## THERMAL SCIENCE

International Scientific Journal

### CONDUCTION AND CONVECTION HEAT TRANSFER CHARACTERISTICS OF WATER-BASED AU NANOFLUIDS IN A SQUARE CAVITY WITH DIFFERENTIALLY HEATED SIDE WALLS SUBJECTED TO CONSTANT TEMPERATURES

**ABSTRACT**

The present work deals with the natural convection in a square cavity filled with the water-based Au nanofluid. The cavity is heated on the vertical and cooled from the adjacent wall, while the other two horizontal walls are adiabatic. The governing differential equations have been solved by the standard finite volume method and the hydrodynamic and thermal fields were coupled together using the Boussinesq approximation. The main objective of this study is to investigate the influence of the nanoparticles’ volume fraction on the heat transfer characteristics of Au nanofluids at the given base fluid’s (i.e. water) Rayleigh number. Accurate results are presented over a wide range of the base fluid Rayleigh number and the volume fraction of Au nanoparticles. It is shown that adding nanoparticles in a base fluid delays the onset of convection. Contrary to what is argued by many authors, we show by numerical simulations that the use of nanofluids can reduce the heat transfer rate instead of increasing it.

**KEYWORDS**

PAPER SUBMITTED: 2013-06-04

PAPER REVISED: 2013-06-05

PAPER ACCEPTED: 2013-06-08

PUBLISHED ONLINE: 2013-06-16

**THERMAL SCIENCE** YEAR

**2014**, VOLUME

**18**, ISSUE

**Supplement 1**, PAGES [S189 - S200]

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