CFD ANALYSIS OF NEWTONIAN AND NON-NEWTONIAN FLOW AND HEAT TRANSFER ACROSS A PAIR -OF- S1DE BY-SIDE CYLINDERS

Abstract

Flow and heat transfer of non-Newtonian power-law fluids across a pair of identical circular cylinders in side-by-side arrangement are investigated numerically by solving the continuity, momentum and energy equations along with the appropriate boundary conditions. The numerical calculations are performed in an unconfined computational domain for the following range of physical parameters: Reynolds number, Re = 1 — 40 and power-law index, n = 0.4 — 1.8 (covering shear-thinning, n <1; Newtonian, n =1 and shear-thickening, n > I behaviors) for gap ratio, T/D = 1.5 - 4.0 at a constant ' Prandtl number of 50. The global characteristics such as drag coefficients and average Nusselt number, etc. are calculated and the representative streamline and isotherm contours are presented for the above range of conditions. It has been found that the individual and overall drag coefficients decrease and the average Nusselt number increases with Reynolds number for all T/D and n considered here. The heat transfer is found higher in shear-thinning fluids than Newtonian fluids and followed by shear-thickening fluids for 1.5 <— T / D <— 4.0 and 1 <— Re <40. Keywords: Side-by-side circular cylinders; non-Newtonian fluids; streamlines; isotherms; drag and Nusselt number.