Influence of fin geometry on heat transfer and friction in plate fin heat exchangers: a CFD approach

Abstract
Plate fin heat exchangers (PFHEs) are widely recognized for their compact design and high thermal efficiency, making them a popular choice in various heat transfer applications. Some common types of geometries which are used in the case of PFHEs are rectangular fins, triangular fins, wavy fins and offset strip fins. These geometries vary primarily in the arrangement of the fins, with rectangular and triangular fins arranged in-line, while offset and wavy fins are arranged in a staggered formation. These configurations help to increase the turbulence, which enhances the heat transfer. With a change in the height to width ratio, fin height and fin spacing (fin width) the heat exchanger’s performance changes. For wavy fins, different configurations were achieved by altering the amplitude and wavelength, while for triangular fins, modifications in the base and height were made to explore various designs. Over the past decades, many researchers have conducted both numerical and experimental analyses on these varieties of fins in the case of PFHEs for optimization of design parameters to improve efficiency. In the present analysis, a computational fluid dynamics (CFD) study has been conducted to find the heat transfer process that is affected by rectangular and offset strip fins. Using different combinations of geometrical parameters, numerical calculations for pressure drop and heat transfer analysis were performed using the ANSYS FLUENT solver. In this study, water has been used as a working medium and the operating conditions were varied, having Renolds numbers ranging from 250 to 8000. This study employs periodic boundary conditions to conduct the analysis and draw meaningful conclusions. In addition to this the impact of these parameters on the friction factor was studied with a change in Nusselt number with respect to Reynolds number.