气膜孔内局部堵塞对气膜冷却特性的影响

Effect of partial blockage inside film hole on film cooling characteristics

在吹风比为0.3-1.5,堵塞比为0.1-0.5范围内,对平板上单排倾斜气膜孔内局部堵塞所引起的冷气射流流动和冷却特性变化进行了数值研究,分析了堵塞比、堵塞位置和吹风比对绝热气膜冷却效率的影响.在研究参数范围内的研究结果表明：气膜孔出口端前缘的局部堵塞有利于抑制肾形涡,对气膜孔下游的绝热气膜冷却效率有改善作用,并且随着堵塞比和吹风比的增加,对冷却效果的改善越为明显.而在气膜孔出口端尾缘或侧边的堵塞则在较大的堵塞比下削弱气膜冷却效果.相对于气膜孔出气端的局部堵塞,在气膜孔进气端和中部的堵塞对绝热气膜冷却效率的影响要微弱得多.

Numerical investigations were performed to study the effects of partial blockage inside discrete holes on coolant jet flow and film cooling characteristics over a flat plate from a row of inclined holes,under the blowing ratios of 0.3-1.5and blockage ratios of0.1-0.5.The influences of blockage ratio,blockage position and blowing ratio on adiabatic film cooling effectiveness were revealed.The results in parameter range show that the partial blockage located at the leading edge near film jet exit is beneficial for suppressing the motion of kidney vortex pair,resulting in enhancement of the adiabatic film cooling effectiveness,especially under higher blowing ratio and higher blockage ratio cases.The partial blockage located at the trailing or lateral edges near the film jet exit weaken the adiabatic film cooling effectiveness under higher blockage ratio cases.Compared to the corresponding case of partial blockage located near the film jet exit,the partial blockage located at the film jet inlet or middle position has less impact on the film cooling.