Effects of curved vortex generators on the air-side performance of fin-and-tube heat exchangers

摘要

Numerical simulations are performed to examine the thermal and flow characteristics of curved vortex generators (VGs) on the fin surfaces of fin-and-tube heat exchangers. The performance of VGs with different curvatures are evaluated at various attack angles. In addition, the effects of parameters including position, size and inclination angle are also investigated. The heat transfer performance and pressure loss are analyzed using the dimensionless parametersNu/Nu0,f/f0, andR=(Nu/Nu0)/(f/f0)1/3withReDcranging from 405 to 4050. The numerical result reveals that the value ofRshows an upward trend with the increase ofReDc, indicating a better thermal hydraulic performance is obtained at higherReDcfor the present study. It is also found that the VGs with a curvature of 0.25 show best thermal hydraulic performance and the highest value ofR?=?1.06 is achieved at an angle of attack ofβ?=?15°. Further parametrical study reveals that when the VGs are deployed at a non-dimensional horizontal distance ofS1??=?0.232 and vertical distance ofS2??=?0.697, better thermal hydraulic performance is achieved. The VGs with a smaller height and larger inclination angle show better thermal hydraulic performance at lowReDc(ReDc?