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Computational Thermal Sciences: An International Journal
ESCI SJR: 0.249 SNIP: 0.434 CiteScore™: 0.7

ISSN Imprimir: 1940-2503
ISSN En Línea: 1940-2554

Computational Thermal Sciences: An International Journal

DOI: 10.1615/ComputThermalScien.2016013798
pages 193-208


K. Sunil Arjun
Department of Mechanical Engineering, Indian School of Mines, Dhanbad-826004, India
K. Rakesh
Department of Mechanical Engineering, Indian School of Mines, Dhanbad-826004, India


Water and its nanofluids with alumina (Al2O3) are used as the coolant fluid in a circular microchannel heat exchanger to justify the utility of a nanomaterial as a heat transfer enhancer using ANSYS Fluent 15.0. The 2D axis symmetric geometry with structured mesh and 100×18 nodes are used for single-phase flow with Al2O3 nanoparticles of 23 nm average diameter. Viscous laminar and standard k−ε models are used to predict the steady temperature in laminar and turbulent zones. The simulated heat transfer coefficient values in both laminar and turbulent zones have been compared with the published experimental values and very close agreement is observed statistically. Nanofluids increase the heat transfer coefficient by 15% and 12% in comparison to its base fluids in laminar and turbulent zones, respectively. The relation between heat transfer coefficient and thermal conductivity of nanofluids is proved. The entrance length for fully developed velocities and the increase in temperature depend on Re, with the latter also depending on Pe, but the temperature distribution is found to be independent of radial position even for very low Pe. The velocity contours at the outlet show that the wall effect penetrates more towards the center and the thickness of the zone with maximum velocity shrinks with increase in Re. With increase in Re, the temperature decreases and pressure drop increases. The velocity and wall and nanofluid temperatures calculated can also well predict the experimental data. The effect of Re, Pe, nanofluid concentrations, velocity, pressure, and temperature contours on the flow behavior of the microchannels was analyzed in laminar and turbulent cases.