Computation of nonequilibrium high-temperature axisymmetric boundary-layer flows.

Efficient and accurate Hermitian-type multipoint finite difference methods are used to develop a general boundary-layer code for analyzing reacting flows around bodies of revolution. The main motivation is to build a reliable code that can be used for the investigation of the influence of different physico-chemical models for transport properties, chemical kinetics, and finite rate wall catalysis on practically relevant quantities like heat flux and skin friction at the body surface. Special care has been devoted to the correct modeling of diffusion fluxes, an aspect that is often neglected in literature. The exact Stefan-Maxwell equations are used to model the diffusion fluxes and are solved with an efficient iterative technique. Finite rate catalysis is an important aspect of thermal protection system (TPS) materials studies, for which a boundary-layer code is a very useful tool because it allows the computation of the heat flux at a cost that is a fraction of a Navier-Stokes approach. Wall catalyticity effects are taken into account by means of a model that allows one to express a suitable set of wall reactions with the associated reaction-rate probabilities. Computations performed on a variety of problems and the results shown here on some typical test cases indicate the ability and reliability of the code to cope with a wide range of nonequilibrium conditions, making it a potentially useful tool for physico-chemical and TPS material studies.