Simple Mechanistically Consistent Formulation for Volume of Fluid Based Computations of Condensing Flows

Abstract

Numerous investigations have been conducted to extend adiabatic liquid–gas volumeoffluid (VOF) flow solvers to include condensation phenomena by adding an energy equation and phasechange source terms. Some proposed phasechange models employ empirical rate parameters, or adapt heattransfer correlations, and thus must be tuned for specific applications. Generally applicable models have also been developed that rigorously resolve the phasechange process, but require interface reconstruction, significantly increasing computational cost, and software complexity. In the present work, a simplified firstprinciplesbased condensation model is developed, which forces interfacecontaining mesh cells to the equilibrium state. The operation on cells instead of complex interface surfaces enables the use of fast graph algorithms without reconstruction. The model is validated for horizontal film condensation, and converges to exact solutions with increasing mesh resolution. Agreement with established results is demonstrated for smooth and wavy fallingfilm condensation.