Thermo-hydraulic Characterization of the Smooth Wavy Fin-and-elliptical Tube Heat Exchangers Using New Type Vortex Generators

Abstract

In the present study, 3D computational analysis was performed to investigate heat transfer and pressure drop characteristics of flow in new Smooth Wavy Fin-and-Elliptical Tube (SWFET) heat exchanger model with new vortex generators. Performance results are presented in terms of non-dimensional parameters, friction factor f and Colburn j factor. Four new types of vortex generators were considered; rectangular trapezoidal winglet (RTW), angle rectangular winglet (ARW), curved angle rectangular winglet (CARW) and Wheeler wishbone (WW). Fluid flow and heat transfer are simulated and the results are compared. The SST k–ω turbulence model is used, with steady-state solvers to calculate pressure drop, flow and temperature fields. The influences of the geometrical factors of mounted vortex generators including attack angles of the winglets (αVG = 15°, 30°, 45°, 60° and 75̊) and width/length aspect ratio (w/l = 0.5,1.0) of the Wheeler wishbones in enhancing the heat transfer performance of a smooth wavy fin heat exchanger with a three-row staggered elliptical tube bundle are investigated. The Reynolds number ranges from 500 to 3000 based on the hydraulic diameter. A parametric study on the winglet vortex generators indicated that for the small attack angle, CARW vortex generators gives better thermohydraulic performance under the present conditions. The best thermal performance of the SWFET heat exchanger with winglet VGs in the larger attack angle, was obtained at RTW VGs arrangement. For the SWFET heat exchangers, the WW VGs with width/length aspect ratio of w/l = 0.5 provide the best heat transfer performance.