Experimental and computational study on reduction of aerodynamic heating load by film cooling in hypersonic flows

In the present study, heat protection due to mass addition on the blunt body is experimentally and numerically investigated. Experiments are conducted by using a conventional blowdown-type wind tunnel. For the experiments on heat protection with mass addition, a hemisphere model is used and the coolant N2 gas is supplied tangentially through a slot. Significant decreases of surface heat flux are obtained and the tangential film cooling is proved to be more effective on heat protection at the nose of the blunt body. In numerical analysis, axisymmetric full Navier- Stokes equations are solved by an implicit finite difference method. LU-SGS and AUSMDV scheme are applied. The k-e turbulence model accounting for both compressibility and low Reynolds-number effects is also incorporated. The numerical results show good agreements with experiments and more detailed investigation of the flow inside the boundary layer indicates that the boundary layer is consists of two sub layers and that the inner layer plays a role like adiabatic wall structure on the surface. These characteristics are considered to be most essential in the determination of film cooling effects in this type of hypersonic flow.