高载荷低压涡轮叶片尾缘劈缝的叶栅损失影响

Effects of Trailing Edge Cutback on the Aerodynamic Loss of a High Load Low-Pressure Turbine Blade Cascade

对带尾缘劈缝低压涡轮导叶在不同劈缝宽度与冷气吹风比条件下的叶栅出口的流场进行了数值研究。结果表明,增大吹风比可降低总压损失,掺混损失则先减后增。低吹风比时,总压损失几乎不受劈缝宽度影响,掺混损失随劈缝宽度增大而降低;高吹风比时,总压损失随劈缝宽度增大而降低,掺混损失反之。综合考虑劈缝宽度与吹风比,冷气流量一致时较宽的劈缝对掺混损失抑制的效果更好。

A numerical study was conducted to investigate the flow field downstream a low-pressure turbine guide vane cascade. The effects of both cutback width and blowing ratio on the cascade＇s aerodynamics are studied. It is found that the total pressure loss of the cascade decreases while the mixing loss between the mainstream and coolant increases firstly and then decreases with the increase of blowing ratio. When blowing ratio is small, total pressure loss changes little and mixing loss decreases with the increase of cutback width; when blowing ratio is large, total pressure loss decreases and mixing loss increases with the increase of cutback width. Considering the effects of cutback width and blowing ratio on lowering mixing loss, wider cutback is better when coolant flow rate is the same.