Experimental Study On Hypersonic Boundary Layer Transition Of Delta Wing And Cone

Boundary layer transition is an important factor that must be considered in the design of hypersonic vehicle.It plays an important role in thermal protection and aerodynamic performance optimization of aircraft.Delta wing and cone are the common basic shapes of hypersonic vehicles.Therefore,it is of great value to study the transition of delta wing and conical boundary layer.Temperature Sensitive Paints(TSP),Nano-tracer Planar Laser Scattering(NPLS)and Pulsation Pressure Testing Technology are used in this paper to investigate the hypersonic boundary layers transition of delta wings and cone at different Reynolds numbers and angles of attack.First,TSP technology is constructed,which can visually reflect the flow phenomena in the boundary layer transition front and near wall region.The principle,hardware selection and usage of TSP system are described in detail.The operation parameters and the accomplishment of the quiet flow field in the hypersonic quietwind tunnel are briefly introduced,and then the NPLS technique and the pulsating pressure measurement technique are introduced.The developed TSP technique and the existing NPLS technique in the laboratory are used to study the boundary layer transition of delta wings.By means of TSP technique,the position and shape of boundary layer transition front are obtained,and the influence of attack angle and Reynolds number on boundary layer transition is obtained in the meantime.NPLS technique was used to observe the fine flow structure of the delta wing near the wall.What's more,the development of the delta wing boundary layer and the flow structure on the leeward side of the delta wing during the transition of the boundary layer were revealed.The conical boundary layer transition with a head radius of 1.5mm was experimentally studied by using TSP,NPLS and pulsating pressure measurement techniques.The "V-shaped distribution" of the boundary layer transition front on the windward surface of a cone is obtained,while the cross-flow,flow reattachment and detachment vortices on the leeward surface are obtained.Finally,three techniques were used to confirm each other and the cross flow was detected.