Transfer coefficients on the surfaces of a transverse plate situated in a duct flow

Experiments have been performed to determine the heat-/mass-transfer coefficients on the upstream and downstream faces of a wall-attached transverse plate which partially blocks the flow cross section of a square duct. The experiments involved mass transfer and were carried out via the naphthalene sublimation technique, with air as the working fluid. By virtue of the analogy between heat and mass transfer, the results are also relevant to heat transfer. The transverse plates employed in the experiments gave rise to blockages which ranged from one-sixth to two-thirds of the duct cross section. The duct Reynolds number was varied from 5000 to 30 000. It was found that at a given Reynolds number, both the upstream-face and downstream-face transfer coefficients were quite insensitive to the extent of the blockage. The upstream-face coefficients were generally higher than those for the downstream face, but the differences diminished with increasing Reynolds number. The coefficients exhibited a power-law dependence on the Reynolds number, the power being approximately one-half for the upstream face and two-thirds for the downstream face.