Enhancement of heat transfer and heat exchanger effectiveness in a double pipe heat exchanger filled with porous media: Numerical simulation and sensitivity analysis of turbulent fluid flow

A 2-D numerical simulation and sensitivity analysis are carried out on turbulent heat transfer and heat exchanger effectiveness enhancement in a double pipe heat exchanger filled with porous media. The Darcy-Brinkman-Forchheimer and the k-epsilon turbulent models are employed to achieve heat transfer and heat exchanger effectiveness in the presented model. The sundry parameters Reynolds number (3000 <= Re <= 5000), Darcy number (10(-5) <= Da <= 10(-3)) and the porous substrate thickness (1/3 <= delta <= 1) are studied. It is found that the mean Nusselt number increases by increasing the values of Reynolds number and dwindling of the Darcy number and porous substrate thickness. In addition, the heat exchanger effectiveness enhances with the Re and Da numbers and delta. The sensitivity analysis revealed that to maximize only the mean Nusselt number then it can be achieved for Re = 5000, Da = 10(-5) and delta = 1/3. However, to maximize only the heat exchanger effectiveness then it attains at Re = 5000, Da = 10(-3) and delta = 1. On the other hand, to maximize Nu and E simultaneously, then it can be obtained for Re = 5000, Da = 10(-5) and delta = 1. (C) 2016 Elsevier Ltd. All rights reserved.