|Alternative Title||A Coupling Calculation with Aerodynamic -Ablation and Thermal Response for nose-tip of Re-entry Vehicle|
|Place of Conferral||北京|
|Keyword||耦合计算 碳基复合材料 烧蚀 网格移动 重映|
Aerodynamic heating is exceedingly serious during the re-entry of hypersonic vehicles into the atmosphere, and the aerodynamic environment surrounding the aircraft, especially the front edge, is extremely harsh. In order to ensure the normal operation of the main structure, it is necessary to perform thermal protection on the places where the aerodynamic environment is intensely severe. Ablative thermal protection is one of methods which more commonly used in engineering. Accurately calculating the amount of ablation and determining the thickness of the ablative coating are important tasks in the design of ablative thermal protection in the project. The recession of ablative material is not only related to the ablation performance of the heat-resistant material itself, but also the aerodynamic thermal environment around the aircraft has a great influence on it. The aerodynamic conditions, temperature field and ablation affect each other, so it is necessary to make a program which for the coupling calculation of the temperature field distribution, aerodynamic condition and ablation of carbon-based composite material is of great significance for accurately simulating ablation boundary recession and determining the thickness of the thermal protection material.
This paper developed a set of coupled calculation methods considering the aerodynamic, ablation and transient temperature distributions. Firstly, the trajectory of the blunt body reentry is discretized, and the aerodynamic-ablation-heat transfer coupling calculation is performed in each discrete state to obtain the ablation recession amount in a very small time period, and the grid mobile algorithm is used to regenerate the calculation. The domain remaps the old grid quantity to the new grid, and then iterates for the next period of time to calculate the amount of ablation in each period in order to achieve the purpose of simulating ablation and receding.
The aerodynamic thermal parameters need to be known in the coupling calculation. An engineering algorithm was used to calculate the aerodynamic heat around the blunt body in the thesis. The pressure distribution and heat flow distribution around the blunt double cone model and the single cone model are calculated, and the results of accurate numerical simulation are given. Achieves pneumatic calculations and ablation-heat transfer module data exchange.
The ablation performance of C/C composites was analyzed in detail. The ablation model and procedure based on the equilibrium chemical reaction were given. The relationship between the ablation products and the temperature and pressure was analyzed using the procedure of this paper. The ablation module changes the boundary between the aerodynamic calculation and the heat conduction calculation area. In this thesis, using the related technology in the ALE method, the algorithm of the grid refresh and the remapping algorithm for the quadrilateral element are given.
Based on the above work, this paper simulates the reentry process of a specific blunt body. Two methods, engineering algorithm and numerical simulation, were used to solve the aerodynamic heat around the reentry blunt body, and the aerodynamic results were transferred to the ablation-heat conduction module for coupling calculation. The calculation results show that the approximate shape of the ablation profile can be obtained by the coupling calculation method. At the same time, the key factors affecting the ablation profile are also analyzed.
|田保未. 钝头体再入气固热耦合计算方法研究[D]. 北京. 中国科学院大学,2018.|
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