Implementation of Radiation, Ablation, and Free Energy minimization Modules for Coupled Simulations of Hypersonic Flow,” AIAA Paper 2009-1399

A description of models and boundary conditions required for coupling radiation and ablation physics to a hypersonic flow simulation is provided. Chemical equilibrium routines for varying elemental mass fraction are required in the flow solver to integrate with the equilibrium chemistry assumption employed in the ablation models. The capability also enables an equilibrium catalytic wall boundary condition in the non-ablating case. The paper focuses on numerical implementation issues using FIRE II, Mars return, and Apollo 4 applications to provide context for discussion. Variable relaxation factors applied to the Jacobian elements of partial equilibrium relations required for convergence are defined. Challenges of strong radiation coupling in a shock capturing algorithm are addressed. Results are presented to show how the current suite of models responds to a wide variety of conditions involving coupled radiation and ablation. I. Nomenclature Bold face, lowercase variable names refer to vectors. Bold face, uppercase variable names refer to matri-ces. Bracketed entry indicates units or quantity used to non-dimensionalize. Roman symbol