Drag on partially contaminated bubble swarms in power-law fluids

Abstract

The relative motion between swarms of bubbles and a contaminated power-law fluid is numerically investigated using a computational fluid dynamic based approach. The effects of bubble holdup and the degree of contamination are incorporated in the solver by means of a cell model and spherical stagnant cap model, respectively. The continuity and momentum equations are solved using a finite difference method based semi-implicit simplified marker and cell method (SMAC) on a staggered grid arrangement in spherical coordinates. The final steady velocity and pressure fields are used to delineate effects of Reynolds number (Re: 1–200), bubble holdup (Φ: 0.1–0.5), power law index (n: 0.6–0.8), and stagnant cap angle (α: 0°–180°) on streamlines, vorticity contours, surface vorticity and drag coefficients of contaminated bubbles.