高超声速飞行器翼前缘射流降热研究

Aerodynamic Heating Reduction with Jet Array over Leading Edge of Hypersonic Vehicle

目的获得高超声速飞行器翼前缘射流降热机理。方法通过计算流体力学(CFD)方法,针对典型高超声速带翼飞行器开展飞行马赫数为15条件下的射流干扰热环境规律研究,分析无射流翼前缘气动加热特性,确定热流严酷射流开孔区域,分别在翼前缘激波干扰及翼后段布置射流孔,并设计射流流动参数,开展射流总压与来流总压比率在0.002～0.02范围内的流场仿真计算,获得局部流动及表面热流分布特性,针对计算结果进行对比分析。结果随着总压比率逐渐增大,激波干扰以及机翼后段射流孔区域热流均显著降低,降幅达76%～99%。翼中段无射流典型位置总压比率为0.002时热流增高,增幅为11%～24%,随着射流总压增大热流降低,降幅达68%～86%。高射流总压比率局部射流孔前热流增大2倍以上。结论射流影响下降热机理是射流将高温气体推离壁面,局部表面热流显著降低。低射流总压比率亚音速射流作用区域向下游延伸距离短,不会引起局部再附热流增大。高射流总压比率音速射流降热影响向下游明显延伸,增强射流强度可以增加延伸区长度,同时会诱导局部射流孔前再附热流显著增大。

Objective To obtain the aerodynamic heating reduction mechanism over the leading edge for hypersonic vehicle. Methods A CFD study was carried out to research the rules of aerodynamic heating reduction with jet array over leading edge of hypersonic vehicle with a free-stream Mach number of 15, to determine the opening area of hypersonic flow. Holes for jet flow were set on the front wing edge of shock wave and rear wing section. Flow parameters were designed to simulate and calculate the flow field with ratio of total jet pressure and total incoming flow pressure between 0.002 and 0.02 to obtain regional flow field and surface heat flux features. Furthermore, the calculated results were compared and analyzed. Results With the increase of the total pressure ratio, 76%-99% of aerodynamic reduction was achieved at the jet impinged positions both in the shock in-teraction and wing tip rear regions. In the region of middle wind tip without jets, the heat flux was increased by 11%-24% with a total pressure ratio of 0.002; while the heat flux was decreased by 68%-86% with the increase of the total pressure ratio. It was also observed that the regional heat flux in front of the first jet orifice was amplified drastically above 2 times. Conclusion The aerodynamic heating reduction with jets is due to the jets injection which could push the high temperature gas far from the wall and lower the regional high heat flux. The zone of action for subsonic jet flow of total pressure ratio of low jet flow extends downstream only in a certain short distance, which would not generate higher heat flux at the attached point. While the high total pressure performs a sonic jet flow, it could be concluded that the heat reduction effects would be available in a long distance along the downstream region and the affected region would be enlarged by a higher total pressure ratio, which could produce a more obvious peak heat flux in the attached region simultaneously.