METASTABLE FLUID-FLOW DESCRIBED VIA A DISCRETE-VELOCITY COAGULATION-FRAGMENTATION MODEL

A discrete-velocity Boltzmann model is introduced. It is based on two principles: (i) clusters of particles move in R(3) with seven fixed mo menta; (ii) clusters may gain or lose particles according to the rules of Becker-Db;ring cluster equations. The model provides a kinetic rep resentation of evaporation and condensation. The model is used to obta in macroscopic fluid equations which are valid into the metastable flu id regime, 0 less than or equal to rho < rho(s) + O(mu(sigma)), where sigma is any positive number, mu is the inelastic Knudsen number, and rho(s) is the saturation density.