A SIMULATIVE ANALYSIS FOR HEAT TRANSFER ENHANCEMENT USING RECTANGULAR WING & WINGLET TYPE VORTEX GENERATOR IN A TRIANGULAR CHANNEL

The augmentation of heat transfer through different ways has been developing as an intense area of research since many years. The recent increase in the use of heat exchangers for industrial applications has called for improvement in their design, efficiency & compactness. In general, the thermal resistance offered by the gases (air in particular is pretty large; therefore, performance of heat exchangers with gas as the working fluids becomes practically important. One of the most common techniques for compensating the poor heat transfer properties of gases is that the surface area density of plate heat exchangers be increased by using the secondary fins such as offset fins, triangular fins, wavy fins, louvered fins etc. In addition to this a promising technique for enhancement of heat transfer is use of longitudinal vortex generators. The longitudinal vortices are produced due to the pressure difference generated between the front and back of the vortex generator. The longitudinal vortices facilitate the exchange of fluid near the walls with the fluid in the core and hence, the thermal boundary layer is disturbed. It causes an increase in temperature gradient at surface which leads to heat transfer augmentation. An innovative design of triangular shaped secondary fins with rectangular wing or winglet vortex generator mounted on the bottom of the channel for enhancing heat transfer is proposed. The computational details have been given for analysis of problem in the ANSYS FLUENT 18 which mainly describes about the solution algorithm and solution schemes as well as under relaxed factors required for the recent problems. As the solution is converged after certain number of iterations, the value of pressure-drop and Nusselt number, average temperature, friction factor is calculated for different attack angles and at different locations and compared with plain channel for same parameter.