NUMERICAL MODELLING BASED ON LATTICE BOLTZMANN METHOD OF THE BEHAVIOUR OF BUBBLES FLOW AND COALESCENCE IN MICROCHANNELS

摘要

This paper introduces a newly developed model of lattice Boltzmann method (LBM) for simulating bubbles flow and coalescence in a microchannel. The model is developed based on the work by Inamuro et al. (2004) aiming to test the suitability of LBM for studying the dynamics of bubbles flow and coalescence in a surface dominated rectangular microchannel and to reduce computational cost. A simple linear function is applied to the order parameter to approximate the density within the interface of gas-liquid and meanwhile employing a new form of the free energy density (rather than the van der Waals free energy) to extend the suitability of the model for simulating two-phase flow on wetted solid boundaries. The evolution of two isothermal air bubbles flowing through a water-filled microchannel and the interactions between the flow fields and the interface of gas-liquid are obtained and investigated numerically.