叶顶凹槽间隙气膜冷却的传热数值研究

eat Transfer Numerical Research on Film Cooling of Tip Groove Clearance

关键词:  涡轮动叶  叶顶凹槽  间隙泄漏流  气膜冷却  气热耦合

Key words:  Turbine rotor  Tip groove  Clearance leakage flow  Film cooling  Conjugate heat transfer

摘要:

采用三维气热耦合数值模拟方法，分析了凹槽间隙底面受到泄漏流冲击的流动特性，对气膜冷却参数对凹槽间隙气膜冷却换热效果的影响进行了研究，探讨了吹风比、冷却孔位置、冷却孔角度对壁面换热的影响，并结合三维流固耦合计算，研究了叶顶气膜冷却方式对叶顶表面传热的影响。结果表明，冷却孔位于间隙流动冲击凹槽底面上游位置能有效降低壁面Nu数，获得较低的叶片表面平均温度，此时大吹风比效果更好；所选取的冷却方式使得E3高压涡轮第一级动叶的最大无量纲温度降低了0.156。

Abstract:

Using a three dimensional conjugate heat transfer numerical simulation，the clearance flow characteristics of groove bottom by the impact of leakage flow was analyzed. Then the effects of film cooling parameters on heat transfer efficiency with groove-clearance film cooling were studied. The influence of the location，angle，blowing ratio of the cooling hole on the wall heat transfer was discussed. And combined with three dimensional fluid-structure interaction simulations，the influence of blade-tip film cooling on heat transfer of tip surface was studied. The results show that the cooling hole in the upstream position of groove bottom with clearance flow impact can effectively reduce the wall Nusselt number. A lower average temperature of the blade surface is obtained and the large blowing ratio is better. The selected cooling system makes the peak non-dimensional temperature decrease of 0.156 for the first-stage rotor of E3 high pressure turbine.