Primož Ternik (Author), Rebeka Rudolf (Author), Zoran Žunič (Author)

Abstract

The present work deals with the natural convection in a square cavity filled with a water-based Au nanofluid. The cavity is heated from the lower and cooled from the adjacent wall, while the other two walls are adiabatic. Theg overning differential equations have been solved with the standard finite volume method and the hydrodynamic and thermal fields have been coupled using the Boussinesq approximation. The main objective of this study is to investigate the influence of the nanoparticlesć volume fraction on the heat-transfer characteristics of Au nanofluids at a given base-fluid (i.e., water) Rayleigh number Rabf. Accurate results are presented over a wide range of the base-fluid Rayleigh numbers (102 £ Rabf £ 105) and the volume fraction of Au nanoparticles (0 % £ j £ 10 %). It is shown that adding nanoparticles to the base fluid delays the onset of convection. Contrary to what is argued by many authors, we show, with numerical simulations, that the use of nanofluids can reduce the heat transfer instead of increasing it.

Keywords

Rayleigh-Bénard natural convection;water-Au nanofluid;heat transfer;numerical modelling;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UM FS - Faculty of Mechanical Engineering
Publisher: Inštitut za kovinske materiale in tehnologije Ljubljana
UDC: 519.61/.64:620.3:536.2
COBISS: 16819990 Link will open in a new window
ISSN: 1580-2949
Parent publication: Materiali in tehnologije
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Other data

Secondary language: Slovenian
Secondary title: Numerična analiza prenosa toplote nanotekočin voda-Au v razmerah Reyleigh-Bénardove naravne konvekcije
Secondary abstract: V prispeveku obravnavamo naravno konvekcijo v kvadratni kotanji, napolnjeni z nanotekočino voda-Au. Kotanja je bila greta s spodnje in hlajena s priležne zgornje stene, preostali dve steni sta bili adiabatni. Vodilne diferencialne enačbe smo reševali s standardno metodo končnih prostornin. Hidrodinamično in temperaturno polje sta bila sklopljena z uporabo Boussinesqove aproksimacije. Glavni cilj prispevka je raziskati vpliv prostorninskega deleža nanodelcev na značilnosti prenosa toplote Au-nanotekočine pri podani vrednosti Rayleighjevega števila nosilne tekočine (vode) Rabf. Natančni rezultati so predstavljeni za široko območje vrednosti Rayleighjevega števila nosilne tekočine (102 £ Rabf £ 105) in prostorninskega deleža Au-nanodelcev (0 % £ j £10 %). Pokazali smo, da dodajanje nanodelcev v nosilno tekočino zakasni začetek naravne konvekcije. V nasprotju s trditvami mnogih avtorjev smo z numeričnimi simulacijami pokazali, da lahko uporaba nanodelcev prenos toplote zmanjša in ne poveča.
Secondary keywords: Rayleigh-Bénardova naravna konvekcija;nanotekočina voda-Au;prenos toplote;numerično modeliranje;
URN: URN:NBN:SI
Type (COBISS): Scientific work
Pages: str. 211-215
Volume: ǂLetn. ǂ47
Issue: ǂšt. ǂ2
Chronology: mar.-apr. 2013
ID: 1439440