The effect of circular hole spring tape on the turbulent heat transfer and entropy analysis in a heat exchanger tube: an experimental study

Abstract

The current paper is focused on the experimental investigation of the turbulent forced convection with circular-hole spring tape (CHST) inserts in a circular tube. The CHST inserts with different hole and spring ratios, are investigated for a wide ranges of Reynolds number (10,000–50,000). Results show that use of CHST provides an increase in heat transfer by 35% and 51% when assessed with other inserts and plain tube, respectively. Furthermore, an entropy generation study shows that the irreversibility rises significantly with the increase of diameter ratio and Reynolds number. The overall enhancement ratio has been evaluated to study the effect of the CHST. The thermo-hydraulic performance are approximately more than unity for all the cases which indicates that the consequence of HT augmentation due to the augmenting apparatus is more governing than the consequence of the growing friction penalty. Thermo-hydraulic performance of c = 0, y = 1.5 (maximum value) is 25% higher than c = 0.6, y = 3.0 (minimum value). A predictive Nusselt number and friction factor correlations are also developed.