Aerodynamic thermal ablation matching coupling simulation design method

Abstract

The invention discloses an aerodynamic thermal ablation matching coupling simulation design method, which comprises the following steps of: S1, selecting a typical state point of a flight orbit to calculate an incoming flow condition aiming at an unablated aircraft profile, and simulating thermal environments of lap joint parts of different types of thermal protection materials; s2, ablation simulation analysis is carried out to determine the ablation amount and the ablation contour of the two sides of the lap joint part, and the initial ablation matching step height h0 of the materials on the two sides is calculated; s3, estimating an ablation deterioration factor, and estimating an ablation matching step height H after an ablation deterioration effect on the basis of h0; ablated step appearance modeling is carried out, and the aircraft appearance with the local ablated step appearance is obtained; s4, regenerating an aircraft surface and external flow field grid, carrying out three-dimensional aerodynamic thermal simulation design, and giving a thermal environment of a material lap joint part; s5, carrying out ablation simulation analysis again, and calculating a secondary ablation matching step height h1; s6, h1 and H are compared, and simulation is finished after it is confirmed that the flight test ablation amount is enveloped by the estimated ablation amount in S3.

Description

Technical Field

[0001] The invention relates to an aerodynamic thermal ablation matching coupling simulation design method, which is suitable for the simulation and design of aerodynamic thermal and thermal protection systems of high-speed aircraft and belongs to the field of aerodynamic thermal and thermal protection. Background Art

[0002] When an aircraft flies at high speed in the atmosphere, it rubs against the surrounding air violently and strongly compresses the air in front of it. Under the dual effects of viscous dissipation effect and strong shock wave compression, a large amount of kinetic energy of the high-speed flow is converted into internal energy, causing the temperature in the shock layer to rise sharply, which can reach more than 10,000K, causing serious aerodynamic heating on the surface of the aircraft. Therefore, it is necessary to design advanced thermal protection systems to break through the "thermal barrier" problem in the development of high-speed aircraft. At present, various types of high-speed aircraft thermal protection systems mainly use ablative thermal protection technology. For local high heat flux interference areas, it is a common design method to use relatively large areas with higher performance thermal protection materials. However, due to differences in thermal properties, different types of thermal protection materials have different pyrolysis and ablation rates, resulting in discontinuous changes in the shape of the material overlap, which further affects the aerodynamic thermal environment and causes material ablation matching and aerodynamic thermal coupling problems. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide an aerodynamic thermal ablation matching coupling simulation design method, and to efficiently calculate the ablation shape changes at the overlapped parts of different heat-resistant materials and the coupling effect of the aerodynamic thermal environment.

[0004] The technical solution of the present invention is: in the first aspect, a method for designing a pneumatic thermal ablation matching coupling simulation is provided, wherein:

[0005] S1. Carry out three-dimensional aerodynamic thermal simulation based on the external flow field grid and incoming flow conditions of the unablated aircraft shape to provide the thermal environment of the overlapping parts of different types of thermal protection materials;

[0006] S2. Carry out ablation simulation analysis on the thermal protection materials on both sides of the overlapped part, determine the ablation amount and ablation profile on both sides, calculate the difference in ablation amount of the materials on both sides, and record it as the initial ablation matching step height h0;

[0007] S3. Estimate the ablation deterioration factor and the ablation matching step height H after the ablation deterioration effect based on experience or ground test results; and simultaneously carry out ablation step shape modeling based on the ablation deterioration factor and the ablation profile obtained in S2 to obtain the aircraft shape with a local ablation step shape;

[0008] S4. Regenerate the outer flow field grid of the aircraft surface for the aircraft shape with local ablation step shape obtained in S3, and carry out three-dimensional aerodynamic thermal simulation design to give the thermal environment of the material overlap part considering the change of ablation shape;

[0009] S5, based on the thermal environment of the material overlapped part determined in step S4, the thermal protection materials on both sides of the material overlapped part are respectively subjected to ablation simulation analysis again to determine the ablation amount and ablation profile on both sides, and the difference between the ablation amounts of the materials on both sides is calculated, which is recorded as the secondary ablation matching step height h1;

[0010] S6. Compare the secondary ablation matching step height h1 obtained in step S5 with the ablation matching step height H estimated in S3. If h1≤H, confirm that the estimated ablation amount in S3 can envelope the flight test ablation amount, and the simulation is completed; if h1>H, return to S3, increase the ablation deterioration factor and iterate again.

[0011] Preferably, in S1, parameters of typical state points of the flight trajectory are selected to calculate the incoming flow conditions.

[0012] Preferably, in S3, the ablation matching step height H after the ablation deterioration effect is estimated based on the initial ablation matching step height h0.

[0013] Preferably, in S4, a three-dimensional aerodynamic thermal simulation design is carried out based on the typical track state points selected in S1.

[0014] Preferably, the parameters of the typical state points of the flight trajectory include: flight altitude and speed.

[0015] Preferably, the thermal environment data includes heat flow and pressure.

[0016] In a second aspect, an aerodynamic thermal ablation matching coupling simulation design system is provided, which is characterized by comprising: an aircraft surface external flow field grid generation module, a thermal protection material thermal environment simulation module, an ablation simulation analysis module, an ablation deterioration estimation module, and an ablation amount confirmation module; wherein:

[0017] The aircraft surface external flow field grid generation module is used to simulate the aircraft shape, generate the corresponding aircraft surface external flow field grid, and output it to the thermal protection material thermal environment simulation module;

[0018] The thermal environment simulation module of thermal protection materials selects the parameters of typical state points of the flight trajectory to calculate the incoming flow conditions, and conducts three-dimensional aerodynamic thermal simulation based on the external flow field grid and the incoming flow conditions to obtain the thermal environment of the overlapping parts of different types of thermal protection materials, and outputs it to the ablation simulation analysis module;

[0019] The ablation simulation analysis module performs ablation simulation analysis on the thermal protection materials on both sides of the overlapped part, determines the ablation amount and ablation profile on both sides, calculates the difference in ablation amount of the materials on both sides, and outputs it to the ablation deterioration estimation module or the ablation amount confirmation module;

[0020] The ablation deterioration estimation module estimates the ablation deterioration factor, estimates the ablation matching step height H after the ablation deterioration effect based on the difference in the ablation amount of the materials on both sides given by the ablation simulation analysis module, and outputs it to the ablation amount confirmation module;

[0021] The ablation amount confirmation module is used to analyze whether the result of the ablation simulation analysis module is within the envelope of the ablation matching step height H after the ablation deterioration effect output by the ablation deterioration estimation module.

[0022] Preferably, in the aerodynamic thermal ablation matching coupling simulation of a flight trajectory, the system workflow is as follows:

[0023] S1. For the unablated aircraft shape, the aircraft surface external flow field grid generation module generates the external flow field grid; the thermal protection material thermal environment simulation module selects the parameters of the typical state points of the flight trajectory to calculate the incoming flow conditions, and conducts three-dimensional aerodynamic thermal simulation based on the external flow field grid and the incoming flow conditions to give the thermal environment of the overlapping parts of different types of thermal protection materials;

[0024] S2, the ablation simulation analysis module performs ablation simulation analysis on the thermal protection materials on both sides of the overlapped part, determines the ablation amount and ablation profile on both sides, calculates the difference in ablation amount of the materials on both sides, records it as the initial ablation matching step height h0, and outputs it to the ablation deterioration estimation module;

[0025] S3, the ablation deterioration estimation module estimates the ablation deterioration factor based on experience or ground test results, estimates the ablation matching step height H after the ablation deterioration effect based on the initial ablation matching step height h0, and outputs it to the ablation amount confirmation module;

[0026] At the same time, the outer flow field grid generation module of the aircraft surface carries out the ablation step shape modeling of the aircraft surface according to the ablation deterioration factor and the ablation profile obtained in S2, and obtains the aircraft shape with a local ablation step shape;

[0027] S4, the aircraft surface external flow field grid generation module regenerates the external flow field grid based on the aircraft shape with a local ablation step shape, and carries out a three-dimensional aerodynamic thermal simulation design based on the typical state points of the orbit selected in S1, and gives the thermal environment of the material overlap part considering the change of the ablation shape, and outputs it to the ablation simulation analysis module;

[0028] S5. The ablation simulation analysis module performs ablation simulation analysis again on the thermal protection materials on both sides of the material overlap part based on the thermal environment of the material overlap part determined in step S4, determines the ablation amount and ablation profile on both sides, calculates the difference in the ablation amount of the materials on both sides, records it as the secondary ablation matching step height h1, and outputs it to the ablation amount confirmation module;

[0029] S6. The ablation amount confirmation module compares the secondary ablation matching step height h1 obtained in step S5 with the ablation matching step height H estimated in S3. If h1≤H, it is confirmed that the estimated ablation amount in S3 can envelope the flight test ablation amount, and the simulation is completed; if h1>H, it returns to S3 and iterates again after the ablation deterioration estimation module increases the ablation deterioration factor.

[0030] Preferably, the parameters of typical state points of the flight trajectory selected by the thermal protection material thermal environment simulation module include: flight altitude and speed.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] (1) The method of the present invention can carry out aerodynamic thermal ablation matching coupling simulation along the flight trajectory, taking into account the ablation shape changes at the overlap of different heat-resistant materials and the coupling effect of the aerodynamic thermal environment, with high accuracy;

[0033] (2) Compared with the aerodynamic heat / ablation shape tightly coupled calculation method, the present invention has higher calculation efficiency and does not require multiple rounds of iterations. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of ablation matching of different heat-resistant materials of the present invention;

[0035] Figure 2 This is a flow chart of the aerodynamic thermal ablation matching coupling simulation design method of the present invention. DETAILED DESCRIPTION

[0036] Aiming at the ablation matching and aerodynamic thermal coupling problems caused by the overlap of different thermal protection materials, the present invention provides an aerodynamic thermal ablation matching coupling simulation design method along the flight trajectory. The technical characteristics of this method are: it can consider the coupling process of aerodynamic heat and ablation shape changes, has high calculation efficiency, and does not require multiple rounds of iterations.

[0037] The process of the present invention is as follows Figure 2 As shown, specifically:

[0038] 1. For the unablated aircraft shape, generate the aircraft surface and external flow field grids, select the height, speed and angle of attack of typical state points of the flight trajectory to calculate the incoming flow conditions, carry out three-dimensional aerodynamic thermal simulation calculations based on the grids and incoming flow conditions, and give the thermal environment (heat flow, pressure) of the overlap parts of different types of thermal protection materials.

[0039] 2. Based on the thermal environment of the material overlap determined in step 1, ablation simulation analysis is performed on the thermal protection materials on both sides of the overlap to determine the ablation amount and ablation profile on both sides, and the difference in the ablation amount of the materials on both sides is calculated, which is recorded as the initial ablation matching step height h0. The ablation matching results of different thermal protection materials before and after ablation are shown in Figure 2. Figure 1 shown.

[0040] 3. Based on the initial ablation matching step height h0 obtained in step 2, the ablation deterioration factor is estimated according to experience or ground test results, and the ablation matching step height H after considering the ablation deterioration effect is estimated on the basis of h0; at the same time, according to the ablation deterioration factor and the ablation profile obtained in step 2, the ablation step shape modeling is carried out to obtain the aircraft shape with a local ablation step shape.

[0041] 4. For the aircraft shape with local ablation step shape obtained in step 3, regenerate the aircraft surface and external flow field grid, carry out three-dimensional aerodynamic thermal simulation design for the typical orbit state points selected in step 1, and give the thermal environment (heat flow, pressure) of the material overlap parts considering the change of ablation shape.

[0042] 5. Based on the thermal environment of the material overlap determined in step 4, ablation simulation analysis is performed again for the thermal protection materials on both sides of the material overlap on the basis of the initial ablation matching step height h0 state, the ablation amount and ablation profile on both sides are determined, and the difference in the ablation amount of the material on both sides is calculated, which is recorded as the secondary ablation matching step height h1.

[0043] 6. Compare the secondary ablation matching step height h1 obtained in step 5 with the ablation matching step height H estimated in step 3. If h1≤H, confirm that the estimated ablation amount in step 3 can envelope the flight test ablation amount, and the simulation is completed; if h1>H, return to step 3, appropriately increase the ablation deterioration factor and iterate again.

[0044] In a second aspect, the present invention provides an aerodynamic thermal ablation matching coupling simulation design system, which is characterized by comprising: an aircraft surface and external flow field grid generation module, a thermal protection material thermal environment simulation module, an ablation simulation analysis module, an ablation deterioration estimation module, and an ablation amount confirmation module; wherein:

[0045] The aircraft surface external flow field grid generation module is used to simulate the aircraft shape, generate the corresponding aircraft surface and external flow field grids, and output them to the thermal protection material thermal environment simulation module;

[0046] The thermal environment simulation module of thermal protection materials selects the parameters of typical state points of the flight trajectory to calculate the incoming flow conditions, and conducts three-dimensional aerodynamic thermal simulation based on the external flow field grid and the incoming flow conditions to obtain the thermal environment of the overlapping parts of different types of thermal protection materials, and outputs it to the ablation simulation analysis module;

[0047] The ablation simulation analysis module performs ablation simulation analysis on the thermal protection materials on both sides of the overlapped part, determines the ablation amount and ablation profile on both sides, calculates the difference in ablation amount of the materials on both sides, and outputs it to the ablation deterioration estimation module or the ablation amount confirmation module;

[0048] The ablation deterioration estimation module estimates the ablation deterioration factor, estimates the ablation matching step height H after the ablation deterioration effect based on the difference in the ablation amount of the materials on both sides given by the ablation simulation analysis module, and outputs it to the ablation amount confirmation module;

[0049] The ablation amount confirmation module is used to analyze whether the result of the ablation simulation analysis module is within the envelope of the ablation matching step height H after the ablation deterioration effect output by the ablation deterioration estimation module.

[0050] Furthermore, in the aerodynamic thermal ablation matching coupling simulation of a flight trajectory, the system workflow is as follows:

[0051] S1. For the unablated aircraft shape, the aircraft surface external flow field grid generation module generates the external flow field grid; the thermal protection material thermal environment simulation module selects the parameters of the typical state points of the flight trajectory to calculate the incoming flow conditions, and conducts three-dimensional aerodynamic thermal simulation based on the external flow field grid and the incoming flow conditions to give the thermal environment of the overlapping parts of different types of thermal protection materials;

[0052] S2, the ablation simulation analysis module performs ablation simulation analysis on the thermal protection materials on both sides of the overlapped part, determines the ablation amount and ablation profile on both sides, calculates the difference in ablation amount of the materials on both sides, records it as the initial ablation matching step height h0, and outputs it to the ablation deterioration estimation module;

[0053] S3, the ablation deterioration estimation module estimates the ablation deterioration factor based on experience or ground test results, estimates the ablation matching step height H after the ablation deterioration effect based on the initial ablation matching step height h0, and outputs it to the ablation amount confirmation module;

[0054] At the same time, the outer flow field grid generation module of the aircraft surface carries out the ablation step shape modeling of the aircraft surface according to the ablation deterioration factor and the ablation profile obtained in S2, and obtains the aircraft shape with a local ablation step shape;

[0055] S4, the aircraft surface external flow field grid generation module regenerates the external flow field grid based on the aircraft shape with a local ablation step shape, and carries out a three-dimensional aerodynamic thermal simulation design based on the typical state points of the orbit selected in S1, and gives the thermal environment of the material overlap part considering the change of the ablation shape, and outputs it to the ablation simulation analysis module;

[0056] S5. The ablation simulation analysis module performs ablation simulation analysis again on the thermal protection materials on both sides of the material overlap part based on the thermal environment of the material overlap part determined in step S4, determines the ablation amount and ablation profile on both sides, calculates the difference in the ablation amount of the materials on both sides, records it as the secondary ablation matching step height h1, and outputs it to the ablation amount confirmation module;

[0057] S6. The ablation amount confirmation module compares the secondary ablation matching step height h1 obtained in step S5 with the ablation matching step height H estimated in S3. If h1≤H, it is confirmed that the estimated ablation amount in S3 can envelope the flight test ablation amount, and the simulation is completed; if h1>H, it returns to S3 and iterates again after the ablation deterioration estimation module increases the ablation deterioration factor.

[0058] The parameters of typical state points of the flight trajectory selected by the thermal protection material thermal environment simulation module include: flight altitude and speed.

[0059] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

Claims

1. A pneumatic thermal ablation matching coupling simulation design method, characterized in that include: S1. Carry out three-dimensional aerodynamic thermal simulation based on the external flow field grid and incoming flow conditions of the unablated aircraft shape to provide the thermal environment of the overlapping parts of different types of thermal protection materials; S2. Carry out ablation simulation analysis on the thermal protection materials on both sides of the overlapped part, determine the ablation amount and ablation profile on both sides, calculate the difference in ablation amount of the materials on both sides, and record it as the initial ablation matching step height h0; S3. Estimate the ablation deterioration factor and the ablation matching step height H after the ablation deterioration effect based on experience or ground test results; and simultaneously carry out ablation step shape modeling based on the ablation deterioration factor and the ablation profile obtained in S2 to obtain the aircraft shape with a local ablation step shape; S4. Regenerate the outer flow field grid of the aircraft surface for the aircraft shape with local ablation step shape obtained in S3, and carry out three-dimensional aerodynamic thermal simulation design to give the thermal environment of the material overlap part considering the change of ablation shape; S5, based on the thermal environment of the material overlapped part determined in step S4, the thermal protection materials on both sides of the material overlapped part are respectively subjected to ablation simulation analysis again to determine the ablation amount and ablation profile on both sides, and the difference between the ablation amounts of the materials on both sides is calculated, which is recorded as the secondary ablation matching step height h1; S6. Compare the secondary ablation matching step height h1 obtained in step S5 with the ablation matching step height H estimated in S3. If h1≤H, confirm that the estimated ablation amount in S3 can envelope the flight test ablation amount, and the simulation is completed; if h1>H, return to S3, increase the ablation deterioration factor and iterate again.

2. The aerodynamic thermal ablation matching coupling simulation design method according to claim 1, characterized in that: In S1, parameters of typical state points of the flight trajectory are selected to calculate the incoming flow conditions.

3. The aerodynamic thermal ablation matching coupling simulation design method according to claim 1, characterized in that: In S3, the ablation matching step height H after the ablation deterioration effect is estimated based on the initial ablation matching step height h0.

4. The aerodynamic thermal ablation matching coupling simulation design method according to claim 2, characterized in that: In S4, a three-dimensional aerodynamic thermal simulation design is carried out based on the typical track state points selected in S1.

5. The aerodynamic thermal ablation matching coupling simulation design method according to claim 1, characterized in that: The parameters of typical state points of the flight trajectory include: flight altitude and speed.

6. The aerodynamic thermal ablation matching coupling simulation design method according to claim 1, characterized in that: Thermal environment data includes heat flow and pressure.

7. A pneumatic thermal ablation matching coupling simulation design system, characterized in that include: Aircraft surface external flow field grid generation module, thermal protection material thermal environment simulation module, ablation simulation analysis module, ablation deterioration estimation module, ablation amount confirmation module; Among them: The aircraft surface external flow field grid generation module is used to simulate the aircraft shape, generate the corresponding aircraft surface external flow field grid, and output it to the thermal protection material thermal environment simulation module; The thermal environment simulation module of thermal protection materials selects the parameters of typical state points of the flight trajectory to calculate the incoming flow conditions, and conducts three-dimensional aerodynamic thermal simulation based on the external flow field grid and the incoming flow conditions to obtain the thermal environment of the overlapping parts of different types of thermal protection materials, and outputs it to the ablation simulation analysis module; The ablation simulation analysis module performs ablation simulation analysis on the thermal protection materials on both sides of the overlapped part, determines the ablation amount and ablation profile on both sides, calculates the difference in ablation amount of the materials on both sides, and outputs it to the ablation deterioration estimation module or the ablation amount confirmation module; The ablation deterioration estimation module estimates the ablation deterioration factor, estimates the ablation matching step height H after the ablation deterioration effect based on the difference in the ablation amount of the materials on both sides given by the ablation simulation analysis module, and outputs it to the ablation amount confirmation module; The ablation amount confirmation module is used to analyze whether the result of the ablation simulation analysis module is within the envelope of the ablation matching step height H after the ablation deterioration effect output by the ablation deterioration estimation module.

8. The aerodynamic thermal ablation matching coupling simulation design system according to claim 7, characterized in that: In the aerodynamic thermal ablation matching coupling simulation of a flight trajectory, the system workflow is as follows: S1. For the unablated aircraft shape, the aircraft surface external flow field grid generation module generates the external flow field grid; the thermal protection material thermal environment simulation module selects the parameters of the typical state points of the flight trajectory to calculate the incoming flow conditions, and conducts three-dimensional aerodynamic thermal simulation based on the external flow field grid and the incoming flow conditions to give the thermal environment of the overlapping parts of different types of thermal protection materials; S2, the ablation simulation analysis module performs ablation simulation analysis on the thermal protection materials on both sides of the overlapped part, determines the ablation amount and ablation profile on both sides, calculates the difference in ablation amount of the materials on both sides, records it as the initial ablation matching step height h0, and outputs it to the ablation deterioration estimation module; S3, the ablation deterioration estimation module estimates the ablation deterioration factor based on experience or ground test results, estimates the ablation matching step height H after the ablation deterioration effect based on the initial ablation matching step height h0, and outputs it to the ablation amount confirmation module; At the same time, the outer flow field grid generation module of the aircraft surface carries out the ablation step shape modeling of the aircraft surface according to the ablation deterioration factor and the ablation profile obtained in S2, and obtains the aircraft shape with a local ablation step shape; S4, the aircraft surface external flow field grid generation module regenerates the external flow field grid based on the aircraft shape with a local ablation step shape, and carries out a three-dimensional aerodynamic thermal simulation design based on the typical state points of the orbit selected in S1, and gives the thermal environment of the material overlap part considering the change of the ablation shape, and outputs it to the ablation simulation analysis module; S5. The ablation simulation analysis module performs ablation simulation analysis again on the thermal protection materials on both sides of the material overlap part based on the thermal environment of the material overlap part determined in step S4, determines the ablation amount and ablation profile on both sides, calculates the difference in the ablation amount of the materials on both sides, records it as the secondary ablation matching step height h1, and outputs it to the ablation amount confirmation module; S6. The ablation amount confirmation module compares the secondary ablation matching step height h1 obtained in step S5 with the ablation matching step height H estimated in S3. If h1≤H, it is confirmed that the estimated ablation amount in S3 can envelope the flight test ablation amount, and the simulation is completed; if h1>H, it returns to S3 and iterates again after the ablation deterioration estimation module increases the ablation deterioration factor.

9. The aerodynamic thermal ablation matching coupling simulation design system according to claim 7, characterized in that: The parameters of typical state points of the flight trajectory selected by the thermal protection material thermal environment simulation module include: flight altitude and speed.

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