Numerical Investigation of Bingham Fluid Flow in the Entrance Region of Rotating Annuli

The study of the entrance region flow is, nowaday, assuming considerable technical importance due to its immediate applications in various designs of chemical and biomedical equipments in which the flows of non-Newtonian fluids are encountered. The flow characteristic of non-Newtonian fluid that is independent of time, and which obeys Bingham’s stress–strain relations, has been investigated at the entrance region of the annular space between two rotating coaxial cylinders. This analysis has been carried out for both the cases when each rotates with different speed in the same direction and as well as in the opposite direction with constant angular velocity. Discussions have been presented for a steady, laminar, isothermal flow condition of the Bingham fluid. The continuity and momentum equations are solved iteratively with finite difference method by using the Prandtl’s boundary layer assumptions. The velocity components and pressure distributions have been obtained numerically for various values of Bingham number and aspect ratio.