气膜孔内置扰动条作用下的射流-横流流场

Investigation of velocity fields in a jet-in-cross-flow by using ridge-shaped tabs

关键词:  航空、航天推进系统  扰动条  射流  流场

Key words:  Aerospace propulsion system  Ridge-shaped tabs  Jet  Velocity fields

摘要:

为改善气膜冷却效率,提出了在倾斜气膜孔前缘内置扰动条的结构。通过与典型的圆柱形气膜孔流场的对比研究,总结出内置扰动条对流场的影响规律。研究结果表明,在射流-横流流场中,内置扰动条减小了射流向主流的穿透,使反向旋转涡对向壁面靠拢,穿透顶点下移;扰动条使下游反向涡对的强度增大;随着吹风比的增大,气膜孔下游同一位置处的流向涡强度增大,这一方面增加了主次流的相互掺混,另一方面也增大了流体沿展向的相互掺混。

Abstract:

In order to improve the film cooling effectiveness,the ridge-shaped tabs located along the upstream edge of declining holes were devised.The effect of the ridge-shaped tabs on the penetration and spreading of a jet in a cross-flow has been studied by numerical simulation.The velocity fields have been compared with the typical cylindrical film cooling holes.The results show that ridge-shaped tabs reduce the jet penetration in a jet-cross flow and make the pair of counter-rotating vortices and the peak of penetration close up to the wall.Ridge-shaped tabs may have increased intensity of vortex.The intensity of streamwise vortex pairs is increased as the blow ratio increases,it can improve the mixing of the jet and cross-flow and increase the penetration of spanwise flow as well.