Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Impact of the double longitudinal vortex generator on enhancement heat transfer for a wavy-fin compact heat exchanger with circular and elliptical tubes
Submission Author:
Laís Bandini , SP
Co-Authors:
Laís Bandini, Leandro Salviano
Presenter: Laís Bandini
doi://10.26678/ABCM.COBEM2023.COB2023-1414
Abstract
The growing industrial development over the last decades led to the improvement of several thermal devices. Among the main types of equipment that have evolved in the last decades, heat exchangers stand out. The field of application of heat exchangers is wide, present from the most complex industrial processes to domestic equipment for daily use. In the industrial segment, they can be used directly in product heating and cooling processes, or even indirectly, as condensers and evaporators. Combined passive heat transfer enhancement techniquesare a successful approach in thermal engineering. The present work investigates the impact of double longitudinal vortex generator in a compact wavy-fin heat exchanger operating at a low Reynolds number, related to refrigeration and air conditioning systems, by combining passives techniques of wavy fin and longitudinal vortices generators. The computational modeling considers a tridimensional model, for an incompressible, steady-state and turbulent flow. The heat exchanger with wavy fins is evaluated considering circular and elliptical tubes for staggered arrangement combined with vortex generator of delta-winglet and rectangular-winglet with an aspect ratio of 2 and angles of attack of 15º, 30º and 45º. The heat transfer has been evaluated by Colburn Factor and pressure loss through Friction Factor. Mesh sensitivity analysis is ensured by Grid Convergence Index and the numerical robustness is verified through experimental comparison. In comparison with the reference cases, the results show that there is no need to use the second vortex generator for all evaluated angles, taking into account the elliptical tube with the delta-winglet generator. As for the cases with circular tube and rectangular-winglet vortex generators for all angles of attack analyzed, the second vortex generator has an important contribution. Overall, the results showed that in some cases, not using the second vortex generator does not generate heat transfer loss, allowing, among other things, the reduction of materials for the fabrication process and manufacturing.
Keywords
Compact Heat Exchanger, Longitudinal vortex generator, Computational Fluid Dynamics, Passive techniques
