钝体前缘喷流热防护数值分析

A Numerical Analysis of Protection of Blunt Leading Edge from Aerodynamic Heating by Opposed Jet

高超声速飞行器飞行过程中面临严重的气动加热,将导致飞行器结构在高温作用下发生破坏,因此必须采取必要的热防护措施。反向喷流热防护因具有可重复使用和防热效果好等特点,适合用在未来的可重复使用航天器中,尤其适用于锐边缘结构的热防护。但反向喷流的加入,使流场变的非常复杂,增加了飞行器壁面热流预测和气动力计算的难度。本文在已有试验基础上数值模拟了反向喷流流场,模型为前端带喷口的钝头结构,自由来流马赫数为3.98,反向喷流与自由来流的总压比分别取0.4、0.6和0.8。数值结果与试验结果拟合良好,初步揭示了喷流热防护的防热机理,并在此基础上,定性分析了给定喷流秒流量下喷流控制参数对降热效果的影响。

Severe aerodynamic heating will cause catastrophic failure in hypersonic vehicle structures under high temperature,thus requiring necessary thermal protection methods.The thermal by protection the opposing jet is suitable for future aerospace vehicles,especially sharp edge vehicles,because of its reusability and excellent thermal protective performance.The introduction of opposing jet would cause complex flow field,which makes it difficult to compute wall heat flux and aerodynamics.In the present paper,base on experimental data,the opposing jet flow field is simulated numerically.A blunt body model with jet spout is investigated.The velocity of free coming flow is 3.98 Mach.The pressure ratio between opposing jet flow and free coming flow are 0.4,0.6 and 0.8,respectively.The results show that the numerical and experimental results are in good agreement,thus demonstrating the basic thermal protection mechanism of opposing jet heat protection.Further,effects of jet control parameters on heat reduction are qualitatively researched at a given jet flow-per-second.