Research Center for Engineering of
                Systems with Complex Fluids
Title: Experimental and Numerical Assessment of the Velocity Profiles Using a Passive Method For Swirling Flow Control
Published In: 6th IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems, Ljubljana, Slovenia
Description: The hydraulic turbines operated at partial discharge (especially hydraulic turbines with fixed blades, i.e. Francis turbine), developing a central stagnant region in the conical diffuser of draft tube. As a result, the helical vortex breakdown, also known in the literature like “precessing vortex rope” is developed. This paper introduces a novel approach for mitigating the swirling flow instabilities using a diaphragm into the cone. Consequently, the severe flow deceleration and corresponding central stagnant region are diminished, with an efficient mitigation of the precessing helical vortex. Four cases (one without and three with diaphragm) are numerically and experimentally investigated. The velocity profiles measurements will show that the diaphragm can mitigate the stagnant region associated to the vortex rope.
Publication year: 2015
Keywords:conical diffuser, swirling flow, velocity profiles, passive method, stagnant region
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Authors: TANASA Constantin , BOSIOC Ilie Alin , MUNTEAN Sebastian , SUSAN-RESIGA Romeo ,
Type: International Conference Proceedings
Laboratory: Numerical Simulation and Parallel Computing Laboratory
Institution: UPT