Multiphysics modeling of a gas bubble expansion

Abstract: In this work we use Comsol Multiphysics 4.2 to model a gas bubble expansion in a viscous liquid initially at rest. The aim of the present work is to improve a computational model developed early under simpler conditions [1], by considering now the expansion of a spherical bubble and more realistic physical properties. Surface tension effects on the gas-liquid interface are set for an aluminum-hydrogen system and a step function is considered for modeling the pressure on the boundary. Due to the axial symmetry, the model equations are solved on a two-dimensional mesh with adaptive mesh refinement in time. In order to capture the interface between the two fluids, the capabilities of the level set method are exploited. The numerical findings verify that the computational model is effective. The simulations, carried out for different cases, predict well bubble expansion, interface movement and fluid flow.