Numerical simulation of the motion of a Taylor drop in a non-Newtonian fluid

Abstract

In this study, the motion of a Taylor drop in a non-Newtonian fluid in a vertical tube is investigated numerically. The governing equations are solved using a volume of fluid (VOF) method in a symmetric geometry using OpenFOAM software. The continuous phase fluid behaves as shear-thinning fluid and modeled using Bird–Carreau non-Newtonian model. The effects of the power-law index (n), Froude number (0.05 ≥ Fr ≥ 0.31) and the Eotvos number (9.5 ≥ EoD ≥ 123.7) on the motion and deformation of Taylor drop are studied. The results show that the Froude number increases by increasing the power-law index, leading to an increase in the thickness of the thin layer of the fluid around the drop. For very small power-law indices, n has little effect on the Froude number. The drop deformation in Newtonian fluid (n = 1) is less than that in non-Newtonian ones. It is revealed that the Froude number increases with the Eotvos number. As the Eotvos number decreases, the thickness of the thin layer of the fluid and the drop deformation decrease. The results demonstrate that for EoD > 70, the effect of the Eotvos number on the Froude number is negligible.