孔位对涡轮叶片表面气膜冷却换热系数的影响

Influences of position of hole-rows on film cooling heat transfer of turbine blade surface

关键词:  涡轮叶片  薄膜冷却  传热

Key words:  Turbine blade  Film cooling  Heat transfer

摘要:

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,测量了涡轮导向叶片表面不同位置单排气膜孔喷射时下游的换热系数,研究了孔排位置、吹风比的影响。风洞实验段由3个叶片组成,中间的叶片为试验叶片,由优质木材制成。试验叶片表面上开有15排气膜孔,吸力面3排,前缘区6排,压力面6排。实验中吹风比的变化范围是0.5~2.5。研究结果表明:由于气膜孔排位置的不同,喷气对换热系数的影响范围不同,换热系数受吹风比影响的变化趋势也有所不同。

Abstract:

Film cooling heat transfer of single film row at different locations on turbine blade surface was studied experimentally. A three-blade liner cascade in a large-scale low-speed opening wind tunnel was used in the experiment. There are 15 rows of film cooling holes at the surface of middle blade made of high quality wood. Three rows are on the suction surface. Six rows are on the leading edge. Six rows are on the pressure surface. Film cooling heat transfer on the blade surface is measured in the cases of blowing ratio changes from 0.5 to 2.5. Result shows that the local heat transfer coefficients with film injection are higher than that without film injection for the cases of high blowing ratio, and it is reverse for the cases of low blowing ratio. The regions of influence of film injection are different at the different location of blade.