Abstract :
Experimental investigation on the heat transfer and friction characteristics of rib-grooved artificial roughness on one
broad heated wall of a large aspect ratio duct shows that Nusselt number can be further enhanced beyond that of ribbed
duct while keeping the friction factor enhancement low. The experimental investigation encompassed the Reynolds number
range from 3000 to 21,000; relative roughness height 0.0181–0.0363; relative roughness pitch 4.5–10.0, and groove position
to pitch ratio 0.3–0.7. The effect of important parameters on the heat transfer coefficient and friction factor has been discussed
and the results are compared with the results of ribbed and smooth duct under similar flow conditions. The present
investigation clearly demonstrates that the heat transfer coefficient for rib-grooved arrangement is higher than that for the
transverse ribs, whereas the friction factor is slightly higher for rib-grooved arrangement as compared to that of rectangular
transverse ribs of similar rib height and rib spacing. The conditions for best performance have been determined. Correlations
for Nusselt number and friction factor have been developed that predict the values within reasonable limits.
2005 Elsevier Ltd. All rights reserved
