@Article{hmt.5.19,
AUTHOR = {Amnart Boonloi, Withada Jedasadaratanachai},
TITLE = {3D NUMERICAL ANALYSIS ON FLOW CONFIGURATIONS AND HEAT  TRANSFER CHARACTERISTICS FOR FIN-AND-OVAL-TUBE HEAT  EXCHANGER WITH V-DOWNSTREAM DELTA WINGLET VORTEX  GENERATORS},
JOURNAL = {Frontiers in Heat and Mass Transfer},
VOLUME = {5},
YEAR = {2014},
NUMBER = {1},
PAGES = {1--15},
URL = {http://www.techscience.com/fhmt/v5n1/54896},
ISSN = {2151-8629},
ABSTRACT = {3D numerical investigations for heat transfer characteristics and flow configurations in a fin–and-oval-tube heat exchanger with V-tip pointing 
downstream delta winglet pairs (<i>DDWP</i>) are examined. The <i>DDWP</i>s are placed on the fin surface with pointing downstream and the oval tube row 
number is set at three in a staggered arrangement. The flow attack angles (<i>θ</i> = 15°, 30°, 45° and 60°) and the distance from V-tip to the oval tube 
center in transverse axis (<i>a</i> = 3.77, 4.77 and 5.77 mm) are investigated for Reynolds number based on hydraulic diameter, <i>Re</i> = 500 – 2500. The 
numerical results are compared with the previous experimental results and the validations of the grid system on both heat transfer and friction factor 
are also reported. As the results, it is found that the use of the <i>DDWP</i> performs higher heat transfer rate and the friction factor than the smooth fin 
with no <i>DDWP</i> for all cases. The vortex flows and the impinging jet of the flows over the oval-tube walls lead to the increase in heat transfer rate, but 
also increase in pressure loss. The augmentations are maximum around 1.59 and 4.4 times higher than the smooth fin for heat transfer and friction 
factor, respectively. In addition, the optimum thermal enhancement factor, <i>TEF</i>, is around 1.09 at <i>Re</i> = 2500, <i>a</i> = 5.77 mm and <i>θ</i> = 15°.},
DOI = {10.5098/hmt.5.19}
}