PNNL

Abstract

We introduce the N-phase Conservative Level Set Free-Energy-based Surface Tension model (NCLS-FEST) for multiphase flow (N = 3). The model prevents numerical overlaps of fluids and voids between fluids that are found in the standard Conservative Level Set (CLS) method. The key differences between NCLS-FEST and CLS methods are the multiphase compression-diffusion equation to ensure conservation and a sharp interface at each time step and a free- energy-based surface tension model. We demonstrate that the NCLS-FEST method has accurate results for N-phase fluid flows involving complicated geometrical configurations, including triple lines in the liquid lens problem for three and four fluid phases, with accurate conservation of mass. Additionally, we show that the NCLS-FEST method can be extended to N-phase fluid-solid flow, where the solid phase is modeled by a static fluid phase.