Numerical investigation of double-diffusive mixed convection of Fe3O4/Cu/Al2O3-water nanofluid flow through a backward-facing-step channel subjected to magnetic field
International Journal of Numerical Methods for Heat & Fluid Flow
ISSN: 0961-5539
Article publication date: 8 June 2021
Issue publication date: 20 January 2022
Abstract
Purpose
This study aims to investigate the buoyancy-induced heat and mass transfer phenomena in a backward-facing-step (BFS) channel subjected to applied magnetic field using different types of nanofluid.
Design/methodology/approach
Conservation equations of mass, momentum, energy and concentration are used through velocity-vorticity form of Navier–Stokes equations and solved using Galerkin’s weighted residual finite element method. The density variation is handled by Boussinesq approximation caused by thermo-solutal buoyancy forces evolved at the channel bottom wall having high heat and concentration. Simulations were carried out for the variation of Hartmann number (0 to 100), buoyancy ratio (−10 to +10), three types of water-based nanofluid i.e. Fe3O4, Cu, Al2O3 at χ = 6%, Re = 200 and Ri = 0.1.
Findings
The mutual interaction of magnetic force, inertial force and nature of thermal-solutal buoyancy forces play a significant role in the heat and mass transport phenomena. Results show that the size of the recirculation zone increases at N = 1 for aiding thermo-solutal buoyancy force, whereas the applied magnetic field dampened the fluid-convection process. With an increase in buoyancy ratio, Al2O3 nanoparticle shows a maximum 54% and 67% increase in convective heat and mass transfer, respectively at Ha = 20 followed by Fe3O4 and Cu. However, with increase in Ha the Nuavg and Shavg diminish by maximum 62.33% and 74.56%, respectively, for Fe3O4 nanoparticles at N = 5 followed by Al2O3 and Cu.
Originality/value
This research study numerically examines the sensitivity of Fe3O4, Cu and Al2O3 nanoparticles in a magnetic field for buoyancy-induced mixed convective heat and mass transfer phenomena in a BFS channel, which was not analyzed earlier.
Keywords
Acknowledgements
The institute fellowship provided by the Ministry of Human Resource and Development (MHRD), New Delhi, to the first author to support the PhD work is highly acknowledged. The authors also want to thank the Institute Computer Centre of Indian Institute of Technology Roorkee for providing the required computational facilities to run the simulations.
Declaration of interest statement: The authors declare that there is no conflict of interest.
Citation
Nath, R. and Murugesan, K. (2022), "Numerical investigation of double-diffusive mixed convection of Fe3O4/Cu/Al2O3-water nanofluid flow through a backward-facing-step channel subjected to magnetic field", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 32 No. 3, pp. 889-914. https://doi.org/10.1108/HFF-02-2021-0151
Publisher
:Emerald Publishing Limited
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