旋转状态下气膜冷却换热系数的实验

Experiment of heat transfer coefficients of film cooling over a rotating blade

关键词:  气膜冷却  换热系数  旋转叶片  实验

Key words:  Film cooling  Heat transfer  Rotating blade  Experiment

摘要:

采用平板叶片模型,测量了静止和旋转状态气膜冷却换热系数(hg)的分布规律,重点研究旋转对气膜冷却换热系数的影响。测试表面气膜孔直径D=4 mm,流向倾角α=30°,展向倾角φ=90°。实验转速ω=0,800 r/min,主流雷诺数ReD=3 191,吹风比M=0.4~2.0,密度比DR=1.02。采用宽幅低温液晶测量叶片表面的温度场。结果表明,旋转使得气膜在展向上发生较明显的偏转,且吸力面上气膜偏转程度要大于压力面;吹风比对换热系数的影响较大,且这种影响在静止与旋转状态差别很大。

Abstract:

Measurements of heat transfer coefficient(hg) were presented for single film hole with a diameter of D=4 mm in 30° inclined injection on a rotating flat form blade.Tests were conducted at the rotating speed(ω) of 0 r/min and 800 r/min,respectively.The mainstream Reynolds number based on the film hole diameter(ReD) was 3 191.The blowing ratio(M) was controlled to be from 0.4 to 2.0 while the density ratio(DR) of 1.02 was obtained with air injection.Thermochromic liquid crystal(TLC) was used to obtain the temperature distributions on the blade surface.The results show that an obvious deflexion in the spanwise direction is occurred under rotating case and the deflexion angle on the suction surface is greater than that on the pressure surface;the blowing ratio performs great influence on the heat transfer coefficient,and the influences are different between the stationary and rotating cases.