An improved Coupled Level Set and Volume of Fluid (i-CLSVoF) framework for droplet evaporation

Abstract

We present an improved Coupled Level Set and Volume of Fluid (i-CLSVoF) framework without explicit interface reconstruction for modelling micro-sized droplets with and without evaporation. A new surface tension force model with additional filtering steps is developed and implemented in the i-CLSVoF framework to suppress un-physical spurious velocities. Numerical benchmark cases demonstrate the excellence of the i-CLSVoF framework in reducing the un-physical spurious velocities. A simple yet efficient velocity-potential based approach is proposed to reconstruct a divergence-free velocity field for the advection of the free surface when the phase changes. The new approach fixes the numerical issues resulting from the evaporation-induced velocity jump at the interface. The smeared mass source term approach proposed in this work guarantees more numerical stability than the non-smeared approach.Two different evaporation models (constant mass flux and thermally driven evaporation models) are implemented into i-CLSVoF. Extensive numerical validations are conducted to validate the evaporation models.

Modelling Droplet Evaporation with an Improved Coupled Level Set and Volume of Fluid (I-Clsvof) Framework

“…The agreement between the numerical and corresponding analytical solutions is encouraging and promising. The model developed in this work demonstrates exemplary performance in modelling surface-tension dominant flow with and without evaporation [7].…”