Experimental and numerical investigations of thermal-hydraulic characteristics in a novel airfoil fin heat exchanger

Abstract

A novel airfoil fin (AFF) Printed Circuit Heat Exchanger (PCHE) with a 100 kW class heat transfer capacity was experimentally tested as a cooler in a supercritical CO2 system. Numerical analysis was also conducted to have an insight into the flow and heat transfer mechanism in the AFF channels. The results showed that the novel AFF structure has superior hydraulic performance as the pressure drop in the AFF PCHE is only about 1/6 of that in the zigzag channel PCHE with a comparative heat transfer rate. In comparison with the mass flow rate and operating pressure, the inlet temperature has relatively insignificant effect on the heat transfer rate and pressure drop in the AFF heat exchanger. The broadening of the fin has no obvious improvement in heat transfer coefficient but increases the friction factor massively, and thereby resulting in worse comprehensive performance in the fin channel. At smaller temperature and mass flow rate, the periodic fluctuations of the heat transfer coefficient and comprehensive performance criterion could be weakened significantly. In addition, the determinant effect of the effective thermal conductivity in the viscous sublayer and buffer layer on local heat transfer coefficient is also validated in AFF channels.