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This paper deals with three-dimensional, turbulent, confined impinging flows. Various turbulence models are examined with reported laser-Doppler velocimetry data and flow-visualization photographs. The turbulence models considered are the k - [epsilon] k - [epsilon] with the Richardson number correction for swirling and recirculating flows (k - [epsilon] w/scm), algebraic Reynolds stress (k - [epsilon] - A), and modified k - kl models. The k - [epsilon] and k - [epsilon] - A models are found to be superior to the k - [epsilon] w/scm and modified k - kl models in predicting the main flow characteristics. The k - [epsilon] - A model provides a better quantitative agreement with the experimental data than can be achieved with the k - [epsilon] model, however, less computational effort is spent with the k - [epsilon] model than with the k - [epsilon] - A model. Also, the effect of the inlet velocity profile on the characteristics of the confined impinging flows is addressed in this study.

Abstract: An experimental study of heat transfer in a radially rotating rectangular channel of aspect ratio 1/2 with two opposite walls roughened by 45° staggered ribs is performed. Heat transfer distributions along centerlines of two rib-roughened surfaces are measured for the radially outward airflow at test conditions of Reynolds number (Re), rotation number (Ro) and density ratio (Δρ/ρ) in the ranges of 5000–15,000, 0–2 and 0.07–0.28. The rotating test rig permits the generation of heat transfer data with Ro considerably higher than previous data ranges. A selection of experimental data illustrates the individual and interactive influences of Re, Ro and buoyancy number (Bu) on local heat transfer with two channel orientations of 0° and 45°. With Ro varying from 0.1 to 2, heat transfer ratios between rotating and static channels on the stable and unstable rib-roughened surfaces with 0° (45°) of channel orientation are in the ranges of 0.5–1.42 (0.5–1.49) and 1.08–2.73 (1.06–2.21) respectively. A set of heat transfer correlations for the test geometry with channel orientations of 0° is derived to evaluate the local Nusselt number (Nu) in the periodically developed region with Re, Ro and Bu as the controlling flow parameters. [Copyright &y& Elsevier]