Analysis of hydrothermal performance for laminar forced convective flow through a wavy channel with porous blocks

Abstract

Purpose The purpose of this paper is to investigate computationally the hydrothermal characteristics for forced convective laminar flow of water through a channel with a top wavy wall and a flat bottom wall having metallic porous blocks. Design/methodology/approach The governing equations are solved computationally using a finite element method–based numerical solver COMSOL Multiphysics® for the following range of parameters: 10 ≤ Reynolds number (Re) ≤ 500 and 10–4 ≤ Darcy number (Da) ≤ 10–1. Findings The presence of porous blocks significantly influences the heat transfer rate, and the value of local Nusselt number increases with the increase in Da. The value of the average Nusselt number decreases with Da for the top wall and the same is enhanced for the bottom wall of the wavy channel with porous blocks (WCPB). The value of the average Nusselt number for WCPB is significantly higher than that of the wavy channel without porous block (WCWPB), plane channel without porous block (PCWPB) and plane channel with the porous block (PCPB) at higher Re. For PCPB, the performance factor (PF) is always higher than that of WCWPB and WCPB for Da = 10–4 and Da = 10–3. Also, PF for WCPB is higher than that of WCWPB for higher Re except for Da = 10–4. Further, the value of for WCPB is higher than that of PCPB at Da = 10–2 and 10–1 at Re = 500. Practical implications The current study is useful in designing efficient heat exchangers for process plants, solar collectors and aerospace applications. Originality/value The analysis of thermo-hydraulic characteristics for laminar flow through a channel with a top wavy wall and a flat bottom wall having metallic porous blocks have been analyzed for the first time. Further, a comparative assessment of the performance has been performed with a wavy channel without a porous block, a plane channel without a porous block and a plane channel with porous blocks.