Mixed Convection Heat Transfer from a Heated Square Cylinder Immersed in Upward Flow of Power-Law Fluids

Abstract

This paper examines the effects of thermal buoyancy on momentum and heat transfer characteristics of confined square cylinder submerged in incompressible power-law fluid. The detailed flow and temperature fields are visualized in terms of streamlines and isotherm contours. The numerical results have been presented and discussed for the range of conditions as (10 ≤Re≤ 40), Richardson number (0 ≤Ri≤ 1), and power-law index (0.4 ≤n≤ 1.2) at Prandtl numberPr= 50, at fixed value of blockage ratioβ= 25%. The results showed that the augmentation of the power-law index in the absence of thermal buoyancy causes a separation to diminish for the valueRe= 40. The thermal buoyancy delays the flow separation in different power-law indexes gradually and at some critical value of the buoyancy parameter it completely disappears resulting a creeping flow around a cylinder. Moreover, the recirculation length and skin friction are calculated to support the above finding. The decrease in the power-Law index promotes the heat transfer rate. The Nusselt numbers are computed to predict the heat transfer rates of power-law fluids under the superimposed thermal buoyancy condition.