Natural convection in a rectangular cavity filled with nanofluids: Effect of variable viscosity

Abstract

Purpose

This paper aims to develop a numerical study of the steady natural convection in a rectangular cavity filled with the CuO–water-based nanofluid. It is assumed that the viscosity of nanofluids depends on the temperature and on the nanofluids volume fraction.

Design/methodology/approach

The mathematical nanofluid model has been formulated on the basis of the model proposed by Buongiorno (2006). The system of partial differential equations is written in terms of a dimensionless stream function, vorticity, temperature and the volume fraction of the nanoparticles, and is solved numerically using the finite difference method for different values of the governing parameters.

Findings

It is found that both fluid flow and heat transfer coefficient are affected by the considered parameters. Thus, the Nusselt number is slowly increasing with increasing volume fraction from 2 per cent to 5 per cent and it is more pronounced increasing with increasing Rayleigh number from 10³ to 10⁵.

Originality/value

Buongiorno’s (2006) nanofluid model has been applied for the flow with the characteristics as mentioned in the paper. A comprehensive survey on the behavior of flow and heat transfer characteristics has been presented. All plots presented in the paper are new and are not reported in any other study.

Citation

Revnic, C., Abu-Nada, E., Grosan, T. and Pop, I. (2018), "Natural convection in a rectangular cavity filled with nanofluids: Effect of variable viscosity", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 28 No. 6, pp. 1410-1432. https://doi.org/10.1108/HFF-06-2017-0244