Combined effects of corrugated walls and porous inserts on performance improvement in a heat exchanger channel

Abstract

In this paper, a numerical study is performed to investigate the combined effects of corrugated walls and porous inserts on heat transfer enhancement and thermal-hydraulic performance in a channel. Accordingly, a sinusoidal wavy wall channel partially filled with a porous material placed at its core is considered. The Darcy-Brinkman-Forchheimehr model is considered to study the flow in porous region and finite volume method (FVM) with SIMPLE algorithm are applied to solve the governing equations. It was found that the amplitude of the wavy wall has a considerable effect on average Nusselt number especially at small Darcy numbers. For example, at Re = 300, δ=0.3, α=0.2 and Da=10−2 the average Nusselt number of wavy channel increases about 12% in comparison with the straight one, while it improves about 38% at Da=10−4. Moreover, there is an optimum value of Darcy number corresponding to maximum performance evaluation criteria (PEC). At δ=0.3 and Re=300, for straight channel and wavy channel with α=0.1 the optimum value of Darcy number occurs at Da=10−3, while for α=0.2 and 0.3 the Da=10−4 leads to the maximum PEC.