CFD analysis for thermo-hydraulic properties in a tubular heat exchanger using curved circular rings

The never-ending demands of humans have led researchers to find more efficient energy conversion technologies. Enhancing heat transfer rate in a tubular heat exchanger through curved circular rings is one type of passive method that is studied in this work. The computational analysis has been done using ???FLUENT??? module of ANSYS 16.0. The tubular heat exchanger has internal diameter of 68.1 mm, length of 1.5 m and constant heat flux of 1000 W m???2. Air is the working fluid, which flows in Re varying from 3000 to 21,000. After reaching steady state conditions, the Nusselt number and friction factor are calculated for CCR rings. Furthermore, perforation has been done on these rings with perforation index 8, 12 and 16% and thermo-hydraulic properties are investigated. Computational results show that perforating the rings have a significant effect on heat transfer and friction factor. Greater the perforation index, greater is the Nu and TPF. The maximum enhancements obtained in Nu and TPF are 7.4 and 1.56 times, respectively (as compared to that of smooth tube), for PCCR-16%.