Uncertainty Analysis of Aeroheating Predictions for Titan Entries

A sensitivity and parametric uncertainty analysis of the stagnation point convective heating rate is performed on a Huygens geometry entering the Titan atmosphere. The purpose of the study is to determine which CFD input parameters has the largest effect on the convective heating at fullycatalytic surface. The primary contributors to the heating rate sensitivity and uncertainty were the N2N2, N 2-N, and N 2-H binary collision integrals. Diatomic nitrogen is the dominant species in the shock layer and the diffusion of atomic nitrogen and hydrogen to the vehicle surface is the major rate limiting process to the surface recombination. In terms of input parameter type, the binary collision integrals contributed from 73% to 87% of the overall convective heating rate uncertainty. None of the other input parameter types (dissociation reaction rates, exchange reaction rates, vibrationdissociation coupling parameters, vibrational-translational relaxation times) contributed more than 12.5%.