MODELING OF NITROGEN AND OXYGEN RECOMBINATION ON PARTIAL CATALYTIC SURFACES

In connection with recombination coefficients derived from experimenta l data described in the literature, a reaction scheme including detail ed rate expressions for O and N atom recombination on the surface of r e-entry vehicles. is established, consisting of elementary reaction st eps. To validate the reaction mechanism derived, surface chemistry and fluid mechanical processes are coupled assuming a one-dimensional sta gnation flow field. A quantitative agreement is achieved between recom bination coefficients resulting from the numerical computations and th ose calculated from experiments. The temperature dependence of the rec ombination coefficient is explained by elementary reaction steps. Furt hermore,the reaction scheme established is implemented in a two-dimens ional Navier-Stokes code computing the re-entry flow around a simple g eometry to show the importance of a detailed modeling of sufrace react ions.