Numerical Simulation of Viscoplastic Fluid Flows Through an Axisymmetric Contraction

Abstract

Flows of viscoplastic fluids through sudden, conical axisymmetric contraction are studied. A finite-element numerical simulation is performed using a biviscosity approximation. Inertia is neglected. The effects of yield stress are analyzed, as are those of shear-thinning, contraction angle, and contraction ratio. The pressure losses, detailed structure of the flow such as the rigid static and moving zones, and the vortex are given in relation to these parameters. Consistent comparisons are also made with the experimental results obtained in the laboratory.