Significant Aerodynamic Heating Phenomenon ofAblative Heatshield at Downstream Region from Stagnation Point

开发了以烧蚀器为隔热层的基于轨迹的统一的进入舱气动热分析代码。利用该代码对星尘样品返回舱进行了进入飞行模拟，模拟结果表明，由于边界层的早期转变，加热速率显著增加。我们还计算了先驱者-金星任务中4个进入探测器的流场。各探测车辆在下游区域的升温速率均显著提高。在热电偶温度与飞行数据的比较中显示出合理的一致性。研究表明，下游地区明显的加热现象是由烧蚀产物气体引起的较早的湍流过渡引起的。还指出，如果我们采用假定烧蚀产物气体固有湍流的Park喷射诱导湍流模型，就有可能对这一现象进行定量预测。伽利略号探测器进入木星大气层后，在下游区域也观测到明显的空气动力加热现象。在并行计算机系统上开发了一个光谱详细的辐射耦合CFD程序，该程序将用于伽利略探测器进入飞行的模拟。

We have developed a trajectory-based unified aerodynamic heating analysis code for entry capsule that employs ablator as heatshield. Using the code, an entry flight simulation for Stardust sample return capsule has been conducted in which significant increase of heating rate due to an earlier transition of the boundary layer was indicated. We have also calculated flow field for 4 entry probe vehicles in the Pioneer-Venus mission. Significantly higher heating rate at downstream region was obtained for all probe vehicles. A reasonable agreement is shown in the comparison of thermocouple temperatures with that given in the flight data. It is shown that significant heating phenomenon at downstream region is caused by an earlier turbulent transition due to ablation product gas. It is also indicated that a quantitative prediction of this phenomenon is possible if we employ Park's injection-induced turbulence model that assumes ablation product gas to be inherently turbulent.Significant aerodynamic heating at downstream region was also observed when Galileo probe vehicle entered into Jovian atmosphere. A spectrally detailed radiation coupled CFD code on a parallel computer system has been developed that will be used in the simulation of entry flight for Galileo probe vehicle.