Characteristics of synchronous and asynchronous modes of fluctuations in Francis turbine draft tube during load variation

被引:2
作者
Goyal R. [1 ,2 ]
Cervantes M.J. [2 ,3 ]
Gandhi B.K. [1 ]
机构
[1] Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee
[2] Division of Fluid and Experimental Mechanics, Department of Engineering Sciences and Mathematics, Lulea University of Technology, Norrbotten
[3] Water Power Laboratory, Department of Energy and Process Engineering, Norwegian University of Science and Technology, Trondheim
关键词
Francis turbine; Load acceptance; Load rejection; Particle image velocimetry; Pressure measurements; Rotating vortex rope formation; Synchronous and asynchronous modes; Transient;
D O I
10.5293/IJFMS.2017.10.2.164
中图分类号
学科分类号
摘要
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.
引用
收藏
页码:164 / 175
页数:11
相关论文
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