Effects of finite sublimation rate of carbon graphite on stagnation heating
Abstract
Reacting stagnation point boundary layers were analytically modeled for sublimation assumptions of the boundary conditions. The study was conducted to upgrade predictions of the aerothermal heating environment that will be experienced by a Jovian probe with a carbon ablative shield. The effect of finite rate sublimation was examined using the KnudsenLangmuir equations with specified sublimation coefficients in the surface boundary conditions. The flow was assumed axisymmetric, steady, laminar, viscous, and compressible, and the atmosphere was assumed to be a hydrogen/helium mixture. Exact solutions were obtained for the boundary layer equations for both sublimation assumptions. The results suggest that the mass loss rate of equilibrium flow with the equilibrium assumption is significantly larger than found with the finite rate assumption. Carbon heating rates are not affected by the sublimation rate law and are affected by the chemical reactions, especially hydrogen dissociationrecombination in the gas phase.
 Publication:

13th Symposium on Space Technology and Science
 Pub Date:
 1982
 Bibcode:
 1982spte.symp..599A
 Keywords:

 Ablative Materials;
 Carbonaceous Materials;
 Graphite;
 Heat Shielding;
 Stagnation Point;
 Sublimation;
 Atmospheric Entry;
 Atom Concentration;
 Boundary Conditions;
 Boundary Layer Equations;
 Heat Transfer;
 Hydrogen Atoms;
 Jupiter Probes;
 Fluid Mechanics and Heat Transfer