基于温敏漆技术的圆锥高超声速大攻角绕流背风面流动结构实验研究

Experimental Study of Flow on the Leeward Side of a Cone at a High Angle of Attack Based on Temperature Sensitive Paint

高超声速流动中,大攻角下圆锥背风面边界层会存在流动分离与再附、边界层转捩等多种流动现象,进而对圆锥表面温度分布产生显著的影响。为了对这一复杂流动规律及其对表面温升分布的影响进行讨论,研究基于温敏漆技术,得到了在Mach数为6的低湍流度来流条件下,攻角为10°的圆锥背风面温升分布结果。通过对不同位置、不同方位角处温升分布曲线的分析,对大攻角下圆锥背风面边界层流动发展过程及不同发展阶段的流动特征进行了讨论。同时,通过对来流总压的调节,得到了不同Reynolds数下的圆锥背风面温升分布结果,总结了Reynolds数对流动的影响规律。研究发现,高超声速大攻角圆锥背风面边界层流动发展过程中会依次出现层流分离、定常横流涡影响、转捩以及湍流分离与再附等流动特征,而在不同的Reynolds数下,各个流动特征产生影响的范围不同,随着Reynolds数的降低,层流范围和定常横流涡影响范围均有所增加,而从观察到横流影响到转捩开始发生的范围基本相同。

In the hypersonic flow of a cone at a high angle of attack,there will be complex flow phenomena,such as flow separation,crossflow vortices and boundary layer transition.The flow phenomena will affect the temperature distribution on the cone surface significantly.The temperature rise distribution results on the cone leeward surface with an attack angle of 10°were obtained from the temperature sensitive paint system in Mach 6 hypersonic low turbulence wind tunnel.Through the experimental results,complex flow law and its influence on the distribution of surface temperature were discussed.With the analysis of temperature rise distribution curves at different positions and different azimuth angles,the development process of the flow on the conical leeward surface and the flow characteristics at different development stages were discussed.By adjusting the total pressure of the incoming flow,the temperature rise distribution results with different Reynolds numbers were obtained,and the influence of Reynolds number on the flow was summarized.Results show that the laminar separation,stationary crossflow vortices,boundary layer transition,turbulent separation and reattachment would occur in sequence during the development of the boundary layer flow on the leeward surface.As the Reynolds number decreases,the range of laminar flow and the range of stationary crossflow vortices increase,and the range from the observation of the stationary crossflow vortices to the beginning of transition is basically the same.