Modeling of homogeneous condensation in supersonic plumes with the DSMC method

A particle simulation method to model water condensation process in the supersonic rocket plume is proposed and developed. The classic nucleation theory is used to predict nucleation, condensation and the evaporation rates for water clusters. Microscopic kinetic models are developed to simulate collisional processes between water clusters and monomers, between water clusters and foreign molecules, and evaporation of monomers from water clusters. The direct simulation Monte Carlo (DSMC) method integrates these models to simulate an axisymmetric multispecies gas expansion coupled with condensation. The developed computational scheme, verified by the well known empirical scaling laws of condensation in supersonic micro-jets, is then applied to predict the spatial distributions of water cluster number density, size and temperature in the rocket exhaust plume.