Abstract: The loss features of a typical large expansion ratio transonic turbine and the effects of two trailing edge cooling methods，including trailing edge ejection and pressure side ejection，on losses are investigated by numerical method. It can be found that most of the loss is profile loss which is about 65% of total loss and shock wave loss is the main source of profile loss. For the trailing edge ejection，the pressure at base region arises because of the coolant ejection which leads to decrease of the flow acceleration caused by the expansion wave. Thus the Mach number and shock wave loss are decreased. For the pressure side ejection，the trailing edge shock system is changed and the original shock wave is split into two or more than two weak shock waves which result in the decrease of shock wave loss. Both of the two trailing edge cooling methods are beneficial to reduce the shock wave loss of transonic turbine with large expansion ratio，but the pressure side ejection is more effective.

Key words: Large expansion ratio transonic turbine；Trailing edge shock wave；Trailing edge slot；Flow loss；Numerical simulation

摘要： 为了揭示跨声速大膨胀比涡轮损失的主要特点和两种不同尾缘冷却方式对损失的影响，以典型大膨胀比跨声速涡轮和跨声速叶栅为研究对象开展了数值研究。研究发现大膨胀比跨声速涡轮的主要损失是叶型损失，占到总损失的65%左右，尾缘激波损失是叶型损失的主要来源。尾缘全劈缝冷气入射通过提高尾缘基压区基压来减少尾缘膨胀波对气流的加速程度，从而降低最高马赫数和激波损失，尾缘压力面劈缝冷气入射通过改变叶片尾缘压力面激波波系结构，使原来的一道激波变成两道或者两道以上的弱激波，从而减少激波损失。两种尾缘冷气方式都有利于降低大膨胀比跨声速涡轮激波损失，但压力面劈缝冷气入射方式效果更为明显。

关键词: 大膨胀比跨声速涡轮；尾缘激波；尾缘劈缝；流动损失；数值模拟