The viscosity distribution around a rising bubble in shear-thinning non-newtonian fluids
Résumé
The viscosity distribution of the liquid around a rising bubble in carboxymethyl cellulose (CMC) aqueous solutions was measured experimentally by particle image velocimetry (PIV). The effect of the concentration of CMC solutions on the viscosity distribution around a bubble and the coupling relations between the viscosity field, flow field and shear stress field were also studied. Results indicated that the specific viscosity (non-dimensionalized by eta(0)) decreases with the increase in CMC solution concentration due to a shear thinning effect. Within the experimental range, similar viscosity distributions of liquids around a rising bubble were found: a hollow cylindrical low viscosity region around the bubble wake and a high viscosity region in the central bubble wake.