A two-phase model based on the double-diffusive approach is used to perform a numerical study on natural convection of water-based nanofluids in differentially- heated horizontal semi-annuli, assuming that Brownian diffusion and thermophoresis are the only slip mechanisms by which the solid phase can develop a significant relative velocity with respect to the liquid phase. The system of the governing equations of continuity, momentum, and energy for the nanofluid, and continuity for the nanoparticles, is solved by the way of a computational code which incorporates three empirical correlations for the evaluation of the effective thermal conductivity, the effective dynamic viscosity, and the thermophoretic diffusion coefficient, all based on a wide number of literature experimental data. The pressure-velocity coupling is handled through the SIMPLE-C algorithm. Numerical simulations are executed for three different nanofluids, using the diameter and the average volume fraction of the suspended nanoparticles, the cavity size, the average temperature, and the temperature difference imposed across the cavity, as independent variables. It is found that the impact of the nanoparticle dispersion into the base liquid increases remarkably with increasing the average temperature, whereas, by contrast, the other controlling parameters have moderate effects. Moreover, at temperatures of the order of room temperature or just higher, the heat transfer performance of the nanofluid is significantly affected by the choice of the solid phase material.

Buoyancy-induced convection of water-based nanofluids in differentially-heated horizontal Semi-Annuli / Quintino, Alessandro; Ricci, Elisa; Habib, Emanuele; Corcione, Massimo. - In: THERMAL SCIENCE. - ISSN 0354-9836. - STAMPA. - 21:6(2017), pp. 2643-2660. [10.2298/TSCI170119136Q]

Buoyancy-induced convection of water-based nanofluids in differentially-heated horizontal Semi-Annuli

Quintino, Alessandro;Ricci, Elisa;Habib, Emanuele;Corcione, Massimo
2017

Abstract

A two-phase model based on the double-diffusive approach is used to perform a numerical study on natural convection of water-based nanofluids in differentially- heated horizontal semi-annuli, assuming that Brownian diffusion and thermophoresis are the only slip mechanisms by which the solid phase can develop a significant relative velocity with respect to the liquid phase. The system of the governing equations of continuity, momentum, and energy for the nanofluid, and continuity for the nanoparticles, is solved by the way of a computational code which incorporates three empirical correlations for the evaluation of the effective thermal conductivity, the effective dynamic viscosity, and the thermophoretic diffusion coefficient, all based on a wide number of literature experimental data. The pressure-velocity coupling is handled through the SIMPLE-C algorithm. Numerical simulations are executed for three different nanofluids, using the diameter and the average volume fraction of the suspended nanoparticles, the cavity size, the average temperature, and the temperature difference imposed across the cavity, as independent variables. It is found that the impact of the nanoparticle dispersion into the base liquid increases remarkably with increasing the average temperature, whereas, by contrast, the other controlling parameters have moderate effects. Moreover, at temperatures of the order of room temperature or just higher, the heat transfer performance of the nanofluid is significantly affected by the choice of the solid phase material.
2017
Enhanced heat transfer; Horizontal semi-annuli; Nanofluid; Natural convection; Two-phase approach; Renewable Energy, Sustainability and the Environment
01 Pubblicazione su rivista::01a Articolo in rivista
Buoyancy-induced convection of water-based nanofluids in differentially-heated horizontal Semi-Annuli / Quintino, Alessandro; Ricci, Elisa; Habib, Emanuele; Corcione, Massimo. - In: THERMAL SCIENCE. - ISSN 0354-9836. - STAMPA. - 21:6(2017), pp. 2643-2660. [10.2298/TSCI170119136Q]
File allegati a questo prodotto
File Dimensione Formato  
Quintino_buoyancy-induced_2017.pdf

accesso aperto

Tipologia: Versione editoriale (versione pubblicata con il layout dell'editore)
Licenza: Creative commons
Dimensione 964.56 kB
Formato Adobe PDF
964.56 kB Adobe PDF

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1081334
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 1
  • ???jsp.display-item.citation.isi??? 1
social impact