This investigation presents numerical results for both laminar and turbulent flow and heat transfer for an in-line tube bank ranging in size from 1 to 20 tube rows over a Reynolds number range of 100-1000. Both the longitudinal and transverse pitches were fixed at 1.5D. It was demonstrated that the most useful heat transfer results were expressible as a total-tube-bank-averaged Nusselt number value, which is in contradiction to other investigations. For sufficiently lengthy tube banks, the existence of a fully developed regime characterized by an axially unchanging array-average Nusselt number was identified. It was found that the highest array-average heat transfer coefficients occurred in the initial portion of the tube bank, also in contradiction with information conveyed in some of the literature. A special case in which only a single tube in the array was thermally active was investigated in deference to experiments conducted under that condition. The present results obtained by numerical simulation compared favorably to existing experimental data. (C) 2018 Elsevier Ltd. All rights reserved.