NUMERICAL MODELLING OF CONDUCTION-DRIVEN BULK EVAPORATION AND CONDENSATION PROCESSES WITH CONSTANT VOLUME

Abstract

This work is to develop a control volume finite-difference method to model the bulk evaporation and condensation processes involved in liquid–vapour phase changes. An internal energy formulation, for these phase change processes that occur under the constraint of constant volume, is proposed. All calculations are carried out on a fixed grid using the cylindrical co-ordinate system. The well-established enthalpy formulation and the proposed internal energy formulation are compared. Both formulations yield identical results with similar computational efficiencies, while the internal energy formulation has a more concise and compact form. Two iterative methods for the update of the vapour-phase fraction, the E-based and T-based methods, are investigated. Numerical experiments reveal that for the evaporation problems, the E-based method is superior to the T-based method in terms of computational efficiency. The internal energy formulation and the E-based method are used to compute the bulk evaporation and condensation processes under different conditions. The evolution of the phase change processes is investigated.