Development of a Phase-Change Model for the Volume-of-Fluid Method in OpenFOAM

In this study, the volume-of-fluid method in the OpenFOAM open-source CFD package will be extended to consider the phase-change phenomena with a modified model due to the condensation and boiling processes. This model is suitable for the case, in which the unsaturated and saturated phases both are present and for which an initial interface is not needed to begin boiling and condensation processes. Both phases (liquid and vapor) are incompressible and immiscible. The interface between two phases is tracked with the color-function volume-of-fluid (CF-VOF) method. Surface tension is taken into consideration by the continuous surface force (CSF) model. Pressure-velocity coupling will be solved with the PISO algorithm in the collocated grid. The accuracy of this phase-change model is verified by two evaporation problems (a one-dimensional Stefan problem and a two-dimensional film-boiling problem) and two condensation problems (a one-dimensional Stefan problem and filmwise condensation). The simulation results of this model show good agreement with the classical analytical or numerical results, proving its accuracy and feasibility.