单排圆柱孔射流气膜加热与气膜冷却方式的对比

Comparison Between Film Heating and Film Cooling Schemes for Row of Cylindrical Holes

为了揭示气膜加热和气膜冷却两种方式在影响规律机制上的异同,通过数值计算研究了两种方式单排圆柱孔在典型吹风比下(0.5,1.0和1.5)的射流-主流相干特征,并分析了热气流-冷气流温度比变化对气膜绝热加热或冷却效率的影响。研究结果表明:在相同的吹风比下,在气膜加热方式下喷注射流向主流的穿透趋向更为显著,引起喷注射流抬离壁面并在气膜孔出口附近诱导出尺度更大的卵形涡对;当温度比接近于1时,气膜绝热加热效率与气膜绝热冷却效率差异较小,随着温度比偏离1的程度加剧,气膜绝热加热效率与气膜绝热冷却效率差异显著增大。

To reveal the s imilarities and differences between film cooling and film heating in the physica l mechanisms,a numerical investigation is performed for a row of cylindrical holes under some typical blowing ratios(0.5,1.0 and 1.5).The interaction features of jet-mainstream,as well as the effect of temperature ratio between the hot flow and cold flow on the film adiabatic heating or cooling effectiveness are analyzed.The results show that the jet penetration into the mainstream under the film heating scheme is more significant related to the film cooling scheme,causing the jet to lift off the surface and inducing bigger counter-rotating vortex pair downstream the film-hole.When the temperature ratio is close to 1,the film adiabatic heating effectiveness is nearly the same as the film adiabatic cooling effectiveness.However,once the temperature ratio is far deviated from 1,the difference between film adiabatic heating effectiveness and film adiabatic cooling effectiveness is behaved obviously.