scholarly journals Numerical analyses of water hammer and water-mass oscillations in a hydropower plant for the most extreme operational regimes

2019 ◽  
Vol 47 (1) ◽  
pp. 7-15
Author(s):  
Jovan Ilić ◽  
Aleksandar Petković ◽  
Ivan Božić
Keyword(s):  
Water Mass ◽  
Water Hammer ◽  
Hydropower Plant ◽  
Numerical Analyses

Transient Pressure Analysis of a Prototype Pump Turbine: Field Tests and Simulation

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Jinhong Hu ◽  
Jiandong Yang ◽  
Wei Zeng ◽  
Jiebin Yang
Keyword(s):  
Field Tests ◽  
Water Hammer ◽  
Hydropower Plant ◽  
Pressure Pulsations ◽  
Transient Pressure ◽  
Pump Turbine ◽  
Operation Conditions ◽  
Spiral Case ◽  
Transient Events ◽  
Transient Variations

The transient behaviors of a prototype pump turbine are very important to the safe operation of a pumped-storage power plant. This is because the water hammer pressure during transient events affects the pressure surges in the spiral case (SC) and the draft tube (DT). In addition, the transient pressure pulsations in the vaneless space (VL) are important in the evaluation of the life of the runner. Although several detailed studies have been conducted on the water hammer pressure of a hydropower plant, very few have considered the transient pressure pulsations that occur in the pump turbine. The objective of the present study was to determine the characteristics of the transient pressure pulsations of a 300-MW prototype Francis pump turbine during load rejection and power failure. For this purpose, the frequency features in the steady-state were first analyzed using fast Fourier transform. A Savitzky–Golay filter was then used to extract the water hammer pressure and pulsating pressure from the acquired raw pressure signals. Further, a one-dimensional (1D) method of characteristics (MOC) mathematical model of the pump-turbine was established and used to simulate the transient variations of the flow discharge during transient events, to enable the division of the transient operation conditions into several domains. Finally, the characteristics of the transient pressure pulsations in the SC, vaneless space, and DT were investigated in the time and frequency domains. This paper also discusses the causes of the pressure pulsations that occur under different modes of operation of a pump turbine.

Advance in Research on Air Cushion Surge Chamber in Hydropower Plant

2007 ◽  
Author(s):  
Jianyong Hu ◽  
Jian Zhang ◽  
Lisheng Suo ◽  
Jie Fang
Keyword(s):  
Engineering Geology ◽  
Water Hammer ◽  
Hydropower Plant ◽  
Control Mode ◽  
Normal Operation ◽  
Air Leakage ◽  
Surge Tank ◽  
Key Factor ◽  
Air Cushion ◽  
Operation Control

Air cushion surge chamber is an important measure of water hammer protection in hydropower plant. Compared with conventional surge tank, air cushion surge chamber is more efficient to decrease the water hammer pressure and improve operating condition of turbine and is more economic. At the same time, because it is often constructed in the ground, it destroyed the natural environment slightly less than conventional surge tank. Condition of engineering geology is a key factor if air cushion surge chamber will be applied. Quantity of air leakage is directly relative to the normal operation of air surge chamber. Appropriate design of operation control mode is also important to the safety of hydropower plant. In this paper, principle and application of air cushion surge chamber in hydropower plant are introduced briefly; the main engineering problems are presented; achievements of research are summarized and analyzed including engineering geology, air characteristics, prediction and control of air leakage, hydraulic performance and operation control. Finally, problems that need to be research in the future and prospective applications are provided.

Assessment and Performance Evaluation of Water Hammer in Hydroelectric Plants With Hydropneumatic Tank and Pressure Regulating Valve

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Bagaragaza Romuald ◽  
Zhang Jian ◽  
Yu Xiao Dong ◽  
Dusabemariya Claire
Keyword(s):  
Transient Flow ◽  
Negative Impact ◽  
Kinetic Characteristic ◽  
Water Hammer ◽  
Electric Power System ◽  
Water Diversion ◽  
Hydropower Plant ◽  
Pipeline System ◽  
Hydraulic Transient ◽  
The Impact

Abstract The simulation approach of pipeline systems, pressure regulating valve (PRV), and hydropneumatic tank (HPT) in hydropower plants (HPP) is performed. The article used suitable protection devices such as hydropneumatic tank and pressure regulating valves to protect the hydro-electric system against water hammer negative effects. The method of characteristics solves hydraulic transient in the HPP system. This article simulates transient phenomena in a hydro-electric power system using FORTRAN language. The aim was to find out and diminish the water hammer at the entrance of the spiral case as well as the pipeline system. The paper has four major philosophies: simulation with no protection, simulation with hydropneumatic tank, simulation with pressure regulating valve, and the combination of hydropneumatic tank with the pressure regulating valve. The results show that a combination of the pressure regulating valve and the hydropneumatic tank is adequate appliances to lessen the effect of water hammer/transient flow in a hydropower plant system. However, in the transient process of the water diversion system, the gas' kinetic characteristic in the hydropneumatic tank has certain complexity when there is high fluctuation in the surge chamber. The study proved that the wicket gate's stepwise could cut down the impact of the water hammer automatically than applying the linear closure law on the network. The automated pressure regulating valve with a high opening stepwise can decrease the negative impact of water hammer significantly. The results from this research paper show that pipeline diameter has crucial factors that influence hydraulic transient in hydropower plant systems.

Ultrastructure of Some Planktonic Formainifera

1974 ◽  
Vol 32 ◽  
pp. 190-191
Author(s):  
William H. Zucker
Keyword(s):  
Cell Biology ◽  
Water Mass ◽  
Planktonic Foraminifera ◽  
Uranyl Acetate ◽  
Ethanol Dehydration ◽  
Globigerinoides Ruber ◽  
Light Microscope Level ◽  
Globigerina Bulloides ◽  
Glutaraldehyde Solution ◽  
Diamond Knife

Planktonic foraminifera are widely-distributed and abundant zooplankters. They are significant as water mass indicators and provide evidence of paleotemperatures and events which occurred during Pleistocene glaciation. In spite of their ecological and paleological significance, little is known of their cell biology. There are few cytological studies of these organisms at the light microscope level and some recent reports of their ultrastructure.Specimens of Globigerinoides ruber, Globigerina bulloides, Globigerinoides conglobatus and Globigerinita glutinata were collected in Bermuda waters and fixed in a cold cacodylate-buffered 6% glutaraldehyde solution for two hours. They were then rinsed, post-fixed in Palade's fluid, rinsed again and stained with uranyl acetate. This was followed by graded ethanol dehydration, during which they were identified and picked clean of debris. The specimens were finally embedded in Epon 812 by placing each organism in a separate BEEM capsule. After sectioning with a diamond knife, stained sections were viewed in a Philips 200 electron microscope.

Refurbishment and upgrading of Chancy-Pougny hydropower plant

2016 ◽  
pp. 40-49 ◽  
Author(s):  
Emmanuel Maginot ◽  
Lionel Orcel ◽  
Didier Jimenez
Keyword(s):  
Hydropower Plant
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