EFFECT OF SURFACTANT OF TERMINAL VELOCITY OF AND MASS TRANSFER FROM A FLUID SPHERE IN A NON-NEWTONIAN FLUID.

In the reported experiments, the effect of interfacial tension gradients on creeping flow past a fluid sphere (bubble or drop) in a non-Newtonian fluid has been investigated. The drag force and the Sherwood number for contaiminated fluid spheres moving in a non-Newtonian fluid are obtained by an approximate solution of equations of motion in the creeping flow regime. It has been found that surface-active agents decrease both the terminal velocity and the mass transfer rate. The influence of the flow index of the power-law on both the drag coefficient and the Sherwood number is superimposed over the influence of the interfacial tension gradient. Comparisons between the present analysis and the available experimental data in the literature show reasonable agreement for the terminal velocity and the Sherwood number.