MOMENTUM AND HEAT TRANSFER PHENOMENA OF POWER-LAW DILATANT FLUIDS AROUND AN ASYMMETRICALLY CONFINED CYLINDER

Abstract

The kinematic flow behavior of the power-law dilatant fluids across an asymmetrically confined (heated) circular cylinder between two rectilinear parallel walls is different from that of its symmetrical orientation due to the change of interaction between the wall boundary layer and the wake at the rear part of the obstacle. The present study numerically investigates the flow across an asymmetrically confined cylinder in a channel for fluids obeying Ostwald-de Wale (Power-law) equation for the settings: power-law index, 1  n  1.8 ; Reynolds number, 1 ≤ Re ≤ 40 ; gap ratio, 0.375 ≤ γ ≤ 1 ; blockage ratio (β) = 0.2-0.34 and heat transfer characteristics developed at Prandtl numbers (Pr) =1-50. The total drag coefficient and its individual components (friction and pressure drag coefficients) have been analyzed as a function of Re,  , γ and n. The overall drag coefficient was found to increase with blockage and behavior of fluid, while it drops gradually for increasing Re. The asymmetric configuration is seen to mitigate the overall as well as individual drag coefficients. The surface heat transfer coefficient in the form of Nusselt number and Colburn jh factor as a function of above physical parameters has been thoroughly discussed. Heat transfer is found to increase with the increasing Re and wall confinement, while the increasing dilatant behavior impedes the same. As expected, heat transfer results have been reconciled in a single curve in Colburn jh factor for a range of Re, β,γ,n and Pr.