动量比对涡轮叶片气膜孔流量系数的影响

采用放大的叶片模型，利用大尺寸低速线性叶栅风洞进行实验，测量了涡轮工作叶片表面不同位置处6排气膜孔的流量系数，研究了不同吹风比、密度比和雷诺数对流量系数的影响。结果表明：（1）用二次流与主流的动量比来描述气膜孔流量系数的变化规律较为恰当。该参数可以综合吹风比和密度比的影响；（2）气膜孔流量系数随动量比的增大而增加，在小动量比下，影响尤为明显；（3）叶片表面不同位置处气膜孔的流量系数有较大的差别。表明气膜孔出口处的流动状态对流量系数有较大的影响。

Influence of Momentum Ratio on the Discharge Coefficient of Film Cooling Holes on Blade Surface in a Turbine Cascade

Discharge coefficients of film cooling holes were investigated on the turbine blade surface with a scaled up low speed turbine cascade. Discharge coefficients with coolant injection were determined at different momentum ratio, density ratio and Reynolds number. The results show that: (1) The distribution of discharge coefficients is mainly determined by momentum ratio of secondary to mainstream fluid for same geometry, as both momentum and density ratios have been considered. (2) The film hole flow coefficient is increased with momentum ratio, especially when momentum ratio is small. (3) Turbine blade surface film holes discharge coefficients are greatly different in different film hole array position.