Nanofluids flow in microchannels in presence of heat source/sink and asymmetric heating

A. Malvandi*, S. A. Moshizi, D. D. Ganji

*Corresponding author for this work

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The effect of thermal asymmetry on forced convection of alumina/water nanofluid in a parallel-plate microchannel in the presence of heat source/sink is theoretically investigated.Walls are subjected to different heat fluxes, q′′wt for the top wall and q′′wb for the bottom wall, and nanoparticles are assumed to have a slip velocity relative to the base fluids induced by Brownian motion and thermophoresis. Because of low-dimensional structures in microchannels, a linear slip condition is considered at the surfaces, which appropriately represents the nonequilibrium region near the interface. Considering hydrodynamically and thermally fully developed flow, the basic partial differential equations including the continuity, momentum, energy, and nanoparticle fraction have been reduced to two-point ordinary boundary value differential equations before they have been solved numerically. It is shown that nanoparticles eject themselves from the heated walls, construct a depleted region, and accumulate in the core region, but they are more likely to accumulate near the wall with the lower heat flux. In addition, the imposed thermal asymmetry would change the direction of nanoparticle migration, and it distorts the symmetry of the velocity, temperature and nanoparticle concentration profiles. Moreover, one-sided heating leads to a best heat transfer rate for larger nanoparticles but with a penalty of a very high-pressure drop. In contrast, for the smaller nanoparticles, asymmetric heating leads to a better heat transfer rate and a reasonable increase in the pressure drop. Also, the performance of the system is increased in the presence of heat absorption, since it enhances the heat transfer rate with no significant change in the pressure drop.

Original languageEnglish
Pages (from-to)111-119
Number of pages9
JournalJournal of Thermophysics and Heat Transfer
Volume30
Issue number1
DOIs
Publication statusPublished - Jan 2016
Externally publishedYes

Fingerprint Dive into the research topics of 'Nanofluids flow in microchannels in presence of heat source/sink and asymmetric heating'. Together they form a unique fingerprint.

Cite this