Viscous dissipation effect on entropy generation of nanofluid flow in microchannels

Tiew Wei Ting, Yew Mun Hung, Ningqun Guo

Research output: Contribution to conferencePaper

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Abstract

An analytical study of the viscous dissipation effect on entropy generation of forced convection of water-alumina nanofluid in a circular microchannel subjected to exponential wall heat flux is reported. Closed form solutions of the temperature distributions in the streamwise direction for the models with and without viscous dissipation term in the energy equation are obtained. The two models are compared by analyzing their relative deviations in entropy generation for different Reynolds number and nanoparticle volume fraction. The incorporation of viscous dissipation prominently affects the temperature distribution and consequently the entropy generation. The increase in the entropy generation is mainly attributable to the increase in the fluid friction irreversibility. The addition of nanoparticle increases the effective thermal conductivity and viscosity of nanofluid which induces escalation in the heat transfer and fluid friction irreversibilities, respectively. By taking the viscous dissipation effect into account, the exergetic effectiveness for forced convection of nanofluid in microchannels attenuate with increasing nanoparticle volume fraction. From the aspect of the second law of thermodynamics, the widespread conjecture that nanofluids possess advantage over pure fluid associated with higher overall effectiveness is invalidated.

Original languageEnglish
DOIs
Publication statusPublished - 2013
EventASME Micro/Nanoscale Heat and Mass Transfer International Conference (MNHMT) 2013 - Hong Kong, China
Duration: 11 Dec 201314 Dec 2013
Conference number: 4th

Conference

ConferenceASME Micro/Nanoscale Heat and Mass Transfer International Conference (MNHMT) 2013
Abbreviated titleMNHMT 2013
Country/TerritoryChina
CityHong Kong
Period11/12/1314/12/13

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