Hi, I am trying to simulate condensation of water in air. I am using the shan-chen multi-phase multi-component model in order to achieve this (a variation of the Lattice Boltzmann Equation, not too important). The goal ultimately is to study the effect of condensation in fuel cell membranes. I am struggling a bit with some physical concepts. Modelling water/vapour makes sense to me and I have successfully used the single-component multi-phase model to simulate condensation of water droplets in vapour. Taking air into consideration it becomes a bit more difficult. Basically the air contains vapour so the air is actually random gases + vapour so these are two components. The vapour itself consists of two phases vapour and liquid. Ultimately I want to show how condensation causes water droplets to form. However due to the nature of the multi-component model all I seem to get is separation of the two components (basically fluid-fluid separation). How do I within the H20 fluid distinguish between vapour and liquid? For those of you not familiar with the Lattice Boltzmann Equation, what I have for each component is a probability distribution function which allows recovery of the macroscopic density at each lattice. If this post is in the wrong forum I apologize, please move it.