Determination of critical thickness of porous layer for passive heat transfer enhancement for flow over 2-D cylinder

Abstract

This study focuses on flow and heat transfer around a circular cylinder having porous surface. The Reynolds number (Re) is constant at Re = 100 and Darcy number (Da) is varied from 10– 6 to 10– 2 for porous layer thickness d = 0.2 R − 0.5 R . While various parametric studies have been carried out to study this geometry, no study has provided a critical thickness of porous layer for the range of (Da) studied herein. The specific focus of the parametric nature of the study is novel in that it approaches the problem from the perspective of flow and heat transfer variables to determine the critical thickness of porous layer, as opposed to viewing it as a whole. This differs from previous studies in that the problem is fundamentally limited to this simplistic system without adding many interconnected variables that will further increase complexity. The dependency of flow and heat transfer modification on various physical parameters such as the porous layer thickness, upstream and downstream lengths is investigated in detail, and a critical thickness (which optimizes the fluid flow and heat transfer characteristics) h = 0.5 R is determined. Finally, the heat transfer characteristics are analyzed to study the heat transfer behavior of the porous layer, and to determine the critical thickness of porous layer for efficient heat transfer.