内冷通道横流对气膜冷却效率的影响

在吹风比(Br)为0.5~2.0、横流比(Cr)为0~3.0范围内,采用数值模拟方法研究了内部冷却通道横流对单排圆柱形气膜孔气膜冷却特性的影响。相比于基准的无横流进气方式,横流进气诱导冷却气流在气膜孔内形成旋流流动,使得气膜射流与主流的相互作用更为复杂。横流比的影响在不同的吹风比下有较大差异:在较小的吹风比下,横流比小于1.0的气膜绝热冷却效率略高于无横向进气的基准情形,而横流比大于2.0的气膜绝热冷却效率相对基准情形有一定幅度的下降;在较高的吹风比下,横流进气带来气膜绝热冷却效率的增强,横流比为2.0的气膜绝热冷却效率相对较高。在大横流比下,随着吹风比的增加,气膜在展向的覆盖范围明显扩大。

Effect of Internal Crossflow in Coolant Channel on Adiabatic Film Cooling Effectiveness

The effect of internal crossflow in cooling channel on film cooling performance over a flat plate with a row of cylindrical film cooling holes is numerically investigated over a wide range of blowing ratios from 0.5 to 2.0 and crossflow ratios from 0 to 3.0. The results show that the internal coolant flow leads to a changed film cooling performance. By comparison to the baseline stagnant plenum coolant supply or no-crossflow case, the internal crossflow coolant supply induces swirling flow inside film hole, making the interaction between coolant jet and primary flow more complicated. At lower blowing ratio, the laterally averaged adiabatic film cooling effectiveness for the internal crossflow coolant supply is increased a little compared with the plenum coolant supply case when the crossflow ratio is less than 1.0,and the situation is reverse when the crossflow ratio is greater than 2.0. At higher blowing ratio, the internal crossflow coolant supply is benefit to improving film cooling effectiveness, especially when the crossflow ratio equals to 2.0. Under higher crossflow ratio, the lateral spreading of the film coolant increases obviously with increasing of blowing ratio.