Abstract: Detailed heat transfer measurements were conducted on the endwall surface of a large-scale low speed turbine cascade with single row injection on the endwall upstream of leading edge. Local film cooling effectiveness and heat transfer coefficient with coolant injection were determined at blowing ratio 1,2,3 and injection angle 25, 35, 45. The corresponding endwall thermal loads were calculated on the assumption of a typical real engine case. The influence of injection angle on the endwall film cooling was studied. The results show that the film-cooling effectiveness could be increased obviously by decreasing injection angle, and the heat transfer coefficient increase remarkably at the same time. The actual cooling effect is determined by the endwall thermal loads.

Key words: Turbine cascade;Gas injection;Injection angle;Heat transfer;Film cooling

摘要： 在大尺寸低速平面叶栅风洞中,对前缘上游有单排气膜孔的涡轮导向叶栅端壁气膜冷却进行了详细的传热实验。在喷射角为25°,35°和45°以及吹风比为1,2,3下测量了端壁面上的局部冷却效率和换热系数,并由此计算出了叶栅实际工作状态下的端壁热负荷。着重研究了喷射角对端壁气膜冷却的影响。数据表明减小喷射角度虽然能够显著的提高冷却效率,但同时也明显的增大了换热系数,最终的冷却效果取决于端壁热负荷的大小。

关键词: 涡轮叶栅;气体喷射;喷射角;传热;薄膜冷却