Numerical simulation of galileo probe entry flowfield with radiation and ablation

A trajectory-based heating analysis of the Galileo probe entry flowfield is attempted to reproduce the heatshield recession data obtained during the entry flight. In the calculation, the mass conservation equations for the freestream gas (hydrogen-helium gas mixture) and the ablation product gas are solved with an assumption of thermochemical equilibrium. The ablation process is assumed to be quasi steady and is coupled with the flowfield calculation. The radiative energy transfer calculation is tightly coupled with the flowfield calculation, where the absorption coefficients of the gas mixture are given by the multiband radiation model having 4781 wavelength points for wavelength range from 750 to 15,000 Å. The injection-induced turbulence model proposed by Park is employed to account for the enhanced turbulence effect due to the ablation product gas. It is shown that the final recession profile of the flight data at the frustum region can be closely reproduced if the injection-induced turbulence model is employed, although that at the stagnation region is overestimated. The cause of the enhanced radiative heating that occurs at the frustum region is given in connection with the enhanced turbulence effect in the shock layer.