火星进入过程中的耦合热化学烧蚀与稀薄粒子侵蚀

中文摘要 AI 辅助

火星尘埃颗粒直径约为几微米，与高超声速激波层中气体的平均自由程相当。其克努森数范围约为0.2至100，使其处于过渡流和自由分子流区域，而飞行器周围的流动则为连续介质。作者先前针对双温度热化学非平衡流开发的双向流-粒耦合方法被扩展至退缩和热解的热防护表面。气体-表面相互作用和材料内部响应在不同时间尺度上分别求解。表面平衡在每个流动步长下交换，而内部响应则在物理时间窗口内隐式耦合。流-材料耦合通过石墨电弧射流测量进行评估。该框架应用于Schiaparelli从50公里至30公里的轨迹。对三种表面化学模型（平衡模型、Park-5和Zhluktov-Abe）在固定几何、焦炭引起的退缩以及焦炭烧蚀与粒子侵蚀组合情况下进行了比较。在最终轨迹点，驻点热流在不同化学模型间差异为30-75%。对于平衡模型，表面退缩使热流变化小于1%，但降低了壁面温度并增加了热解气体注入。粒子侵蚀导致驻点退缩1.73毫米，超过焦炭引起的退缩，并使所有三种模型的总退缩增加一倍以上。据作者所知，本研究首次对稀薄和连续介质阻力相关性之间的粒子侵蚀进行了定量比较，连续介质相关性低估了驻点侵蚀速率31-35%。

英文摘要

Martian dust particles are a few micrometers in diameter, comparable to the mean free path of the gas in the hypersonic shock layer. Their Knudsen number ranges from approximately 0.2 to 100, placing them in the transitional and free-molecular regimes, whereas the flow around the vehicle is a continuum. The two-way flow-particle coupling previously developed by the authors for a two-temperature thermochemical nonequilibrium flow is extended to a receding and pyrolyzing heat shield surface. The gas-surface interaction and the in-depth material response are solved on separate time scales. The surface balances are exchanged at every flow step, while the in-depth response is coupled implicitly over physical time windows. The flow-material coupling is assessed against graphite arc-jet measurements. The framework is applied to the Schiaparelli trajectory from 50 to 30 km. Three surface chemistry models (equilibrium, Park-5, and Zhluktov-Abe) are compared for fixed geometry, char-induced recession, and combined char ablation and particle erosion. At the final trajectory point, the stagnation point heat flux differs by 30-75% among the chemistry models. For the equilibrium model, surface recession changes this heat flux by less than 1% but lowers wall temperature and increases pyrolysis gas injection. Particle erosion contributes 1.73 mm of stagnation point recession, exceeding the char-induced recession, and more than doubles the total recession for all three models. To the authors' knowledge, this study provides the first quantitative comparison of particle erosion between rarefied and continuum drag correlations, and the continuum correlation underestimates the stagnation point erosion rate by 31-35%.

发表机构

• University of Central Florida（中佛罗里达大学）

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