Effects of aspect ratio on mixed convection in a horizontal rectangular duct with heated and cooled side walls

Abstract

This paper describes the effect of aspect ratio on mixed convection in a horizontal rectangular duct with heated and cooled side walls numerically and experimentally. In the numerical analysis, fluid flow and temperature distributions for Ri=1.61, Pr=6.99, Re=100 and aspect ratio, Ar=0.2–10, were obtained by solving dimensionless governing equations using the SIMPLE procedure. The QUICK scheme was applied to the convective term of these equations. In the experimental analysis, the flow behavior for Ar=0.5–2 was visualized by the dye-injection method. Numerical results showed that the swirl flow was generated along the flow direction, and its pitch length was influenced by Ar. The pitch length was the shortest when Ar=0.5–1, and this tendency was the same in numerical results and experimental results. The heat transfer behavior was also discussed corresponding to the flow, and the heat transfer ratio was highest at Ar=1 in 0.2 ≤ Ar ≤ 10. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20391