Experimental investigating the thermal and hydraulic performance of heat exchangers with helix wire finned tube

In this study, the helix wire finned tube is introduced as a novel design to increase the performance, reduce weight, and manufacturing price of the heat exchangers. The helix wire fin can make turbulence in the fin-side flow, creates a larger contact surface, more flow trapping and increment in the residence time for enhancement of the heat transfer. The effect of Reynolds number inside and outside of the finned tube and inter-tube distance on the thermo-hydraulic performance of the heat exchanger has been investigated experimentally. The results show that increasing the Reynolds outside the finned tube causes an 80% enhancement in the performance evaluation criterion of the heat exchanger. Also, helix wire finned tubes provide a maximum of 65% and 57% better thermal performance compared to spiral and serrated fins. Increasing the Reynolds number of the outside and inside tube flow causes a 40% and 50% enhancement in the Nusselt number of the fin-side flow, respectively. Moreover, increasing the longitudinal distance between the tube rows reduces the Nusselt number and friction factor of the fin-side flow by 20% and 45%, respectively. Finally, an experimental correlation is derived to calculate the Nusselt number of the air-side flow.