密度比对涡轮叶片气膜孔流量系数的影响

试验测量了某涡轮工作叶片表面不同位置气膜孔在不同密度比、吹风比和雷诺数下的流量系数,分析了各种因素对流量系数的影响程度,重点研究了二次流-主流密度比对流量系数的影响.试验结果表明:(1)密度比对不同位置气膜孔流量系数的影响也有差别:在吸力面、前缘等位置密度比对气膜孔流量系数影响较大;在压力面密度比对气膜孔流量系数影响较小.(2)以往采用空气作为主流及二次流,在低温差下进行试验所获的流量系数在用于涡轮叶片气膜冷却的实际情况时,必须进行修正.

Influence of density ratio on the discharge coefficient of turbine blade film cooling holes

Discharge coefficients of the film cooling holes were investigated using a large-scale low speed turbine cascade.Discharge coefficients with coolant injection were determined at different density ratio,blowing ratio and Reynolds number.The results show that the influence of density ratio of secondary flow to mainstream flow on discharge coefficients of the film cooling holes is different at different hole array position.The effect of density ratio on suction surface and leading edge is more evident.The data of turbine blade surface film holes discharge coefficients obtained from experiments with small difference in temperature of the secondary and mainstream airflow should be corrected when it was attempted to apply to practice.