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Auswahl der wissenschaftlichen Literatur zum Thema „Francis vertical turbine“
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Zeitschriftenartikel zum Thema "Francis vertical turbine"
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Ameen, Ameen Mohammed Salih, Zainah Ibrahim, Faridah Othman, Nadhir Al-Ansari und Zaher Mundher Yaseen. „Minimizing the Principle Stresses of Powerhoused Rock-Fill Dams Using Control Turbine Running Units: Application of Finite Element Method“. Water 10, Nr. 9 (25.08.2018): 1138. http://dx.doi.org/10.3390/w10091138.
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This study focuses on improving the safety of embankment dams by considering the effects of vibration due to powerhouse operation on the dam body. The study contains two main parts. In the first part, ANSYS-CFX is used to create the three-dimensional (3D) Finite Volume (FV) model of one vertical Francis turbine unit. The 3D model is run by considering various reservoir conditions and the dimensions of units. The Re-Normalization Group (RNG) k-ε turbulence model is employed, and the physical properties of water and the flow characteristics are defined in the turbine model. In the second phases, a 3D finite element (FE) numerical model for a rock-fill dam is created by using ANSYS®, considering the dam connection with its powerhouse represented by four vertical Francis turbines, foundation, and the upstream reservoir. Changing the upstream water table minimum and maximum water levels, standers earth gravity, fluid-solid interface, hydrostatic pressure, and the soil properties are considered. The dam model runs to cover all possibilities for turbines operating in accordance with the reservoir discharge ranges. In order to minimize stresses in the dam body and increase dam safety, this study optimizes the turbine operating system by integrating turbine and dam models.
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Gordon, J. L. „Hydroelectric turbine setting – a rational approach“. Canadian Journal of Civil Engineering 18, Nr. 1 (01.02.1991): 27–35. http://dx.doi.org/10.1139/l91-004.
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There are no standards for the setting of a hydraulic turbine with respect to the tailwater level. Manufacturers rely on hydraulic model data to determine the required protection against cavitation, and never publish these data. Utilities and consultants must then rely on the interpretation of published statistical data relating submergence to various turbine parameters. In this paper, an alternative approach is proposed wherein a general equation is developed relating the submergence of a stainless steel or cast steel runner to the number of runner blades, the plant capacity factor, the turbine throat velocity, the tailwater level above sea level, the water temperature, and the acceptable amount of cavitation. The equations have been tested on 39 different power plants having either horizontal or vertical axis Kaplan, propeller, or Francis turbines, both large and small. The equations are particularly useful for establishing the turbine diameter and setting during feasibility assessment, and for comparing manufacturer's suggested turbine parameters in the final design stage. The equations can also be used to determine the capacity of a new runner in an existing casing. Key words: hydroelectric, turbines, cavitation, design.
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Doan, Minh N., Yuriko Kai, Takuya Kawata und Shinnosuke Obi. „Flow Field Measurement of Laboratory-Scaled Cross-Flow Hydrokinetic Turbines: Part I—The Near-Wake of a Single Turbine“. Journal of Marine Science and Engineering 9, Nr. 5 (01.05.2021): 489. http://dx.doi.org/10.3390/jmse9050489.
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Recent developments in marine hydrokinetic (MHK) technology have put the cross-flow (often vertical-axis) turbines at the forefront. MHK devices offer alternative solutions for clean marine energy generation as a replacement for traditional hydraulic turbines such as the Francis, Kaplan, and Pelton. Following previous power measurements of laboratory-scaled cross-flow hydrokinetic turbines in different configurations, this article presents studies of the water flow field immediately behind the turbines. Two independent turbines, which operated at an average diameter-based Reynolds number of approximately 0.2×105, were driven by a stepper motor at various speeds in a closed circuit water tunnel with a constant freestream velocity of 0.316 m/s. The wakes produced by the three NACA0012 blades of each turbine were recorded with a monoscopic particle image velocimetry technique and analyzed. The flow structures with velocity, vorticity, and kinetic energy fields were correlated with the turbine power production and are discussed herein. Each flow field was decomposed into the time averaged, periodic, and random components for all the cases. The results indicate the key to refining the existed turbine design for enhancement of its power production and serve as a baseline for future comparison with twin turbines in counter-rotating configurations.
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Ha, Hyun Cheon. „Preload Effects of a Guide Bearing on the Metal Temperature and the Shaft Vibration“. Journal of Tribology 123, Nr. 1 (01.08.2000): 144–50. http://dx.doi.org/10.1115/1.1327587.
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Segment type vertical guide bearings are widely used for vertical rotating machinery; nevertheless, bearing problems, such as excessive vibration and temperature rise, frequently take place in the actual rotating machine. The purpose of the present work is to investigate the influence of preload effects of a segment type vertical guide bearing on the bearing metal temperature and the shaft vibration, in a hydraulic pump-turbine. Investigations have been performed not only by in-situ measurement but also by theoretical analysis. A guide bearing consists of eight pads and runs bi-directionally. Both the shaft vibration and the bearing metal temperature are very high in the non-preloaded bearing but are slight in the preloaded bearing, comparatively. Bearing metal temperature is decreased by the increase of cooling effect of the lubricant due to the preload effect. Shaft vibration is also decreased by the increase of bearing stiffness. Theoretical analysis shows that the segment type vertical guide bearing has an optimum preload ratio at which the bearing stiffness reaches a maximum value while the bearing metal temperature is minimized. Furthermore, it is found that the characteristics of shaft vibration of a Francis type hydraulic pump-turbine highly depend on the generating power.
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Kurir, Valerij. „Optimization the shape of the Francis hydraulic turbine“. E3S Web of Conferences 220 (2020): 01067. http://dx.doi.org/10.1051/e3sconf/202022001067.
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The article presents one of the possible methods for optimizing the blade shape of a Francis radial-axial hydraulic turbine. The method for optimizing the shape of the turbine blade is based on the criterion of the maximum mechanical moment developed by the turbine. The blade shape optimization operation is conventionally divided into two stages. At the first stage of optimization of the blade shape, the analytical expression of the moment developed by the turbine is presented in a Taylor series by variable parameters − the coordinates of the vertices of the characteristic polyhedron of the median surface of the turbine blade. Adding the boundary conditions in the formulation of the optimization problem in the form of equalities − the contact of the median surface of the turbine blade with the turbine hub and rim, as well as conditions in the form of inequalities − the concavity of the greater part the median surface allows to reduce the problem of optimizing the blade shape to a standard linear programming problem. It is proposed to carry out 50−60 similar operations with small steps in the variables − the coordinates of the vertices of the characteristic polyhedron. Thus, it is necessary to move into the zone of optimal values of the coordinates of the vertices of the characteristic polyhedron of the median surface of the blade. At the second stage, it is proposed to continue the search for the optimal values of the coordinates of the vertices of the characteristic polyhedron of the median surface of the blade, applying for this purpose one of the most effective algorithms of genetic optimization.
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Childs, Dara W., und Ameen Muhammed. „Comments on a Newly-Identified Destabilizing Rotordynamic Mechanism Arising in Vertical Hydraulic Turbines and the Back Shrouds of Centrifugal Impellers“. Journal of Engineering for Gas Turbines and Power 136, Nr. 4 (10.12.2013). http://dx.doi.org/10.1115/1.4025889.
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In three 2010 papers, Tsujimoto et al. (2010, “Moment Whirl Due to Leakage Flow in the Back Shroud Clearance of a Rotor,” Int. J. Fluid Mach. Syst., 3(3), pp. 235–244), Song et al. (2010, “Rotordynamic Instability Caused by the Fluid Force Moments on the Backshroud of a Francis Turbine Runner,” Int. J. Fluid Mach. Syst., 3(1), pp. 76–79), and Song et al. (2010, “Rotordynamic Moment on the Backshroud of a Francis Turbine Runner Under Whirling Motion,” ASME J. Fluids Eng., 132, p. 071102) discussed and explained a novel destabilizing mechanism arising in both hydraulic turbines and the back surface of vertical pump impellers. The destabilizing mechanism can be explained via a reaction force-moment model that includes both the customary radial displacement vector of an impeller plus the pitch and yaw degrees of freedom. This coupling between radial displacements and tilt plus the coupling of the shaft support structure can create negative damping. In 1993, Verhoeven et al. (1993, “Rotor Instability of a Single Stage Centrifugal Pump, Supersynchronous Whirling at Almost Twice the Operating Speed, A Case History,” Proceedings of the 1st International Symposium on Pump Noise and Vibration, pp. 457–468) identified negative damping arising from U-shaped wearing-ring seals as causing a super-synchronous instability in a horizontal coke-crusher pump. However, several case studies have been presented of super-synchronously unstable pumps for which (until now) no explanation could be provided. Tsujimoto–Song started with a 2DOF model for a vertically suspended disk via a cantilevered shaft. They used an f = ma model for the lateral displacements of the disk and used flexibility coefficients to account for reaction forces and moments from the back shroud of the impeller. The present work starts with a 4DOF model that includes the disk's displacements and pitch and yaw degrees of freedom. The Guyan reduction is used to create two reduced 2DOF models: model A that retains the displacements and discards the rotations and model B that retains the rotations and discards the displacements. Model A produces a requirement for instability that is inconsistent with Tsujimoto–Song's experience and predictions. However, it is useful in predicting the reaction moments produced by a nominally planar precession of the impeller. The instability requirement of Model B is consistent with Tsujimoto's experience and predictions. A comparison of the predicted reaction moments of model A and Tsujimoto's reaction-moment data supports the instability predictions of model B (and Tsujimoto–Song) that the instability arises due to coupling between the displacement and rotation degrees of freedom in the 4 × 4 damping matrix.
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Koirala, Ravi, Bhola Thapa, Biraj Singh Thapa und Balendra Chhetry. „Design optimization of head cover of vertical francis turbine from maintenance perspective in context to sediment laden river projects“. Fluid Mechanics research International Journal 2, Nr. 1 (31.01.2018). http://dx.doi.org/10.15406/fmrij.2018.02.00016.
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Dhakal, Ganesh P., Kazumoto Onodera und Tetsuro Yoneda. „Geotechnical studies of the Lam Ta Khong pumped storage project, Thailand“. Journal of Nepal Geological Society 22 (01.12.2000). http://dx.doi.org/10.3126/jngs.v22i0.32316.
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The Lam Ta Khong Project in Nakhornratchasima is the biggest pumped storage hydropower project of Thailand. The project is capable of producing 1,000 MW of electricity at the peak hour of demand. It consists of an upper pond transitory reservoir, twin inclined penstocks, a powerhouse, twin surge chambers, and twin tailrace tunnels. The powerhouse is underground with the dimensions of 175x25x50 m3, and houses 4 (each of 250 MW capacity) Francis type reversible pump turbines.
The rock mass classification system of the Electric Power Development Co. Ltd. (EPDC), Japan, was used in the project area in order to select an appropriate support system for the tunnel. The majority of rocks in the project area are sandstone and siltstone. The sandstone is interbedded with claystone at shallow depths. The sandstone at greater depths is fine grained and contains two sets of joint nearly perpendicular to each other and almost vertical. These joints were responsible for frequent block falls during the excavation. Especially, the joint surfaces with slickensides contributed to frequent block falls. The near-surface highly weathered rocks required stronger support for the excavated part than the less weathered ones at greater depths. The deformation of rock mass due to excavation in the powerhouse was monitored by nine multiple borehole extensometers with one to four measuring heads (points). The monitoring results showed safe conditions in the powerhouse.
Dissertationen zum Thema "Francis vertical turbine"
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Sitte, David. „Odezva atypického vertikálního rotoru vodní turbíny na buzení nevývažkem oběžného kola a nevývažkem rotoru generátoru“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443737.
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This master’s thesis deals with the dynamic behaviour of vertical Francis turbine, which is atypical its shaft length. In the first part of thesis, there is theoretic research of water turbine, which is followed by derivation of equations for the Stodola rotor. The second part deals with the creation of the turbine shaft in 1D and 3D. A modal analysis was performed in the ANSYS Workbench software, based on which the Campbell diagram is created and it was determined the critical speed. And the harmonic analysis from which was determined the forces response in radial bearings, amplitude of deviation in radial direction in the turbine impeller and the generator and the axial displacement located in turbine impeller and axial bearing. 1D and 3D solutions were compared between themselves.
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Brandão, Jose Geraldo Trani. „Vibrações em turbina francis com enfase em vertice de nucleo“. [s.n.], 1987. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264839.
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Orientadores: Hans Ingo Weber, Marcio Tadeu de AlmeidaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Campinas
Made available in DSpace on 2018-07-14T07:21:41Z (GMT). No. of bitstreams: 1 Brandao_JoseGeraldoTrani_M.pdf: 2216073 bytes, checksum: 9c04e0dfde6fa264a12e6fe97f2a7d6d (MD5) Previous issue date: 1987
Resumo: No Brasil grande parte das Usinas Hidrelétrica utiliza Turbinas Francis, onde existe uma grande quantidade de fenômenos vibratórios que trazem sérios problemas estruturais. As vibrações tornam-se problemáticas quando as mesmas operam em carga parcial, e o fenômeno, aqui denominado de "Vórtice de Núcleo", se destaca excitando as estruturas em baixa freqüência. Este problema tornou-se mais crítico a partir da época em que se começou a utilização de Turbinas Francis da nova geração, denominadas Turbinas Francis Rápidas. Objetivando estudar o fenômeno na sua forma de excitação, na faixa de operação em que o mesmo atua com maior intensidade e, se possível, fornecer subsídios para o projeto destas máquinas hidráulicas, o fenômeno foi modelado e testa do em um banco experimental de ensaio com um modelo reduzido, onde se pode verificar a sua validade.
Abstract:The most of Hydroelectric Power Plants, in Brazil, use Francis Turbines, where a lot of vibrating phenomenon's result in serious structural problems.The vibrations cause so much trouble, mainly, when the turbines operate under part loads and the phenomenon, here named the "Vortex Core", appears excitating the structures at low frequencies. The problem caused by the vibrations became more critical since the first use of the new generation Francis Turbines called Fast Francis Turbine. With the purpose of studying the excitation provoked by Vortex Core phenomenon, in the operation Range where it drives the turbine with its highest intensity, and if possible, to give more information for the design of these hydraulic machines, the phenomenon was modeled and tested in an experimental set up using a small turbine where the validity of the mathematical model was checked.
Mestrado
Mestre em Engenharia Mecânica
Bücher zum Thema "Francis vertical turbine"
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Wolf, E. L. Wind, hydro and tides Fully sustainable energy. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198769804.003.0008.
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Wind-turbine science and technology is outlined, following the work of Betz. Rotor design, blade construction and aspects of electric power generation are described, principally for large horizontal-axis devices, with some mention of vertical axis wind turbines. Hydropower and pumped storage are treated, with mention of Francis and Kaplan turbines. A summary of tidal energy is included. We now go into detail on some aspects of these topics. As these forms of energy come either from the Sun (in an indirect fashion) or from the motion of the Earth and Moon, they are available on an indefinite term into the future.
Konferenzberichte zum Thema "Francis vertical turbine"
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Faria, Marco Tulio C., Fernando R. Queiroz, Eduardo B. Medeiros und Carlos B. Martinez. „Acoustic Emission Tests in the Monitoring of Cavitation Erosion in Hydraulic Turbines“. In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62960.
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This work presents an experimental study about the application of acoustic emission (AE) techniques in the monitoring of cavitation erosion mass loss in small Francis turbines. A vertical Francis turbine test bench is specially devised to perform some experiments designed to evaluate the influence of small surface mass losses on turbine blades in the acoustic emission signals. An AE wideband transducer is employed in the test bench instrumentation system. In order to evaluate the AE levels associated with the turbine erosion stages, a small defect is introduced into the turbine runner. This defect is intended to simulate a small mass loss in the turbine runner. The measurements of the AE signals are performed in the Turbine Francis model at two situations: 1) turbine without defect, which means that the runner blades are free of apparent geometric imperfections; 2) turbine with defect, which is represented by a small hole drilled into a runner blade. The AE transducer is installed on the turbine draft tube and the AE measurements are performed at several operating conditions. The preliminary results obtained for the AE amplitude in this investigation show that the small defect introduced into a runner blade causes variations in the AE levels measured in the experiments, confirming that there is a large potential for the application of AE monitoring techniques in the accurate evaluation of cavitation wear on hydraulic turbines in field.
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Dourado, Arinan De P., Jefferson S. Barbosa, Tobias S. Morais, Aldemir Ap Cavalini und Valder Steffen. „Uncertainty Analysis of a Francis Hydropower Unit“. In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85428.
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This contribution is dedicated to the analysis of uncertainties affecting the vibration responses of a Francis hydropower unit. The system is composed by a vertical rotor and three hydrodynamic bearings: i) a combined tilting-pad guide/thrust bearing, located close to the generator; ii) an intermediate radial tilting-pad bearing; iii) and a cylindrical bearing located close to the Francis turbine. The bearings are represented by using linearized stiffness and damping coefficients. A fuzzy uncertainty analysis was applied aiming at determining the extreme vibration responses of the system. In this case, the bearings stiffness coefficients, generator mass, and Young’s modulus of the shaft were considered as uncertain information. The fuzzy analysis was carried out through the so-called α-level optimization approach due to its mathematical simplicity. Finally, a sensitivity analysis was performed based on the obtained results to determine the uncertain parameters that most affect the rotor responses. The obtained results demonstrate the representativeness of the conveyed methodology.
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Menet, J. L., und S. Dupont. „Aerodynamic characterization of a vertical axis wind turbine using a mechatronical experimental setup“. In 2016 11th France-Japan & 9th Europe-Asia Congress on Mechatronics (MECATRONICS) /17th Internationall Conference on Research and Education in Mechatronics (REM). IEEE, 2016. http://dx.doi.org/10.1109/mecatronics.2016.7547146.
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