Open AccessHEAT TRANSFER ENHANCEMENT AND PRESSURE DROP FOR FIN-AND-TUBE COMPACT HEAT EXCHANGERS WITH DELTA WINGLET-TYPE VORTEX GENERATORS
Author(s) -
Seyed Alireza Ghazanfari,
Mazlan Abdul Wahid
Publication year - 2018
Publication title -
facta universitatis. series: mechanical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 16
eISSN - 2335-0164
pISSN - 0354-2025
DOI - 10.22190/fume180117024g
Subject(s) - fin , wingtip device , plate fin heat exchanger , micro heat exchanger , heat transfer , heat transfer enhancement , pressure drop , mechanics , heat spreader , plate heat exchanger , heat exchanger , materials science , vortex generator , dynamic scraped surface heat exchanger , shell and tube heat exchanger , concentric tube heat exchanger , heat transfer coefficient , thermodynamics , mechanical engineering , vortex , composite material , engineering , critical heat flux , physics , aerodynamics
Heat transfer rate, pressure loss and efficiency are considered as the most important parameters in designing compact heat exchangers. Despite different types of heat exchangers, fin-and-tube compact heat exchangers are still common device in different industries due to the diversity of usage and the low space installation need. The efficiency of the compact heat exchanger can be increased by introducing the fins and increasing the heat transfer rate between the surface and the surroundings. Numerous modifications can be applied to the fin surface to increase heat transfer. Delta-winglet vortex generators (VGs) are known to enhance the heat transfer between the energy carrying fluid and the heat transfer surfaces in plate-fin-and-tube banks, but they have drawbacks as well. They increase the pressure loss and this should be considered. In this paper, the thermal efficiency of compact heat exchanger with VGs is investigated in different variations. The angle of attack, the length and horizontal and vertical position of winglet are the main parameters to consider. Numerical analyses are carried out to examine finned tube heat exchanger with winglets at the fin surface in a relatively low Reynolds number flow for the inline tube arrangements. The results showed that the length of the winglet significantly affects the improvement of heat transfer performance of the fin-and-tube compact heat exchangers with a moderate pressure loss penalty. In addition, the results show that the optimization cannot be performed for one criterion only. More parameters should be considered at the same time to run the process properly and improve the heat exchanger efficiency.