The Influence of magnetic field on heat transfer of magnetic nanofluid in a sinusoidal double pipe heat exchanger

In this article, the effect of magnetic field on the Nanofluid flow inside a sinusoidal two-tube heat exchanger is investigated numerically. This study focuses on the influence of variable magnetic field in the heat transfer of heat exchanger while mixture is single phase. In this heat exchanger, the inner tube is sinusoidal and the outer tube is considered smooth. The magnetic field is established orthogonal to sinusoidal tube. The basis fluid is water with 4 vol.% Nano particles (Fe3O4). In our study, Ferrofluid flows in the internal tube (sinusoidal tube) as hot fluid and air flows counter currently as cold fluid in external tube. The finite volume method with the SIMPLEC algorithm is used for handling the pressure-velocity coupling. The numerical results present validated data with experimentally measured data and show good agreement with measurement. The influence of the variation of different parameters like geometric shape, intensity of magnetic field non-dimensional number and Reynolds number, on heat transfer is investigated. According to obtained results, sinusoidal formation of the internal tube significantly increases the Nusselt number inside a two-tube heat exchanger. Also, magnetic field enhances diffusion of the cold boundary layer to the central parts of the inner tube for various geometric shape coefficients. Our findings show that the diffusion also elevates as the intensity of the magnetic field is increased. So, Nusselt number and heat transfer increase and this augmentation intensifies in high Reynolds number. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.