a b s t r a c tA numerical analysis using Ansys Fluent was carried out to investigate the forced convection of powerlaw fluids (power-law index varying from 0.2 to 1.8) around a heated semi-circular cylinder with wall confinement (or blockage ratio) of 25%, Prandtl number of 50, and Reynolds numbers 1-40. Flow and thermal fields were found to be steady for Re up to 40. The shear-thickening behavior was found to have a higher value of drag coefficient, whereas the shear-thinning behavior had a smaller value of drag coefficient when compared with Newtonian fluids in the steady regime. The wake size was found shorter in shear-thickening fluids than Newtonian and shear-thinning fluids. An overall heat transfer rate was calculated and found to increase with the rise in Reynolds number. The average Nusselt numbers were observed higher for shear-thinning fluids than Newtonian and shear-thickening fluids; and the maximum enhancement in the heat transfer was achieved approximately 47% as compared to Newtonian fluids. The present results have also been correlated in terms of wake length, drag coefficient and average Nusselt number expressions for various Reynolds numbers and power-law indices studied. In addition, the effects of blockage ratios ranging from 16.67% to 50% on the engineering output parameters with varying powerlaw index at Re = 40 were reported.
Flow and heat transfer characteristics around a semi-circular cylinder placed in a confined channel are 29 investigated in the unsteady regime. The two-dimensional simulations are carried out for varying values 30 of control parameters: Reynolds number (Re) = 50-200 and Prandtl number (Pr) = 0.7, 10 and 100 at a 31 fixed blockage ratio of 25% for Newtonian constant-property fluid. Continuity, Navier-Stokes and energy 32 equations with appropriate boundary conditions are solved using the commercial computational fluid 33 dynamics solver Ansys Fluent. The transition from steady to time-periodic flow occurs between 34 Re = 69 and 70. The effect of Prandtl number on Nusselt number is pronounced; the ratio of Nusselt num-35 ber values belonging to Pr = 100 and those belonging to Pr = 0.7 ranges from 6.3 to 6.5 over the Reynolds 36 number domain investigated. Finally, the present numerical results are used to develop drag coefficient, 37 Strouhal number and Nusselt number correlations.
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