Mass and Heat Transfer in the Problem of a Finite Thickness Ablating Piston

摘要

The heat and mass transfer at the surface of a finite thickness ablating piston is considered. The piston is either impulsively put in motion or its speed follows an assigned time law. In both cases the wall reaches an hypersonic speed and its surface at the gas/solid interface is diffusive. The coupled problem of the temperature distribution in the two phases is dealt with by solving the parabolic heat conduction equation in the slab by means of an integral boundary layer approach and by adopting a Direct Simulation MonteCarlo Method for the gas phase. The solid and the gas regions are coupled by proper boundary conditions. A time scale analysis was necessary to take into account the more rapidly changing gas characteristics with respect to those of the solid.