不同孔型对高超声速逆喷流气膜冷却影响

Effect of different hole shapes on hypersonic counter-jet film cooling

主要对不同孔型在不同质量流量下对高超声速逆喷流气膜冷却影响规律开展研究,得到不同孔型对气膜冷却效果的影响规律。采用CFD计算方法,对飞行高度为50 km,飞行马赫数为15条件下圆柱孔、收缩孔、扩张孔、收缩-扩张孔4种孔型开展研究。研究显示:小流量供气时,收缩孔和圆柱孔会出现长穿透模态(LPM)工作状态,扩张孔和收缩-扩张孔则不会出现;随着喷流流量的增大,喷流会从LPM转向短穿透模态(SPM),此时继续增大气膜喷流流量,并不会显著增大冷却收益。综合整个流域的变化,扩张孔在高超声速飞行器头部逆流喷流气膜冷却中是比较稳定可靠的气膜冷却孔。

The influences of different cooling holes at different mass flow rates on film cooling effect were studied by researching the relationship between the film cooling hole shape and counter jet flowing. The CFD method was used to study 4 kinds of working conditions of the cylindrical hole, the shrinkage hole, the expansion hole and the shrinkage-expansion hole under flight height 50 km, flight Mach number 15 condition. Results show that: under the small mass flow rate, long penetration model(LPM) will occur in the shrinkage hole and the cylindrical hole, unlike the case of the expansion hole and the shrinkage-expansion hole. With the increase of the jet mass flow rate, the jet will change from LPM mode to short penetration model(SPM) mode, and the cooling benefit will not appreciably increase with the increasing jet mass flow rate. Considering the changes of the whole working states, the expansion hole is a relatively stable and reliable film cooling hole in the counter-jet film cooling.