MICROGRAVITY NUCLEATION OF REFRACTORY MATERIALS - MODELING OF TRANSPORT PROCESSES IN THE NUCLEATION CHAMBER

A two-part mathematical model has been developed to describe the trans port processes in a nucleation chamber designed for condensation of re fractory vapors in a microgravity environment. The model solves the tr ansient diffusion equations for temperature and concentration fields i n cylindrical coordinates using finite differences and the alternating direction implicit method. Vapor supersaturation ratios are then comp uted from the evolving concentration profiles thus permitting one to e stimate the conditions at the location in the chamber where nucleation is observed in experiments.