Turbulent fluid flow and heat transfer induced by square-ribbed surface roughness in concentric annuli.
|Title:||Turbulent fluid flow and heat transfer induced by square-ribbed surface roughness in concentric annuli.|
|Authors:||Ahn, Soo Whan.|
|Abstract:||In this study, the asymmetric turbulent fluid flow and heat transfer induced by square-rib roughness elements in concentric annuli are analytically studied in an attempt to investigate the resultant effect of artificial roughness on the heat transfer and friction forces. In the analysis, a turbulence model based on a modified Prandtl's mixing length theory based on a previous study of the flow in parallel plates with a rough surface on one side is used to determine the velocity distribution and friction. The two velocity profiles in the problem are matched using a force balance. The temperature distribution is then predicted and heat transfer coefficients are calculated. The results of the velocity profiles and friction factors are in good agreement with the experimental results. The effects of various parameters such as the roughness ratio, the pitch to roughness ratio, the radius ratio, etc. on friction factor and Nusselt number are investigated. The present study demonstrates that certain artificial roughness elements may be used to enhance heat transfer rates with advantages from the overall efficiency point of view.|
|Collection||Thèses, 1910 - 2010 // Theses, 1910 - 2010|