不同湍流度下吹风比对涡轮导向叶片吸力面气膜冷却的影响

采用基于窄带热色液晶测量的瞬态全表面传热测量技术,研究了不同主流湍流度下的吹风比对涡轮导向叶片气膜冷却的影响,获得了叶片吸力面侧圆柱形孔排气膜冷却效率和表面传热系数比的全表面分布数据。结果表明:由于气膜射流与主流掺混的相互作用会随着主流湍流度的变化而变化,因此在主流湍流度不同时,吹风比对气膜冷却效率和表面传热系数比的影响规律会有所不同；主流湍流度较小时,吹风比的增大会显著减弱气膜覆盖效果与气膜冷却效率,但是在大湍流度下,吹风比的影响较弱,尤其是在远下游区域；相同的主流湍流度条件下,吹风比的增大会使得表面传热系数提高,但是在大湍流度下,换热增强效果较弱；相同吹风比下,高湍流度下的表面传热系数比相对较小。 

Effects of blowing ratio on turbine vane suction side film cooling under different turbulence intensity conditions

The effects of blowing ratio on turbine vane film cooling under different mainstream turbulence intensity conditions were studied using the transient heat transfer measurement technique with narrow-band thermochromic liquid crystal in the whole region. The spatial distributions of film cooling effectiveness of cylindrical holes on the suction side of a turbine vane and surface heat transfer coefficient ratio in whole region were obtained. The results showed that the mixing effect and interaction intensity of film jets and mainstream changed with the mainstream turbulence intensity, so the effects of blowing ratio on the film cooling effectiveness and surface heat transfer coefficient ratio were different under different mainstream turbulence intensities. In experimental conditions, when the mainstream turbulence intensity was small, the film coverage and cooling effectiveness rapidly deteriorated with the increase of blowing ratio. However, the change of blowing ratio had relatively weaker effect under large mainstream turbulence intensity, especially in the far downstream region. Under the same mainstream turbulence intensity conditions, the increase of blowing ratio can enhance the surface heat transfer coefficient. However, the enhancement effect was relatively small under large mainstream turbulence intensity. Under the same blowing ratio, the surface heat transfer coefficient was relatively small when the turbulence intensity was high.