Response of Charring Ablators to Severe Aerodynamic and Erosion Environments

Results of an analytical study for the transient and quasi-steady response of a typical charring ablator to severe aerodynamic and erosion environments are reported for heating loads and particle-surface interactions which are representative of wind tunnel tests as well as re-entry conditions. The coupled erosion-char formation process is shown to be self-limiting, and both discrete and continuous models for erosion of partially charred material, based on experimental data for virgin and fully charred material, are found to give similar results. The numerical solution procedure is illustrated for typical re-entry conditions with cloud and/or dust layers located at altitudes of 50, 35, and 10 kft. Application of simple quasi-steady theory is shown to under-predict total recession.