Steady flow of non-Newtonian fluids: Momentum and heat transfer around a rectangular cylinder

Abstract

This research aims to explore the impact of cross-sectional aspect ratio (AR), power-law index (n), Reynolds number (Re), and Prandtl number (Pr) on convective heat transfer rates using the Nusselt number (Nu) and coefficient of drag (CD) as a key metric. Numerical simulations employ the ANSYS FLUENT solver with the finite volume method. The SIMPLE scheme couples pressure and velocity, and the QUICK differencing scheme discretizes convective terms. This study varies the aspect ratio by adjusting the length-to-width ratio (b/D) to explore different configurations of AR = 1–5 and Pr = 0.7, 1, and 7, which investigate 5 ≤ Re ≤ 10 and 0.2 ≤ n ≤ 1, respectively. An increase in the Reynolds number is observed to diminish the thermal boundary layer thickness, resulting in an escalation of heat transfer rates. Additionally, the Nusselt number exhibits an upward trend with an increase in the Prandtl number. The investigation reveals a decrease in Nu with an increase in both AR and n. Specifically, higher aspect ratios and power-law indices are associated with reduced heat transfer rates. The AR emerges as a significant factor, influencing the coefficient of drag, with CD values showing an increase as AR rises, particularly at low Re. Moreover, CD is found to increase with an elevation in the n value. This study explores new ground by investigating power-law fluid behavior and heat transfer phenomenon across varied aspect ratios. These insights not only enhance the design of heat transfer systems with non-Newtonian fluids but also pave the way for future research in this less explored domain.