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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/11080
Title: Characteristics of synchronous and asynchronous modes of fluctuations in Francis turbine draft tube during load variation
Authors: Goyal R.
Cervantes M.J.
Gandhi, Bhupendra K.
Published in: International Journal of Fluid Machinery and Systems
Abstract: Francis turbines are often operated over a wide load range due to high flexibility in electricity demand and penetration of other renewable energies. This has raised significant concerns about the existing designing criteria. Hydraulic turbines are not designed to withstand large dynamic pressure loadings on the stationary and rotating parts during such conditions. Previous investigations on transient operating conditions of turbine were mainly focused on the pressure fluctuations due to the rotor-stator interaction. This study characterizes the synchronous and asynchronous pressure and velocity fluctuations due to rotor-stator interaction and rotating vortex rope during load variation, i.e. best efficiency point to part load and vice versa. The measurements were performed on the Francis-99 test case. The repeatability of the measurements was estimated by providing similar movement to guide vanes twenty times for both load rejection and load acceptance operations. Synchronized two dimensional particle image velocimetry and pressure measurements were performed to investigate the dominant frequencies of fluctuations, vortex rope formation, and modes (rotating and plunging) of the rotating vortex rope. The time of appearance and disappearance of rotating and plunging modes of vortex rope was investigated simultaneously in the pressure and velocity data. The asynchronous mode was observed to dominate over the synchronous mode in both velocity and pressure measurements. © 2017, Turbomachinery Society of Japan. All rights reserved.
Citation: International Journal of Fluid Machinery and Systems (2017), 10(2): 164-175
URI: https://doi.org/10.5293/IJFMS.2017.10.2.164
http://repository.iitr.ac.in/handle/123456789/11080
Issue Date: 2017
Publisher: Turbomachinery Society of Japan
Keywords: Francis turbine
Load acceptance
Load rejection
Particle image velocimetry
Pressure measurements
Rotating vortex rope formation
Synchronous and asynchronous modes
Transient
ISSN: 18829554
Author Scopus IDs: 57191617201
55328928400
7006087147
Author Affiliations: Goyal, R., Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee, 247667, India, Division of Fluid and Experimental Mechanics, Department of Engineering Sciences and Mathematics, Lulea University of Technology, Norrbotten, 97187, Sweden
Cervantes, M.J., Division of Fluid and Experimental Mechanics, Department of Engineering Sciences and Mathematics, Lulea University of Technology, Norrbotten, 97187, Sweden, Water Power Laboratory, Department of Energy and Process Engineering, Norwegian University of Science and Technology, Trondheim, 7491, Norway
Gandhi, B.K., Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee, 247667, India
Funding Details: Rahul Goyal, Prof. Michel J. Cervantes are grateful to the Swedish Water Power Center (SVC) for the financial support. The authors would like to thank the Norwegian Hydropower Centre (NVKS) for the financial support. The measurements have been carried out in collaboration between LTU, Sweden, NTNU, Norway, and IIT Roorkee. The author?s gratitude also goes to the staff of water power laboratory, NTNU, Norway.
Corresponding Author: Goyal, R.; Department of Mechanical and Industrial Engineering, Indian Institute of TechnologyIndia; email: goel.rahul87@gmail.com
Appears in Collections:Journal Publications [ME]

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