Study of the Effects of Density, Thickness and Heat Load on Heat Shielding Performance of Phenolic Carbon Ablators Using a One-Dimensional Ablation Analysis Code

The effects of density, thickness and heat load upon the heat shield performance of the lightweight phenolic carbon ablators named LATS (Lightweight Ablator series for Transfer vehicle Systems) were examined quantitatively for both arc-heated test and re-entry heating conditions using a one-dimensional ablation analysis code. Thermal conductivity values of the ablator were tuned based on the arc-heated test results by matching the calculated temperatures to the measured data. Main findings are: (1) For both heating conditions, the heat shielding performance of the ablator has the same tendencies with respect to parameters of the ablator density, thickness and heat load. (2) The dependency of the back surface temperature upon the ablator density is small especially for a large ablator thickness. (3) The surface recession decreases with the increase of the density. However, the mass loss increases almost linearly with the increase of the density. (4) The ablator necessary thickness, with which the maximum back surface temperature equals to the pre-determined allowable temperature value, is nearly constant as the density changes. The ablator necessary mass increases almost linearly, with the increase of the density. (5) In considering the mechanism of nearly equal necessary thickness of the ablator, it is very important that the thermal diffusivity does not vary much with different densities of the LATS ablator. (6) From the point of the reduction of the ablator weight, the selection of a lower density ablator is more advantageous than that of a higher density ablator