涡轮工作叶片表面气膜冷却效率的实验研究

Film cooling effectiveness measurements for gas holes on blade surface in a turbine cascade

在大尺寸低速线性叶栅风洞上进行实验,采用放大的叶片模型,测量了涡轮工作叶片表面不同位置单排气膜孔的气膜冷却效率,研究了孔排位置、吹风比及来流雷诺数的影响。试验叶片表面上开有8排气膜孔,其中吸力面2排,前缘区3排,压力面3排。实验的参数变化范围是:基于叶片弦长的来流雷诺数250000～450000,吹风比0 5～2 5。结果表明,由于气膜孔排位置的不同,其下游冷却效率受来流雷诺数及吹风比影响的变化趋势也有所不同,孔排位置一定时,冷却效率主要由吹风比决定。该实验结果对涡轮叶片型面气膜冷却的实际工程设计研究有重要意义。

Film cooling effectiveness of single row holes located at different sites on turbine blade surface were studied experimentally in a large-scale liner cascade. There were eight rows of film cooling holes on the surface of blade, two rows on the suction surface, three rows on the leading edge and three rows on the pressure surface. The Film cooling effectiveness on the blade surface were measured in the cases of mainstream Reynolds number from 250000 to 450000 and blowing ratio from 0.5 to 2.5. The influences of the location of film cooling holes on cooling effectiveness were described. The experimental results show that the film cooling effectiveness are mainly determined by blowing ratios.