Transient characteristics during the co-closing guide vanes and runner blades of a bulb turbine in load rejection process

Huixiang Chen, Daqing Zhou, Kan Kan, Junxun Guo, Yuan Zheng, Maxime Binama, Zhe Xu and Jiangang Feng

Renewable Energy, 2021, vol. 165, issue P2, 28-41

Abstract: The transient characteristics associated with the machine load rejection process are investigated due to its close relationship with hydraulic facilities’ safety in low-head tubular turbines, especially in double-regulated bulb turbine. Load-rejection transient characteristics of a double regulated bulb turbine during the co-closing guide vanes (GVs) and runner blades (RBs) procedure were numerically and experimentally studied in this paper. The co-adjusting of GVs and RBs is realized through the usage of dynamic mesh technology. During the process, the speed is augmented by 33.9% by the time it reaches its peak value, where the corresponding maximum negative axial force is 43% of the initial value. The three-dimensional (3D) unsteady numerical simulation method reveals that severe impact of backflow from RBs causes significant fluctuation of torque and axial force during the co-closing procedure. A low-pressure vortex rope is also cut off by gravity-dominant pressure distribution, which leads to hydraulic instability and complex flow structure. The system performance characteristics have been obtained through experimental testing, where the dynamic instability during the co-closing procedure has been showcased. This article presents a novel prediction model and a foundations for further transient characteristics studies and prediction for turbine system with adjustable RBs and GVs.

Keywords: Double-regulated bulb turbine; Transient characteristics; Numerical simulation; Load rejection; Dynamic mesh (search for similar items in EconPapers)
Date: 2021
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Citations: View citations in EconPapers (8)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:renene:v:165:y:2021:i:p2:p:28-41

DOI: 10.1016/j.renene.2020.11.064

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