纵向涡发生器对涡轮叶片前缘冲击冷却的影响

Effect of Longitudinal Vortex Generator on Impingement Cooling over Leading Edge of a Gas Turbine Blade

采用三维数值方法对涡轮叶片前缘射流腔内的流动和换热特性进行了研究。在射流腔内安置一对三角形纵向涡发生器,研究了纵向涡发生器的安置角度、两纵向涡发生器间的距离以及纵向涡发生器距射流孔中心的距离对流动和换热的影响,分析了纵向涡发生器强化冲击换热的机理。结果表明:当在射流孔前的上壁面上增加一对纵向涡发生器后,射流孔前的横流流速减小,射流穿透力增大,射流腔内湍动能增大,从而造成靶面换热极值及高换热区域显著增大;在研究的纵向涡发生器各位置参数范围内,当横流雷诺数较低时,各参数对靶面换热的影响不大。

The flow and heat transfer on leading edge of a gas turbine blade were investigated by using 3-D numerical method.A pair of delta-winglet vortex generators（VGP）was installed in the jet cavity to study the effects of following factors on the impingement heat transfer,such as the attack angle of VGP,the spacing between two VGPs and the distance between the VGP and the jet nozzle.In addition,the mechanism of heat transfer enhancement by longitudinal vortex generator was discussed in detail.Results show that the cross flow velocity in front of the jet nozzle decreases in case the delta-winglet VGP is placed on the top wall,when both the jet penetration and the turbulent kinetic energy improve accordingly in the jet cavity,resulting in significantly increased peak value of heat transfer and enlarged area of heat transfer region.However,the effects of VGP geometry parameters on the heat transfer are not significant at a lower cross-flow Reynolds number.