Numerical Simulation and Validation of a High Head Model Francis Turbine at Part Load Operating Condition

被引：20

作者：

Goyal R. ^{[1
]}

Trivedi C. ^{[2
]}

Kumar Gandhi B. ^{[1
]}

Cervantes M.J. ^{[3
]}

机构：

[1] Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee

[2] Norwegian University of Science and Technology, Trondheim

[3] Division of Fluid and Experimental Mechanics, Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå

来源：

Journal of The Institution of Engineers (India): Series C | 2018年 / 99卷 / 05期

关键词：

Francis turbine; Numerical simulation; Part load; Pressure pulsation; Rotor–stator interaction; Vortex rope;

D O I：

10.1007/s40032-017-0380-z

中图分类号：

学科分类号：

摘要：

Hydraulic turbines are operated over an extended operating range to meet the real time electricity demand. Turbines operated at part load have flow parameters not matching the designed ones. This results in unstable flow conditions in the runner and draft tube developing low frequency and high amplitude pressure pulsations. The unsteady pressure pulsations affect the dynamic stability of the turbine and cause additional fatigue. The work presented in this paper discusses the flow field investigation of a high head model Francis turbine at part load: 50% of the rated load. Numerical simulation of the complete turbine has been performed. Unsteady pressure pulsations in the vaneless space, runner, and draft tube are investigated and validated with available experimental data. Detailed analysis of the rotor stator interaction and draft tube flow field are performed and discussed. The analysis shows the presence of a rotating vortex rope in the draft tube at the frequency of 0.3 times of the runner rotational frequency. The frequency of the vortex rope precession, which causes severe fluctuations and vibrations in the draft tube, is predicted within 3.9% of the experimental measured value. The vortex rope results pressure pulsations propagating in the system whose frequency is also perceive in the runner and upstream the runner. © 2017, The Institution of Engineers (India).

引用

页码：557 / 570

页数：13

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