气膜冷却对激波与边界层相互作用影响的数值模拟

Numerical simulation of effects of film-cooling on interaction between shock wave and boundary layer

关键词:  气膜冷却  激波  边界层  相互作用  数值仿真

Key words:  Film-cooling  Shock wave  Boundary layer  Interaction  Numerical simulation

摘要:

针对跨声速平面叶栅中气膜冷却对流场的影响,采用数值模拟的方法,分析了激波和边界层的相互作用及引入气膜冷却之后三者之间的影响。结果表明,由于激波形成的逆压力梯度导致边界层出现分离现象,在引入冷却射流以后被部分抑制,流场细节显示在原分离处新形成了两个方向相反的分离旋涡。保持冷却条件不变,随着孔间距的减小,边界层分离现象被抑制的效果更加明显,平面叶栅热力损失系数逐渐减小。当孔径和孔间距之比达到0.67时,相对于没有引入气膜冷却的情况,热力损失系数降低了13%。冷气流量对射流和主流相互作用流场影响显著,冷气出口局部超声速区域显著增大流场损失,降低冷却效果。

Abstract:

In order to understand the influence of the film cooling to transonic plane cascade flow field,the interaction between shock wave and boundary layer and the effect of the film cooling have been analyzed.The results indicate that,the anti-pressure gradient formed by the shock wave results in the boundary layer separation.After the film cooling is adopted,the separation is partly restrained.The detail of the flow field shows that there form two separate vortexes.When the cooling condition has no change,as the hole spacing decrease,the boundary layer separation is restrained more clearly and the thermodynamic loss coefficient decrease gradually.When the ratio of the hole diameter to the hole-spacing is 0.67,the loss coefficient decrease about 13% relative to the condition without film-cooling.The mass flow rate of the film cooling has important effect on the flow field of the interaction between the cooling and the main flow.