Prediction of Bubbles and Drop Dynamics under Different Flow Situations and Phase Change: Lattice Boltzmann Study

Abstract

This paper deals with a numerical investigation about the bubble and drop dynamics under different flow situation and phase change process. Lattice Boltzmann Method (LBM) is used to discretize the governing equations for each of the flow situation related to drop or bubble. Three different cases are simulated related to bubble dynamics. Among them two are about the deformation of bubble in liquid medium with different flow conditions. In the 1st case, the bubble is subjected to flow parabolic velocity profile and in the 2nd case, the bubble is subjected to flow with linear velocity profile. The third one is related to the phase changes. In this case, a superheated bubble is placed in a surrounding of saturated liquid. Only one case is studied about the drop dynamics in which a water drop is placed in a rectangular horizontal channel with air medium subjected to parabolic velocity profile at inlet. In the present investigation, three separate probability distribution functions are used in LBM to handle continuity, momentum and energy equations separately. The interface between the two phasesis considered to be diffused within a narrow zone and it has been modelledwith convective Cahn-Hillard equation. Combined diffused interface-LBM framework is adapted accordingly to handle complex interface separating two phases having high density ratio.