FINITE-ELEMENT ANALYSIS OF MULTICOMPONENT 2-PHASE FLOWS WITH INTERPHASE MASS AND MOMENTUM TRANSPORT

The application of the finite element method to multiphase flow proble ms with interphase mass and heat transfer is described. A general form ulation is used that determines the position of the interfacial bounda ry and allows for multiple solvents, differential volatilities and con centration- and temperature-dependent thermophysical properties. Speci es phase change and the dramatic volume change that accompanies interp hase mass transfer make implementation of the theory challenging, sinc e these events lead to discontinuous velocities and concentrations at phase boundaries. These discontinuities are especially large in proces ses involving rapid evaporation or condensation. As examples we examin e the effects of rapid drying on film and fibre formation of sol-gel m aterials, which are often laden with volatile species.