冷却通道参数对发汗冷却性能影响的数值研究

Numerical Study on the Effect of Cooling Channel Parameters on Transpiration Cooling Performance

为了解决传统多孔材料孔隙结构不可控的问题,制备具有可控微冷通道的冷却结构对提高涡轮叶片冷却效率有着重要意义。为了研究不同冷却通道参数对叶片发汗冷却效率的影响,通过数值模拟方法研究了不同注入比下,仿生树形通道和传统直孔通道发汗冷却多孔板的换热特性及流动机理。同时,研究了6种不同模型参数多孔板在不同注入比下的冷却性能及流场的变化情况。研究结果表明:在内表面比和冷却剂出口面积基本一致的条件下,仿生树形多孔板具有更高的冷却效率;当注入比为2%时,仿生树形多孔板的平均冷却效率提高了5%,且存在一个最佳的注入比使得整体的冷却效率最高;冷却剂的出口面积是影响发汗冷却效率的关键性独立参数,与冷却剂的注入比大小有关;孔隙率对整体的冷却效率影响较小,内表面积比越大,发汗冷却的整体冷却效率越高。

To solve the problem of uncontrollable pore structure in traditional porous materials,it is crucial to prepare a cooling structure with controllable complex micro-cooling channels to improve the cooling efficiency of turbine blades.To study the effect of different cooling channel parameters on the transpiration cooling efficiency of blades,the heat transfer characteristics and flow mechanism of the tree-like channel and the traditional straight hole channel transpiration cooling porous plate under different injection ratios were studied numerically.At the same time,the change of cooling performance and flow field of porous plates with six different model parameters under different injection ratios was studied.The results show that the bionic tree-like porous plate has higher cooling efficiency when the internal surface ratio and the coolant outlet area are basically the same;when the injection ratio is 2%,the average cooling efficiency of the tree-like porous plate is increased by 5%,and there is an optimal injection ratio to make the overall cooling efficiency the highest;the outlet area of coolant is a key independent parameter affecting the transpiration cooling efficiency,which is related to the injection ratio of coolant;the porosity has little effect on the overall cooling efficiency.The larger the internal surface area ratio,the higher the overall cooling efficiency of transpiration cooling.