Steady State Pyrolysis and Ablation Investigation

Compared to non-ablative materials, the stagnation point heat transfer process for ablators is extremely challenging to model, owing to the simultaneous presence of multiple material phases, and to strong diffusion and convection processes that occur from the material to the boundary layer. The objective of this work package is to develop the tools needed to perform careful, quantitative investigations of the interaction of pyrolysis gases with high temperature free stream gases representative of post-shock flow during atmospheric entry. The first part is on the development of quasi-steady state pyrolysis/ablation devices that provide steady pyrolysis or ablation conditions during which accurate species concentration measurements can be obtained using spectroscopic methods. The second part involves developing the spectroscopic measurement capability using a non-pyrolyzing ablative material, such as graphite. The third part is on application of spectroscopic analysis.