Heat transfer and entropy generation of the nanofluid flow inside sinusoidal wavy channels

Corrugating channel walls is a way to enhance heat transfer in heat exchangers. In the current investigation, the entropy generation minimization approach has been employed to optimize heat transfer and fluid flow within a wavy channel. A numerical method has been built to compute entropy generation rate in a sinusoidal wavy-wall channel with copper-water (Cu-water) nanofluid flow. The governing equations have been discretized using finite volume method for a two-dimensional steady flow. The effects of geometrical and flow parameters, including nanoparticles volume fraction (0.01 < phi < 0.05), Richardson number (0.1 < Ri < 10), wave amplitude ratio (0.1 < 03) and wave length ratio (1 < lambda <3), have been investigated. Results reveal that increasing nano particle volume fraction within investigated Richardson number will increase Nusselt number. In addition, the maximum entropy generation rate declines as Richarson number increases. The optimal wave amplitude ratio (corresponding to lowest entropy generation), for wave length ratios of lambda = 1 and lambda = 2, found to be alpha = 0.2. Also, for wave length ratio of lambda = 3, the minimum entropy generation approximately occurs at alpha = 0.1. (C) 2018 Elsevier B.V. All rights reserved.