非定常激波对气膜冷却影响的数值模拟

利用数值计算的方法研究了非定常激波对下游涡轮叶片表面气膜冷却的影响.冷却气流在激波和尾迹经过的过程中,发生了上扬和重新被压制回壁面的现象.考察了壁面上特定点在有气膜和无气膜情况下的换热量.通过计算发现,有气膜时的换热量有不同程度的下降,而且换热量随时间变化的趋势也发生了很大的变化.气膜的覆盖减小了主流场对壁面换热量的影响.

NUMERICAL SIMULATION OF THE UNSTEADY EFFECT OF UPSTREAM SHOCKS ON FILM-COOLING IN A 1+1/2 TURBINE STAGE

2-D,time accurate numerical simulations of the unsteady effects of upstream shocks on film-cooling in a 1 1/2 turbine stage were performed.The heat transfer of several points on blade surface was calculated.Results without film cooling on the surface demonstrated that the surface heat transfer fluctuated intensively during the passing of the upstream wakes and shocks and there are two wave crests and two troughs in the surface heat transfer within a passing period.Time-resolved calculation with film cooling demonstrated that the coolant rises from the surface then return back to surface during the passing of the wakes and the shocks.The unsteady heat transfer signals changed when film cooling is introduced.