Analysis of Yield-Power-Law Fluid Flow in Irregular Eccentric Annuli

Abstract

Fully developed laminar axial flow of yield-power-law fluids in eccentric annuli has been investigated numerically. The annuli may be fully open or partially blocked. General nonorthogonal, boundary-fitted curvilinear coordinates have been used to accurately model the irregular annular geometry due to the presence of a flow blockage. A computer code has been developed using a second-order finite-difference scheme. An exponential model for the shear stress, valid for both yielded and un-yielded regions of the flow, is used in the computation. The effects of pressure gradient, eccentricity, and blockage height on the flow rate have been studied and the results are presented. The flow rate is found to increase with increasing eccentricity for eccentric annuli without any blockage. For partially blocked eccentric annuli, the flow rate at a particular eccentricity decreases as the blockage height is increased.