Grid generation method and system for reverse jet interference problem of rocket

Abstract

The embodiment of the invention provides a grid generation method and system for the reverse jet flow interference problem of a rocket, and the method comprises the steps: dividing the rocket into two regions according to the aerodynamic interference intensity of a jet flow interference flow field; respectively generating structural / non-structural hybrid grids for the two areas according to the reverse jet flow field structure of the rocket; and solving the structured grid and the non-structured grid through a structured grid solver and a non-structured grid solver respectively. According to the method, the advantages of the structured grid and the unstructured grid are fully utilized, the structure is reasonable, the calculation precision and the grid generation efficiency are both considered, and the grid generated according to the strategy is suitable for high-precision simulation of the reverse jet disturbing flow field of the rocket.

Description

Technical Field

[0001] This document relates to the field of computational fluid dynamics technology, and in particular to a grid generation method and system for rocket reverse jet interference problems. Background Art

[0002] Currently, the main technical approaches to rocket recovery include parachute recovery, winged return flight, and vertical landing recovery. Parachute recovery has low cost and relatively simple technology, but low recovery accuracy and high requirements for terrain. Winged return flight can achieve high recovery accuracy, but requires the rocket to have good aerodynamic design and flight control system, and has high requirements for launch and recovery sites. Vertical landing recovery can achieve precise landing of the rocket, and has the characteristics of high precision, high efficiency, and wide adaptability. It can achieve damage-free recovery of the entire rocket body including core components such as the first-stage engine, which can reduce dependence on ground facilities, improve the flexibility and safety of launch, and has high commercial application value. It is the most mainstream method of rocket recovery and has become a hot spot for active research by the world's major aerospace powers.

[0003] The most critical issue in the vertical landing recovery process is how to use the engine's reverse jet to slow down and always keep the rocket's attitude stable, so as to achieve the precise control goal of stable flight attitude and accurate landing point. The first problem to be solved in achieving high-precision control is the complex aerodynamic interference between the engine's reverse jet and the surrounding flow.

[0004] During the rocket reentry, the bottom engine nozzle flies forward, and the engine is decelerated at high altitude. Its aerodynamic characteristics and flow structure are quite different from those of traditional aircraft. When the rocket is inverted, at low Mach numbers, flow separation will occur in the rocket shoulder area. At high Mach numbers, the forward-protruding engine nozzle will produce a strong detached shock wave. The interaction between the engine reverse jet and the mainstream will produce complex aerodynamic interference. Small numerical perturbations may cause the numerical simulation results to not converge and the flow field structure to be inaccurate, which poses a severe challenge to the grid and numerical methods. At present, the numerical simulation research on the rocket reverse jet interference problem mostly adopts methods based on unstructured grids or structured overlapping grids. Some studies have also simplified the rocket configuration (such as not considering complex components such as grid rudders) to reduce the requirements for the grid. Although unstructured grids and structured overlapping grids have strong adaptability to complex configurations, their simulation accuracy is not as good as that of docking structured grids.

[0005] In view of the above problems, according to the flow characteristics of rocket reverse jet interference, the present invention provides a grid generation strategy suitable for the rocket reverse jet interference problem, based on which a high-quality structured / unstructured hybrid grid with a small number of grid units that meets the calculation accuracy requirements of the jet interference problem is generated and numerical calculations are performed. Summary of the invention

[0006] One or more embodiments of this specification provide a grid generation method for rocket reverse jet interference problem, including:

[0007] The rocket is divided into two regions according to the severity of the aerodynamic interference of the jet interference flow field;

[0008] According to the rocket reverse jet flow field structure, structured / unstructured hybrid grids are generated for the two regions respectively;

[0009] The structured grid and unstructured grid are solved by structured grid solver and unstructured grid solver respectively.

[0010] Furthermore, the rocket is divided into two areas according to the severity of the aerodynamic interference of the jet interference flow field:

[0011] According to the severity of aerodynamic disturbance caused by the interaction between the reverse jet and the mainstream of the rocket engine and the influence of aerodynamic disturbance on numerical simulation, the rocket is divided into two regions: the interaction region between the reverse jet and the incoming flow and the rocket body region.

[0012] Furthermore, according to the rocket reverse jet flow field structure, structured / unstructured hybrid grids are generated for the two regions respectively as follows:

[0013] The partitioned docking grid technology is used to generate the structural grid in the interaction area between the reverse jet and the incoming flow;

[0014] Unstructured grids are generated for the complex configuration areas in the rocket body, and structured grids are generated for the remaining areas. The generated structured grids are connected to the unstructured grids through partition docking.

[0015] Furthermore, the method further comprises:

[0016] The structural grid of the nozzle-shock wave interface region in the interaction region between the reverse jet and the incoming flow is encrypted; the nozzle-shock wave interface region is the region near the rocket engine nozzle where the reverse jet meets the incoming flow after being ejected from the nozzle and produces a strong interaction.

[0017] Furthermore, the complex configuration area in the arrow body area includes a leg area and a grid rudder area.

[0018] Furthermore, the method of generating an unstructured grid for the complex configuration area in the rocket body area, generating a structured grid for the remaining areas, and connecting the generated structured grid with the unstructured grid by partitioning and docking the structured grid is specifically as follows:

[0019] Tetrahedral meshes are used to generate boundary layers for the walls of the outrigger area and the grid rudder area;

[0020] The boundary layer is spatially connected with the structural grid generated in the rest of the area through the triangular prism grid.

[0021] Furthermore, the solving of the structured grid and the unstructured grid by the structured grid solver and the unstructured grid solver respectively is specifically as follows:

[0022] The structural area where the complete mesh is generated is solved using the structured mesh solver;

[0023] The unstructured grid plus several layers of structured grid near the boundary of the unstructured grid are solved using the unstructured solver;

[0024] The several layers of structured grids are used as transition layers for data exchange.

[0025] One or more embodiments of this specification provide a grid generation system for rocket reverse jet interference problem, including:

[0026] Region division module: used to divide the rocket into two regions according to the severity of the aerodynamic interference of the jet interference flow field;

[0027] Mesh generation module: used to generate structured / unstructured hybrid meshes for two regions based on the rocket reverse jet flow field structure;

[0028] Mesh solving module: used to solve structured grid and unstructured grid through structured grid solver and unstructured grid solver respectively.

[0029] One or more embodiments of the present specification provide an electronic device, including:

[0030] processor; and,

[0031] A memory arranged to store computer executable instructions, which, when executed, cause the processor to implement the steps of the above-mentioned grid generation method for rocket reverse jet interference problem.

[0032] One or more embodiments of the present specification provide a storage medium for storing computer-executable instructions, which, when executed, implement the steps of the above-mentioned grid generation method for the rocket reverse jet interference problem.

[0033] By adopting the embodiment of the present invention, a grid generation strategy suitable for the rocket reverse jet interference problem is established according to the flow characteristics of the rocket reverse jet interference problem. The advantages of structured grids and unstructured grids are fully utilized, the structure is reasonable, and both calculation accuracy and grid generation efficiency are taken into account. The grid generated by this strategy is suitable for high-precision simulation of the rocket reverse jet interference flow field.

[0034] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0036] Figure 1 A flow chart of a grid generation method for rocket reverse jet interference problem provided for one or more embodiments of this specification;

[0037] Figure 2 An example diagram of the grid division area of ​​the rocket reverse jet interference flow field provided by a grid generation method for the rocket reverse jet interference problem provided by one or more embodiments of this specification;

[0038] Figure 3 A grid diagram of different regions of a rocket reverse jet interference flow field for a grid generation method for a rocket reverse jet interference problem provided by one or more embodiments of this specification;

[0039] Figure 4 A rocket reverse jet interference flow field streamline diagram for a grid generation method for a rocket reverse jet interference problem provided by one or more embodiments of this specification;

[0040] Figure 5 A schematic diagram of the composition of a grid generation system for rocket reverse jet interference problem provided in one or more embodiments of this specification;

[0041] Figure 6 A schematic diagram of the structure of an electronic device provided for one or more embodiments of this specification. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the following will be combined with the drawings in one or more embodiments of this specification to clearly and completely describe the technical solutions in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this document.

[0043] Method Embodiment

[0044] According to an embodiment of the present invention, a grid generation method for rocket reverse jet interference problem is provided. Figure 1 A flowchart of a grid generation method for rocket reverse jet interference problem provided in one or more embodiments of this specification, such as Figure 1 As shown, the grid generation method for the rocket reverse jet interference problem according to an embodiment of the present invention specifically includes:

[0045] S1. The rocket is divided into two regions according to the severity of the aerodynamic interference of the jet interference flow field.

[0046] When the rocket is inverted, at low Mach numbers, flow separation will occur in the shoulder area of ​​the rocket. At high Mach numbers, the forward-protruding engine nozzle will produce a strong detachment shock wave. The interaction between the engine reverse jet and the mainstream will produce complex aerodynamic interference. Even a small numerical disturbance may cause the numerical simulation results to not converge and the flow field structure to be inaccurate, and the requirements for the grid are very strict. The rocket body is downstream of the jet interference, and the aerodynamic interference is not as severe as the area where the jet and the incoming flow directly collide, so the requirements for the grid are not as strict. In view of the flow characteristics of the rocket reverse jet interference problem, according to the severity of the aerodynamic interference generated when the rocket engine reverse jet interacts with the mainstream and the impact of the aerodynamic interference on the numerical simulation, the rocket is divided into two regions: the reverse jet and the incoming flow interaction area and the rocket body area. Figure 2 shown.

[0047] S2. Generate structured / unstructured hybrid grids for the two regions based on the rocket reverse jet flow field structure.

[0048] The partitioned docking grid technology is used to generate the structural grid for the interaction area between the reverse jet and the incoming flow; the advantages of the structural grid are fully utilized to accurately simulate the interaction between the reverse jet and the incoming flow, and accurately predict its aerodynamic characteristics and flow field structure. Furthermore, in order to ensure the grid quality and density of the area where the jet and the incoming flow directly collide, the structural grid of the nozzle-shock wave interface area in the interaction area between the reverse jet and the incoming flow is encrypted; the nozzle-shock wave interface area is the area near the rocket engine nozzle, where the reverse jet meets the incoming flow after being ejected from the nozzle and produces a strong interaction.

[0049] Unstructured grids are generated for complex configuration areas in the rocket body, and structured grids are generated for the remaining areas. The generated structured grids are connected to the unstructured grids through partition docking. Specifically, the complex configuration areas in the rocket body include the leg area and the grid rudder area. The boundary layer is generated by tetrahedral grids on the wall surfaces of the leg area and the grid rudder area. The boundary layer is spatially docked with the structured grids generated in the remaining areas through triangular prism grids, such as Figure 3 As shown in the figure, the time-consuming process of generating structural mesh is avoided while ensuring the mesh quality.

[0050] S3. Solve the structured grid and unstructured grid by using the structured grid solver and unstructured grid solver respectively.

[0051] The structured area of ​​the complete grid is solved using a structured grid solver, and the unstructured grid plus several layers of structured grids near the boundary of the unstructured grid are solved using an unstructured solver. The several layers of structured grids are used as transition layers for data exchange to complete the calculation.

[0052] The following is a specific embodiment of applying this method:

[0053] This example selects a typical rocket reverse jet shape, uses the above-mentioned grid generation method to generate a grid and perform calculations, and the calculation conditions are the incoming flow Mach number M∞=0.8,3, the simulation altitude H=5,40km, and the angle of attack α=0°. The final generated grid and calculation results are shown in Figure 4 As shown in the figure, it can be seen that the grid generation strategy provided in this paper can generate high-quality structured / unstructured hybrid grids with a small number of grid cells that can meet the calculation accuracy requirements of the jet interference problem, taking into account both calculation accuracy and grid generation efficiency.

[0054] The beneficial effects of the present invention are as follows:

[0055] According to the flow characteristics of the rocket reverse jet interference problem, the present invention establishes a grid generation strategy suitable for the rocket reverse jet interference problem. It fully utilizes the advantages of structured grids and unstructured grids, has a reasonable structure, and takes into account both calculation accuracy and grid generation efficiency. The grid generated by this strategy is suitable for high-precision simulation of the rocket reverse jet interference flow field.

[0056] System Example

[0057] According to an embodiment of the present invention, a grid generation system for rocket reverse jet interference problem is provided. Figure 5 A schematic diagram of a grid generation system for rocket reverse jet interference problem provided in one or more embodiments of this specification, such as Figure 5 As shown, the grid generation system for rocket reverse jet interference problem according to an embodiment of the present invention specifically includes:

[0058] The region division module 50 is used to divide the rocket into two regions according to the severity of the aerodynamic interference of the jet interference flow field;

[0059] Grid generation module 52: used to generate structured / unstructured hybrid grids for two regions respectively according to the rocket reverse jet flow field structure;

[0060] The grid solving module 54 is used to solve the structured grid and the unstructured grid by using the structured grid solver and the unstructured grid solver respectively.

[0061] The embodiment of the present invention is a system embodiment corresponding to the above-mentioned method embodiment. The specific operations of each module can be understood by referring to the description of the method embodiment, which will not be repeated here.

[0062] Device Example 1

[0063] An embodiment of the present invention provides an electronic device, such as Figure 6 As shown, it includes: a memory 60, a processor 62, and a computer program stored in the memory 60 and executable on the processor 62. When the computer program is executed by the processor 62, the following method steps are implemented:

[0064] S1. The rocket is divided into two regions according to the severity of the aerodynamic interference of the jet flow field;

[0065] S2. Generate structured / unstructured hybrid grids for the two regions according to the rocket reverse jet flow field structure;

[0066] S3. Solve the structured grid and unstructured grid by using the structured grid solver and unstructured grid solver respectively.

[0067] Device Example 2

[0068] An embodiment of the present invention provides a computer-readable storage medium, on which a program for implementing information transmission is stored. When the program is executed by the processor 62, the following method steps are implemented:

[0069] S1. The rocket is divided into two regions according to the severity of the aerodynamic interference of the jet flow field;

[0070] S2. Generate structured / unstructured hybrid grids for the two regions according to the rocket reverse jet flow field structure;

[0071] S3. Solve the structured grid and unstructured grid by using the structured grid solver and unstructured grid solver respectively.

[0072] The computer-readable storage medium in this embodiment includes, but is not limited to, ROM, RAM, magnetic disk or optical disk, etc.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A grid generation method for rocket reverse jet interference problem, characterized in that: include: The rocket is divided into two regions according to the severity of the aerodynamic interference of the jet interference flow field; According to the rocket reverse jet flow field structure, structured / unstructured hybrid grids are generated for the two regions respectively; The structured grid and unstructured grid are solved by structured grid solver and unstructured grid solver respectively.

2. The method according to claim 1, characterized in that The rocket is divided into two areas according to the severity of the aerodynamic interference of the jet interference flow field: According to the severity of aerodynamic disturbance caused by the interaction between the reverse jet and the mainstream of the rocket engine and the influence of aerodynamic disturbance on numerical simulation, the rocket is divided into two regions: the interaction region between the reverse jet and the incoming flow and the rocket body region.

3. The method according to claim 2, characterized in that According to the reverse jet flow field structure of the rocket, structured / unstructured hybrid grids are generated for the two regions respectively as follows: The partitioned docking grid technology is used to generate the structural grid in the interaction area between the reverse jet and the incoming flow; Unstructured grids are generated for the complex configuration areas in the rocket body, and structured grids are generated for the remaining areas. The generated structured grids are connected to the unstructured grids through partition docking.

4. The method according to claim 3, characterized in that The method further comprises: The structural grid of the nozzle-shock wave interface region in the interaction region between the reverse jet and the incoming flow is encrypted; the nozzle-shock wave interface region is the region near the rocket engine nozzle where the reverse jet meets the incoming flow after being ejected from the nozzle and produces a strong interaction.

5. The method according to claim 3, characterized in that: The complex configuration areas in the arrow body area include the leg area and the grid rudder area.

6. The method according to claim 1, characterized in that The method of generating an unstructured grid for the complex configuration area in the rocket body area, generating a structured grid for the remaining areas, and connecting the generated structured grid with the unstructured grid by partitioning and docking the structured grid is specifically as follows: Tetrahedral meshes are used to generate boundary layers for the walls of the outrigger area and the grid rudder area; The boundary layer is spatially connected with the structural grid generated in the rest of the area through the triangular prism grid.

7. The method according to claim 1, characterized in that The specific steps of solving the structured grid and the unstructured grid by using the structured grid solver and the unstructured grid solver are as follows: The structural area where the complete mesh is generated is solved using the structured mesh solver; The unstructured grid plus several layers of structured grid near the boundary of the unstructured grid are solved using the unstructured solver; The several layers of structured grids are used as transition layers for data exchange.

8. A grid generation system for rocket reverse jet interference problem, characterized in that: include: Region division module: used to divide the rocket into two regions according to the severity of the aerodynamic interference of the jet interference flow field; Mesh generation module: used to generate structured / unstructured hybrid meshes for two regions based on the rocket reverse jet flow field structure; Mesh solving module: used to solve structured grid and unstructured grid through structured grid solver and unstructured grid solver respectively.

9. An electronic device, characterized in that: include: processor; as well as, A memory arranged to store computer executable instructions, which, when executed, cause the processor to implement the steps of the grid generation method for rocket reverse jet interference problem as described in any one of claims 1 to 7.

10. A storage medium, characterized in that: Used to store computer executable instructions, which, when executed, implement the steps of the grid generation method for rocket reverse jet interference problem as described in any one of claims 1 to 7.

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