Unconfined laminar nanofluid flow and heat transfer around a square cylinder

• Published in: International journal of heat and mass transfer Vol. 55; no. 5; pp. 1475 - 1485
• Main Authors: Etminan-Farooji, Vahid, Ebrahimnia-Bajestan, Ehsan, Niazmand, Hamid, Wongwises, Somchai
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2012; Elsevier
• Subjects: Applied sciences; Chemistry; Colloidal state and disperse state; COMPOSITES; Computational fluid dynamics; Condensed matter: structure, mechanical and thermal properties; COPPER OXIDE; Cylinders; ELECTRICAL CONDUCTIVITY; Energy; Energy. Thermal use of fuels; Exact sciences and technology; FLUID FLOW; FLUIDITY; Fluids; General and physical chemistry; Heat transfer; Heat transfer enhancement; MICROSTRUCTURES; Nanocomposites; Nanofluid; Nanofluids; Nanomaterials; Nanostructure; Peclet number; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Physics; Square cylinder; Theoretical studies. Data and constants. Metering; Thermal properties of condensed matter; Thermal properties of small particles, nanocrystals, nanotubes; Thermophysical properties; Unconfined flow; Heat transfer enhancement; Peclet number; Nanofluid; Thermophysical properties; Unconfined flow; Square cylinder; Water; Aluminium oxide; Ethylene glycol; Forced convection; Nanoparticle; Steady flow; Modeling; Cylinder; Laminar flow; Numerical simulation; Copper oxide; Square section; Heat transfer
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2011.10.030

The momentum and forced convection heat transfer for a laminar and steady free stream flow of nanofluids past an isolated square cylinder have been studied numerically. Different nanofluids consisting of Al 2O 3 and CuO with base fluids of water and a 60:40 (by mass) ethylene glycol and water mixture were selected to evaluate their superiority over conventional fluids. Recent correlations for the thermal conductivity and viscosity of nanofluids, which are functions of particle volumetric concentration as well as temperature, have been employed in this paper. The simulations have been conducted for Pe = 25, 50, 100 and 200, with nanoparticle diameters of 30 and 100 nm and particle volumetric concentrations ranging from 0% to 4%. The results of heat transfer characteristics of nanofluid flow over a square cylinder showed marked improvement comparing with the base fluids. This improvement is more evident in flows with higher Peclet numbers and higher particle volume concentration, while the particle diameter imposes an adverse effect on the heat transfer characteristics. In addition, it was shown that for any given particle diameter there is an optimum value of particle concentration that results in the highest heat transfer coefficient.