Thin-film boundary-layer diffusion of non-equilibrium flow to kinetically limited reactive surfaces via Damk\"ohler thermochemistry tables

Abstract

Traditional ablation thermochemistry tables for atmospheric entry are derived from boundary-layer element diffusion assuming homogeneous and heterogeneous thermochemical equilibrium at the vehicle surface. Prior techniques for finite-rate surface reactions predominantly embed specific heterogeneous reaction models within the homogeneous equilibrium solution procedures and tables. This paper disseminates a boundary-layer integral solution for wall-gas free oxygen coupled to finite-rate surface kinetics. Solutions are pre-tabulated along normalized kinetics variables without direct integration into an equilibrium thermochemistry solver. This technique allows greater flexibility in presumed kinetics rates and wall-gas conditions in simple air-carbon systems, but the extensibility to state-of-the-art simulations and complex materials remains uncertain. A derivation and preliminary results are presented to the encourage further development.