Soltani Dehkharqani Arash, Engström Fredrik, Aidanpää Jan-Olov, Cervantes Michel J
Division of Fluid and Experimental Mechanics, Luleå University of Technology, SE-971 87 Luleå, Sweden.
Division of Product and Production Development, Luleå University of Technology, SE-971 87 Luleå, Sweden.
Sensors (Basel). 2020 Dec 16;20(24):7220. doi: 10.3390/s20247220.
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.
将太阳能和风能等间歇性能源平稳集成到电网中，会因增加非设计工况运行、启停次数及负荷变化，导致水轮机出现新的运行状况。因此，水轮机易受不稳定流动工况和不利负荷波动影响。利用间接测量来预测转轮上的负荷波动，可实现水轮机机组的优化运行，延长水轮机翻新时间间隔，并在极端情况下避免结构故障。本文研究了一种实验方法，通过在旋转和静止参考系下对轴进行测量，来评估和预测卡普兰水轮机转轮在几种稳态运行工况下的流动状况和负荷波动。该机组配备了多个传感器，如微型压力传感器、应变片和接近探头。结果表明，对于卡普兰水轮机的任何螺旋桨曲线，通过对轴进行轴向、扭转和弯曲测量，均可获得与转轮叶片上最小压力和应变波动相对应的导叶开度。轴上的扭转测量可为卡普兰水轮机的指标测试提供支持，特别是在机组运行期间更新凸轮曲线。此外，在从轴获取的数据中，发现了转轮叶片信号上观察到的每种现象的特征，如转轮频率、旋转涡带分量和动静干涉。
