Sublimation and Self Freezing of Planar Surfaces in Rarefied Atmospheres

摘要

A simulation of phase transformations in planar geometries under various boundary conditions is performed. The case of ablation accretion self-freezing under rarefied atmospheres application of external heating is looked at for the ice-water-vapor naphthalene systems. Consideration of ablation is important in applications with space shields in space flight under radiation heat sources along with near vacuum conditions. Recent Noninvasive methods in cryogenic surgery also rely on the production of extreme cold in subcutaneous layers by surface ablation. In this paper sample calculations for water-ice naphthalene give the velocities of the freezing vaporization fronts under various parameter combinations assuming isotropic properties in each phase. It is shown that considerable difference exists between the cases of self-freezing ablation accretion. For instance in the case of water rates of self- ablation without heat sources self-accretion (as in the formation of ice crystals directly from vapor) differ by an order of Magnitude.