Numerical investigation of swirl flow effect on heat exchanger efficiency according to different inlet position and Reynolds number

The aim of this investigation is to determine the configuration that will enable a micro heat exchanger system to function more efficiently. Heat exchangers are devices that can be used for exchanging energy between flows, which can have a wide variety of uses and different configurations; therefore, studies are carried out in order to increase the efficiency of heat exchangers. In this study, heat transfer capacity and system efficiency of the swirl flow were investigated using CFD as compared to the parallel flow heat exchanger, which is another configuration. The air drawn by the fan is sucked into the holes and enters the system, thereby air entering the system impinges on the heat exchanger tube. The flow character has a major role on the Nusselt number and heat transfer coefficient. The main flow variables are Reynolds number and the orientation of the inlet holes. The boundary conditions were determined according to the fan capabilities and power of resistance. The positions and types of the holes were adjusted to allow for axial and tangential impact onto the heat exchanger tube, and the holes were also located in order to obtain the best impingement angle. CFD simulations were carried out with ANSYS Fluent and k-epsilon turbulent model was used with coupled algorithm. The effect of laminar flow on the heat transfer were observed at different Reynolds numbers. Also the effect of swirl flow characteristics on system efficiency is clearly observed as compared to parallel flow.