CFD code comparisons for Mars entry simulations

Abstract

Axisymmetric and three-dimensional Navier-Stokes solutions with CO2 thermochemistry models, catalytic and noncatalytic surface kinetics have been computed for code-to-code comparisons between GASPv3.0, GIANTS and LAURA codes, at the Mars 2001 overshoot peak heating flight conditions. The following parameters and their effects on surface heating have been studied: gas kinetics, chemical reaction rates, diffusion rates, and wall catalysis models. The code-to-code comparative study indicates that the computed non-catalytic heating rates are influenced by the choice of chemical kinetics and transport models. For a non-ablating surface, wall catalysis is an important mechanism for transferring energy to the surface of the vehicle. Surface kinetics and diffusion models drive surface heating to similar levels irrespective of differences in the gas kinetics models, thermal non-equilibrium or numerical algorithms. The calculated solutions show that surface catalysis contributes 60% to 70% of the total heating at the non-ablating vehicle's surface for the surface kinetics models compared. D = NOMENCLATURE mass fraction of species i aft plate diameter (m) base diameter (m) species i diffusion coefficient (m reference diffusion coefficient (m s) = diffusion factor for species i h = static enthalpy (J ' kg ) J kT k L/D M diffusion mass flux (kg ' m ' s') thermal conductivity (W ' m ' K ) me = P = Pr = q = R =