Numerical study of fluid dynamic and heat transfer performance of Al sub(2)O sub(3) and CuO nanofluids in the flat tubes of a radiator

A three-dimensional laminar flow and heat transfer with two different nanofluids, Al sub(2)O sub(3) and CuO, in an ethylene glycol and water mixture circulating through the flat tubes of an automobile radiator have been numerically studied to evaluate their superiority over the base fluid. New corre...

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Bibliographic Details
Published in:The International journal of heat and fluid flow 2010-08, Vol.31 (4), p.613-621
Main Authors: Vajjha, Ravikanth S, Das, Debendra K, Namburu, Praveen K
Format: Article
Language:English
Subjects:
ALUMINUM OXIDE
COMPOSITES
Computational fluid dynamics
COPPER OXIDE
FLUID FLOW
FLUIDITY
Heat transfer
LAMINAR FLOW
MATHEMATICAL ANALYSIS
Mathematical models
MICROSTRUCTURES
Nanocomposites
Nanofluids
Nanomaterials
Nanostructure
TUBE
Tubes
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Summary:A three-dimensional laminar flow and heat transfer with two different nanofluids, Al sub(2)O sub(3) and CuO, in an ethylene glycol and water mixture circulating through the flat tubes of an automobile radiator have been numerically studied to evaluate their superiority over the base fluid. New correlations for viscosity and thermal conductivity of nanofluids as a function of particle volumetric concentration and temperature developed from the experiments have been used in this paper. Numerical results from the present simulation were first validated for the flow of water by comparing the friction factor and the Nusselt number in flat tubes, for which accurate results are available in the literature. Next, the model was applied to study the peripheral variations of shear stress and convective heat transfer coefficient, both showing higher magnitudes in the flat regions of the tube. Convective heat transfer coefficient in the developing and developed regions along the flat tubes with the nanofluid flow showed marked improvement over the base fluid. Results for the local and the average friction factor and convective heat transfer coefficient show an increase with increasing particle volumetric concentration of the nanofluids. Quantitative results of the increase of the heat transfer coefficient and the friction factor with increasing volumetric concentrations of nanofluids at various Reynolds numbers are presented. The pressure loss increases with increasing particle volumetric concentrations of nanofluids; however, due to the reduced volumetric flow needed for the same amount of heat transfer, the required pumping power diminishes.
ISSN:0142-727X
DOI:10.1016/j.ijheatfluidflow.2010.02.016