A multiscale approach for building a mechanism based catalysis model for high enthalpy CO2 flow

The principles of the gas-surface-interaction taking place in the chemically reacting flow around an atmospheric re-entry vehicle are investigated. It turns out that the currently very often used approach employing a recombination coefficient has a limited applicability. Serious concerns arise when the interaction model is extrapolated from ground to flight tests. A mechanism based approach taking into account every interaction step is therefore proposed for the carbon dioxide interaction with platinum. The necessary reaction rates are determined using a microscopic model, which are then used in a continuum viscous flow simulation. The dependence of the catalysis on the outer flow conditions and also on the wall temperature is demonstrated.