Thermal hydraulics in air cooled finned heat transfer tube banks are analyzed with the ANSYS FLUENT CFD code, by assuming a periodic boundary condition for the region of interest. The Re-normalization Group (RNG) theory based k-epsilon model is used as a reference turbulence model. Two other turbulence models are used to compare results. They are standard k-epsilon model and realizable k-epsilon model. The loss coefficients of the finned heat "transfer tube as a function of the Reynolds number are calculated using the RNG k-epsilon model and the standard k-epsilon model. Both results are in the band of the measured data in the case of the one pass model. Six-pass finned heat transfer tube banks are calculated using a whole pass model as well as a one-pass model which transfers the calculated outlet conditions to the next pass calculation. Air temperature distribution along the six passes is compared with the result calculated by a one-dimensional system code. Both results agree each other. However, the evaluated Nu number for each pass is slightly higher than the measured data. The evaluated pressure loss coefficient is in the measured data scattering band. (C) 2016 Elseviet Ltd. All rights reserved.