Numerical simulation of non-Newtonian jets emanating from a converging cone

Abstract

The effects of the rheological properties on the fluid motion of non-Newtonian jets emanating from a converging cone have been investigated theoretically. Three typical non Newtonian fluid models have been considered; i.e. the power-law fluid, the modified Bingham ngham fluid and the Oldroyd-B fluid. The effects of five parameters on the flow field are analyzed in detail; these parameters are: the contraction ratio of the radius of the cone far upstream to that at the cone exit L; the converging angle of the cone 6; the power-law index n; the Bingham number Bn and the Weissenberg number We. The Galerkin finite-element method incorporated with the upwind scheme was applied to solve the flow problems numerically. Full Newton iteration was used to solve the flow fields and the free-surface positions of power-law and modified Bingham fluids. However, the free-surface position of the Oldroyd-B fluid has to be updated by kinematic iteration to avoid numerical oscillations.