带冲击-气膜双层壁结构的涡轮导叶冷却特性源项法数值研究

Numerical Study on Cooling Characteristics of Turbine Guide Vanes with Impingement/Film Double Wall Structure Using Source Term Method

关键词:  源项法  涡轮导叶  双层壁结构  网格密度  流量系数

Key words:  Source term method  Turbine guide vane  Double wall structure  Mesh density  Flow rate coefficient

摘要:

为了降低由于大量冷却孔导致的计算资源消耗，采用源项法对带冲击-气膜双层壁冷却结构的Mark II涡轮导叶传热进行了简化数值模拟，并与不采用源项法的结果进行了对比。分析了冷却孔网格密度以及流量系数经验关系式对源项法模拟精度的影响。结果表明，采用源项法能够基本准确地模拟叶片表面温度分布并且缩短75%的计算时间。当冷却孔进出口面网格最小尺度小于孔径的1/10时，数值模拟结果将不随面网格密度改变。影响模拟精度的主要因素是经验关系式能否准确模拟总冷气流量以及横流对流量系数的影响。

Abstract:

In order to reduce the consumption of calculation resources caused by plenty of cooling holes， the source term method is applied to simulate the heat transfer of Mark II turbine guide vane with impingement/film double-wall cooling structure， and the results are compared with those without source term method. The effects of the mesh density of cooling holes and the empirical formula of flow rate coefficient on the accuracy of the source term method are analyzed. The results show that by using the source term method， the surface temperature distribution of the blade can be simulated accurately and the calculation time can be reduced by 75%. When the minimum surface mesh scale at the inlet and outlet of cooling holes is smaller than 1/10 of the hole diameter， the numerical simulation results will not change with the surface mesh density. The main factor affecting the simulation accuracy is whether or not the empirical formula can accurately simulate the total cooling air flow rate and the influence of crossflow on the flow rate coefficient.