Heat transfer enhancement for combined convection flow of nanofluids in a vertical rectangular duct considering radiation effects |
| |
Authors: | HA Mohammed Nur Irmawati Om NH Shuaib R Saidur |
| |
Affiliation: | 1. Department of Mechanical Engineering, College of Engineering, Universiti Tenaga Nasional, Selangor, Malaysia;2. Department of Mechanical Engineering, University of Malaya, Kuala Lumpur, Malaysia |
| |
Abstract: | In this paper, combined convective heat transfer and nanofluids flow characteristics in a vertical rectangular duct are numerically investigated. This investigation covers Rayleigh numbers in the range of 2 × 106 ≤ Ra ≤ 2 × 107 and Reynolds numbers in the range of 200 ≤ Re ≤ 1000. Pure water and five different types of nanofluids such as Ag, Au, CuO, diamond, and SiO2 with a volume fraction range of 0.5% ≤ φ ≤ 3% are used. The three‐dimensional steady, laminar flow, and heat transfer governing equations are solved using finite volume method (FVM). The effects of Rayleigh number, Reynolds number, nanofluids type, nanoparticle volume fraction of nano‐ fluids, and effect of radiation on the thermal and flow fields are examined. It is found that the heat transfer is enhanced using nanofluids by 47% when compared with water. The Nusselt number increases as the Reynolds number and Rayleigh number increase and aspect ratio decreases. A SiO2 nanofluid has the highest Nusselt number and highest wall shear stress while the Au nanofluid has the lowest Nusselt number and lowest wall shear stress. The results also revealed that the wall shear stress increases as Reynolds number increases, aspect ratio decreases, and nanoparticle volume fraction increases. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20354 |
| |
Keywords: | numerical simulation combined convection vertical rectangular duct nanofluids |
|
|