Effect of MHD on the flow and heat transfer characteristics of nanofluid in a grooved channel with internal heat generation

Abstract

Purpose

The purpose of this study is numerical simulation of magnetohydrodynamics (MHD) water–Al₂O₃ nanofluid mixed convection in a grooved channel with internal heat generation in solid cylinders. Simulations were carried out at Reynolds numbers 50 ≤ Re ≤ 100, Hartmann numbers 0 ≤ Ha ≤ 15, Grashof numbers 5,000 ≤ Gr ≤ 10⁻⁴ and volume fraction 0 ≤ φ ≤ 0.04. The effect of Reynolds number and the influence of magnetic field and pressure drop on convective heat transfer coefficient were studied in different volume fractions of nanoparticles at different Reynolds numbers.

Design/methodology/approach

The results show that average Nusselt number increases by increasing Reynolds and Hartman numbers. Also, when Hartman number increases, velocity profile becomes asymmetric. Pressure distribution shows that magnetic field applies Lorentz force at opposite direction of the flow, which causes asymmetric distribution of pressure. As a result, pressure in the upper half of the cylinder is higher than the lower half. Finally, velocity and temperature contours along the channel for different Hartmann numbers, volume fraction 3 per cent, Re = 50 and 100 and Gr = 10,000, are presented.

Findings

The effect of Reynolds number and the influence of magnetic field and pressure drop on convective heat transfer coefficient were studied in different volume fractions of nanoparticles at different Reynolds numbers.

Originality/value

Effect of MHD on the flow and heat transfer characteristics of Water–Al₂O₃ nanofluid in a grooved channel with internal heat generation in solid cylinders.

Citation

Dehghani, M.S., Toghraie, D. and Mehmandoust, B. (2019), "Effect of MHD on the flow and heat transfer characteristics of nanofluid in a grooved channel with internal heat generation", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 29 No. 4, pp. 1403-1431. https://doi.org/10.1108/HFF-05-2018-0235