Heat transfer in an oval tube heat exchanger with different kinds of longitudinal vortex generators

Abstract

A numerical study was performed on a plate fi n and oval tube heat exchanger with diff erent kinds of longitudinal vortex generators (LVG). The infl uence of LVG on heat transfer and pressure drop is investigated, and eight diff erent LVG geometries are compared: delta-type, rectangular, spoon-type, and fi ve ellipse-shaped cases. The numerical study involves a three-dimensional steady and laminar fl ow and conjugate heat transfer. The results show that one longitudinal vortex (LV) is generated for each LVG for all cases except for the spoon-type case, where two LVs are generated. The results of experimental and numerical investigations were compared validation. The highest increase in heat transfer corresponds to the Delta case (14% for Redh = 720), followed by the Ellipse 1 (13%), Ellipse 2, Ellipse 5 and Rectangular (11% ), Ellipse 3 (8%), and Ellipse 4 and Spoon (7%) cases. The highest increase in the pressure drop corresponds to the Ellipse 1 case (20% for Redh = 720), followed by the Delta (19%), Ellipse 2 (15%), Ellipse 5 (14%), Rectangular (13%), Ellipse 3 (11%), and Ellipse 4 and Spoon (9%) cases. The highest heat transfer rate, with the same fl ow power consumption, corresponds to the Delta, Rectangular, Ellipse 1, 2, and 5 cases.