The influence of tube layout on flow and mass transfer characteristics in tube banks in the transitional flow regime

Flow and mass transfer characteristics in tube banks are investigated in the transitional flow regime at intermediate Reynolds numbers. The tube arrays considered are a staggered tube array and an in-line tube array with longitudinal and transverse pitch-to-diameter ratios of two. The flow is steady at the entrance of the tube banks, but becomes oscillatory downstream of an onset location of vortex shedding. This location moves upstream with increasing Reynolds number, and the upstream development of flow transition is much faster for the staggered array than the in-line array. Therefore, the row-by-row variation of the mass transfer rate is small for the staggered array but considerable for the in-line array. The mass transfer for the staggered array is sensitive to the unsteady wakes of the preceding row tubes, while the surface shear stress is insensitive to such wakes. However, for the in-line array the mass transfer and shear stress are both sensitive to the unsteady wakes.