Heat alleviation studies on hypersonic re-entry vehicles

A numerical simulation has been carried out to investigate the effects of leading edge blowing upon heat alleviation on the surface of hypersonic vehicles. The initial phase of this work deals with the ability of the present CFD-based techniques to solve hypersonic flow field past blunt-nosed vehicles at hypersonic speeds. Towards this end, the authors selected three re-entry vehicles with published flow field data against which the present computed results could be measured. With increasing confidence on the numerical simulation techniques to accurately resolve the hypersonic flow, the boundary condition at the solid blunt surface was then equippedwith the ability to blow the flow out of the solid boundary at a rate of at least 0.01-0.1 times the free stream (rho(infinity)u(infinity)) mass flow rate. The numerical iterative procedure was then progressed until the flow at the surface matched this new 'inviscid like' boundary condition. The actual matching of the flow field at the ejection control surface was achieved by iterating the flow on the adjacent cells until the flow conformed to the conditions prescribed at the control surface. The conditions at the surface could be submitted as rho(infinity)u(infinity) at the surface or could be equipped as a simple static pressure condition providing the desired flow rate. The comparison between the present engineering approach and the experimental data presented in this study demonstrate its ability to solve complex problems in hypersonic.