Open this publication in new window or tab >>2020 (English)In: Sensors, E-ISSN 1424-8220, Vol. 20, no 24, article id 7220Article in journal (Refereed) Published
Abstract [en]
Smooth integration of intermittent energy sources, such as solar and wind power, into the electrical grid induces new operating conditions of the hydraulic turbine by increasing the off-design operations, start/stops, and load variations. Therefore, hydraulic turbines are subject to unstable flow conditions and unfavorable load fluctuations. Predicting load fluctuations on the runner using indirect measurements can allow for optimized operations of the turbine units, increase turbine refurbishment time intervals, and avoid structural failures in extreme cases. This paper investigates an experimental methodology to assess and predict the flow condition and load fluctuations on a Kaplan turbine runner at several steady-state operations by performing measurements on the shaft in the rotating and stationary frame of references. This unit is instrumented with several transducers such as miniature pressure transducers, strain gages, and proximity probes. The results show that for any propeller curve of a Kaplan turbine, the guide vane opening corresponding to the minimum pressure and strain fluctuations on the runner blade can be obtained by axial, torsion, and bending measurements on the shaft. Torsion measurements on the shaft could support index-testing in Kaplan turbines particularly for updating the cam-curve during the unit operation. Furthermore, a signature of every phenomenon observed on the runner blade signals, e.g., runner frequency, rotating vortex rope components, and rotor-stator interaction, is found in the data obtained from the shaft.
Place, publisher, year, edition, pages
MDPI, 2020
Keywords
prototype Kaplan turbine, load fluctuation on the runner, pressure measurement, strain measurement, axial strain, torsion strain, bending strain, indirect measurement
National Category
Fluid Mechanics and Acoustics Applied Mechanics
Research subject
Fluid Mechanics; Machine Design
Identifiers
urn:nbn:se:ltu:diva-82030 (URN)10.3390/s20247220 (DOI)000603243400001 ()33339455 (PubMedID)2-s2.0-85098144932 (Scopus ID)
Note
Validerad;2021;Nivå 2;2021-01-04 (alebob);
Finansiär: Svenskt Vattenkraftcentrum
2020-12-172020-12-172023-09-05Bibliographically approved