Tube Transverse Pitch Effect on Heat/Mass Transfer Characteristics of Flat Tube Bank Fin Mounted With Vortex Generators

For one heat exchanger model of three-row flat tube bank fin mounted with vortex generators (VGs), the effect of transversal tube pitch on heat/mass transfer performance was investigated by the experimental method of naphthalene sublimation. For the same arrangement of VGs around the tube, it is found that the larger the transversal tube pitch, the larger the heat transfer enhancement because of less interactions of vortices generated from different VGs. Interaction of vortices decreases the heat transfer enhancement on the fin surfaces with and without VGs for the case with small transversal tube pitch. For isothermal condition, two correlated equations of average Nusselt number and friction factor considering the fin spacing, the attack angle of VG, the height of VG, the ratio of transversal tube pitch, and Reynolds number are reported.