Numerical Simulation of the Flow in a Kaplan Turbine Model during Transient Operation from the Best Efficiency Point to Part Load

Raluca G. Iovănel, Georgiana Dunca, Diana M. Bucur and Michel J. Cervantes
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Raluca G. Iovănel: Division of Fluid and Experimental Mechanics, Luleå University of Technology, 971 87 Luleå, Sweden
Georgiana Dunca: Department of Hydraulics, Hydraulic Equipment and Environmental Engineering, Politehnica University of Bucharest, 060042 Bucharest, Romania
Diana M. Bucur: Department of Hydraulics, Hydraulic Equipment and Environmental Engineering, Politehnica University of Bucharest, 060042 Bucharest, Romania
Michel J. Cervantes: Division of Fluid and Experimental Mechanics, Luleå University of Technology, 971 87 Luleå, Sweden

Energies, 2020, vol. 13, issue 12, 1-21

Abstract: The aim of this study is to develop a reliable numerical model that provides additional information to experimental measurements and contributes to a better exploitation of hydraulic turbines during transient operation. The paper presents a numerical analysis of the flow inside a Kaplan turbine model operated at a fixed runner blade angle during load variation from the best efficiency point (BEP) to part load (PL) operation. A mesh displacement is defined in order to model the closure of the guide vanes. Two different types of inlet boundary conditions are tested for the transient numerical simulations: linear flow rate variation (InletFlow) and constant total pressure (InletTotalPressure). A time step analysis is performed and the influence of the time discretization over the fluctuating quantities is discussed. Velocity measurements at the corresponding operating points are available to validate the simulation. Spectrogram plots of the pressure signals show the times of appearance of the plunging and rotating modes of the rotating vortex rope (RVR) and the stagnation region developed around the centerline of the draft tube is captured.

Keywords: Kaplan turbine; transient operation; mesh displacement; rotating vortex rope (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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