Effect of the perforation design on the fluid flow and heat transfer characteristics of a plate fin heat exchanger

Abstract

Three dimensional numerical simulations are carried out to explore the performance of vortex generators in a plate fin heat exchanger. Rectangular and perforated wings are used as vortex generators to enhance the heat transfer rates. A comparison is made between the performances of a plate fin with and without baffles. When the heat exchanger is equipped with baffles, the efficiency of two configurations was compared: a baffle with and without perforation. Also, the effects of the perforation shape were studied. It concerns three cases: rectangular, triangular and circular. Validation of our numerical results with the available experimental data has revealed a satisfactory agreement. The obtained results show that the baffled cases perform better than the unbaffled one. The performance factor is found to be higher in the perforated baffle than the baffle without perforation. Compared to the unbaffled case, the maximum thermal performance factor (TPF) of 2.14 was obtained with the circular perforated baffle, followed by the rectangular perforated baffle (TPF = 1.57), triangular baffle (TPF = 1.46) and finally the baffle without perforation (TPF = 1.41). At the end of paper, new correlations for the prediction of friction factor and Nusselt number depending on Reynolds number and the shape of perforation in baffles are developed.