Simulating Gas-Liquid Flows by Means of a Pseudopotential Lattice Boltzmann Method

Abstract

Abstract: Dispersed gas (vapor) liquid flow through an inclined microchannel with bends has successfully been simulated, that is, without numerical difficulties, by means of a two-phase Lattice Boltzmann method. Combining in this method the Shan-Chen(1) pseudopotential interaction model with the Yuan and Schaefer(2) proposal for dealing with nonideal equations of state makes high density ratios achievable. This approach also allows simulation of gas liquid flows without explicitly having to track the phase interfaces. Rather, a potential function related to the equation of state for vapor liquid equilibrium, a coupling strength representing attraction or repulsion between species, and a relaxation time scale take care of microscale and mesoscale phenomena such as phase separation and interfacial tension as well as interphase transport and multiphase flow. In addition, fluid wall interaction (contact angle) is taken into account by selecting proper potential functions and coupling strengths. As far as the phase behavior is concerned, we assessed our method by studying the phase separation process and by validating against Maxwell's equilibrium rule. Qualitative validation of our approach of gas liquid flow has been done with a comparison against experimental data on a single bubble rise. Detailed simulations were carried out for an individual Taylor bubble in a channel, the results of which compared favorably to literature data