Verification of a Finite-Element Model for Pyrolyzing Ablative Materials

Ablating thermal protection system materials have been used in many reentering spacecraft and in other applications such as rocket nozzle linings, fire protection materials, and as countermeasures for directed-energy weapons. The introduction of the finite element model to the analysis of ablation has arguably resulted in improved computational capabilities due to the flexibility and extended applicability of the method, especially to complex geometries. Commercial finite element codes often provide enhanced capabilities over custom, specially-written programs, such as versatility, usability, preand post-processing, grid generation, total life-cycle costs, technical support, maintenance, and speed. Computed results for several test problems using the commercial finite element code COMSOL Multiphysics (COMSOL, Inc. Burlington, Massachusetts) are compared to predictions generated from other computational tools including the Fully Implicit Ablation and Thermal (FIAT) Response code. The results obtained from COMSOL Multiphysics compare favorably with other methods and demonstrate that COMSOL Multiphysics is an accurate and advantageous tool for the analysis of pyrolyzing ablators.