Multidimensional Finite Volume Fully Implicit Ablation and Thermal Response Code

Abstract

A finite volume, fully implicit ablation and thermal response code that simulates the pyrolysis gas flow, thermochemical ablation, and shape change of thermal protection materials and systems in multiple dimensions is developed. Both structured and unstructured grid approaches are implemented. The governing equations (which include energy conservation, pyrolysis gas mass conservation with Darcy’s law, a multicomponent decomposition model, and a surface energy balance) are solved with a moving grid system to simulate the response of charring ablators in aerothermal heating environments. This work demonstrates and validates new capabilities that are added to the code. These expanded capabilities include fully implicit time integration, pyrolysis gas flow due to Darcy’s law, an unstructured grid option, and parallel computing. Three groups of test cases that consider three different charring ablators are presented. In the first group, three-dimensional iso-q-shaped phenolic-impregnated carbon ablator test models with various throughthickness conductivity directions are studied. In the second group, axisymmetric flat-faced dual-layer woven carbon phenolic models are examined. Finally, in the third group, axisymmetric iso-q-shaped three-dimensional multifunctional ablative thermal protection system models are analyzed. For all cases, predictions are compared with available temperature data.