Technical Note Experimental investigation of turbulent heat transfer and fluid flow in internally finned tubes

Abstract

A recent bibliography (Bergles et al. [1] ) lists the literature on turbulent heat transfer in internally finned tubes. An excellent review on this topic is given by Shome [2] . In brief, using a variety of fluids (e.g., air, water, oil, R-113, ethylene glycol/water) , a number of investigators (e.g., Edwards and Jensen [3] , Vasilchenko and Barbaritskaya [4] , Watkinson et al. [5] , Carnavos [6] , Chiou et al. [7] , Kaushik and Azer [8] , Brognaux et al. [9] ) have studied this enhancement technique over a range of number of fins, fin heights, helix angles, and fin profiles. They obtained increases in the Nusselt numbers from 15–180% greater than that in a smooth tube. This benefit was counterbalanced by increases in friction factor of 50–500%. Correlation of the data is difficult because of the many different parameters that can influence the Nusselt number and friction factor. The most widely cited correlations for friction factor and Nusselt number were proposed by Carnavos [6] :