LAUSR

Abstract In the present study, a steady state numerical simulation is performed for investigating the thermal and fluid flow characteristics in a turbulent boundary layer for a flat channel as an element of a compact heat exchanger. A trapezoidal winglet pair (TWP) and curved trapezoidal winglet pair (CTWP) are mounted in the computational domain in order to deliberate the effects of longitudinal vortices induced by CTWP and TWP as the vortex generators. The simulation of the turbulent flow is performed by means of the Reynolds stress model (RSM) and the flow has a Reynolds number in the range 7000–35,000. The flow structure at the presence of longitudinal vortex generator consists of corner (horseshoe) vortex, induced vortex, and the main vortex which cause significant heat transfer effects in the downstream region. The effects on the thermal boundary layer are also studied from the field synergy point of view. Numerical results showed that CTWP has a lower pressure drop and a better overall performance compared to TWP. To achieve a maximum heat transfer augmentation and a minimum pressure drop, optimal height and clearance between two vortex generators have been determined using and combining computational fluid dynamics analysis, artificial neural networks and single-objective genetic algorithm.