Abstract

LI, Shaobai et al. The viscosity distribution around a rising bubble in shear-thinning non-newtonian fluids. Braz. J. Chem. Eng. [online]. 2012, vol.29, n.2, pp. 265-274. ISSN 0104-6632.  http://dx.doi.org/10.1590/S0104-66322012000200007.

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 η₀) 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.

Keywords : Non-Newtonian fluid; Bubble; Viscosity distribution; Shear-thinning effect.