Thermo-hydraulic characteristics of offset strip fin heat exchanger with vortex generators

Abstract

The finned structure of the Offset Strip Fin (OSF) and the vortex generators (VG) both offer significant potential for enhanced heat transfer. This paper investigates the thermal-hydraulic characteristics of the OSF heat exchanger (HEX) with VG installed on the rib base surface. The study examines the geometrical configuration of the VG, including their shape, spatial positioning, longitudinal extent, and angle of attack, to determine their respective impacts on system performance. VG shapes perform differently across various Reynolds numbers (Re), defining the transition point as the Thermal Exchange Efficacy Transition Re (Re_TEET). Findings suggest that increasing the distance of VG from the fin's leading edge, along with extending their length and increasing their angle of attack, collectively improves heat transfer efficiency and reduces the Re_TEET. However, achieving the Re_TEET becomes unfeasible when the angle of attack surpasses a certain threshold. At lower Reynolds numbers, the optimum performance occurs at a 45° angle of attack. As the Reynolds number increases, the optimum performance decreases with an increased angle of attack.