Numerical simulation on heat transfer performance of the fin-and-flat tube bank heat exchanger with vortex generators and analysis with field synergy principle

The periodically fully developed laminar heat transfer in the fin-and-flat tube bank heat exchanger with vortex generators has been investigated by numerical analysis in the Reynolds number range of 400-2000. A set of laminar heat transfer predictions are presented to demonstrate the effects of the Reynolds number, span-wise position of VGs (δ) and the attack angle of VGs (β) on the local, span-averaged, total-averaged Nusselt number and on the local, span-averaged, total-averaged intersection (synergy) angle. By comparison of the Nusselt number with the synergy angle, it is found that the fundamental mechanism of heat transfer enhancement by the longitudinal vortices is the improvement of the synergy between velocity and temperature gradient.