激波对超音速平板发汗冷却的影响

Investigation of Shock Wave Influence on Supersonic Transpiration Cooling

本文分析了激波影响下,不同激波强度,冷却气体和注入率对发汗冷却效果的影响。马赫数3的超音速主流遇到流道内的楔形激波发生器产生斜激波入射到多孔平板表面。楔块楔角φ分别为0°、4°、8°、12°模拟不同的入射激波强度,冷却介质分别为空气、甲烷与氢气。计算结果表明,激波使多孔区域出口表面静压上升,冷却流体流出受阻而破坏冷却效果,且冷却效率随激波强度增强而下降,随冷却气体分子量增大,冷却效率下降幅度减小;但在激波强度较强时,激波在多孔表面形成逆压梯度,迫使冷却流体流向入射点上游区域而使该区域冷却效果得到恢复。提高冷却剂注入率可以减弱激波对冷却效率的破坏作用,但使壁面温度不均匀性增加。

This paper analyzed the impact of the shock wave intensity,cooling gas and the coolant blowing ratio on transpiration cooling.An oblique shock wave was induced by the shock wave generator in the flow channel and incident on the surface of the porous plate.Wedge angle of the shock generator Φ was chosen as 0°,4°,8° and 12° to simulate different incident shock intensities.And air,methane and hydrogen acted as coolant.The results show that the static pressure at the shock wave interaction region rises and the cooling effect decreases with the increasing of shock wave intensity.As the coolant gas molecular weight increases,the extent of cooling efficiency reduction decreases.When the shock wave is strong enough,the adverse pressure gradient at the porous surface forces the coohng fluid flows into the upstream region of the porous plate.Increasing the cooling rate can reduce destructive effect of shock wave,while the wall surface temperature unevenness increases.