双出口气膜孔冷却效率数值模拟

为了优化气膜冷却结构,通过数值模拟研究了一种新型气膜孔(由两个圆柱孔组成的双出口孔)的气膜冷却特性.利用Fluent软件对Navier-Stokes方程进行求解,湍流模型采用两方程Realizablek-ε模型和增强壁面函数处理.圆柱孔射流的冷却效率计算结果和实验数据吻合较好.双出口孔射流冷却效率计算结果表明,双出口孔射流有效地增加了冷气的径向覆盖范围,在吹风比为0.5时,次孔射流起到了减弱主孔出口对旋涡的作用;在吹风比为1.0和2.0时,次孔射流使主孔出口处的对旋涡消失.最高冷却效率对应的吹风比为1.0.双出口孔射流在提高冷却效率的同时,其加工难度较扩张形孔明显降低. 

Numerical simulation of cooling effectiveness with injection of double-outlet hole

In order to optimize the structure of the film cooling,the film cooling performance of a novel hole with double-outlet was investigated by numerical simulation.The Navier-Stokes equation was solved by Fluent.The realizable k-ε model and enhanced function were used.The numerical effectiveness of the cylindrical hole agrees well with the experimental data.The result of the double-outlet hole injection shows that the lateral spreading of the film is improved as compared to the injection of the cylindrical hole.At the blowing ratio of 0.5,the vortices at the trunk hole outlet are reduced by the injection of the branch hole.At the blowing ratio of 1.0 and 2.0,the vortices at the trunk hole outlet are eliminated by the injection of the branch hole.The optimal blowing ratio is found at blowing ratio of 1.0.The double-outlet hole improves the cooling effectiveness significantly while requiring for easily machinable round hole as compared to expanded hole.?