Thermal protection of hypersonic vehicles is of great concern during ascent and re-entry conditions due to higher aerothermal loads. The passive forward-facing cavity is exhibited a substantial reduction of aero heating effects. The experimental studies on unsteady aspects of the flow considering the cavity geometries and heat transfer effects within the cavity are not abundant. In the present study, we investigated the heat transfer variations and nature of shock around a blunt body with cylindrical and parabolic cavity geometries. Experiments are conducted in hypersonic shock tunnels using air as the test gas for flow enthalpy conditions of 3.2 and 5.4 MJ/kg for a free-stream Mach number of 10.9 and 10.2 respectively. The cavity flow is established by verifying the measured heat flux, pressure, and shock oscillation results. The unsteady heat flux measurements and high-speed schlieren imaging is performed to study the effects. The results reveal that the flow with the parabolic cavity geometry shows a significant increase in the mean shock standoff position of about 14% and 30% compared to the blunt-nosed body, and about 7%–18% compared to the cylindrical cavity geometry, with a reduction of bow shock oscillations. As a result, a substantial reduction of heat flux about 34%–59% on the nose surface is noticed and found it is effective for mitigating the aerodynamic heating at higher flow enthalpy conditions. The flow with a cylindrical cavity geometry indicated the substantial increase in the heat flux due to the shock interaction and the significant heat flux variation in the cavity region is recognized and observed that such effects were not prevalent with the parabolic cavity geometry.

由于上升的空气热负荷，在上升和重新进入的情况下，高超声速车辆的热保护受到极大关注。被动式前向腔体显示出空气加热效果的显着降低。考虑型腔几何形状和型腔内传热效应的非定常流动实验研究并不多。在本研究中，我们研究了圆柱体和抛物线形腔体在钝体周围的传热变化和激波性质。实验在高超声速冲击隧道中进行，使用空气作为测试气体，流动焓分别为10.9和10.2时，流动焓为3.2 MJ / kg和5.4 MJ / kg。通过验证测得的热通量，压力和冲击振荡结果来确定腔体流量。进行了非稳态热通量测量和高速schlieren成像，以研究其影响。结果表明，与抛物线形腔体相比，抛物线形腔体的流动显示平均冲击支座位置显着增加，与钝头体相比，分别增加了约14％和30％，与圆柱形腔体的几何形状相比，约增加了7％–18％，减少船首冲击的振荡。结果，发现鼻子表面的热通量显着降低了约34％–59％，并且发现在较高的流动焓条件下，这种方法对于减轻空气动力加热是有效的。