Modeling Gas Nucleation and Condensation Using the Direct Simulation Monte Carlo Method

A general kinetic nucleation and condensation model is proposed and implemented in the direct simulation Monte Carlo method. Both gas and clusters are treated as particles in this model, and clusters possess internal energy and potential energy. Nucleation and condensation processes are treated as collision events, and the probability for possible nucleation or condensation is determined from the nucleation rate and sticking coefficient. Literature review shows that there are many uncertainties in gas nucleation and condensation theory. The proposed model is then very useful for parametric studies. Our parametric studies show that both nucleation rate and sticking coefficient affect properties of the gas and clusters. Simulation of supersonic flow in an expansion nozzle shows that the proposed model is able to simulate complicated flows involving clusters.