Use of an axial nose-tip cavity for delaying ablation onset in hypersonic flow

Abstract

A forward-facing cavity is examined as a means of reducing the severe heating and delaying ablation onset at the nose-tip of a hypersonic vehicle. Whereas previous studies have concentrated on the nature of flow-induced Hartmann-whistle oscillations or on heating rates alone, the present study addresses the effect of the cavity on ablation onset times through experiments and coupled flow field/heat conduction simulation. Using our previously developed experimental technique, a parametric study is undertaken to optimize the forward-facing cavity geometry for the most delayed ablation onset. The geometric parameters of cavity length, lip radius and diameter are independently optimized for a given nose-tip diameter. Then using benchmarked linked flow field/heat conduction simulations, numerical simulations are conducted for each parametrically optimized configuration in order to investigate the flow physics. The impact of the forward-facing cavity on aerodynamic drag is also considered.