深空再入器高超声速边界层失稳预测方法与转捩演化规律研究

The spacecraft represented by the Deep-Space Sampling Reentry Capsule (SRC) is highly susceptible to flow instability due to the large blunt shape and ablation of the rough surface during the reentry process, resulting in the transition of the boundary layer and a sharp increase in the heat flux. It poses great challenges to the design of heat protection for refills. Since there is no in-depth study of the flow stability and transition evolution mechanism of large blunt head shape and distributed roughness in China, it is impossible to establish a systematic understanding of the hypersonic flow transition and its thermal effects of the SRC. This project will focus on the Deep-Space SRC with typical shape and distributed roughness structure, develop the theoretical method for the stability analysis of three-dimensional complex shape nonlinear flow field and the numerical method for hypersonic boundary layer transition simulation, determine the transition criteria. Combined with the hypersonic transfer model, high temperature gas chemical reaction model and RANS/LES hybrid method, this project will explore the influence of the macroscale and microstructure changes of the Deep-Space SRC on the hypersonic boundary layer transition and thermodynamic effect. The expected results will lay the theoretical and method basis for the accurate prediction of the natural transition of the Deep-Space SRC and its thermodynamic effects.

以深空采样再入器（SRC）为代表的航天器在再入过程中极易由于其迎风大钝度外形以及烧蚀粗糙表面，使得流动失稳，造成边界层转捩，导致热流密度激增，给再入器防热安全性设计带来极大挑战。由于国内没有开展过大钝头外形和分布式粗糙度对于流动稳定性与转捩演化机制的深入研究，因此无法建立深空再入器流动转捩演化及其热效应的系统认识。本项目将以典型外形和分布式粗糙度结构的深空再入器为研究对象，发展适用于三维复杂外形非线性流场稳定性分析的理论方法以及用于高超声速边界层转捩模拟的数值方法，确定转捩判据。结合高超声速转捩模型、高温气体化学反应模型与RANS/LES混合方法，本项目将探索深空再入器宏观尺度和微观结构变化对高超声速边界层转捩演化以及气动热效应的影响规律。预期成果将为深空再入器转捩及其气动热效应的准确预测奠定理论与研究方法基础。

以深空采样再入（SRC）为代表的大钝头外形航天器再入过程中极易由于防热结构烧蚀造成粗糙表面，使得流动失稳形成边界层转捩，导致热流密度激增，给再入器防热安全性设计带来极大挑战。由于国内没有开展过大钝头外形和分布式粗糙度对于流动稳定性与转捩演化机制的深入研究，因此无法建立对深空再入器宏观外形参数与微观结构分布对于流动转捩及其热效应影响的系统认识。本项目分别开展了三方面内容的研究：1. 典型SRC 表面流动失稳模式研究；2. 宏观及微观尺度对边界层转捩结构的影响规律研究；3. SRC 高超声速边界层转捩判据的试验验证研究。探究了典型SRC迎风外形在不同特性表面下的流动失稳模式，建立了基于等效沙粒模型的粗糙元诱导Hollis转捩准则与γ-Reθ、k-w-γ转捩模式方法，并将热化学非平衡模型与粗糙元诱导γ-Reθ转捩模式相结合，建立了考虑高温真实气体效应的高超声速边界层流动模拟方法，并完成了地面试验验证。该项目为深空进再入器高超声速边界层失稳与转捩演化的准确预测与热效应分析提供了理论与方法支撑。项目主要研究成果成功应用于天问一号、天问二号的气动热环境评估任务，为防热系统安全高效的材料选型与厚度设计提供了可靠的输入条件，并通过了天问一号火星进入舱飞行测试验证。