Effect and heat transfer correlations of finned tube heat exchanger under unsteady pulsating flows

The enhancement of heat transfer for finned tube heat exchangers by using a pulsating flow was studied. The amplitude, force frequency, Reynolds number and blockage ratio of heat exchangers in pulsating air flows were investigated. The experimental setup of the unsteady pulsating flow was designed and constructed to experiment with such parameters. The air was used as a working fluid. Experiments on unsteady pulsating flows were carried out in the range of 10⩽fp⩽50 Hz and 13.33⩽A⩽15.35%. The results indicate that both the force frequency and amplitude of the pulsating flow play important roles in heat transfers. The heat transfer coefficient of the fin heat exchanger was enhanced to be higher than that of the steady flow condition. The new empirical correlation can predict the experimental applicability of the data within 12.3%.