Numerical study of laminar mixed convection of a nanofluid in horizontal curved tubes

• Published in: Applied thermal engineering Vol. 27; no. 8; pp. 1327 - 1337
• Main Authors: Akbarinia, A., Behzadmehr, A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.2007; Elsevier
• Subjects: Applied sciences; Buoyancy force; Centrifugal force; Curved tube; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat transfer; Mixed convection; Nanofluid; Theoretical studies. Data and constants. Metering; Centrifugal force; Mixed convection; Curved tube; Nanofluid; Buoyancy force; Nusselt number; Hydrodynamics; Combined convection; Numerical analysis; Flow velocity; Horizontal tube; Alumina; Heat transfer
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2006.10.034

Fully developed laminar mixed convection of a nanofluid consisting of water and Al 2O 3 in a horizontal curved tube have been studied numerically. Three-dimensional elliptic governing equations have been used. Simultaneous effects of the buoyancy force, centrifugal force and nanoparticles concentration has been presented and discussed. The nanoparticles volume fraction does not have a direct effect on the secondary flow, axial velocity and the skin friction coefficient. However, its effect on the entire fluid temperature could affect the hydrodynamic parameters when the order of magnitude of the buoyancy force becomes significant compared to the centrifugal force. For a given Reynold number, buoyancy force has a negative effect on the Nusselt number while the nanoparticles concentration has a positive effect on the heat transfer enhancement and also on the skin friction reduction.