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

Abstract

The present work deals with the laminar natural convection in a cubical cavity filled with a homogenous aqueous solution of carboxymethyl cellulose (CMC) based gold (Au) nanofluid obeying the power-law rheological model. The cavity is heated on the vertical and cooled from the adjacent wall, while the other walls are adiabatic. The governing differential equations were solved with the standard finite-volume method and the hydrodynamic and thermal fields are coupled using the Boussinesq approximation. The main objective of this study is to investigate the influence of the nanoparticle volume fraction on the heat-transfer characteristics of CMC-based Au nanofluid over a wide range of the base-fluid Rayleigh number. Accurate numerical results are presented in the form of dimensionless temperature and velocity variations, the mean Nusselt number and the heat-transfer rate. It is shown that adding nanoparticles to the base fluid delays the onset of natural convection. In addition, numerical simulations showed that, just after the onset of natural convection, adding nanoparticles reduces the mean Nusselt number value for any given base-fluid Rayleigh number.

Keywords

natural convection;CMC-Au nanofluid;heat transfer;Nusslet number;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UM FS - Faculty of Mechanical Engineering
UDC: 519.61/.64:536.2:620.3
COBISS: 18404374 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: Značilnosti prenosa toplote nenewtonske Au nanotekočine v kockastem ohišju z različno gretima stranskima stenama
Secondary abstract: Prispevek obravnava naravno konvekcijo v kockastem ohišju, napolnjenem s homogeno nanotekočino karboksimetil celuloza (CMC)-zlato (Au), z reološkim vedenjem, opisanim s potenčnim zakonom. Ohišje je greto na navpični in hlajeno na priležni steni, medtem ko so druge stene adiabatne. Vodilne diferencialne enačbe so bile rešene s standardno metodo končnih prostornin, pri čemer sta hidrodinamično in temperaturno polje sklopljena z Boussinesqovo aproksimacijo. Glavni cilj prispevka je raziskati vpliv prostorninskega deleža nanodelcev na značilnosti prenosa toplote CMC-Au nanotekočine za široko območje vrednosti Rayleighjevega števila nosilne tekočine. Natančni rezultati so predstavljeni v obliki spreminjanja brezdimenzijske temperature in hitrosti, srednje vrednosti Nusseltovega števila in hitrosti prenosa toplote. Pokazano je, da dodajanje nanodelcev v nosilno tekočino zakasni začetek naravne konvekcije. Poleg tega so numerične simulacije pokazale, da takoj za pojavom naravne konvekcije dodajanje nanodelcev zmanjšuje srednjo vrednost Nusseltovega števila za katero koli vrednost Rayleighjevega števila nosilne tekočine.
Secondary keywords: naravna konvekcija;nanotekočina CMC-Au;prenos toplote;Nusseltovo število;
URN: URN:NBN:SI
Type (COBISS): Scientific work
Pages: str. 87-93
Volume: ǂLetn. ǂ49
Issue: ǂšt. ǂ1
Chronology: 2015
ID: 9591578