HEAT-TRANSFER ENHANCEMENT IN FIN-TUBE HEAT-EXCHANGERS BY WINGLET TYPEVORTEX GENERATORS

Numerical investigations of the flow structure and heat transfer enhan cement in a channel with a built-in circular tube and a winglet type v ortex generator are presented. The geometrical configuration represent s an element of a gas-liquid fin-tube crossflow heat exchanger. In the absence of the winglet type vortex generator, relatively little heat transfer takes place in the downstream of the circular tube which is a recirculation region with low velocity fluid. However, in the presenc e of a winglet type longitudinal vortex generator in the wake region b ehind the cylinder, heat transfer in this region can be enhanced as hi gh as 240%. Results show a marked increase in overall channel heat tra nsfer. The enhancement shows great promise in reducing the size of the heat exchangers.