Laminar non-Newtonian flows in eccentric annuli with inner cylinder rotation [electronic resource] /
Abstract (Summary)The hydrodynamic characteristics of fully developed axial laminar flow of non-Newtonian fluids in eccentric annuli with a rotating inner cylinder are investigated. The non-Newtonian, shear-thinning fluid is modeled by the Power-law or Ostwald-de Waele constitutive relationship. Using finite-difference method to solve the governing flow equations in bipolar coordinates, computational results for a wide range of annulus geometry (0.2 <= r* <= 0.8, 0 <=E* <= 0.8), rotational Reynolds number (0 <= Re r <= 150) and flow behavior index(0.4 <= n <= 1) are presented. The rotational speeds considered in this study are restricted to the sub-critical Taylor number regime. The results delineate the effects of annuli r* and E*, and inner cylinder rotation speed on the flow structure and frictional losses. Velocity distributions in the flow cross-section and the variation in friction factors (f Re) for fully developed flows in different eccentric annuli flow index are presented. Here, the non-linear shear behavior of the fluid is found to further aggravate the flow maldistribution, and once again the eccentricity is seen to exhibit a very strong influence on the friction behavior. These results are of significant importance to the design and operation of oil and gas drilling wells.
School:University of Cincinnati
School Location:USA - Ohio
Source Type:Master's Thesis
Date of Publication: