and airflow disturbance intensity of a separation body.
5. The multi-body separation rapid simulation method based on unsteady aerodynamic modeling according to claim 1, wherein in step S2, a Co-Kriging model is adopted for data fusion modeling, static aerodynamic data are regarded as low-fidelity data, unsteady aerodynamic data are regarded as high-fidelity data, model super-parameters are solved through an optimization algorithm, and an aerodynamic prediction model is constructed.
6. The unsteady pneumatic modeling-based multi-body separation rapid simulation method according to claim 1, wherein in step S4, the rigid body six-degree-of-freedom motion equation is: Translation: ; and (3) rotation: ; solving the motion equation by adopting second-order Newmark integral: ; where χ represents v or ω, in actual solution, the rotation equation is expressed in quaternion to avoid singularities due to gimbal deadlock.
7. The unsteady pneumatic modeling-based multi-body separation rapid simulation method according to claim 6, wherein in step S4, the rotation equation is represented by quaternion to avoid singularities caused by a gimbal deadlock.
8. The method for rapid simulation of multi-body separation based on unsteady pneumatic modeling according to claim 1, wherein in step S5, when the surface mesh is moved and rotated, the displacement of each node is calculated according to the position and posture change of the separated body, thereby realizing mesh adjustment.
9. The method for rapidly simulating multi-body separation based on unsteady pneumatic modeling according to claim 1, wherein in step S6, the condition for judging whether the separation process is finished is that the separation duration reaches a preset duration or the distance between the separated bodies is greater than a preset safety distance.
10. The multi-body separation rapid simulation method based on unsteady pneumatic modeling according to claim 9, wherein the preset safety distance is determined according to the size of the separation body and is 3-5 times of the maximum characteristic size of the separation body.

Description

Multi-body separation rapid simulation method based on unsteady pneumatic modeling Technical Field The invention relates to the technical field of multi-body separation simulation, in particular to a multi-body separation rapid simulation method based on unsteady pneumatic modeling. Background In the engineering fields of aerospace, weapons and the like, a multi-body separation process is a key link for influencing equipment safety and task reliability. For example, when the aircraft launches the missile, if collision occurs between the two missiles or the separation gesture is out of control in the separation process, the mission failure and even equipment damage are directly caused, and the two-stage separation safety determines whether the launching mission is successful or not in the multi-stage carrier launching and track entering process. Therefore, in the equipment design stage, it is important to perform accurate and efficient simulation analysis on the multi-body separation process. At present, the multi-body separation simulation mainly adopts two technical paths, namely a simplified simulation method based on an empirical formula or a static aerodynamic model, static aerodynamic data of a separation body is obtained through experiments, an empirical formula or a lookup table is established, and then a rigid motion equation is combined to solve a separation track. The method has the advantages of high calculation efficiency, but has the obvious defect that the unsteady effect of the air flow (such as generation and falling of a separation vortex, air flow interference and the like) in the separation process is ignored, so that the aerodynamic force prediction error is larger, and particularly in the scene of severe air flow disturbance in the initial stage of separation, the deviation between a simulation result and the actual situation can reach more than 20 percent, and the requirement of high-precision design cannot be met. The other is a high-precision simulation method based on unsteady computational fluid dynamics (Unsteady CFD, UCFD), and the method directly carries out numerical solution on the unsteady flow field in the separation process, so that the unsteady aerodynamic characteristics can be accurately captured. However, since the unsteady flow field calculation requires a large amount of calculation resources and time, for complex multi-body separation processes (such as multi-load sequential separation and complex-shape separation), single simulation often requires days or even weeks, and the calculation efficiency is extremely low, so that the requirement of rapid iterative design of equipment is difficult to meet. Therefore, how to improve the efficiency of multi-body separation simulation and balance the contradiction between the precision and the efficiency on the premise of ensuring the simulation precision becomes a technical problem to be solved in the current multi-body separation simulation technical field. Disclosure of Invention The invention aims to provide a multi-body separation rapid simulation method based on unsteady aerodynamic modeling, which is used for constructing a high-precision prediction model by fusing static and unsteady aerodynamic data, so that the calculation efficiency is greatly improved while the simulation precision is ensured. According to the purpose of the invention, the invention provides a multi-body separation rapid simulation method based on unsteady pneumatic modeling, which comprises the following steps of: s1, acquiring static aerodynamic force data of a separator in different states through a computational fluid dynamics CFD method, and constructing a static aerodynamic force database; S2, carrying out fusion modeling on the static aerodynamic data and the unsteady aerodynamic data obtained in the step S1, and constructing an aerodynamic prediction model which can predict aerodynamic force at corresponding time or position in the separation process according to the position and posture information of the separation body; S3, setting an initial time t 0 of multi-body separation simulation, acquiring position information and attitude information of a separation body at time t 0, and inputting the position information and the attitude information into the aerodynamic force prediction model constructed in the step S2 to obtain aerodynamic force corresponding to time t 0; s4, substituting the aerodynamic force at the moment t0 obtained in the step S3 into a rigid body six-degree-of-freedom motion equation, and obtaining the position information and the posture information of the separator at the next moment t 1 through numerical solution, wherein t 1=t0 +deltat, deltat is a set time step; S5, moving and rotating the surface grid of the separator according to the position information and the posture information of the separator at the time t 1 obtained in the step S4, so that the actual positions and the postures of the surface grid and the sep