Thermomechanical Ablation

In order to investigate the heat and mass transfer aspects of thermomechanical ablation, ablation experiments were performed with models made of pure carbon dioxide (CO2) and a glass bead-CO2 composite. The experiments were performed in a low subsonic, low turbulence jet at ambient pressure and near 0 deg C temperature. The model geometry was a hemispherical forebody-cylindrical afterbody with a diameter of 25mm. The stagnation point mass transfer of the pure CO2 models was 6.2% less than predicted by equilibrium theory. The distribution around the hemisphere generally agreed with the predicted laminar heat transfer result of monotonically decreasing heat transfer with distance from the stagnation point. The internal temperature response was approximately 5% higher than the theoretically predicted wall temperature. These results could be correlated by the inclusion of a nonequilibrium sublimation model into the theoretical prediction equations.