ABSTRACT:
This paper expounds the effect of horizontal spacing between two horizontally aligned circular cylinders on laminar natural convection to non-Newtonian power-law fluids. Numerical computations have been carried out for the following range of conditions: Grashof number (10 to 105), Prandtl number (0.71 to 100), horizontal spacing (0 to 20 times the cylinder diameter), and power-law index (0.4 to 1.6). The flow, pressure, and thermal fields are pictorially visualized in terms of streamlines, pressure contours, and temperature contours, respectively. The average Nusselt number shows a positive reliance on both Grashof and Prandtl numbers, whereas an adverse dependence is observed on power-law index. Irrespective of all other parameters, shear-thinning fluid behavior is seen to promote the convection, whereas shear-thickening behavior impedes it with reference to the Newtonian fluid. With decrease in the horizontal spacing, the average Nusselt number increases and attains a maximum value corresponding to the optimal spacing, however, it diminishes greatly with further reduction in spacing. Furthermore, the average Nusselt number is in excess of 21-89% at the optimal spacing compared to no-spacing. Finally, this paper is concluded with producing a new correlation for the average Nusselt number.
