Abstract
Natural heat convection of water-based alumina (Al2O3/water) nanofluids (with volume fraction 1% and 4%) in a horizontal cylinder is numerically investigated. The whole three-dimensional computational fluid dynamics (CFD) procedure is performed in a completely open-source way. Blender, enGrid, OpenFOAM and ParaView are employed for geometry creation, mesh generation, case simulation and post process, respectively. Original solver ‘buoyantBoussinesqSimpleFoam’ is selected for the present study, and a temperature-dependent solver ‘buoyantBoussinesqSimpleTDFoam’ is developed to ensure the simulation is more realistic. The two solvers are used for same cases and compared to corresponding experimental results. The flow regime in these cases is laminar (Reynolds number is 150) and the Rayleigh number range is 0.7 × 107 ~ 5 × 107. By comparison, the average natural Nusselt numbers of water and Al2O3/water nanofluids are found to increase with the Rayleigh number. At the same Rayleigh number, the Nusselt number is found to decrease with nanofluid volume fraction. The temperature-dependent solver is found better for water and 1% Al2O3/water nanofluid cases, while the original solver is better for 4% Al2O3/water nanofluid cases. Furthermore, due to strong three-dimensional flow features in the horizontal cylinder, three-dimensional CFD simulation is recommended instead of two-dimensional simplifications.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-015-0847-x) contains supplementary material, which is available to authorized users.
Highlights
Nanofluid is a suspension containing a certain quantity of nanoscaled solid particles in a conventional cooling liquid, such as water and ethylene glycol [1]
About nanofluid natural heat convection, deterioration was usually illustrated by experimental studies, while enhancement was always reported by numerical studies
The aim of this study is to investigate Al2O3/water nanofluid natural heat convection in a horizontal cylinder by a three-dimensional computational fluid dynamics (CFD) approach
Summary
Nanofluid is a suspension containing a certain quantity of nanoscaled solid particles in a conventional cooling liquid, such as water and ethylene glycol [1]. Nanofluid shows considerably better heat transfer performance than single-phase mediums due to particle’s Brownian motion and interaction [2,3]. Because of the ultra-small particle size, nanofluid is remarkably better than normal multi-phase fluid to eliminate erosion and clogging problems in micro channels [4,5]. Nanofluid is increasingly used in natural convection applications for wide areas [6], such as electronic. To gain a better understanding of nanofluid natural heat convection, many studies have been carried out in both experimental and numerical ways during the past decade [8,9,10]. About nanofluid natural heat convection, deterioration was usually illustrated by experimental studies, while enhancement was always reported by numerical studies
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