Differences caused by noncatalytic vs. fully catalytic wall boundary conditions were assessed using CFD for a 2D-wedge model for a range of Mach numbers (Formula: see text) and altitudes (Formula: see text). For Mach numbers between 8.5 and 10, results showed measurable differences between noncatalytic and fully catalytic models on the integrated wall heating, independent of altitude, as high as Formula: see text for Mach 10 at an altitude of 45 km. Results for a partially catalytic model wall showed an exponential dependency of the wall heating due to the catalytic recombination coefficient of atomic oxygen, Formula: see text, for the regime in question. As Formula: see text approaches one, a partially catalytic model exponentially approaches the fully catalytic model results. In addition to the corridor of potential application for a partially catalytic model, this study provides two important revelations: Formula: see text must be accurate Formula: see text to produce a distinguishable solution in between both extremes (non and fully catalytic) assumptions; and a fully catalytic model should be used in simulations in which Formula: see text are not known for all i-species expected to recombine since it provides the most conservative prediction of wall heating.
Blanco et al. (Thu,) studied this question.