旋转状态气膜换热机理的数值研究

大涡模拟研究了旋转对单孔平板气膜冷却的影响,气膜出流的雷诺数为2600,吹风比为0.5,计算了静止和旋转数为0.02两种状态的流动和换热,从湍流结构演化的角度讨论了旋转状态气膜换热的机理.结果表明:①发卡涡是决定气膜换热的主要湍流结构,旋转状态发卡涡的形状和运动规律主要受哥氏力的影响;②气膜在哥氏力作用下向高半径方向偏...

Numerical simulation of heat transfer physics of film cooling under rotating conditions

Large eddy simulation was used to investigate the effect of rotation on film cooling over flat plate with single hole.The Reynolds number at the jet exit was 2600,and the blowing ratio was 0.5.The flow and heat transfer without rotation and with rotating number of 0.02 were calculated,and the heat transfer mechanics under rotating condition was analyzed through the evolvement of turbulence structure.It was found that hairpin structure determined the heat transfer of film cooling,and the shape and trajectory of hairpin structure was mainly affected by Coriolis force under rotating condition.The film was driven towards high radius side by spanwise Coriolis force,resulting in less mixing between main flow and jet and maintaining low temperature of the film.The Coriolis force normal to the wall reinforced the film attachment and reduced the strength of counter rotating vortex pair,leading to less entrainment of mainflow and better coverage of film.