Computation of Developing Turbulent Flow And Heat Transfer In Stationary And Rotating Smooth Square Ducts

In this paper prediction of developing turbulent flow and heat transfer through ducts of square cross-section, which are either stationary or rotate in orthogonal mode with the axis of rotation normal to the flow direction, is presented and discussed. The main objective is to examine the performance of a set of low-Re turbulence models in prediction of flow and heat transfer in stationary and rotating ducts. Turbulence models used here are a modified version of v 2 − f model (proposed by Lien and Kalitzin [1]), a zonal k-ε model, and both the linear and nonlinear k-ε models. Flow field data were computed at a Reynolds number of 100,000 with rotation numbers (Ro) of 0.0 and 0.1 whilst heat transfer results were obtained for water (Pr=5.81) at a Reynolds number of 36,000 with rotation numbers of 0.0, 0.2 and 0.4. Flow field and heat transfer predictions are compared with the measurements of Macfarlane et al. [2] and Iacovides et al. [3] respectively. The v 2 − f model fails to reproduce velocity field in most locations both in stationary and rotating ducts. On the other hand, the velocity predictions of all k-ε turbulence models are in close agreement with the measured data everywhere except along the pressure side in the fully-developed region where all turbulence models under-predict the measured velocity profile. Although the v 2 − f model performs well in prediction of turbulence quantities in the fully-developed region, its predictions in the developing region is poor. The normal Reynolds stresses are best reproduced by the nonlinear k-ε model. Heat transfer predictions show that all turbulence models can predict correct heat transfer levels in the stationary cases. In the rotating cases, the heat transfer predictions of the nonlinear k-ε model are closer to the measured data. In general, among turbulence models investigated, the nonlinear k-ε returns the most accurate flow and heat transfer predictions.