带锥形扩张支孔射流气膜冷却效率数值模拟

Numerical Simulation of Film Cooling Effectiveness with Conical Expanded Branch Holes

为了探讨由圆柱孔和锥形支孔组成的双出口孔射流气膜冷却特性,利用商业软件对气膜冷却下的流场和温度场进行三维数值模拟。主流雷诺数为10000,吹风比变化范围为0.5～2.0。计算得到了冷却效率云图、冷却效率径向平均值以及近壁面处流场和温度场分布。研究结果表明,圆柱形孔射流的冷却效率数值模拟结果和实验数据吻合得非常好,双出口孔射流的冷却效率相对于圆柱形孔射流的冷却效率明显提高,径向分布非常均匀。双出口孔射流的流动结构和单圆柱孔射流的流动结构明显不同。随着吹风比的增加,冷却效率增大。基于冷却效率的最佳吹风比为1.5。

In order to understand the performance of film cooling with double-outlet holes,which is composed of a cylindrical hole and a conical hole,three-dimensional simulations of flow and temperature distributions with film cooling have been studied by commercial code.The mainstream Reynolds number is 10 000 and the blowing ratio varies from 0.5 to 2.0.The film cooling effectiveness contour,laterally averaged film cooling effectiveness,and the flow and temperature distributions near the surface have been obtained.The results show that the film cooling effectiveness with cylindrical hole injection agrees well with the experimental data.The double-outlet hole injections provide very high and laterally uniform film cooling effectiveness as compared to the case of cylindrical hole injections.The flow with double-outlet hole injection is significantly different from that with cylindrical hole injection.The increasing blowing ratio causes the increasing film cooling effectiveness,and the optimal blowing ratio is 1.5.