Author(s): O. W. H. Wai; C. W. Li; Q. H. Xu; J. M. Zhan; P. K. Chan; J. Yu
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Keywords: No Keywords
Abstract: This paper describes the use of hybrid modeling approach (physical and numerical models) to investigate the hydraulic performance of a vortex drop intake (VDI) with a curved approach channel that is merged with a natural stream. Physical models of the vortex system with 1:20 prototype to model scale were designed to satisfy the dynamic similitude between the actual and laboratory situations ensuring accurate reproduction of the gravitational force as well as the frictional force in the models. Based on the standard k-ε turbulence method, volume-of-fluid method which allows tracking of interfaces between phases in the flow and SIMPLE-C method for pressure-velocity coupling, a numerical model of the VDI with multi-blocks and unstructured grids was also setup. The numerical model was first calibrated by the results obtained from physical modeling tests. Flow patterns of different inflow scenarios and vortex designs were then simulated by the calibrated numerical model. Finally, the computed results were verified against the results of physical modeling tests to determine the optimum design of the vortex drop shaft and identify the location and extent of any hydraulic jumps that might occur in the system. It was observed that if the Froude number is smaller than 5 in the curved approach channel, hydraulic jumps would occur at the junction between the approach channel and vortex entrance causing backflow. The hybrid approach greatly reduces the time and cost of the design process and increases the reliability of the vortex design.
Year: 2009