Multi-objective shape optimization of runner blade for Kaplan turbine

Science.gov (United States)

Semenova, A.; Chirkov, D.; Lyutov, A.; Chemy, S.; Skorospelov, V.; Pylev, I.

2014-03-01

Automatic runner shape optimization based on extensive CFD analysis proved to be a useful design tool in hydraulic turbomachinery. Previously the authors developed an efficient method for Francis runner optimization. It was successfully applied to the design of several runners with different specific speeds. In present work this method is extended to the task of a Kaplan runner optimization. Despite of relatively simpler blade shape, Kaplan turbines have several features, complicating the optimization problem. First, Kaplan turbines normally operate in a wide range of discharges, thus CFD analysis of each variant of the runner should be carried out for several operation points. Next, due to a high specific speed, draft tube losses have a great impact on the overall turbine efficiency, and thus should be accurately evaluated. Then, the flow in blade tip and hub clearances significantly affects the velocity profile behind the runner and draft tube behavior. All these features are accounted in the present optimization technique. Parameterization of runner blade surface using 24 geometrical parameters is described in details. For each variant of runner geometry steady state three-dimensional turbulent flow computations are carried out in the domain, including wicket gate, runner, draft tube, blade tip and hub clearances. The objectives are maximization of efficiency in best efficiency and high discharge operation points, with simultaneous minimization of cavitation area on the suction side of the blade. Multiobjective genetic algorithm is used for the solution of optimization problem, requiring the analysis of several thousands of runner variants. The method is applied to optimization of runner shape for several Kaplan turbines with different heads.

Efficiency limit factor analysis for the Francis-99 hydraulic turbine

Science.gov (United States)

Zeng, Y.; Zhang, L. X.; Guo, J. P.; Guo, Y. K.; Pan, Q. L.; Qian, J.

2017-01-01

The energy loss in hydraulic turbine is the most direct factor that affects the efficiency of the hydraulic turbine. Based on the analysis theory of inner energy loss of hydraulic turbine, combining the measurement data of the Francis-99, this paper calculates characteristic parameters of inner energy loss of the hydraulic turbine, and establishes the calculation model of the hydraulic turbine power. Taken the start-up test conditions given by Francis-99 as case, characteristics of the inner energy of the hydraulic turbine in transient and transformation law are researched. Further, analyzing mechanical friction in hydraulic turbine, we think that main ingredients of mechanical friction loss is the rotation friction loss between rotating runner and water body, and defined as the inner mechanical friction loss. The calculation method of the inner mechanical friction loss is given roughly. Our purpose is that explore and research the method and way increasing transformation efficiency of water flow by means of analysis energy losses in hydraulic turbine.

Evaluation of Hydraulic Loads on the Runner Blades of a Kaplan Turbine using CFD Simulation and Model Test

Directory of Open Access Journals (Sweden)

Zoltan-Iosif Korka

2016-10-01

Full Text Available CFD (Computational Fluid Dynamic is today a standard procedure for analyzing and simulating the flow through several hydraulic machines. In this process, the fluid flow domain is divided into small volumes where the governing equations are converted into algebraic ones, which are numerically solved. Computational results strongly depend on the applied mathematical model and on the numerical methods used for converting the governing equations into the algebraic ones. The goal of the paper is to evaluate, by numerical simulation, the hydraulic loads (forces and torques on the runner blades of an existent Kaplan turbine and to compare them with the experimental results obtained from model test.

Overview of SPH-ALE applications for hydraulic turbines in ANDRITZ Hydro

Science.gov (United States)

Rentschler, M.; Marongiu, J. C.; Neuhauser, M.; Parkinson, E.

2018-02-01

Over the past 13 years, ANDRITZ Hydro has developed an in-house tool based on the SPH-ALE method for applications in flow simulations in hydraulic turbines. The initial motivation is related to the challenging simulation of free surface flows in Pelton turbines, where highly dynamic water jets interact with rotating buckets, creating thin water jets traveling inside the housing and possibly causing disturbances on the runner. The present paper proposes an overview of industrial applications allowed by the developed tool, including design evaluation of Pelton runners and casings, transient operation of Pelton units and free surface flows in hydraulic structures.

Experience in small hydropower indigenous manufacture of mini hydraulic turbines

Energy Technology Data Exchange (ETDEWEB)

Luo Gao Rong [Organization of the United Nations, Beijing (China). International Centre of Small Hydropowers

1995-07-01

This document reports the China experience with fabrication of mini hydraulic turbines for small hydroelectric power plants. The document presents the necessity of indigenous manufacture for MHP equipment, the standardized and serialized production, the planning of the series of turbines, the manufacturing of turbine runners, and as a case study the basic conditions for manufacturing MHP turbines.

Optimization of hydraulic turbine diffuser

Directory of Open Access Journals (Sweden)

Moravec Prokop

2016-01-01

Full Text Available Hydraulic turbine diffuser recovers pressure energy from residual kinetic energy on turbine runner outlet. Efficiency of this process is especially important for high specific speed turbines, where almost 50% of available head is utilized within diffuser. Magnitude of the coefficient of pressure recovery can be significantly influenced by designing its proper shape. Present paper focuses on mathematical shape optimization method coupled with CFD. First method is based on direct search Nelder-Mead algorithm, while the second method employs adjoint solver and morphing. Results obtained with both methods are discussed and their advantages/disadvantages summarized.

Analysis of Pressure Fluctuations in a Prototype Pump-Turbine with Different Numbers of Runner Blades in Turbine Mode

Directory of Open Access Journals (Sweden)

Deyou Li

2018-06-01

Full Text Available In pump-turbines, high pressure fluctuation is one of the crucial instabilities, which is harmful to the stable and effective operation of the entire unit. Extensive studies have been carried out to investigate pressure fluctuations (amplitude and frequency at specific locations. However, limited research was conducted on the distribution of pressure fluctuations in turbine mode in a pump-turbine, as well as the influence of the number of runner blades on pressure fluctuations. Hence, in this study, three dimensional numerical simulations were performed to predict the distribution of pressure fluctuations with different numbers of runner blades in a prototype pump-turbine in turbine mode using the shear stress transport (SST k-ω turbulence model. Three operating points with the same hydraulic head and different mass flow rates were simulated. The distribution of pressure fluctuation components of blade passing frequency and its harmonics in the direction along the whole flow path, as well as along the circumferential direction, was presented. The mass flow rate and number of runner blades have great influence on the distribution of pressure fluctuations, especially at blade passing frequency along circumferential direction. The mass flow rate mainly affects the position of peak pressure fluctuations, while the number of runner blades mainly changes the number of peak pressure fluctuations. Additionally, the number of runner blades influences the dominant frequencies of pressure fluctuations especially in the spiral casing and draft tube.

Failure analysis of a Francis turbine runner

Energy Technology Data Exchange (ETDEWEB)

Frunzaverde, D; Campian, V [Research Center in Hydraulics, Automation and Heat Transfer, ' Eftimie Murgu' University of Resita P-ta Traian Vuia 1-4, RO-320085, Resita (Romania); Muntean, S [Centre of Advanced Research in Engineering Sciences, Romanian Academy - Timisoara Branch Bv. Mihai Viteazu 24, RO-300223, Timisoara (Romania); Marginean, G [University of Applied Sciences Gelsenkirchen, Neidenburger Str. 10, 45877 Gelsenkirchen (Germany); Marsavina, L [Department of Strength, ' Politehnica' University of Timisoara, Bv. Mihai Viteazu 1, RO-300222, Timisoara (Romania); Terzi, R; Serban, V, E-mail: gabriela.marginean@fh-gelsenkirchen.d, E-mail: d.frunzaverde@uem.r [Ramnicu Valcea Subsidiary, S.C. Hidroelectrica S.A., Str. Decebal 11, RO-240255, Ramnicu Valcea (Romania)

2010-08-15

The variable demand on the energy market requires great flexibility in operating hydraulic turbines. Therefore, turbines are frequently operated over an extended range of regimes. Francis turbines operating at partial load present pressure fluctuations due to the vortex rope in the draft tube cone. This phenomenon generates strong vibrations and noise that may produce failures on the mechanical elements of the machine. This paper presents the failure analysis of a broken Francis turbine runner blade. The failure appeared some months after the welding repair work realized in situ on fatigue cracks initiated near to the trailing edge at the junction with the crown, where stress concentration occurs. In order to determine the causes that led to the fracture of the runner blade, the metallographic investigations on a sample obtained from the blade is carried out. The metallographic investigations included macroscopic and microscopic examinations, both performed with light and scanning electron microscopy, as well as EDX - analyses. These investigations led to the conclusion, that the cracking of the blade was caused by fatigue, initiated by the surface unevenness of the welding seam. The failure was accelerated by the hydrogen embrittlement of the filling material, which appeared as a consequence of improper welding conditions. In addition to the metallographic investigations, numerical computations with finite element analysis are performed in order to evaluate the deformation and stress distribution on blade.

Failure analysis of a Francis turbine runner

International Nuclear Information System (INIS)

Frunzaverde, D; Campian, V; Muntean, S; Marginean, G; Marsavina, L; Terzi, R; Serban, V

2010-01-01

The variable demand on the energy market requires great flexibility in operating hydraulic turbines. Therefore, turbines are frequently operated over an extended range of regimes. Francis turbines operating at partial load present pressure fluctuations due to the vortex rope in the draft tube cone. This phenomenon generates strong vibrations and noise that may produce failures on the mechanical elements of the machine. This paper presents the failure analysis of a broken Francis turbine runner blade. The failure appeared some months after the welding repair work realized in situ on fatigue cracks initiated near to the trailing edge at the junction with the crown, where stress concentration occurs. In order to determine the causes that led to the fracture of the runner blade, the metallographic investigations on a sample obtained from the blade is carried out. The metallographic investigations included macroscopic and microscopic examinations, both performed with light and scanning electron microscopy, as well as EDX - analyses. These investigations led to the conclusion, that the cracking of the blade was caused by fatigue, initiated by the surface unevenness of the welding seam. The failure was accelerated by the hydrogen embrittlement of the filling material, which appeared as a consequence of improper welding conditions. In addition to the metallographic investigations, numerical computations with finite element analysis are performed in order to evaluate the deformation and stress distribution on blade.

Experiences with the hydraulic design of the high specific speed Francis turbine

International Nuclear Information System (INIS)

Obrovsky, J; Zouhar, J

2014-01-01

The high specific speed Francis turbine is still suitable alternative for refurbishment of older hydro power plants with lower heads and worse cavitation conditions. In the paper the design process of such kind of turbine together with the results comparison of homological model tests performed in hydraulic laboratory of ČKD Blansko Engineering is introduced. The turbine runner was designed using the optimization algorithm and considering the high specific speed hydraulic profile. It means that hydraulic profiles of the spiral case, the distributor and the draft tube were used from a Kaplan turbine. The optimization was done as the automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. The number of blades is shown as the parameter which changes the resulting specific speed of the turbine between n s =425 to 455 together with the cavitation characteristics. Minimizing of cavitation on the blade surface as well as on the inlet edge of the runner blade was taken into account during the design process. The results of CFD analyses as well as the model tests are mentioned in the paper

Experiences with the hydraulic design of the high specific speed Francis turbine

Science.gov (United States)

Obrovsky, J.; Zouhar, J.

2014-03-01

The high specific speed Francis turbine is still suitable alternative for refurbishment of older hydro power plants with lower heads and worse cavitation conditions. In the paper the design process of such kind of turbine together with the results comparison of homological model tests performed in hydraulic laboratory of ČKD Blansko Engineering is introduced. The turbine runner was designed using the optimization algorithm and considering the high specific speed hydraulic profile. It means that hydraulic profiles of the spiral case, the distributor and the draft tube were used from a Kaplan turbine. The optimization was done as the automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. The number of blades is shown as the parameter which changes the resulting specific speed of the turbine between ns=425 to 455 together with the cavitation characteristics. Minimizing of cavitation on the blade surface as well as on the inlet edge of the runner blade was taken into account during the design process. The results of CFD analyses as well as the model tests are mentioned in the paper.

Effects of draft tube on the hydraulic performance of a Francis turbine

International Nuclear Information System (INIS)

Jeon, J H; Byeon, S S; Kim, Y J

2013-01-01

The draft tube is an important component of a Francis turbine which influences the hydraulic performance. It is located just under the runner and allowed to decelerate the flow velocity exiting the runner, thereby converting the excess of kinetic energy into static pressure. In this study, we have numerically investigated the hydraulic performance of a Francis turbine on the 15MW hydropower generation with various design parameters (three types of draft tube, thickness of guide vane) through a three-dimensional numerical method with the SST turbulent model. The vortex rope characteristics of the draft tube were confirmed. The results of the vortex flow fields and flow characteristics were graphically depicted with different design parameters and operating conditions

Study on an Axial Flow Hydraulic Turbine with Collection Device

Directory of Open Access Journals (Sweden)

Yasuyuki Nishi

2014-01-01

Full Text Available We propose a new type of portable hydraulic turbine that uses the kinetic energy of flow in open channels. The turbine comprises a runner with an appended collection device that includes a diffuser section in an attempt to improve the output by catching and accelerating the flow. With such turbines, the performance of the collection device, and a composite body comprising the runner and collection device were studied using numerical analysis. Among four stand-alone collection devices, the inlet velocity ratio was most improved by the collection device featuring an inlet nozzle and brim. The inlet velocity ratio of the composite body was significantly lower than that of the stand-alone collection device, owing to the resistance of the runner itself, the decreased diffuser pressure recovery coefficient, and the increased backpressure coefficient. However, at the maximum output tip speed ratio, the inlet velocity ratio and the loading coefficient were approximately 31% and 22% higher, respectively, for the composite body than for the isolated runner. In particular, the input power coefficient significantly increased (by approximately 2.76 times owing to the increase in the inlet velocity ratio. Verification tests were also conducted in a real canal to establish the actual effectiveness of the turbine.

Experimental and Numerical Simulations Predictions Comparison of Power and Efficiency in Hydraulic Turbine

Directory of Open Access Journals (Sweden)

Laura Castro

2011-01-01

Full Text Available On-site power and mass flow rate measurements were conducted in a hydroelectric power plant (Mexico. Mass flow rate was obtained using Gibson's water hammer-based method. A numerical counterpart was carried out by using the commercial CFD software, and flow simulations were performed to principal components of a hydraulic turbine: runner and draft tube. Inlet boundary conditions for the runner were obtained from a previous simulation conducted in the spiral case. The computed results at the runner's outlet were used to conduct the subsequent draft tube simulation. The numerical results from the runner's flow simulation provided data to compute the torque and the turbine's power. Power-versus-efficiency curves were built, and very good agreement was found between experimental and numerical data.

Research of performance prediction to energy on hydraulic turbine

International Nuclear Information System (INIS)

Quan, H; Li, R N; Li, Q F; Han, W; Su, Q M

2012-01-01

Refer to the low specific speed Francis turbine blade design principle and double-suction pump structure. Then, design a horizontal double-channel hydraulic turbine Francis. Through adding different guide vane airfoil and and no guide vane airfoil on the hydraulic conductivity components to predict hydraulic turbine energy and using Fluent software to numerical simulation that the operating conditions and point. The results show that the blade pressure surface and suction surface pressure is low when the hydraulic turbine installation is added standard positive curvature of the guide vane and modified positive curvature of guide vane. Therefore, the efficiency of energy recovery is low. However, the pressure of negative curvature guide vane and symmetric guide vane added on hydraulic turbine installations is larger than that of the former ones, and it is conducive to working of runner. With the decreasing of guide vane opening, increasing of inlet angle, flow state gets significantly worse. Then, others obvious phenomena are that the reflux and horizontal flow appeared in blade pressure surface. At the same time, the vortex was formed in Leaf Road, leading to the loss of energy. Through analyzing the distribution of pressure, velocity, flow lines of over-current flow in the the back hydraulic conductivity components in above programs we can known that the hydraulic turbine installation added guide vane is more reasonable than without guide vanes, it is conducive to improve efficiency of energy conversion.

Mixed-flow vertical tubular hydraulic turbine. Determination of proper design duty point

Energy Technology Data Exchange (ETDEWEB)

Sirok, B. [Ljubljana Univ. (Slovenia). Faculty of Mechanical Engineering; Bergant, A. [Litostroj Power, d.o.o., Ljubljana (Slovenia); Hoefler, E.

2011-12-15

A new vertical single-regulated mixed-flow turbine with conical guide apparatus and without spiral casing is presented in this paper. Runner blades are fixed to the hub and runner band and resemble to the Francis type runner of extremely high specific speed. Due to lack of information and guidelines for the design of a new turbine, a theoretical model was developed in order to determinate the design duty point, i.e. to determine the optimum narrow operation range of the turbine. It is not necessary to know the kinematic conditions at the runner inlet, but only general information on the geometry of turbine flow-passage, meridional contour of the runner and blading, the number of blades and the turbine speed of rotation. The model is based on the integral tangential lift coefficient, which is the average value over the entire runner blading. The results are calculated for the lift coefficient 0.5 and 0.6, for the flow coefficient range from 0.2 to 0.36, for the number of the blades between 5 and 13, and are finally presented in the Cordier diagram (specific speed vs. specific diameter). Calculated results of the turbine optimum operation in Cordier diagram correspond very well to the adequate area of Kaplan turbines with medium and low specific speed and extends into the area of Francis turbines with high specific speed. Presented model clearly highlights the parameters that affect specific load of the runner blade row and therefore the optimum turbine operation (discharge - turbine head). The presented method is not limited to a specific reaction type of the hydraulic turbine. The method can therefore be applied to a wide range from mixed-flow (radial-axial) turbines to the axial turbines. Applicability of the method may be considered as a tool in the first stage of the turbine design i.e. when designing the meridional geometry and selecting the number of blades according to calculated operating point. Geometric and energy parameters are generally defined to an

New parameters influencing hydraulic runner lifetime

International Nuclear Information System (INIS)

Sabourin, M; Bouffard, D A; Thibault, D; Levesque, M

2010-01-01

Traditionally, hydraulic runner mechanical design is based on calculation of static stresses. Today, validation of hydraulic runner design in terms of reliability requires taking into account the fatigue effect of dynamics loads. A damage tolerant approach based on fracture mechanics is the method chosen by Alstom and Hydro-Quebec to study fatigue damage in runners. This requires a careful examination of all factors influencing material fatigue behavior. Such material behavior depends mainly on the chemical composition, microstructure and thermal history of the component, and on the resulting residual stresses. Measurement of fracture mechanics properties of various steels have demonstrated that runner lifetime can be significantly altered by differences in the manufacturing process, although remaining in accordance with agreed practices and standards such as ASTM. Carbon content and heat treatment are suspected to influence fatigue lifetime. This will have to be investigated by continuing the current research.

New parameters influencing hydraulic runner lifetime

Energy Technology Data Exchange (ETDEWEB)

Sabourin, M; Bouffard, D A [Alstom Hydro Canada Inc, Hydraulic Engineering, 1350 chemin St-Roch, Sorel-Tracy (Quebec), J3P 5P9 (Canada); Thibault, D [Hydro-Quebec, Institut de Recherche d' Hydro-Quebec 1800 boul. Lionel-Boulet, Varennes (Quebec), J3X 1S1 (Canada); Levesque, M, E-mail: michel.sabourin@power.alstom.co [Ecole Polytechnique de Montreal, Departement de genie mecanique C.P.6079, succ. Centre-ville, Montreal (Quebec), H3C 3A7 (Canada)

2010-08-15

Traditionally, hydraulic runner mechanical design is based on calculation of static stresses. Today, validation of hydraulic runner design in terms of reliability requires taking into account the fatigue effect of dynamics loads. A damage tolerant approach based on fracture mechanics is the method chosen by Alstom and Hydro-Quebec to study fatigue damage in runners. This requires a careful examination of all factors influencing material fatigue behavior. Such material behavior depends mainly on the chemical composition, microstructure and thermal history of the component, and on the resulting residual stresses. Measurement of fracture mechanics properties of various steels have demonstrated that runner lifetime can be significantly altered by differences in the manufacturing process, although remaining in accordance with agreed practices and standards such as ASTM. Carbon content and heat treatment are suspected to influence fatigue lifetime. This will have to be investigated by continuing the current research.

Extensive use of computational fluid dynamics in the upgrading of hydraulic turbines

Energy Technology Data Exchange (ETDEWEB)

Sabourin, M.; Eremeef, R.; De Henau, V.

1995-12-31

Computational fluid dynamics codes, based on turbulent Navier-Stokes equations, allow evaluation of the hydraulic losses of each turbine component with precision. Using those codes with the new generation of computers enables a wide variety of component geometries to be modelled and compared to the original designs under flow conditions obtained from testing, at a reasonable cost and in a relatively short time. This paper reviews the actual method used in the design of a solution to a turbine rehabilitation project involving runner replacement, redesign of upstream components (stay vanes and wicket gates), and downstream components (draft tubes and runner outlets). The paper shows how computational fluid dynamics can help hydraulic engineers to obtain valuable information not only on performance enhancement but also on the phenomena that produce the enhancement, and to reduce the variety of modifications to be tested.

Studies on water turbine runner which fish can pass through: In case of single stage axial runner

International Nuclear Information System (INIS)

Shimizu, Yukimari; Maeda, Takao; Nagoshi, Osamu; Ieda, Kazuma; Shinma, Hisako; Hagimoto, Michiko

1994-01-01

The relationship between water turbine runner design and operation and the safe passage of fish through the turbine is studied. The kinds of fish used in the tests are a dace, a sweet fish and a small salmon. A single stage axial runner is used. The velocity and pressure distributions were measured inside the turbine casing and along the casing wall. Many pictures showing fish passing through the rotating runner were taken and analyzed. The swimming speed of the fish was examined from video recordings. Fish pass through the runner more rapidly when they can determine and choose the easier path. Injury and mortality of fish are affected by the runner speed and the location of impact of the runner on the fish body

Hydraulic turbines

International Nuclear Information System (INIS)

Meluk O, G.

1998-01-01

The hydraulic turbines are defined according to the specific speed, in impulse turbines and in reaction turbines. Currently, the Pelton turbines (of impulse) and the Francis and Kaplan turbines (of reaction), they are the most important machines in the hydroelectric generation. The hydraulic turbines are capable of generating in short times, large powers, from its loads zero until the total load and reject the load instantly without producing damages in the operation. When the hydraulic resources are important, the hydraulic turbines are converted in the axle of the electric system. Its combination with thermoelectric generation systems, it allow the continuing supply of the variations in demand of energy system. The available hydraulic resource in Colombia is of 93085 MW, of which solely 9% is exploited, become 79% of all the electrical country generation, 21% remaining is provided by means of the thermoelectric generation

Determination of the performance of the Kaplan hydraulic turbines through simplified procedure

Science.gov (United States)

Pădureanu, I.; Jurcu, M.; Campian, C. V.; Haţiegan, C.

2018-01-01

A simplified procedure has been developed, compared to the complex one recommended by IEC 60041 (i.e. index samples), for measurement of the performance of the hydraulic turbines. The simplified procedure determines the minimum and maximum powers, the efficiency at maximum power, the evolution of powers by head and flow and to determine the correct relationship between runner/impeller blade angle and guide vane opening for most efficient operation of double-regulated machines. The simplified procedure can be used for a rapid and partial estimation of the performance of hydraulic turbines for repair and maintenance work.

ANALYTICAL EVALUATION OF CRACK PROPAGATION FOR BULB HYDRAULIC TURBINES SHAFTS

Directory of Open Access Journals (Sweden)

Mircea O. POPOVICU

2011-05-01

Full Text Available The Hydroelectric Power Plants uses the regenerating energy of rivers. The hydraulic Bulb turbines running with low heads are excellent alternative energy sources. The shafts of these units present themselves as massive pieces, with cylindrical shape, manufactured from low-alloyed steels. The paper analyses the fatigue cracks occurring at some turbines in the neighbourhood of the connection zone between the shaft and the turbine runner flange. To obtain the tension state in this zone ANSIS and AFGROW computing programs were used. The number of running hours until the piercing of the shaft wall is established as a useful result.

CFD Simulation and Optimization of Very Low Head Axial Flow Turbine Runner

Directory of Open Access Journals (Sweden)

Yohannis Mitiku Tobo

2015-10-01

Full Text Available The main objective of this work is Computational Fluid Dynamics (CFD modelling, simulation and optimization of very low head axial flow turbine runner  to be used to drive  a centrifugal pump of turbine-driven pump. The ultimate goal of the optimization is to produce a power of 1kW at head less than 1m from flowing  river to drive centrifugal pump using mechanical coupling (speed multiplier gear directly. Flow rate, blade numbers, turbine rotational speed, inlet angle are parameters used in CFD modeling,  simulation and design optimization of the turbine runner. The computed results show that power developed by a turbine runner increases with increasing flow rate. Pressure inside the turbine runner increases with flow rate but, runner efficiency increases for some flow rate and almost constant thereafter. Efficiency and power developed by a runner drops quickly if turbine speed increases due to higher pressure losses and conversion of pressure energy to kinetic energy inside the runner. Increasing blade number increases power developed but, efficiency does not increase always. Efficiency increases for some blade number and drops down due to the fact that  change in direction of the relative flow vector at the runner exit, which decreases the net rotational momentum and increases the axial flow velocity.

Development of a 5kw Francis Turbine Runner Using Computation ...

African Journals Online (AJOL)

A small scale Francis turbine runner for a turbine located at Awba dam in the University of Ibadan with designed head and flow rate of 6m and 0.244m3/s is designed. The basic design of the Francis turbine runner is completed based on basic fluid dynamics turbo machinery principles. A 2-D and 3-D steady state, ...

3D numerical simulation of transient processes in hydraulic turbines

International Nuclear Information System (INIS)

Cherny, S; Chirkov, D; Lapin, V; Eshkunova, I; Bannikov, D; Avdushenko, A; Skorospelov, V

2010-01-01

An approach for numerical simulation of 3D hydraulic turbine flows in transient operating regimes is presented. The method is based on a coupled solution of incompressible RANS equations, runner rotation equation, and water hammer equations. The issue of setting appropriate boundary conditions is considered in detail. As an illustration, the simulation results for runaway process are presented. The evolution of vortex structure and its effect on computed runaway traces are analyzed.

3D numerical simulation of transient processes in hydraulic turbines

Science.gov (United States)

Cherny, S.; Chirkov, D.; Bannikov, D.; Lapin, V.; Skorospelov, V.; Eshkunova, I.; Avdushenko, A.

2010-08-01

An approach for numerical simulation of 3D hydraulic turbine flows in transient operating regimes is presented. The method is based on a coupled solution of incompressible RANS equations, runner rotation equation, and water hammer equations. The issue of setting appropriate boundary conditions is considered in detail. As an illustration, the simulation results for runaway process are presented. The evolution of vortex structure and its effect on computed runaway traces are analyzed.

Hydraulic and structural co-simulation analysis of turbine runner during operation

International Nuclear Information System (INIS)

Markov, Zoran; Popovski, Predrag; Lipej, Andrej; Djelic, Vesko

2006-01-01

Modern concept of HPP refurbishment procedure consists of many aspects of the turbine re-design. One of the most useful data is the previous operational data during the lifetime of the unit. In many cases, high stressed areas are damaged. Lack of the measurements makes the solution of the problems and verification of the numerical results very difficult. This work represents an integrated approach in solving hydraulic and structural problems in design stage or optimization of an aial hydro turbine. CFD approach is implemented in solving the flow through a complete aial turbine, taking into account all the necessary factors influencing the real flow. Frozen rotor condition is taken as an input in the computations. The results from the CFD calculations are used as an input for the performed FEA modeling and structural analysis.

Hydraulic turbines and auxiliary equipment

Energy Technology Data Exchange (ETDEWEB)

Luo Gaorong [Organization of the United Nations, Beijing (China). International Centre of Small Hydroelectric Power Plants

1995-07-01

This document presents a general overview on hydraulic turbines and auxiliary equipment, emphasizing the turbine classification, in accordance with the different types of turbines, standard turbine series in China, turbine selection based on the basic data required for the preliminary design, general hill model curves, chart of turbine series and the arrangement of application for hydraulic turbines, hydraulic turbine testing, and speed regulating device.

Research on Darrieus-type hydraulic turbine for extra-low head hydropower utilization

International Nuclear Information System (INIS)

Furukawa, A; Watanabe, S; Okuma, K

2012-01-01

A Darrieus-type turbine has been investigated for extra-low head hydropower utilization. In the present paper, authors'research on Darrieus-type hydraulic turbine is briefly reviewed. The working principle of Darrieus turbine is explained with advantage of its simple structure, at first. Then the fluid-dynamic difference between rotating and linear motions of a blade in a uniform flow is clarified with guiding principle of high performance design of Darrieus turbine. Cavitation problem is also described. Next, effects of duct-casing, consisting of an intake, runner section and draft tube, are discussed and a simplified structure of Darrieus turbine is shown by installing the inlet nozzle. Finally, in the practical use, an adjustment of inlet nozzle section by lowering the inlet nozzle height is proposed when flow rate is varied temporally and seasonally.

Hydraulic development of high specific-speed pump-turbines by means of an inverse design method, numerical flow-simulation (CFD) and model testing

International Nuclear Information System (INIS)

Kerschberger, P; Gehrer, A

2010-01-01

In recent years an increased interest in pump-turbines has been recognized in the market. The rapid availability of pumped storage schemes and the benefits to the power system by peak lopping, providing reserve and rapid response for frequency control are becoming of growing advantage. In that context it is requested to develop pump-turbines that reliably stand dynamic operation modes, fast changes of the discharge rate by adjusting the variable diffuser vanes as well as fast changes from pump to turbine operation. Within the present study various flow patterns linked to the operation of a pump-turbine system are discussed. In that context pump and turbine mode are presented separately and different load cases at both operation modes are shown. In order to achieve modern, competitive pump-turbine designs it is further explained which design challenges should be considered during the geometry definition of a pump-turbine impeller. Within the present study a runner-blade profile for a low head pump-turbine has been developed. For the initial hydraulic runner-blade design, an inverse design method has been applied. Within this design procedure, a first blade geometry is generated by imposing the pressure loading-distribution and by means of an inverse 3D potential-flow-solution. The hydraulic behavior of both, pump-mode and turbine-mode is then evaluated by solving the full 3D Navier-Stokes equations in combination with a robust turbulence model. Based on this initial design the blade profile has been further optimized and redesigned considering various hydraulic pump-turbine requirements. Finally, the progress in hydraulic design is demonstrated by model test results which show a significant improvement in hydraulic performance compared to an existing reference design.

Hydraulic development of high specific-speed pump-turbines by means of an inverse design method, numerical flow-simulation (CFD) and model testing

Science.gov (United States)

Kerschberger, P.; Gehrer, A.

2010-08-01

In recent years an increased interest in pump-turbines has been recognized in the market. The rapid availability of pumped storage schemes and the benefits to the power system by peak lopping, providing reserve and rapid response for frequency control are becoming of growing advantage. In that context it is requested to develop pump-turbines that reliably stand dynamic operation modes, fast changes of the discharge rate by adjusting the variable diffuser vanes as well as fast changes from pump to turbine operation. Within the present study various flow patterns linked to the operation of a pump-turbine system are discussed. In that context pump and turbine mode are presented separately and different load cases at both operation modes are shown. In order to achieve modern, competitive pump-turbine designs it is further explained which design challenges should be considered during the geometry definition of a pump-turbine impeller. Within the present study a runner-blade profile for a low head pump-turbine has been developed. For the initial hydraulic runner-blade design, an inverse design method has been applied. Within this design procedure, a first blade geometry is generated by imposing the pressure loading-distribution and by means of an inverse 3D potential-flow-solution. The hydraulic behavior of both, pump-mode and turbine-mode is then evaluated by solving the full 3D Navier-Stokes equations in combination with a robust turbulence model. Based on this initial design the blade profile has been further optimized and redesigned considering various hydraulic pump-turbine requirements. Finally, the progress in hydraulic design is demonstrated by model test results which show a significant improvement in hydraulic performance compared to an existing reference design.

Unsteady load on an oscillating Kaplan turbine runner

Science.gov (United States)

Puolakka, O.; Keto-Tokoi, J.; Matusiak, J.

2013-02-01

A Kaplan turbine runner oscillating in turbine waterways is subjected to a varying hydrodynamic load. Numerical simulation of the related unsteady flow is time-consuming and research is very limited. In this study, a simplified method based on unsteady airfoil theory is presented for evaluation of the unsteady load for vibration analyses of the turbine shaft line. The runner is assumed to oscillate as a rigid body in spin and axial heave, and the reaction force is resolved into added masses and dampings. The method is applied on three Kaplan runners at nominal operating conditions. Estimates for added masses and dampings are considered to be of a magnitude significant for shaft line vibration. Moderate variation in the added masses and minor variation in the added dampings is found in the frequency range of interest. Reference results for added masses are derived by solving the boundary value problem for small motions of inviscid fluid using the finite element method. Good correspondence is found in the added mass estimates of the two methods. The unsteady airfoil method is considered accurate enough for design purposes. Experimental results are needed for validation of unsteady load analyses.

Numerical analysis of solid–liquidtwo-phase turbulent flow in Francis turbine runner with splitter bladesin sandy water

Directory of Open Access Journals (Sweden)

Hua Hong

2015-03-01

Full Text Available As the key component of a hydroelectric power generation system, hydraulic turbine plays a decisive role in the overall performance of the system. There are many sandy rivers in the world, and turbines working in these rivers are seriously damaged. Therefore, the research of flow in sandy water has great theoretical significance and practical value. Based on the specific hydrological conditions of a hydropower station, the solid–liquid two-phase flow in the whole flow passage of a Francis turbine with splitter blades in sandy water was numerically studied. A geometric model of the whole flow passage of the Francis turbine was established on the basis of given design parameters. The solid–liquid two-phase turbulent flows in Francis turbine runner under three different loads were numerically analyzed by using this model. The three different loads are as follows: Condition 1: single unit with 1/4 load, Condition 2: single unit with 1/2 load, and Condition 3: single unit with full load. The distributions of pressure and sand concentration on the leading side and the suction side of the runner blades, as well as the velocity vector distribution of water and sand on the horizontal section of the runner, were obtained under different load conditions. Therefore, the damages to various flow passage components by sand can be qualitatively predicated under various conditions. To guarantee the safety and stability of the unit, the adverse conditions shall be avoided, which can provide certain reference for plant operation.

Determination of turbine runner dynamic behaviour under operating condition by a two-way staggered fluid-structureinteraction method

International Nuclear Information System (INIS)

Dompierre, F; Sabourin, M

2010-01-01

This paper presents the application of the two-way fluid-structure interaction method introduced by ANSYS to calculate the dynamic behaviour of a Francis turbine runner under operating condition. This time-dependant calculation directly takes into account characteristics of the flow and particularly the pressure fluctuations caused by the rotor-stator interaction. This formulation allows the calculation of the damping forces of the whole system implicitly. Thereafter, the calculated dynamic stress can be used for a fatigue analysis. A verification of the mechanical and fluid simulations used as input for the fluid-structure interaction calculation is first performed. Subsequently, a connection of these two independent simulations is made. A validation according to the hydraulic conditions is made with the measurements from the scale model testing. Afterwards, the static displacement of the runner under the hydraulic load is compared with the results of a classical static analysis for verification purposes. Finally, the natural frequencies deduced by the post-processing of the dynamic portion of the runner displacement with respect to time are compared with the natural frequencies obtained from a classical acoustic modal analysis. All comparisons show a good agreement with experimental data or results obtained with conventional methods.

Determination of turbine runner dynamic behaviour under operating condition by a two-way staggered fluid-structureinteraction method

Energy Technology Data Exchange (ETDEWEB)

Dompierre, F; Sabourin, M, E-mail: frederick.dompierre@power.alstom.co [Alstom Power Systems, Hydro 1350 chemin Saint-Roch, Sorel-Tracy (Quebec), J3R 5P9 (Canada)

2010-08-15

This paper presents the application of the two-way fluid-structure interaction method introduced by ANSYS to calculate the dynamic behaviour of a Francis turbine runner under operating condition. This time-dependant calculation directly takes into account characteristics of the flow and particularly the pressure fluctuations caused by the rotor-stator interaction. This formulation allows the calculation of the damping forces of the whole system implicitly. Thereafter, the calculated dynamic stress can be used for a fatigue analysis. A verification of the mechanical and fluid simulations used as input for the fluid-structure interaction calculation is first performed. Subsequently, a connection of these two independent simulations is made. A validation according to the hydraulic conditions is made with the measurements from the scale model testing. Afterwards, the static displacement of the runner under the hydraulic load is compared with the results of a classical static analysis for verification purposes. Finally, the natural frequencies deduced by the post-processing of the dynamic portion of the runner displacement with respect to time are compared with the natural frequencies obtained from a classical acoustic modal analysis. All comparisons show a good agreement with experimental data or results obtained with conventional methods.

Numerical Investigation of the Internal Flow in a Banki Turbine

Directory of Open Access Journals (Sweden)

Jesús De Andrade

2011-01-01

Full Text Available The paper refers to the numerical analysis of the internal flow in a hydraulic cross-flow turbine type Banki. A 3D-CFD steady state flow simulation has been performed using ANSYS CFX codes. The simulation includes nozzle, runner, shaft, and casing. The turbine has a specific speed of 63 (metric units, an outside runner diameter of 294 mm. Simulations were carried out using a water-air free surface model and k-ε turbulence model. The objectives of this study were to analyze the velocity and pressure fields of the cross-flow within the runner and to characterize its performance for different runner speeds. Absolute flow velocity angles are obtained at runner entrance for simulations with and without the runner. Flow recirculation in the runner interblade passages and shocks of the internal cross-flow cause considerable hydraulic losses by which the efficiency of the turbine decreases significantly. The CFD simulations results were compared with experimental data and were consistent with global performance parameters.

Part 1 - Experimental study of the pressure fluctuations on propeller turbine runner blades during steady-state operation

Science.gov (United States)

Houde, S.; Fraser, R.; Ciocan, G. D.; Deschênes, C.

2012-11-01

A good evaluation of the unsteady pressure field on hydraulic turbine blades is critical in evaluating the turbine lifespan and its maintenance schedule. Low-head turbines such as Kaplan and Propeller, using a relatively low number of blades supported only at the hub, may also undergo significant deflections at the blade tips which will lead to higher amplitude vibration compared to Francis turbines. Furthermore, the precise evaluation of the unsteady pressure distribution on low-head turbines is still a challenge for computational fluid dynamics (CFD). Within the framework of an international research consortium on low-head turbines, a research project was instigated at the Hydraulic Machines Laboratory in Laval University (LAMH) to perform experimental measurements of the unsteady pressure field on propeller turbine model runner blades. The main objective of the project was to measure the pressure fluctuations on a wide band of frequencies, both in a blade-to-blade channel and on the pressure and suction side of the same blade, to provide validation data for CFD computations. To do so, a 32 channels telemetric data transmission system was used to extract the signal of 31 pressure transducers and two strain gages from the rotating part at an acquisition frequency of 5 KHz. The miniature piezoelectric pressure transducers were placed on two adjacent runner blades according to an estimated pressure distribution coming from flow simulations. Two suction sides and one pressure side were instrumented. The strain gages were mounted in full-bridge on both pressure and suction sides to measure the blade span wise deflection. In order to provide boundary conditions for flow simulations, the test bench conditions during the measurements were acquired. The measurements were made in different operating conditions ranging from part load, where a cavitating vortex occurs, to full load under different heads. The results enabled the identification and the quantification of the

Effect of Jet Shape on Flow and Torque Characteristics of Pelton Turbine Runner

OpenAIRE

Vishal Gupta,; Dr. Vishnu Prasad

2014-01-01

In Pelton turbine, the energy carried by water is converted into kinetic energy by providing nozzle at the end of penstock. The shape of jet affects the force and torque on the bucket and runner of turbine. The nozzle of circular cross section is commonly used. In this paper attempt has been made to study the effect of four different jet shapes on the flow and torque characteristics of Pelton turbine runner through numerical simulation.

Validations of CFD against detailed velocity and pressure measurements in water turbine runner flow

Science.gov (United States)

Nilsson, H.; Davidson, L.

2003-03-01

This work compares CFD results with experimental results of the flow in two different kinds of water turbine runners. The runners studied are the GAMM Francis runner and the Hölleforsen Kaplan runner. The GAMM Francis runner was used as a test case in the 1989 GAMM Workshop on 3D Computation of Incompressible Internal Flows where the geometry and detailed best efficiency measurements were made available. In addition to the best efficiency measurements, four off-design operating condition measurements are used for the comparisons in this work. The Hölleforsen Kaplan runner was used at the 1999 Turbine 99 and 2001 Turbine 99 - II workshops on draft tube flow, where detailed measurements made after the runner were used as inlet boundary conditions for the draft tube computations. The measurements are used here to validate computations of the flow in the runner.The computations are made in a single runner blade passage where the inlet boundary conditions are obtained from an extrapolation of detailed measurements (GAMM) or from separate guide vane computations (Hölleforsen). The steady flow in a rotating co-ordinate system is computed. The effects of turbulence are modelled by a low-Reynolds number k- turbulence model, which removes some of the assumptions of the commonly used wall function approach and brings the computations one step further.

Load variation effects on the pressure fluctuations exerted on a Kaplan turbine runner

International Nuclear Information System (INIS)

Amiri, K; Cervantes, M J; Mulu, B; Raisee, M

2014-01-01

Introduction of intermittent electricity production systems like wind power and solar systems to electricity market together with the consumption-based electricity production resulted in numerous start/stops, load variations and off-design operation of water turbines. The hydropower systems suffer from the varying loads exerted on the stationary and rotating parts of the turbines during load variations which they are not designed for. On the other hand, investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of rotating vortex rope (RVR) in the draft tube. The RVR induces oscillating flow both in plunging and rotating modes which results in oscillating force with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. The purpose of this study is to investigate the effect of transient operations on the pressure fluctuations on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors. The model was run in off-cam mode during different load variation conditions to check the runner performance under unsteady condition. The results showed that the transients between the best efficiency point and the high load happens in a smooth way while transitions to/from the part load, where rotating vortex rope (RVR) forms in the draft tube induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode of the RVR

Load variation effects on the pressure fluctuations exerted on a Kaplan turbine runner

Science.gov (United States)

Amiri, K.; Mulu, B.; Raisee, M.; Cervantes, M. J.

2014-03-01

Introduction of intermittent electricity production systems like wind power and solar systems to electricity market together with the consumption-based electricity production resulted in numerous start/stops, load variations and off-design operation of water turbines. The hydropower systems suffer from the varying loads exerted on the stationary and rotating parts of the turbines during load variations which they are not designed for. On the other hand, investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of rotating vortex rope (RVR) in the draft tube. The RVR induces oscillating flow both in plunging and rotating modes which results in oscillating force with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. The purpose of this study is to investigate the effect of transient operations on the pressure fluctuations on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors. The model was run in off-cam mode during different load variation conditions to check the runner performance under unsteady condition. The results showed that the transients between the best efficiency point and the high load happens in a smooth way while transitions to/from the part load, where rotating vortex rope (RVR) forms in the draft tube induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode of the RVR.

Part 1 – Experimental study of the pressure fluctuations on propeller turbine runner blades during steady-state operation

International Nuclear Information System (INIS)

Houde, S; Fraser, R; Ciocan, G D; Deschênes, C

2012-01-01

A good evaluation of the unsteady pressure field on hydraulic turbine blades is critical in evaluating the turbine lifespan and its maintenance schedule. Low-head turbines such as Kaplan and Propeller, using a relatively low number of blades supported only at the hub, may also undergo significant deflections at the blade tips which will lead to higher amplitude vibration compared to Francis turbines. Furthermore, the precise evaluation of the unsteady pressure distribution on low-head turbines is still a challenge for computational fluid dynamics (CFD). Within the framework of an international research consortium on low-head turbines, a research project was instigated at the Hydraulic Machines Laboratory in Laval University (LAMH) to perform experimental measurements of the unsteady pressure field on propeller turbine model runner blades. The main objective of the project was to measure the pressure fluctuations on a wide band of frequencies, both in a blade-to-blade channel and on the pressure and suction side of the same blade, to provide validation data for CFD computations. To do so, a 32 channels telemetric data transmission system was used to extract the signal of 31 pressure transducers and two strain gages from the rotating part at an acquisition frequency of 5 KHz. The miniature piezoelectric pressure transducers were placed on two adjacent runner blades according to an estimated pressure distribution coming from flow simulations. Two suction sides and one pressure side were instrumented. The strain gages were mounted in full-bridge on both pressure and suction sides to measure the blade span wise deflection. In order to provide boundary conditions for flow simulations, the test bench conditions during the measurements were acquired. The measurements were made in different operating conditions ranging from part load, where a cavitating vortex occurs, to full load under different heads. The results enabled the identification and the quantification of the

Optimization of the Runner for Extremely Low Head Bidirectional Tidal Bulb Turbine

Directory of Open Access Journals (Sweden)

Yongyao Luo

2017-06-01

Full Text Available This paper presents a multi-objective optimization procedure for bidirectional bulb turbine runners which is completed using ANSYS Workbench. The optimization procedure is able to check many more geometries with less manual work. In the procedure, the initial blade shape is parameterized, the inlet and outlet angles (β1, β2, as well as the starting and ending wrap angles (θ1, θ2 for the five sections of the blade profile, are selected as design variables, and the optimization target is set to obtain the maximum of the overall efficiency for the ebb and flood turbine modes. For the flow analysis, the ANSYS CFX code, with a SST (Shear Stress Transport k-ω turbulence model, has been used to evaluate the efficiency of the turbine. An efficient response surface model relating the design parameters and the objective functions is obtained. The optimization strategy was used to optimize a model bulb turbine runner. Model tests were carried out to validate the final designs and the design procedure. For the four-bladed turbine, the efficiency improvement is 5.5% in the ebb operation direction, and 2.9% in the flood operation direction, as well as 4.3% and 4.5% for the three-bladed turbine. Numerical simulations were then performed to analyze the pressure pulsation in the pressure and suction sides of the blade for the prototype turbine with optimal four-bladed and three-bladed runners. The results show that the runner rotational frequency (fn is the dominant frequency of the pressure pulsations in the blades for ebb and flood turbine modes, and the gravitational effect, rather than rotor-stator interaction (RSI, plays an important role in a low head horizontal axial turbine. The amplitudes of the pressure pulsations on the blade side facing the guide vanes varies little with the water head. However, the amplitudes of the pressure pulsations on the blade side facing the diffusion tube linearly increase with the water head. These results could provide

Numerical Simulation of the Francis Turbine and CAD used to Optimized the Runner Design (2nd).

Science.gov (United States)

Sutikno, Priyono

2010-06-01

Hydro Power is the most important renewable energy source on earth. The water is free of charge and with the generation of electric energy in a Hydroelectric Power station the production of green house gases (mainly CO2) is negligible. Hydro Power Generation Stations are long term installations and can be used for 50 years and more, care must be taken to guarantee a smooth and safe operation over the years. Maintenance is necessary and critical parts of the machines have to be replaced if necessary. Within modern engineering the numerical flow simulation plays an important role in order to optimize the hydraulic turbine in conjunction with connected components of the plant. Especially for rehabilitation and upgrading existing Power Plants important point of concern are to predict the power output of turbine, to achieve maximum hydraulic efficiency, to avoid or to minimize cavitations, to avoid or to minimized vibrations in whole range operation. Flow simulation can help to solve operational problems and to optimize the turbo machinery for hydro electric generating stations or their component through, intuitive optimization, mathematical optimization, parametric design, the reduction of cavitations through design, prediction of draft tube vortex, trouble shooting by using the simulation. The classic design through graphic-analytical method is cumbersome and can't give in evidence the positive or negative aspects of the designing options. So it was obvious to have imposed as necessity the classical design methods to an adequate design method using the CAD software. There are many option chose during design calculus in a specific step of designing may be verified in ensemble and detail form a point of view. The final graphic post processing would be realized only for the optimal solution, through a 3 D representation of the runner as a whole for the final approval geometric shape. In this article it was investigated the redesign of the hydraulic turbine's runner

Experimental comparison of cavitation erosion rates of different steels used in hydraulic turbines

International Nuclear Information System (INIS)

Ton-That, L

2010-01-01

The prediction of cavitation erosion rates has an important role in order to evaluate the exact life of components in fluid machineries. Hydro-Quebec has studied this phenomenon for several years, in particular in hydraulic turbine runners, to try to understand the different degradation mechanisms related to this phenomenon. This paper presents part of this work. In this study, we carried out experimental erosion tests to compare different steels used in actual hydraulic turbine runners (carbon steels, austenitic and martensitic stainless steels) to high strength steels in terms of cavitation erosion resistance. The results for these different classes of steels are presented. The tests have been performed in a cavitating liquid jet apparatus according to the ASTM G134-95 standard to simulate the flow conditions. The mass loss has been followed during the exposure time. The maximum depth of erosion, the mean depth of erosion, and the mean depth erosion rate are determined. As a result we found that ASTM-A514 high strength steels present excellent cavitation erosion resistance properties. The cavitation eroded surface is followed by optical profilometry technique. Determination of mechanical properties and examinations of the eroded surfaces of the samples have also been carried out in order to identify the erosion mechanisms involved in the degradation of these kinds of materials.

Hydro turbine rehab benefits from modeling

International Nuclear Information System (INIS)

Froehlich, D.R.; Veatch, J.A.

1991-01-01

The turbine aging process, while seemingly imperceptible, inevitably results in reduced turbine efficiency and capacity. The primary causes of these reductions are runner hydraulic profile changes during weld repairs, surface finish deterioration from cavitation, and runner seal clearance increases due to wear. Many aging turbines require more frequent repairs due to runner cavitation, and wicket gate mechanism, shaft seal, and guide bearing wear. In many instances turbine component repair can be performed in-place. On older units, runner seals, wicket gate bearings, and wicket gate end seals can be repaired only when the turbine is disassembled. Since the significant cost to disassemble and overhaul units must be offset by future maintenance savings and generation increases, turbine rehabilitation is often postponed as owners consider other alternatives. Rehabilitation is a general term used to describe a wide range of turbine reconditioning and design alternatives. Turbine rehabilitation can include a major overhaul of components, runner replacement, and component modifications. Deteriorated runners can be replaced with either a new identical runner or a new modern design having increased efficiency and capacity. The comparative turbine performance of an original, existing, and a modern runner design are shown in this paper. Component overhauls can extend turbine life and restore original efficiency and capacity to existing units. However, the overhaul of existing components cannot increase plant capacity and generation above the as-new values. As a result, owners of aging plants are considering the benefits of replacing existing turbines with modern, more efficient, higher capacity turbines, or expanding the sites. Where expansion is not feasible, hydroelectric power plant owners are finding that turbine rehabilitation is the most cost-effective method to increase plant value and life

Aperiodic pressure pulsation under non optimal hydraulic turbine regimes at low swirl number

Science.gov (United States)

Skripkin, S. G.; Tsoy, M. A.; Kuibin, P. A.; Shtork, S. I.

2017-09-01

Off-design operating conditions of hydraulic turbines is hindered by pressure fluctuations in the draft tube of the turbine. A precessing helical vortex rope develops, which imperils the mechanical structure and limits the operation flexibility of hydropower station. Understanding of the underlying instabilities of precessing vortex rope at low swirl number is incomplete. In this paper flow regimes with different residual swirl is analysed, particular attention is paid to the regime with a small swirl parameter. Study defines upper and low boundaries of regime where aperiodic pressure surge is observed. Flow field at the runner exit is investigated by Laser Doppler Velocimetry and high-speed visualizations, which are complemented draft tube wall pressure measurements.

Transmission of High Frequency Vibrations in Rotating Systems. Application to Cavitation Detection in Hydraulic Turbines

Directory of Open Access Journals (Sweden)

David Valentín

2018-03-01

Full Text Available One of the main causes of damage in hydraulic turbines is cavitation. While not all cavitation appearing in a turbine is of a destructive type, erosive cavitation can severely affect the structure, thus increasing maintenance costs and reducing the remaining useful life of the machine. Of all types of cavitation, the maximum erosion occurs when clouds of bubbles collapse on the runner surface (cloud cavitation. When this occurs it is associated with a substantial increase in noise, and vibrations that are propagated everywhere throughout the machine. The generation of these cavitation clouds may occur naturally or it may be the response to a periodic pressure fluctuation, like the rotor/stator interaction in a hydraulic turbine. Erosive bubble cavitation generates high-frequency vibrations that are modulated by the shedding frequency. Therefore, the methods for the detection of erosive cavitation in hydraulic turbines are based on the measurement and demodulation of high-frequency vibrations. In this paper, the feasibility of detecting erosive cavitation in hydraulic turbines is investigated experimentally in a rotating disk system, which represents a simplified hydraulic turbine structure. The test rig used consists of a rotating disk submerged in a tank of water and confined with nearby axial and radial rigid surfaces. The excitation patterns produced by cloud cavitation are reproduced with a PZT (piezoelectric patch located on the disk. These patterns include pseudo-random excitations of different frequency bands modulated by one low carrier frequency, which model the erosive cavitation characteristics. Different types of sensors have been placed in the stationary and in the rotating parts (accelerometers, acoustic emission (AE, and a microphone in order to detect the excitation pattern. The results obtained for all the sensors tested have been compared in detail for the different excitation patterns applied to the disk. With this information

Hydraulic design development of Xiluodu Francis turbine

International Nuclear Information System (INIS)

Wang, Y L; Li, G Y; Shi, Q H; Wang, Z N

2012-01-01

Hydraulic optimization design with CFD (Computational Fluid Dynamics) method, hydraulic optimization measures and model test results in the hydraulic development of Xiluodu hydropower station by DFEM (Dongfang Electric Machinery) of DEC (Dongfang Electric Corporation) of China were analyzed in this paper. The hydraulic development conditions of turbine, selection of design parameter, comparison of geometric parameters and optimization measure of turbine flow components were expatiated. And the measures of improving turbine hydraulic performance and the results of model turbine acceptance experiment were discussed in details.

Detection of cavitation vortex in hydraulic turbines using acoustic techniques

International Nuclear Information System (INIS)

Candel, I; Ioana, C; Bunea, F; Politehnica University of Bucharest (Romania))" data-affiliation=" (Power Engineering Faculty, Politehnica University of Bucharest (Romania))" >Dunca, G; Politehnica University of Bucharest (Romania))" data-affiliation=" (Power Engineering Faculty, Politehnica University of Bucharest (Romania))" >Bucur, D M; Division Technique Générale, Grenoble (France))" data-affiliation=" (Electricité de France, Division Technique Générale, Grenoble (France))" >Reeb, B; Ciocan, G D

2014-01-01

Cavitation phenomena are known for their destructive capacity in hydraulic machineries and are caused by the pressure decrease followed by an implosion when the cavitation bubbles find an adverse pressure gradient. A helical vortex appears in the turbine diffuser cone at partial flow rate operation and can be cavitating in its core. Cavity volumes and vortex frequencies vary with the under-pressure level. If the vortex frequency comes close to one of the eigen frequencies of the turbine, a resonance phenomenon may occur, the unsteady fluctuations can be amplified and lead to important turbine and hydraulic circuit damage. Conventional cavitation vortex detection techniques are based on passive devices (pressure sensors or accelerometers). Limited sensor bandwidths and low frequency response limit the vortex detection and characterization information provided by the passive techniques. In order to go beyond these techniques and develop a new active one that will remove these drawbacks, previous work in the field has shown that techniques based on acoustic signals using adapted signal content to a particular hydraulic situation, can be more robust and accurate. The cavitation vortex effects in the water flow profile downstream hydraulic turbines runner are responsible for signal content modifications. Basic signal techniques use narrow band signals traveling inside the flow from an emitting transducer to a receiving one (active sensors). Emissions of wide band signals in the flow during the apparition and development of the vortex embeds changes in the received signals. Signal processing methods are used to estimate the cavitation apparition and evolution. Tests done in a reduced scale facility showed that due to the increasing flow rate, the signal -- vortex interaction is seen as modifications on the received signal's high order statistics and bandwidth. Wide band acoustic transducers have a higher dynamic range over mechanical elements; the system

Water turbine technology for small power stations

Science.gov (United States)

Salovaara, T.

1980-02-01

The paper examines hydro-power stations and the efficiency and costs of using water turbines to run them. Attention is given to different turbine types emphasizing the use of Kaplan-turbines and runners. Hydraulic characteristics and mechanical properties of low head turbines and small turbines, constructed of fully fabricated steel plate structures, are presented.

Multiobjective optimal design of runner blade using efficiency and draft tube pulsation criteria

International Nuclear Information System (INIS)

Pilev, I M; Sotnikov, A A; Rigin, V E; Semenova, A V; Cherny, S G; Chirkov, D V; Bannikov, D V; Skorospelov, V A

2012-01-01

In the present work new criteria of optimal design method for turbine runner [1] are proposed. Firstly, based on the efficient method which couples direct simulation of 3D turbulent flow and engineering semi empirical formulas, the combined method is built for hydraulic energy losses estimation in the whole turbine water passage and the efficiency criterion is formulated. Secondly, the criterion of dynamic loads minimization is developed for those caused by vortex rope precession downstream of the runner. This criterion is based on the finding that the monotonic increase of meridional velocity component in the direction to runner hub, downstream of its blades, provides for decreasing the intensity of vortex rope and thereafter, minimization of pressure pulsation amplitude. The developed algorithm was applied to optimal design of 640 MW Francis turbine runner. It can ensure high efficiency at best efficiency operating point as well as diminished pressure pulsations at full load regime.

Recent experience of IFFM PAS in the design process of lowhead propeller hydraulic turbines for Small Hydro

International Nuclear Information System (INIS)

Kaniecki, M; Krzemianowski, Z

2010-01-01

The paper contains the short description of the design process of the axial flow turbines for Small Hydro. The crucial elements of the process are: ARDES programme for 1D inverse problem (containing the statistic information of the well performed hydraulic units, applying the lifting aerofoil theory); determination of universal hill diagram and optimization of the runner blades geometry by utilization of the 3D CFD codes. As the result of design process with utilization of both design steps, the generated runner blades geometry (1D inverse problem) and some computational results of 3D CFD solver have been presented. As the conclusion some crucial remarks of the designed process have been brought forward.

Surrogate runner model for draft tube losses computation within a wide range of operating points

International Nuclear Information System (INIS)

Susan-Resiga, R; Ciocan, T; Muntean, S; De Colombel, T; Leroy, P

2014-01-01

We introduce a quasi two-dimensional (Q2D) methodology for assessing the swirling flow exiting the runner of hydraulic turbines at arbitrary operating points, within a wide operating range. The Q2D model does not need actual runner computations, and as a result it represents a surrogate runner model for a-priori assessment of the swirling flow ingested by the draft tube. The axial, radial and circumferential velocity components are computed on a conical section located immediately downstream the runner blades trailing edge, then used as inlet conditions for regular draft tube computations. The main advantage of our model is that it allows the determination of the draft tube losses within the intended turbine operating range in the early design stages of a new or refurbished runner, thus providing a robust and systematic methodology to meet the optimal requirements for the flow at the runner outlet

Resonance investigation of pump-turbine during startup process

International Nuclear Information System (INIS)

He, L Y; Wang, Z W; Kurosawa, S; Nakahara, Y

2014-01-01

The causes of resonance of a certain model pump-turbine unit during startup process were investigated in this article. A three-dimensional full flow path analysis model which contains spiral case, stay vanes, guide vanes, runner, gaps outside the runner crown and band, and draft tube was constructed. The transient hydraulic excitation force of full flow path was analyzed under five conditions near the resonance region. Based on one-way fluid- structure interaction (FSI) analysis model, the dynamic stress characteristics of the pump-turbine runner was investigated. The results of pressure pulsation, vibration mode and dynamic stress obtained from simulation were consistent with the test results. The study indicated that the hydraulic excitation frequency (Z g *f n ) Hz due to rotor-stator interference corresponding to the natural frequency of 2ND+4ND runner mode is the main cause of resonance. The relationship among pressure pulsation, vibration mode and dynamic stress was discussed in this paper. The results revealed the underlying causes of the resonance phenomenon

Hydraulic design of Three Gorges right bank powerhouse turbine for improvement of hydraulic stability

International Nuclear Information System (INIS)

Shi, Q

2010-01-01

This paper presents the hydraulic design of Three Gorges Right Bank Powerhouse turbine for improvement of hydraulic stability. The technical challenges faced in the hydraulic design of the turbine are given. The method of hydraulic design for improving the hydraulic stability and particularly for eliminating the upper part load pressure pulsations is clarified. The final hydraulic design results of Three Gorges Right Bank Powerhouse turbine based on modern hydraulic design techniques are presented.

Hydraulic design of Three Gorges right bank powerhouse turbine for improvement of hydraulic stability

Energy Technology Data Exchange (ETDEWEB)

Shi, Q, E-mail: qhshi@dfem.com.c [Dong Fang Electrical Machinery Co., Ltd., DEC 188, Huanghe West Road, Deyang, 618000 (China)

2010-08-15

This paper presents the hydraulic design of Three Gorges Right Bank Powerhouse turbine for improvement of hydraulic stability. The technical challenges faced in the hydraulic design of the turbine are given. The method of hydraulic design for improving the hydraulic stability and particularly for eliminating the upper part load pressure pulsations is clarified. The final hydraulic design results of Three Gorges Right Bank Powerhouse turbine based on modern hydraulic design techniques are presented.

Pump Application as Hydraulic Turbine – Pump as Turbine (PaT)

OpenAIRE

Rusovs, D

2009-01-01

The paper considers pump operation as hydraulic turbine with purpose to produce mechanical power from liquid flow. The Francis hydraulic turbine was selected for comparison with centrifugal pump in reverse operation. Turbine and centrifugal pump velocity triangles were considered with purpose to evaluate PaT efficiency. Shape of impeller blades for turbine and pumps was analysed. Specific speed calculation is carried out with purpose to obtain similarity in pump and turbine description. For ...

Flow field study in a bulb turbine runner using LDV and endoscopic S-PIV measurements

International Nuclear Information System (INIS)

Lemay, S; Fraser, R; Ciocan, G D; Aeschlimann, V; Deschênes, C

2014-01-01

The flow in the inter-blade channels of a bulb turbine was measured using two different techniques. The first involved a classical laser Doppler velocimetry (LDV) setup whereas the second integrated endoscopic cameras to a stereoscopic particle image velocimetry (S-PIV) system. This paper presents results from both measurement campaigns and also provides some key conclusions based on the two datasets. Before getting into the thick of the data though, the technical aspect of both measurement configurations is addressed. A quick overview of the LDV setup is presented, but the main focus is on the novelties and challenges brought by the use of endoscopic cameras to achieve S-PIV measurements between the runner blades. Endoscopic PIV systems have already led to successful measurements of flow fields in a few studies concerning turbomachinery, especially in aerodynamics. However, to the author's knowledge, the realisation of such measurements in a hydraulic turbine is a first. After this outline of the techniques used, the results and conclusions are shown. First, the influence of the guide vanes wakes on the runner flow is described. The size, localisation, strength and dissipation of those structures are inferred from the information coming from both measurement techniques. Then, a flow imbalance is assessed circumferentially. On another subject, the blade tip vortices are identified and characterized using the LDV data. The size, position and direction of rotation of those structures are all extracted from the measured flow field. Finally, the PIV data allows the identification of yet another vortex located near the suction side of the blades and originating from the corner between the leading edge and the hub when operating the bulb turbine at part load

Controls of Hydraulic Wind Turbine

Directory of Open Access Journals (Sweden)

Zhang Yin

2016-01-01

Full Text Available In this paper a hydraulic wind turbine generator system was proposed based on analysis the current wind turbines technologies. The construction and principles were introduced. The mathematical model was verified using MATLAB and AMsim. A displacement closed loop of swash plate of motor and a speed closed loop of generator were setup, a PID control is introduced to maintain a constant speed and fixed frequency at wind turbine generator. Simulation and experiment demonstrated that the system can connect grid to generate electric and enhance reliability. The control system demonstrates a high performance speed regulation and effectiveness. The results are great significant to design a new type hydraulic wind turbine system.

Influence of Hydraulic Design on Stability and on Pressure Pulsations in Francis Turbines at Overload, Part Load and Deep Part Load based on Numerical Simulations and Experimental Model Test Results

International Nuclear Information System (INIS)

Magnoli, M V; Maiwald, M

2014-01-01

Francis turbines have been running more and more frequently in part load conditions, in order to satisfy the new market requirements for more dynamic and flexible energy generation, ancillary services and grid regulation. The turbines should be able to be operated for longer durations with flows below the optimum point, going from part load to deep part load and even speed-no-load. These operating conditions are characterised by important unsteady flow phenomena taking place at the draft tube cone and in the runner channels, in the respective cases of part load and deep part load. The current expectations are that new Francis turbines present appropriate hydraulic stability and moderate pressure pulsations at overload, part load, deep part load and speed-no-load with high efficiency levels at normal operating range. This study presents series of investigations performed by Voith Hydro with the objective to improve the hydraulic stability of Francis turbines at overload, part load and deep part load, reduce pressure pulsations and enlarge the know-how about the transient fluid flow through the turbine at these challenging conditions. Model test measurements showed that distinct runner designs were able to influence the pressure pulsation level in the machine. Extensive experimental investigations focused on the runner deflector geometry, on runner features and how they could reduce the pressure oscillation level. The impact of design variants and machine configurations on the vortex rope at the draft tube cone at overload and part load and on the runner channel vortex at deep part load were experimentally observed and evaluated based on the measured pressure pulsation amplitudes. Numerical investigations were employed for improving the understanding of such dynamic fluid flow effects. As example for the design and experimental investigations, model test observations and pressure pulsation curves for Francis machines in mid specific speed range, around n qopt = 50

Integrity and life estimation of turbine runner cover in a hydro power plant

Directory of Open Access Journals (Sweden)

A. Sedmak

2016-03-01

Full Text Available This paper presents integrity and life estimation of turbine runner cover in a vertical pipe turbines, Kaplan 200 MW nominal output power, produced in Russia, and built in six hydro-generation units of hydroelectric power plant „Đerdap 1” in Serbia. Fatigue and corrosion-fatigue interaction have been taken into account using experimentally obtained material properties, as well as analytical and numerical calculations of stress state, to estimate appropriate safety factors. Fatigue crack growth rate, da/dN, was also calculated, indicated that internal defects of circular or elliptical shape, found out by ultrasonic testing, do not affect reliable operation of runner cover.

Review of fluid and control technology of hydraulic wind turbines

Institute of Scientific and Technical Information of China (English)

Maolin CAI; Yixuan WANG; Zongxia JIAO; Yan SHI

2017-01-01

This study examines the development of the fluid and control technology of hydraulic wind turbines.The current state of hydraulic wind turbines as a new technology is described,and its basic fluid model and typical control method are expounded by comparing various study results.Finally,the advantages of hydraulic wind turbines are enumerated.Hydraulic wind turbines are expected to become the main development direction of wind turbines.

Review of fluid and control technology of hydraulic wind turbines

Science.gov (United States)

Cai, Maolin; Wang, Yixuan; Jiao, Zongxia; Shi, Yan

2017-09-01

This study examines the development of the fluid and control technology of hydraulic wind turbines. The current state of hydraulic wind turbines as a new technology is described, and its basic fluid model and typical control method are expounded by comparing various study results. Finally, the advantages of hydraulic wind turbines are enumerated. Hydraulic wind turbines are expected to become the main development direction of wind turbines.

Valve exploiting the principle of a side channel turbine

Directory of Open Access Journals (Sweden)

Jandourek Pavel

2017-01-01

Full Text Available The article deals with a side channel turbine, which can be used as a suitable substitute for a pressure reducing valve. Reducing valves are a source of hydraulic losses. The aim is to replace them by a side channel turbine. With that in mind, hydraulic losses can be replaced by a production of electrical energy at comparable characteristics of the valve and the turbine. The basis for the design is the loss characteristics of the valve. Thereby creating a kind of turbine valve with speed-controlled flow in dependence of runner revolution.

Influence of Working Environment on Fatigue Life Time Duration for Runner Blades of Kaplan Turbines

Directory of Open Access Journals (Sweden)

Ana-Maria Budai

2010-10-01

Full Text Available The paper present an analytical analyzes refer to influence of working environment on life time duration in service of runner blades of Kaplan turbines. The study are made using only analytical method, the entry dates being obtained from measurements made in situ for a Kaplan turbine. To calculate the maximum number of stress cycles whereupon the runner blades work without any damage it was used an analytical relation known in specialized literatures under the name of Morrow’s relation. To estimate fatigue life time duration will be used a formula obtained from one of most common cumulative damage methodology taking in consideration the real exploitation conditions of a specified Kaplan turbine.

Efficient runner safety assessment during early design phase and root cause analysis

International Nuclear Information System (INIS)

Liang, Q W; Lais, S; Gentner, C; Braun, O

2012-01-01

Fatigue related problems in Francis turbines, especially high head Francis turbines, have been published several times in the last years. During operation the runner is exposed to various steady and unsteady hydraulic loads. Therefore the analysis of forced response of the runner structure requires a combined approach of fluid dynamics and structural dynamics. Due to the high complexity of the phenomena and due to the limitation of computer power, the numerical prediction was in the past too expensive and not feasible for the use as standard design tool. However, due to continuous improvement of the knowledge and the simulation tools such complex analysis has become part of the design procedure in ANDRITZ HYDRO. This article describes the application of most advanced analysis techniques in runner safety check (RSC), including steady state CFD analysis, transient CFD analysis considering rotor stator interaction (RSI), static FE analysis and modal analysis in water considering the added mass effect, in the early design phase. This procedure allows a very efficient interaction between the hydraulic designer and the mechanical designer during the design phase, such that a risk of failure can be detected and avoided in an early design stage.The RSC procedure can also be applied to a root cause analysis (RCA) both to find out the cause of failure and to quickly define a technical solution to meet the safety criteria. An efficient application to a RCA of cracks in a Francis runner is quoted in this article as an example. The results of the RCA are presented together with an efficient and inexpensive solution whose effectiveness could be proven again by applying the described RSC technics. It is shown that, with the RSC procedure developed and applied as standard procedure in ANDRITZ HYDRO such a failure is excluded in an early design phase. Moreover, the RSC procedure is compatible with different commercial and open source codes and can be easily adapted to apply for

Efficient runner safety assessment during early design phase and root cause analysis

Science.gov (United States)

Liang, Q. W.; Lais, S.; Gentner, C.; Braun, O.

2012-11-01

Fatigue related problems in Francis turbines, especially high head Francis turbines, have been published several times in the last years. During operation the runner is exposed to various steady and unsteady hydraulic loads. Therefore the analysis of forced response of the runner structure requires a combined approach of fluid dynamics and structural dynamics. Due to the high complexity of the phenomena and due to the limitation of computer power, the numerical prediction was in the past too expensive and not feasible for the use as standard design tool. However, due to continuous improvement of the knowledge and the simulation tools such complex analysis has become part of the design procedure in ANDRITZ HYDRO. This article describes the application of most advanced analysis techniques in runner safety check (RSC), including steady state CFD analysis, transient CFD analysis considering rotor stator interaction (RSI), static FE analysis and modal analysis in water considering the added mass effect, in the early design phase. This procedure allows a very efficient interaction between the hydraulic designer and the mechanical designer during the design phase, such that a risk of failure can be detected and avoided in an early design stage.The RSC procedure can also be applied to a root cause analysis (RCA) both to find out the cause of failure and to quickly define a technical solution to meet the safety criteria. An efficient application to a RCA of cracks in a Francis runner is quoted in this article as an example. The results of the RCA are presented together with an efficient and inexpensive solution whose effectiveness could be proven again by applying the described RSC technics. It is shown that, with the RSC procedure developed and applied as standard procedure in ANDRITZ HYDRO such a failure is excluded in an early design phase. Moreover, the RSC procedure is compatible with different commercial and open source codes and can be easily adapted to apply for

Development and optimization design of pit turbine with super low-head

International Nuclear Information System (INIS)

Yang, C X; Li, X X; Huang, F J; Zheng, Y; QZhou, D

2012-01-01

Tubular turbines have many advantages such as large flow, high-speed, high efficiency, wide and high efficiency area, compact structure, simple layout, etc. With those advantages, tubular turbine is becoming one of the most economic and suitable types of turbines to develop low head hydraulic resources. According to the general situation of the hydropower station in the north of Jiangsu, a super low head pit turbine which head is set as about 2m is developed by the research to utilize the low head hydraulic resource.The CFD technology was used to calculate the flow field. The computing zone was meshed with unstructured gird. The whole flow passage of shaft type tubular turbine was calculated by 3-d steady turbulent numerical simulation. The detail of flowthrough the whole flowpassage was attained and the influence to the turbine's performance was analyzed by the low head runner blade's various diameters, airfoils and setting angles. The best turbine runner was obtained by considering all the methods. Meeting the station's requirements, the results show that the runner exhibits the highest performance in the efficiency, hydraulic loss and static pressure sides with 1.75m diameter, optimized airfoil and 23 degree setting angle. The developed super low head pit turbine shows highest efficiency under the design condition of 2.1m water head and 10m 3 /s flow rate. GD-WS-35 turbine model test was carried out tostudy the performance of the turbine. On the basis ofmodel transformation principle,the numerical simulationresultof GD-WS-175turbine was compared with the model results. It's showed that the model test result is basically consistent with numerical simulationresult. The producing error in the numerical computation is not easy to control. The efficiency's error range is ±3%.

Engineering & Performance of DuoTurbo: Microturbine with Counter-Rotating Runners

Science.gov (United States)

Biner, D.; Hasmatuchi, V.; Violante, D.; Richard, S.; Chevailler, S.; Andolfatto, L.; Avellan, F.; Münch, C.

2016-11-01

Considering the nuclear phase-out strategy of several European countries and the future tendency to promote renewable energies, the exploitation of small hydropower sites (industrial partners. The modular in-line “plug & play” technology requires low investment, reaching economic feasibility with an available power between 5 kW and 25 kW. One stage of the microturbine consists of two axial counter-rotating runners that form a compact independent unit. Each runner of the turbine holds its own rim generator, the DuoTurbo-configuration involving that each hydraulic runner is integral with each electrical rotor. The possibility of stacking several stages in series enables covering quite a wide range of hydraulic power and, thus, recovering a maximum of energy dissipated in release valves of water supply systems. The present work introduces the global concept of the implemented prototype of the DuoTurbo-microturbine, to target a maximal injected power of 5 kW for a discharge of 9 l/s and a head of 24.5 m per stage. The main features of the hydraulic, the mechanical, the electrical and the electronic design are presented. The hydraulic performance is, then, assessed using CFD simulations for the expected operating range. Finally, the performance measurements of the single-stage prototype installed in the hydraulic test rig of the HES-SO Valais//Wallis are presented.

Numerical Analysis of Flow in Kaplan Turbine Runner Blades Anticavitation Lip with Modified Hydro-dynamic Profile

Directory of Open Access Journals (Sweden)

Vasile Cojocaru

2011-09-01

Full Text Available In order to increase the lifetime of runner blades of Kaplan turbines damaged by cavitation erosion, an anticavitation lip is attached to the periphery of the runner blades on the suction side. The anticavitation lip overtakes the cavitation pitting which appears between the runner blades and the runner chamber. A blade with the original anticavitation lip was modeled using CAE. The numerical simulations showed the tip vortex position and the source of the cavitation erosion. Using these data, a modified profile of the anticavitation lip was designed.

Performance assessment of a small wind turbine with crossflow runner by numerical simulations

Energy Technology Data Exchange (ETDEWEB)

Dragomirescu, A. [University Politehnica of Bucharest, Department of Hydraulics, Hydraulic Machinery and Environmental Engineering, Splaiul Independentei 313, 060042 Bucharest (Romania)

2011-03-15

Most of the classical wind turbines are not able to start at wind speeds as low as 2-3 m/s. Other turbines, like Savonius, have a low maximum efficiency, which renders them useless in poor wind conditions. Therefore, new turbine designs are required to harvest wind power even when the wind speed is low. A wind turbine having a crossflow runner, similar to the Banki water turbine, is studied numerically in this work in order to estimate its performance. The results obtained suggest that this turbine has a considerable high starting torque and its maximum power coefficient is comparable to those of horizontal axis wind turbines. Based on the results obtained, some improvements of the design are proposed in order to further increase turbine performance. (author)

Multimodel Robust Control for Hydraulic Turbine

OpenAIRE

Osuský, Jakub; Števo, Stanislav

2014-01-01

The paper deals with the multimodel and robust control system design and their combination based on M-Δ structure. Controller design will be done in the frequency domain with nominal performance specified by phase margin. Hydraulic turbine model is analyzed as system with unstructured uncertainty, and robust stability condition is included in controller design. Multimodel and robust control approaches are presented in detail on hydraulic turbine model. Control design approaches are compared a...

Computation and analysis of cavitating flow in Francis-class hydraulic turbines

Science.gov (United States)

Leonard, Daniel J.

can occur more abruptly in the model than the prototype, due to lack of Froude similitude between the two. When severe cavitation occurs, clear differences are observed in vapor content between the scales. A stage-by-stage performance decomposition is conducted to analyze the losses within individual components of each scale of the machine. As cavitation becomes more severe, the losses in the draft tube account for an increasing amount of the total losses in the machine. More losses occur in the model draft tube as cavitation formation in the prototype draft tube is prevented by the larger hydrostatic pressure gradient across the machine. Additionally, unsteady Detached Eddy Simulations of the fully-coupled cavitating hydroturbine are performed for both scales. Both mesh and temporal convergence studies are provided. The temporal and spectral content of fluctuations in torque and pressure are monitored and compared between single-phase, cavitating, model, and prototype cases. A shallow draft tube induced runner imbalance results in an asymmetric vapor distribution about the runner, leading to more extensive growth and collapse of vapor on any individual blade as it undergoes a revolution. Unique frequency components manifest and persist through the entire machine only when cavitation is present in the hub vortex. Large maximum pressure spikes, which result from vapor collapse, are observed on the blade surfaces in the multiphase simulations, and these may be a potential source of cavitation damage and erosion. Multiphase CFD is shown to be an accurate and effective technique for simulating and analyzing cavitating flow in Francis-class hydraulic turbines. It is recommended that it be used as an industrial tool to supplement model cavitation experiments for all types of hydraulic turbines. Moreover, multiphase CFD can be equally effective as a research tool, to investigate mechanisms of cavitating hydraulic turbines that are not understood, and to uncover unique new

Analysis of the Kaplan turbine draft tube effect

International Nuclear Information System (INIS)

Motycak, L; Skotak, A; Obrovsky, J

2010-01-01

The aim of this paper is to present information about possible problems and errors which can appear during numerical analyses of low head Kaplan turbines with a view to the runner - draft tube interaction. The setting of numerical model, grid size, used boundary conditions are the interface definition between runner and draft tube are discussed. There are available data from physical model tests which gives a great opportunity to compare CFD and experiment results and on the basis of this comparison to determine the approach to the CFD flow modeling. The main purpose for the Kaplan turbine model measurement was to gather the information about real flow field. The model tests were carried out in new hydraulic laboratory of CKD Blansko Engineering. The model tests were focused on the detailed velocity measurements downstream of the runner by differential pressure probe and on the velocity measurement downstream of the draft tube elbow by Particle Image Velocimetry method (PIV). The data from CFD simulation were compared to the velocity measurement results. In the paper also the design of the original draft tube modification due to flow improvement is discussed in the case of the Kaplan turbine uprating project. The results of the draft tube modification were confirmed by model tests in the hydraulic laboratory as well.

Analysis of the Kaplan turbine draft tube effect

Energy Technology Data Exchange (ETDEWEB)

Motycak, L; Skotak, A; Obrovsky, J, E-mail: motycak.vhs@cbeng.c [CKD Blansko Engineering, a.s., Capkova 2357/5, Blansko 67801 (Czech Republic)

2010-08-15

The aim of this paper is to present information about possible problems and errors which can appear during numerical analyses of low head Kaplan turbines with a view to the runner - draft tube interaction. The setting of numerical model, grid size, used boundary conditions are the interface definition between runner and draft tube are discussed. There are available data from physical model tests which gives a great opportunity to compare CFD and experiment results and on the basis of this comparison to determine the approach to the CFD flow modeling. The main purpose for the Kaplan turbine model measurement was to gather the information about real flow field. The model tests were carried out in new hydraulic laboratory of CKD Blansko Engineering. The model tests were focused on the detailed velocity measurements downstream of the runner by differential pressure probe and on the velocity measurement downstream of the draft tube elbow by Particle Image Velocimetry method (PIV). The data from CFD simulation were compared to the velocity measurement results. In the paper also the design of the original draft tube modification due to flow improvement is discussed in the case of the Kaplan turbine uprating project. The results of the draft tube modification were confirmed by model tests in the hydraulic laboratory as well.

Analysis of the Kaplan turbine draft tube effect

Science.gov (United States)

Motycak, L.; Skotak, A.; Obrovsky, J.

2010-08-01

The aim of this paper is to present information about possible problems and errors which can appear during numerical analyses of low head Kaplan turbines with a view to the runner - draft tube interaction. The setting of numerical model, grid size, used boundary conditions are the interface definition between runner and draft tube are discussed. There are available data from physical model tests which gives a great opportunity to compare CFD and experiment results and on the basis of this comparison to determine the approach to the CFD flow modeling. The main purpose for the Kaplan turbine model measurement was to gather the information about real flow field. The model tests were carried out in new hydraulic laboratory of CKD Blansko Engineering. The model tests were focused on the detailed velocity measurements downstream of the runner by differential pressure probe and on the velocity measurement downstream of the draft tube elbow by Particle Image Velocimetry method (PIV). The data from CFD simulation were compared to the velocity measurement results. In the paper also the design of the original draft tube modification due to flow improvement is discussed in the case of the Kaplan turbine uprating project. The results of the draft tube modification were confirmed by model tests in the hydraulic laboratory as well.

Power Swing Generated in Francis Turbines by Part Load and Overload Instabilities

Directory of Open Access Journals (Sweden)

David Valentín

2017-12-01

Full Text Available Hydropower plays a key role in the actual energy market due to its fast response and regulation capacity. In that way, hydraulic turbines are increasingly demanded to work at off-design conditions, where complex flow patterns and cavitation appear, especially in Francis turbines. The draft tube cavitation surge is a hydraulic phenomenon that appears in Francis turbines below and above its Best Efficiency Point (BEP. It is a low frequency phenomenon consisting of a vortex rope in the runner outlet and draft tube, which can become unstable when its frequency coincides with a natural frequency of the hydraulic circuit. At this situation, the output power can significantly swing, endangering the electrical grid stability. This study is focused on the detection of these instabilities in Francis turbines and their relationship with the output power swings. To do so, extensive experimental tests for different operating conditions have been carried out in a large prototype Francis turbine (444 MW of rated power within the frame of the European Project Hyperbole (FP7-ENERGY-2013-1. Several sensors have been installed in the hydraulic circuit (pressure sensors in the draft tube, spiral casing, and penstock, in the rotating and static structures (vibration sensors, proximity probes, and strain gauges in the runner and in the shaft, as well as in the electrical side (output power, intensity, and voltage. Moreover, a numerical Finite Element Method (FEM has been also used to relate the hydraulic excitation with the output power swing.

The calculation of fluid-structure interaction and fatigue analysis for Francis turbine runner

International Nuclear Information System (INIS)

Wang, X F; Li, H L; Zhu, F W

2012-01-01

Francis turbine, as a widely used hydro turbine, is especially suited for the hydropower station with high hydraulic head and higher hydraulic head. For such turbine generator units all around the world, the crack streaks usually come out after a long time use and the resulted accidents may cause huge losses. Hence, it is meaningful to refine the design assuring the stability and safety of the Francis turbine. In this paper, the stiffness and strength as well as the fatigue life of the Francis turbine are studied. Concerning on the turbine of one certain hydropower station, the flow field inside the turbine are first simulated and the pressure distribution around the blades are derived. Meanwhile, the stress distributions of the blades are also obtained. Based on these, the fatigue analyses are applied on the turbine. According to the results of fatigue analyses, some optimal designs on the turbine are verified. The results show that with the optimal designs, the hydraulic performances of the turbine do not change too much while the maximum stress on the turbine decrease and the fatigue life increase as well.

Turbine hydraulic assessment and optimization in rehabilitation projects

International Nuclear Information System (INIS)

Bornard, L; Debeissat, F; Labrecque, Y; Sabourin, M; Tomas, L

2014-01-01

As turbines age after years of operation, a major rehabilitation is needed to give new life. The owner has two choices: resetting the turbine to the original state or an upgrade with new hydraulic components designed and optimized using state of the art technology. The second solution is by far a more interesting option which can maximize the efficiency gain, increase the turbine capacity and revenues, eliminate cavitation erosion and the needs for repair, reduce the turbine instabilities and smooth unit regulation, and adapt the design to new operation conditions. This paper shows some aspects of the turbine hydraulic assessment and possible solutions to improve existing water passages

Design, Modeling, and CFD Analysis of a Micro Hydro Pelton Turbine Runner: For the Case of Selected Site in Ethiopia

Directory of Open Access Journals (Sweden)

Tilahun Nigussie

2017-01-01

Full Text Available This paper addresses the design, modeling, and performance analysis of a Pelton turbine using CFD for one of the selected micro hydro potential sites in Ethiopia to meet the requirements of the energy demands. The site has a net head of 47.5 m and flow rate of 0.14 m3/s. The design process starts with the design of initial dimensions for the runner based on different literatures and directed towards the modeling of bucket using CATIA V5. The performance of the runner has been analyzed in ANSYS CFX (CFD under given loading conditions of the turbine. Consequently, the present study has also the ambition to reduce the size of the runner to have a cost effective runner design. The case study described in this paper provides an example of how the size of turbine can affect the efficiency of the turbine. These were discussed in detail which helps in understanding of the underlying fluid dynamic design problem as an aid for improving the efficiency and lowering the manufacturing cost for future study. The result showed that the model is highly dependent on the size and this was verified and discussed properly using flow visualization of the computed flow field and published result.

Performance analysis of a counter-rotating tubular type micro-turbine by experiment and CFD

International Nuclear Information System (INIS)

Lee, N J; Choi, J W; Hwang, Y H; Kim, Y T; Lee, Y H

2012-01-01

Micro hydraulic turbines have a growing interest because of its small and simple structure, as well as a high possibility of using in micro and small hydropower applications. The differential pressure existing in city water pipelines can be used efficiently to generate electricity in a way similar to that of energy being generated through gravitational potential energy in dams. The pressure energy in the city pipelines is often wasted by using pressure reducing valves at the inlet of water cleaning centers. Instead of using the pressure reducing valves, a micro counter-rotating hydraulic turbine can be used to make use of the pressure energy. In the present paper, a counter-rotating tubular type micro-turbine is studied, with the front runner connected to the generator stator and the rear runner connected to the generator rotor. The performance of the turbine is investigated experimentally and numerically. A commercial ANSYS CFD code was used for numerical analysis.

Small hydraulic turbine drives

Science.gov (United States)

Rostafinski, W. A.

1970-01-01

Turbine, driven by the fluid being pumped, requires no external controls, is completely integrated into the flow system, and has bearings which utilize the main fluid for lubrication and cooling. Torque capabilities compare favorably with those developed by positive displacement hydraulic motors.

A discussion on turbine design for safe operation

International Nuclear Information System (INIS)

Brekke, H

2012-01-01

The paper gives a brief description of the hydraulic design of Francis and Pelton runners. The dynamic behaviour at part load has been a major problem for low head and medium head Francis turbines. The main reason for this has been inter blade separation and unstable swirl flow in the draft tube. A description is given on the hydraulic design of X-BLADE runners to obtain stable operation on the whole range of operation by reducing the cross flow. A classical theoretical analysis is also given on the dynamic hydraulic load on Pelton buckets. Several CFD analyses of this non stationary flow have been presented during the last decade, but the velocity distribution in the jets have not been correct. Experimental research work is presented on the complexity of this problem.

A discussion on turbine design for safe operation

Science.gov (United States)

Brekke, H.

2012-11-01

The paper gives a brief description of the hydraulic design of Francis and Pelton runners. The dynamic behaviour at part load has been a major problem for low head and medium head Francis turbines. The main reason for this has been inter blade separation and unstable swirl flow in the draft tube. A description is given on the hydraulic design of X-BLADE runners to obtain stable operation on the whole range of operation by reducing the cross flow. A classical theoretical analysis is also given on the dynamic hydraulic load on Pelton buckets. Several CFD analyses of this non stationary flow have been presented during the last decade, but the velocity distribution in the jets have not been correct. Experimental research work is presented on the complexity of this problem.

Numerical analysis on pump turbine runaway points

International Nuclear Information System (INIS)

Guo, L; Liu, J T; Wang, L Q; Jiao, L; Li, Z F

2012-01-01

To research the character of pump turbine runaway points with different guide vane opening, a hydraulic model was established based on a pumped storage power station. The RNG k-ε model and SMPLEC algorithms was used to simulate the internal flow fields. The result of the simulation was compared with the test data and good correspondence was got between experimental data and CFD result. Based on this model, internal flow analysis was carried out. The result show that when the pump turbine ran at the runway speed, lots of vortexes appeared in the flow passage of the runner. These vortexes could always be observed even if the guide vane opening changes. That is an important way of energy loss in the runaway condition. Pressure on two sides of the runner blades were almost the same. So the runner power is very low. High speed induced large centrifugal force and the small guide vane opening gave the water velocity a large tangential component, then an obvious water ring could be observed between the runner blades and guide vanes in small guide vane opening condition. That ring disappeared when the opening bigger than 20°. These conclusions can provide a theory basis for the analysis and simulation of the pump turbine runaway points.

Study on the Pressure Pulsation inside Runner with Splitter Blades in Ultra-High Head Turbine

International Nuclear Information System (INIS)

Meng, L; Zhang, S P; Zhou, L J; Wang, Z W

2014-01-01

Runners with splitter blades were used widely for the high efficiency and stability. In this paper, the unsteady simulation of an ultra-high head turbine at the best efficiency point, 50% and 75% discharge points were established, to analyze the pressure pulsation in the vaneless space, rotating domain and the draft tube. First of all, runners with different length splitter blades and without splitter blades were compared to learn the efficiency and the pressure distribution on the blade surface. And then the amplitude of the pressure pulsation was analysed. The peak efficiency of the runner with splitter blades is remarkably higher than that of the corresponding impeller without splitter blades. And the efficiency of the turbine is the highest when the length ratio of the splitter blades is 0.75 times the main blades. The pressure pulsation characteristics were also influenced, because the amplitudes of the pulsation induced by the RSI phenomenon were changed as a result of more blades. At last, the best design plan of the length of the splitter blades (length ratio=0.825) was obtained, which improved the pressure pulsation characteristics without significant prejudice to the efficiency

Influence of the vibro-acoustic sensor position on cavitation detection in a Kaplan turbine

Science.gov (United States)

Schmidt, H.; Kirschner, O.; Riedelbauch, S.; Necker, J.; Kopf, E.; Rieg, M.; Arantes, G.; Wessiak, M.; Mayrhuber, J.

2014-03-01

Hydraulic turbines can be operated close to the limits of the operating range to meet the demand of the grid. When operated close to the limits, the risk increases that cavitation phenomena may occur at the runner and / or at the guide vanes of the turbine. Cavitation in a hydraulic turbine can cause material erosion on the runner and other turbine parts and reduce the durability of the machine leading to required outage time and related repair costs. Therefore it is important to get reliable information about the appearance of cavitation during prototype operation. In this experimental investigation the high frequency acoustic emissions and vibrations were measured at 20 operating points with different cavitation behaviour at different positions in a large prototype Kaplan turbine. The main goal was a comparison of the measured signals at different sensor positions to identify the sensitivity of the location for cavitation detection. The measured signals were analysed statistically and specific values were derived. Based on the measured signals, it is possible to confirm the cavitation limit of the examined turbine. The result of the investigation shows that the position of the sensors has a significant influence on the detection of cavitation.

Influence of the vibro-acoustic sensor position on cavitation detection in a Kaplan turbine

International Nuclear Information System (INIS)

Schmidt, H; Kirschner, O; Riedelbauch, S; Necker, J; Kopf, E; Rieg, M; Arantes, G; Wessiak, M; Mayrhuber, J

2014-01-01

Hydraulic turbines can be operated close to the limits of the operating range to meet the demand of the grid. When operated close to the limits, the risk increases that cavitation phenomena may occur at the runner and / or at the guide vanes of the turbine. Cavitation in a hydraulic turbine can cause material erosion on the runner and other turbine parts and reduce the durability of the machine leading to required outage time and related repair costs. Therefore it is important to get reliable information about the appearance of cavitation during prototype operation. In this experimental investigation the high frequency acoustic emissions and vibrations were measured at 20 operating points with different cavitation behaviour at different positions in a large prototype Kaplan turbine. The main goal was a comparison of the measured signals at different sensor positions to identify the sensitivity of the location for cavitation detection. The measured signals were analysed statistically and specific values were derived. Based on the measured signals, it is possible to confirm the cavitation limit of the examined turbine. The result of the investigation shows that the position of the sensors has a significant influence on the detection of cavitation

Investigation of a High Head Francis Turbine at Runaway Operating Conditions

Directory of Open Access Journals (Sweden)

Chirag Trivedi

2016-03-01

Full Text Available Hydraulic turbines exhibit total load rejection during operation because of high fluctuations in the grid parameters. The generator reaches no-load instantly. Consequently, the turbine runner accelerates to high speed, runaway speed, in seconds. Under common conditions, stable runaway is only reached if after a load rejection, the control and protection mechanisms both fail and the guide vanes cannot be closed. The runner life is affected by the high amplitude pressure loading at the runaway speed. A model Francis turbine was used to investigate the consequences at the runaway condition. Measurements and simulations were performed at three operating points. The numerical simulations were performed using standard k-ε, k-ω shear stress transport (SST and scale-adaptive simulation (SAS models. A total of 12.8 million hexahedral mesh elements were created in the complete turbine, from the spiral casing inlet to the draft tube outlet. The experimental and numerical analysis showed that the runner was subjected to an unsteady pressure loading up to three-times the pressure loading observed at the best efficiency point. Investigates of unsteady pressure pulsations at the vaneless space, runner and draft tube are discussed in the paper. Further, unsteady swirling flow in the blade passages was observed that was rotating at a frequency of 4.8-times the runaway runner angular speed. Apart from the unsteady pressure loading, the development pattern of the swirling flow in the runner is discussed in the paper.

Hydraulic efficiency of a Rushton turbine impeller

Science.gov (United States)

Chara, Z.; Kysela, B.; Fort, I.

2017-07-01

Based on CFD simulations hydraulic efficiency of a standard Rushton turbine impeller in a baffled tank was determined at a Reynolds number of ReM=33330. Instantaneous values of pressure and velocity components were used to draw up the macroscopic balance of the mechanical energy. It was shown that the hydraulic efficiency of the Rushton turbine impeller (energy dissipated in a bulk volume) is about 57%. Using this result we estimated a length scale in a non-dimensional equation of kinetic energy dissipation rate in the bulk volume as L=D/2.62.

Optimization of hydraulic turbine governor parameters based on WPA

Science.gov (United States)

Gao, Chunyang; Yu, Xiangyang; Zhu, Yong; Feng, Baohao

2018-01-01

The parameters of hydraulic turbine governor directly affect the dynamic characteristics of the hydraulic unit, thus affecting the regulation capacity and the power quality of power grid. The governor of conventional hydropower unit is mainly PID governor with three adjustable parameters, which are difficult to set up. In order to optimize the hydraulic turbine governor, this paper proposes wolf pack algorithm (WPA) for intelligent tuning since the good global optimization capability of WPA. Compared with the traditional optimization method and PSO algorithm, the results show that the PID controller designed by WPA achieves a dynamic quality of hydraulic system and inhibits overshoot.

Analysis of a pico tubular-type hydro turbine performance by runner blade shape using CFD

Science.gov (United States)

Park, J. H.; Lee, N. J.; Wata, J. V.; Hwang, Y. C.; Kim, Y. T.; Lee, Y. H.

2012-11-01

There has been a considerable interest recently in the topic of renewable energy. This is primarily due to concerns about environmental impacts of fossil fuels. Moreover, fluctuating and rising oil prices, increase in demand, supply uncertainties and other factors have led to increased calls for alternative energy sources. Small hydropower, among other renewable energy sources, has been evaluated to have adequate development value because it is a clean, renewable and abundant energy resource. In addition, small hydropower has the advantage of low cost development by using rivers, agricultural reservoirs, sewage treatment plants, waterworks and water resources. The main concept of the tubular-type hydro turbine is based on the difference in water pressure levels in pipe lines, where the energy which was initially wasted by using a reducing valve at the pipeline of waterworks, is collected by turbine in the hydro power generator. In this study, in order to acquire the performance data of a pico tubular-type hydro turbine, the output power, head and efficiency characteristics by different runner blade shapes are examined. The pressure and velocity distributions with the variation of guide vane and runner vane angle on turbine performance are investigated by using a commercial CFD code.

Numerical Simulation and Validation of a High Head Model Francis Turbine at Part Load Operating Condition

Science.gov (United States)

Goyal, Rahul; Trivedi, Chirag; Kumar Gandhi, Bhupendra; Cervantes, Michel J.

2017-07-01

Hydraulic turbines are operated over an extended operating range to meet the real time electricity demand. Turbines operated at part load have flow parameters not matching the designed ones. This results in unstable flow conditions in the runner and draft tube developing low frequency and high amplitude pressure pulsations. The unsteady pressure pulsations affect the dynamic stability of the turbine and cause additional fatigue. The work presented in this paper discusses the flow field investigation of a high head model Francis turbine at part load: 50% of the rated load. Numerical simulation of the complete turbine has been performed. Unsteady pressure pulsations in the vaneless space, runner, and draft tube are investigated and validated with available experimental data. Detailed analysis of the rotor stator interaction and draft tube flow field are performed and discussed. The analysis shows the presence of a rotating vortex rope in the draft tube at the frequency of 0.3 times of the runner rotational frequency. The frequency of the vortex rope precession, which causes severe fluctuations and vibrations in the draft tube, is predicted within 3.9% of the experimental measured value. The vortex rope results pressure pulsations propagating in the system whose frequency is also perceive in the runner and upstream the runner.

Hydraulic Soft Yaw System for Multi MW Wind Turbines

DEFF Research Database (Denmark)

Stubkier, Søren

energy and an increase in the loading of the wind turbine structure and components. This dissertation examines the hypothesis that there are advantages of basing a yaw system on hydraulic components instead of normal electrical components. This is done through a state of the art analysis followed...... in the wind turbine yaw system along with minor reductions in the blades and main shaft. Optimization of the damping and stiffness of the hydraulic soft yaw system have been conducted and an optimum found for load reduction. Linear control algorithms for control of damping pressure peaks have been developed...... the full turbine code in FAST, and the mathematical model of the hydraulic yaw system in Matlab/Simulink and Amesim is developed in order to analyze a full scale model of the hydraulic yaw system in combination with the implemented friction model for the yaw system. These results are also promising...

Influence of the rotor-stator interaction on the dynamic stresses of Francis runners

International Nuclear Information System (INIS)

Guillaume, R; Scolaro, D; Deniau, J L; Colombet, C

2012-01-01

Thanks to advances in computing capabilities and Computational Fluid Dynamics (CFD) techniques, it is now possible to calculate realistic unsteady pressure fields in Francis turbines. This paper will explain methods to calculate the structural loads and the dynamic behaviour in order to optimize the turbine design and maximize its reliability and lifetime. Depending on the operating conditions of a Francis turbine, different hydraulic phenomena may impact the mechanical behaviour of the structure. According to their nature, these highly variable phenomena should be treated differently and specifically in order to estimate the potential risks arising on submerged structures, in particular the runner. The operating condition studied thereafter is the point at maximum power with the maximum head. Under this condition, the runner is excited by only one dynamic phenomenon named the Rotor-Stator Interaction (RSI). The origin of the phenomenon is located on the radial gap of the turbine and is the source of pressure fluctuations. A fluid-structure analysis is performed to observe the influence of that dynamic pressure field on the runner behaviour. The first part of the paper deals with the unsteady fluid computation. The RSI phenomenon is totally unsteady so the fluid simulation must take into account the entire machine and its rotation movement, in order to obtain a dynamic pressure field. In the second part of the paper, a method suitable for the RSI study is developed. It is known that the fluctuating pressure in this gap can be described as a sum of spatial components. By evaluating these components in the CFD results and on the scale model, it is possible to assess the relevance of the numerical results on the whole runner. After this step, the numerical pressure field can be used as the dynamic load of the structure. The final part of the paper presentsthe mechanical finite element calculations. A modal analysis of the runner in water and a harmonic analysis of its

Unsteady CFD simulation for bucket design optimization of Pelton turbine runner

Science.gov (United States)

KUMASHIRO, Takashi; FUKUHARA, Haruki; TANI, Kiyohito

2016-11-01

To investigate flow patterns on the bucket of Pelton turbine runners is one of the important issues to improve the turbine performance. By studying the mechanism of loss generation on the flow around the bucket, it becomes possible to optimize the design of inner and outer bucket shape. For making it into study, computational fluid dynamics (CFD) is quite an effective method. It is normally used to simulate the flow in turbines and to expect the turbine performances in the development for many kind of water turbine including Pelton type. Especially in the bucket development, the numerical investigations are more useful than observations and measurements obtained in the model test to understand the transient flow patterns. In this paper, a numerical study on two different design buckets is introduced. The simplified analysis domain with consideration for reduction of computational load is also introduced. Furthermore the model tests of two buckets are also performed by using the same test equipment. As the results of the model test, a difference of turbine efficiency is clearly confirmed. The trend of calculated efficiencies on both buckets agrees with the experiment. To investigate the causes of that, the difference of unsteady flow patterns between two buckets is discussed based on the results of numerical analysis.

Study of the velocity distribution influence upon the pressure pulsations in draft tube model of hydro-turbine

Science.gov (United States)

Sonin, V.; Ustimenko, A.; Kuibin, P.; Litvinov, I.; Shtork, S.

2016-11-01

One of the mechanisms of generation of powerful pressure pulsations in the circuit of the turbine is a precessing vortex core, formed behind the runner at the operation points with partial or forced loads, when the flow has significant residual swirl. To study periodic pressure pulsations behind the runner the authors of this paper use approaches of experimental modeling and methods of computational fluid dynamics. The influence of velocity distributions at the output of the hydro turbine runner on pressure pulsations was studied based on analysis of the existing and possible velocity distributions in hydraulic turbines and selection of the distribution in the extended range. Preliminary numerical calculations have showed that the velocity distribution can be modeled without reproduction of the entire geometry of the circuit, using a combination of two blade cascades of the rotor and stator. Experimental verification of numerical results was carried out in an air bench, using the method of 3D-printing for fabrication of the blade cascades and the geometry of the draft tube of hydraulic turbine. Measurements of the velocity field at the input to a draft tube cone and registration of pressure pulsations due to precessing vortex core have allowed building correlations between the velocity distribution character and the amplitude-frequency characteristics of the pulsations.

Hydraulic Yaw System for Wind Turbines with New Compact Hydraulic Motor Principle

DEFF Research Database (Denmark)

Sørensen, Rasmus Mørk; Hansen, Michael Rygaard; Mouritsen, Ole Ø.

2011-01-01

This paper presents a new hydraulic yaw system for wind turbines. The basic component is a new type of hydraulic motor characterized by an extraordinary high specific displacement yielding high output torque in a compact form. The focus in the paper is the volumetric efficiency of the motor, which...

Modeling and control of a hybrid wind-tidal turbine with hydraulic accumulator

International Nuclear Information System (INIS)

Fan, YaJun; Mu, AnLe; Ma, Tao

2016-01-01

This paper presents the modeling and control of a hybrid wind-tidal turbine with hydraulic accumulator. The hybrid turbine captures the offshore wind energy and tidal current energy simultaneously and stores the excess energy in hydraulic accumulator prior to electricity generation. Two hydraulic pumps installed respectively in wind and tidal turbine nacelles are used to transform the captured mechanical energy into hydraulic energy. To extract the maximal power from wind and tidal current, standard torque controls are achieved by regulating the displacements of the hydraulic pumps. To meet the output power demand, a Proportion Integration Differentiation (PID) controller is designed to distribute the hydraulic energy between the accumulator and the Pelton turbine. A simulation case study based on combining a 5 MW offshore wind turbine and a 1 MW tidal current turbine is undertaken. Case study demonstrates that the hybrid generation system not only captures all the available wind and tidal energy and also delivers the desired generator power precisely through the accumulator damping out all the power fluctuations from the wind and tidal speed disturbances. Energy and exergy analyses show that the energy efficiency can exceed 100% as the small input speeds are considered, and the exergy efficiency has the consistent change trends with demand power. Further more parametric sensitivity study on hydraulic accumulator shows that there is an inversely proportional relationship between accumulator and hydraulic equipments including the pump and nozzle in terms of dimensions. - Highlights: • A hybrid wind-tidal turbine is presented. • Hydraulic accumulator stores/releases the surplus energy. • Standard torque controls extract the maximal power from wind and tidal. • Generator outputs meet the electricity demand precisely. • Parametric sensitivity study on accumulator is implemented.

Laboratory developments of a diagonal turbine for medium head small hydro power plants (25 - 100 m). Final report; Turbines diagonales. Programme de developpement d'une turbine hydraulique diagonale destinee a equiper les petites centrales a moyenne chute (25 a 100 m) - Rapport final

Energy Technology Data Exchange (ETDEWEB)

Choulot, A.; Denis, V.

2009-11-15

The first result of the project was the mechanical design of the diagonal turbine and, in particular, the runner and the adjustable blade driving system. The system was designed for the 12-blade runner and is thus suitable for any lower number of blades. With a reference runner diameter of 329.4 mm, the laboratory test model corresponds approximately to the smallest size for a prototype of Diagonal turbine. The mechanical design is thus available for any larger prototype. The complementary use of numerical simulations and laboratory tests provided a deep understanding of the hydraulic behaviour of the Diagonal turbine. Based on this extensive knowledge, the mechanical set-up and hydraulic design was significantly improved. The developments showed that the effect of the gap between the discharge ring and the blades on both the efficiency and cavitation behaviour was significantly enhanced compared to Kaplan turbines. The optimization of this gap together with improvements of the geometry enabled to raise the maximum efficiency from 86.5% with the initial configuration to more than 92%, and to significantly reduce the development of cavitation. The first developed configuration was the 8-blade runner. Various guide vane configurations were tested. The analysis of numerical and experimental results led to the development of an optimal configuration with a maximum efficiency of 92% and a satisfactory cavitation behaviour suitable for heads up to 50 m. The development of the 12-blade runner fully profited from the knowledge gained with the 8 blade configuration. The improved blade design process significantly fastened the development phase necessary to obtain high performances. The maximum efficiency is above 92% and the cavitation behaviour allows 80 m heads. Based on these good results, a first demonstration project was launched to equip the Montsalvens site (Switzerland). The objective is to install a turbine at the foot of the Montsalvens dam of the existing hydro

Development and industrial tests of the first LNG hydraulic turbine system in China

Directory of Open Access Journals (Sweden)

Jie Chen

2016-10-01

Full Text Available The cryogenic hydraulic turbine can be used to replace the conventional J–T valve for LNG or mixed refrigerant throttling and depressurization in a natural gas liquefaction plant. This advanced technology is not only to enhance the efficiency of the liquefaction plant, but to usher a new trend in the development of global liquefaction technologies. China has over 136 liquefaction plants, but the cryogenic hydraulic turbines have not been deployed in industrial utilization. In addition, these turbines cannot be manufactured domestically. In this circumstance, through working on the key technologies for LNG hydraulic turbine process & control system development, hydraulic model optimization design, structure design and manufacturing, the first domestic cryogenic hydraulic turbine with a flow rate of 40 m3/h was developed to recover the pressure energy from the LNG of cold box. The turbine was installed in the CNOOC Zhuhai Natural Gas Liquefaction Plant for industrial tests under multiple working conditions, including start-stop, variable flow rates and variable rotation speeds. Test results show that the domestic LNG cryogenic hydraulic turbine has satisfactory mechanical and operational performances at low temperatures as specified in design. In addition, the process & control system and frequency-conversion power-generation system of the turbine system are designed properly to automatically and smoothly replace the existing LNG J–T valve. As a result, the domestic LNG cryogenic hydraulic turbine system can improve LNG production by an average of 2% and generate power of 8.3 kW.

Vortex rope patterns at different load of hydro turbine model

Directory of Open Access Journals (Sweden)

Skripkin Sergey

2017-01-01

Full Text Available Operation of hydraulic turbines beyond optimal conditions leads to formation of precessing vortex core in a draft tube that generates powerful pressure pulsations in a hydraulic system. In case of resonance it leads to stability decreasing of hydraulic unit and electrical grid on the whole. In present work, such regimes are explored in a conical part of simplified turbine model. Studies are performed at constant flowrate Q = 70 m3/h and varying the runner rotational speed to explore different loads of the hydroturbine unit. The experiments involve pressure measurements, high speed-visualization and velocity measurements by means of laser Doppler anemometer technique. Interesting finding is related with abrupt increasing precession frequency at low swirl parameter of flow near optimal regime.

Details about turbine design of the new RADAG hydro power plant; Details der Maschinentechnik des Neubaus des RADAG-Wehrkraftwerks

Energy Technology Data Exchange (ETDEWEB)

Kolb, Stephan; Merkle, Dieter [Schluchseewerk AG, Laufenburg (Germany); Kesselring, Peter [Ing.-Buero Kesselring, Rheinfelden (Germany)

2010-07-01

The installed turbine is a Kaplan type with a horizontal axis. The 4 blades of the runner and the runner's cover are manufactured in stainless steel, having a diameter of 6 100 mm. The circle of guide vanes is driven by two hydraulic servos and can be closed in an emergency situation by an additional 11 to weight. (orig.)

Application study of magnetic fluid seal in hydraulic turbine

International Nuclear Information System (INIS)

Yu, Z Y; Zhang, W

2012-01-01

The waterpower resources of our country are abundant, and the hydroelectric power is developed, but at present the main shaft sealing device of hydraulic turbine is easy to wear and tear and the leakage is great. The magnetic fluid seal has the advantages of no contact, no wear, self-healing, long life and so on. In this paper, the magnetic fluid seal would be used in the main shaft of hydraulic turbine, the sealing structure was built the model, meshed the geometry, applied loads and solved by using MULTIPHYSICS in ANSYS software, the influence of the various sealing structural parameters such as tooth width, height, slot width, sealing gap on the sealing property were analyzed, the magnetic fluid sealing device suitable for large-diameter shaft and sealing water was designed, the sealing problem of the hydraulic turbine main shaft was solved effectively which will bring huge economic benefits.

Effects of turbine's selection on hydraulic transients in the long pressurized water conveyance system

International Nuclear Information System (INIS)

Zhou, J X; Hu, M; Cai, F L; Huang, X T

2014-01-01

For a hydropower station with longer water conveyance system, an optimum turbine's selection will be beneficial to its reliable and stable operation. Different optional turbines will result in possible differences of the hydraulic characteristics in the hydromechanical system, and have different effects on the hydraulic transients' analysis and control. Therefore, the premise for turbine's selection is to fully understand the properties of the optional turbines and their effects on the hydraulic transients. After a brief introduction of the simulation models for hydraulic transients' computation and stability analysis, the effects of hydraulic turbine's characteristics at different operating points on the hydro-mechanical system's free vibration analysis were theoretically investigated with the hydraulic impedance analysis of the hydraulic turbine. For a hydropower station with long water conveyance system, based on the detailed hydraulic transients' computation respectively for two different optional turbines, the effects of the turbine's selection on hydraulic transients were analyzed. Furthermore, considering different operating conditions for each turbine and the similar operating conditions for these two turbines, free vibration analysis was comprehensively carried out to reveal the effects of turbine's impedance on system's vibration characteristics. The results indicate that, respectively with two different turbines, most of the controlling parameters under the worst cases have marginal difference, and few shows obvious differences; the turbine's impedances under different operating conditions have less effect on the natural angular frequencies; different turbine's characteristics and different operating points have obvious effects on system's vibration stability; for the similar operating conditions of these two turbines, system's vibration characteristics are basically consistent with

Fixed-Time Stability of the Hydraulic Turbine Governing System

Directory of Open Access Journals (Sweden)

Caoyuan Ma

2018-01-01

Full Text Available This paper studies the problem of fixed-time stability of hydraulic turbine governing system with the elastic water hammer nonlinear model. To control and improve the quality of hydraulic turbine governing system, a new fixed-time control strategy is proposed, which can stabilize the water turbine governing system within a fixed time. Compared with the finite-time control strategy where the convergence rate depends on the initial state, the settling time of the fixed-time control scheme can be adjusted to the required value regardless of the initial conditions. Finally, we numerically show that the fixed-time control is more effective than and superior to the finite-time control.

The Effect of Flowing Water on Turbine Rotor Vibrations

Energy Technology Data Exchange (ETDEWEB)

Jansson, Ida

2010-07-01

There is a lack of standardized rules on how the fluid in the turbine should be included in rotor models of hydraulic machinery. This thesis is an attempt to shed some light on this issue. We approach the problem from two viewpoints, situated at place at a hydropower plant and by mathematical analysis. One goal of the thesis is to develop a measurement system that monitors the instantaneous pressure at several locations of a runner blade on a 10 MW Kaplan prototype in Porjus along Lule river. Paper A outlines the development of the measurement system and the instrumentation of the runner blade. Miniature piezo-resistive pressure transducers were mounted flush to the surface. If instrumentation is successful, the pressure field of the runner blade could be measured simultaneously as the loads and displacements of the guide bearings and the generator. The second objective is concerned with how the motion-induced fluid force affects the dynamic behaviour of the rotor. Inertia and angular momentum of the fluid and shrouding are expected to influence the dynamic behaviour of the turbine. Paper B scrutinizes this assumption by presenting a simple fluid-rotor model that captures the effects of inertia and angular momentum of the fluid on the motion of a confined cylinder. The simplicity of the model allows for powerful analytical solution methods. The results show that fluid inertia, angular momentum and shrouding of hydraulic turbines could have substantial effects on lateral rotor vibrations. This calls for further investigation with a more complex fluid-rotor model that accounts for flexural bending modes.

ESRC guide vanes of hydraulic turbine for Three Gorges project

Directory of Open Access Journals (Sweden)

Rui CHEN

2005-05-01

Full Text Available The mechanical properties and internal quality of low carbon martensite Electroslag Remelting Casting (ESRCstainless steel castings are superior to that of sand casting ones. The key technologies for the equipments and ESRC processes have been resolved during the experimental research period of guide vanes of hydraulic turbines for Three Gorges project. And ESRC guide vanes of hydraulic turbines for Three Gorges project have been produced successfully.

Pressure measurements and high speed visualizations of the cavitation phenomena at deep part load condition in a Francis turbine

International Nuclear Information System (INIS)

Yamamoto, K; Müller, A; Favrel, A; Landry, C; Avellan, F

2014-01-01

In a hydraulic power plant, it is essential to provide a reliable, sustainable and flexible energy supply. In recent years, in order to cover the variations of the renewable electricity production, hydraulic power plants are demanded to operate with more extended operating range. Under these off-design conditions, a hydraulic turbine is subject to cavitating swirl flow at the runner outlet. It is well-known that the helically/symmetrically shaped cavitation develops at the runner outlet in part load/full load condition, and it gives severe damage to the hydraulic systems under certain conditions. Although there have been many studies about partial and full load conditions, contributions reporting the deep part load condition are limited, and the cavitation behaviour at this condition is not yet understood. This study aims to unveil the cavitation phenomena at deep part load condition by high speed visualizations focusing on the draft tube cone as well as the runner blade channel, and pressure fluctuations associated with the phenomena were also investigated

Modernization of vertical Pelton turbines with the help of CFD and model testing

International Nuclear Information System (INIS)

Mack, Reiner; Gola, Bartlomiej; Smertnig, Martin; Wittwer, Bernhard; Meusburger, Peter

2014-01-01

The modernization of water turbines bears a high potential of increasing the already installed hydropower capacity. In many projects the existing waterways allow a substantial increase of the available flow capacity and with it the energy output. But also the upgrading onto a state of the art hydraulic, mechanical and electrical design will increase the available power considerably after the rehabilitation. The two phase nature of the flow in Pelton turbines requires for the hydraulic refurbishment special care in the application of the available design methods. Where the flow in the high pressure section of the turbine is mainly of one phase nature, CFD has been used as a standard tool for many years. Also the jet quality, and with it the exploration of the source of flow disturbances that cause poor free surface quality can be investigated with CFD. The interaction of the jet with the buckets of the runner is also examined by means of CFD. However, its accuracy with respect to hydraulic efficiency is, because of the two phase flow and the transient flow process, in very few cases good enough for a reliable and accurate prediction of absolute numbers. The optimization of hydraulic bucket profiles is therefore always checked with measurements in homologous scaled model turbines. A similar situation exists for the housing flow after the water is discharged from the runner. Here also CFD techniques are available to explore the general mechanisms. However, due to the two phase flow nature, where only a very small space is filled with moving water, the experimental setup in a model turbine is always the final proof for optimizations of housing inserts and modifications. The hydraulic design of a modernization project for a power station equipped with vertical Pelton turbines of two different designs is described in the proposed paper. It will be shown, how CFD is applied to determine the losses in the high pressure section and how these results are combined with the

Modernization of vertical Pelton turbines with the help of CFD and model testing

Science.gov (United States)

Mack, Reiner; Gola, Bartlomiej; Smertnig, Martin; Wittwer, Bernhard; Meusburger, Peter

2014-03-01

The modernization of water turbines bears a high potential of increasing the already installed hydropower capacity. In many projects the existing waterways allow a substantial increase of the available flow capacity and with it the energy output. But also the upgrading onto a state of the art hydraulic, mechanical and electrical design will increase the available power considerably after the rehabilitation. The two phase nature of the flow in Pelton turbines requires for the hydraulic refurbishment special care in the application of the available design methods. Where the flow in the high pressure section of the turbine is mainly of one phase nature, CFD has been used as a standard tool for many years. Also the jet quality, and with it the exploration of the source of flow disturbances that cause poor free surface quality can be investigated with CFD. The interaction of the jet with the buckets of the runner is also examined by means of CFD. However, its accuracy with respect to hydraulic efficiency is, because of the two phase flow and the transient flow process, in very few cases good enough for a reliable and accurate prediction of absolute numbers. The optimization of hydraulic bucket profiles is therefore always checked with measurements in homologous scaled model turbines. A similar situation exists for the housing flow after the water is discharged from the runner. Here also CFD techniques are available to explore the general mechanisms. However, due to the two phase flow nature, where only a very small space is filled with moving water, the experimental setup in a model turbine is always the final proof for optimizations of housing inserts and modifications. The hydraulic design of a modernization project for a power station equipped with vertical Pelton turbines of two different designs is described in the proposed paper. It will be shown, how CFD is applied to determine the losses in the high pressure section and how these results are combined with the

Hydroacoustic simulation of rotor-stator interaction in resonance conditions in Francis pump-turbine

International Nuclear Information System (INIS)

Nicolet, C; Ruchonnet, N; Alligne, S; Avellan, F; Koutnik, J

2010-01-01

Combined effect of rotating pressure field related to runner blade and wakes of wicket gates leads to rotor stator interactions, RSI, in Francis pump-turbines. These interactions induce pressures waves propagating in the entire hydraulic machine. Superposition of those pressure waves may result in standing wave in the spiral casing and rotating diametrical mode in the guide vanes and can cause strong pressure fluctuations and vibrations. This paper presents the modeling, simulation and analysis of Rotor-Stator Interaction of a scale model of a Francis pump-turbine and related test rig using a one-dimensional approach. The hydroacoustic modeling of the Francis pump-turbine takes into account the spiral casing, the 20 guide vanes, the 9 rotating runner vanes. The connection between stationary and rotating parts is ensured by a valve network driven according to the unsteady flow distribution between guide vanes and runner vanes. Time domain simulations are performed for 2 different runner rotational speeds in turbine mode. The simulation results are analyzed in frequency domain and highlights hydroacoustic resonance between RSI excitations and the spiral case. Rotating diametrical mode in the vaneless gap and standing wave in the spiral case are identified. The influence of the resonance on phase and amplitude of pressure fluctuations obtained for both the spiral case and the vaneless gap is analyzed. The mode shape and frequencies are confirmed using eigenvalues analysis.

Transient CFD simulation of a Francis turbine startup

International Nuclear Information System (INIS)

Nicolle, J; Morissette, J F; Giroux, A M

2012-01-01

To assess the life expectancy of hydraulic turbines, it is essential to obtain the loading on the blades, especially during transient operations known to be the most damaging. This paper presents a simplified CFD setup to model the startup phase of a Francis turbine while it goes from rest to speed no-load condition. The fluid domain included one distributor sector coupled with one runner passage. The guide vane motion and change in the angular velocity were included in a commercial code with user functions. Comparisons between numerical results and measurements acquired on a full-size turbine showed that most of the flow physics occurring during startup were captured.

Experimental Pressure Measurements on Hydropower Turbine Runners

Energy Technology Data Exchange (ETDEWEB)

Harding, Samuel F.; Richmond, Marshall C.

2017-04-28

The range of hydrodynamic operating conditions to which the turbine is exposed results in significant pressure fluctuations on both the pressure and suction sides of the blades. Understanding these dynamic pressures has a range of applications. Structurally, the resulting dynamic loads are significant in understanding the design life and maintenance schedule of the bearing, shafts and runner components. The pulsing pressures have also been seen to have a detrimental effect on the surface condition of the blades. Biologically, the pressure gradients and pressure extremes are the primary driver of barotrauma for fish passing through hydroturbines. Improvements in computational fluid dynamics (CFD) can be used to simulate such unsteady pressures in the regions of concern. High frequency model scale and prototype measurements of pressures at the blade are important in the validation of these models. Experimental characterization of pressure fields over hydroturbine blades has been demonstrated by a number of studies which using multiple pressure transducers to map the pressure contours on the runner blades. These have been performed at both model and prototype scales, often to validate computational models of the pressure and flow fields over the blades. This report provides a review of existing studies in which the blade pressure was measured in situ. The report assesses the technology for both model and prototype scale testing. The details of the primary studies in this field are reported and used to inform the types of hardware required for similar experiments based on the Ice Harbor Dam owned by the US Corps of Engineers on the Snake River, WA, USA. Such a study would be used to validate the CFD performed for the BioPA.

Study on the application of energy storage system in offshore wind turbine with hydraulic transmission

International Nuclear Information System (INIS)

Fan, Yajun; Mu, Anle; Ma, Tao

2016-01-01

Highlights: • Hydraulic offshore wind turbine is capable of outputting near constant power. • Open loop hydraulic transmission uses seawater as the working fluid. • Linear control strategy distributes total flow according to demand and supply. • Constant pressure hydraulic accumulator stores/releases the surplus energy. • Simulations show the dynamic performance of the hybrid system. - Abstract: A novel offshore wind turbine comprising fluid power transmission and energy storage system is proposed. In this wind turbine, the conventional mechanical transmission is replaced by an open-loop hydraulic system, in which seawater is sucked through a variable displacement pump in nacelle connected directly with the rotor and utilized to drive a Pelton turbine installed on the floating platform. Aiming to smooth and stabilize the output power, an energy storage system with the capability of flexible charging and discharging is applied. The related mathematical model is developed, which contains some sub-models that are categorized as the wind turbine rotor, hydraulic pump, transmission pipeline, proportional valve, accumulator and hydraulic turbine. A linear control strategy is adopted to distribute the flow out of the proportional valve through comparing the demand power with captured wind energy by hydraulic pump. Ultimately, two time domain simulations demonstrate the operation of the hybrid system when the hydraulic accumulator is utilized and show how this system can be used for load leveling and stabilizing the output power.

A Feasibility Study of Power Generation from Sewage Using a Hollowed Pico-Hydraulic Turbine

OpenAIRE

Tomomi Uchiyama; Satoshi Honda; Tomoko Okayama; Tomohiro Degawa

2016-01-01

This study is concerned with the feasibility of power generation using a pico-hydraulic turbine from sewage flowing in pipes. First, the sewage flow rate at two connection points to the Toyogawa River-Basin Sewerage, Japan, was explored for over a year to elucidate the hydraulic energy potential of the sewage. Second, the performance of the pico-hydraulic turbine was investigated via laboratory experiments that supposed the turbine to be installed in the sewage pipe at the connection points. ...

Investigation of Blade Angle of an Open Cross-Flow Runner

Science.gov (United States)

Katayama, Yusuke; Iio, Shouichiro; Veerapun, Salisa; Uchiyama, Tomomi

2015-04-01

The aim of this study was to develop a nano-hydraulic turbine utilizing drop structure in irrigation channels or industrial waterways. This study was focused on an open-type cross-flow turbine without any attached equipment for cost reduction and easy maintenance. In this study, the authors used an artificial indoor waterfall as lab model. Test runner which is a simple structure of 20 circular arc-shaped blades sandwiched by two circular plates was used The optimum inlet blade angle and the relationship between the power performance and the flow rate approaching theoretically and experimentally were investigated. As a result, the optimum inlet blade angle due to the flow rate was changed. Additionally, allocation rate of power output in 1st stage and 2nd stage is changed by the blade inlet angle.

Control design and optimization for the DOT500 hydraulic wind turbine

NARCIS (Netherlands)

Mulders, S.P.; Jager, Stéphane; Diepeveen, N.F.B.; van Wingerden, J.W.

2017-01-01

The drivetrain of most wind turbines currently being deployed commercially consists of a rotor-gearboxgenerator configuration in the nacelle. This abstract introduces the control system design and optimization for a wind turbine with a hydraulic drivetrain, based on the Delft Offshore Turbine (DOT)

Performance of nano-hydraulic turbine utilizing waterfalls

Energy Technology Data Exchange (ETDEWEB)

Ikeda, Toshihiko; Iio, Shouichiro; Tatsuno, Kenji [Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano, 380-8553 (Japan)

2010-01-15

The aim of this investigation was to develop an environmentally friendly nano-hydraulic turbine utilizing waterfalls. A model of an impulse type hydraulic turbine constructed and tested with an indoor type waterfall to arrive at an optimum installation condition. Effects of an installation parameter, namely distance between the rotor and the waterfall on the power performance were studied. The flow field around the rotor was examined visually to clarify influences of installation conditions on the flow field. The flow visualization showed differences of flow pattern around the rotor by the change of flow rate and rotational speed of the rotor. From this study it was found that the power performances of the rotor were changed with the distance between the rotor and the waterfalls. The maximum power coefficient of this turbine is approximately 60%. Also, to respond to changes in the waterfall flow rate, we placed a flat plate on the upper side of the rotor to control the water flow direction. As a result, we found that the coefficient of this turbine is increased with the flow rate and power could be obtained even when the flow rate changed by 3.5 times if the plate was placed on the upper side of the rotor. Although the power coefficient decreased when the plate was installed, the power coefficient still is from 53 to 58%. (author)

MODEL TESTING OF LOW PRESSURE HYDRAULIC TURBINE WITH HIGHER EFFICIENCY

Directory of Open Access Journals (Sweden)

V. K. Nedbalsky

2007-01-01

Full Text Available A design of low pressure turbine has been developed and it is covered by an invention patent and a useful model patent. Testing of the hydraulic turbine model has been carried out when it was installed on a vertical shaft. The efficiency was equal to 76–78 % that exceeds efficiency of the known low pressure blade turbines. 

The hydraulic turbines of the Three Gorges dam; Les turbines hydrauliques du barrage des trois gorges

Energy Technology Data Exchange (ETDEWEB)

Bremond, J. [Societe GEC-Alsthom Neyrpic (France); Vuillerod, G. [Alsthom Hydro (France)

1999-10-01

As part of the hydroelectric installation of the Three Gorges on the Yangtze river in China, the Alsthom group recorded a major order for the supply of 8 Francis turbines out of the 14 to be installed in the left bank power station. This colossal project will include 26 Francis turbines of 710 MW, a spillway designed for a maximum flow of 116 000 m{sup 3}/s, a ship-lock of 5 steps with a capacity of 10 000 tons and a ship-lift of 3000 tons. The concrete gravity dam will be 2.3 km long. As oriented by the Specifications, and due to their exceptional size (runner diameter: 9800 mm), the design of these units relies upon well-proofed solutions such as those already experienced on the Itaipu south American large scale hydro project, in which Alsthom already contributed 20 years ago. The runners (450 tons each, external diameter 10 600 mm) will be fabricated by welding of separate elements made of martensitic stainless steel. Most of the components have to be delivered in several parts and reassembled at site by welding or bolting. The left bank power station is scheduled to be operational in 2006. (authors) 2 refs.

Analytical Method to Estimate Fatigue Life Time Duration in Service for Runner Blade Mechanism of Kaplan Turbines

Directory of Open Access Journals (Sweden)

Ana – Maria Budai

2010-10-01

Full Text Available The paper present an analytical method that can be used to determianted fatigue life time duration in service for runner blade mechanism of Kaplan turbines. The study was made for lever button of runer blade mechanism using two analytical relation to calculate the maximum number of stress cycles whereupon the mechanism work without any damage. To estimate fatigue life time duration will be used a formula obtained from one of most comon cumulative damage methodology taking in consideration the real exploatation conditions of a specified Kapaln turbine.

Flow Modeling in Pelton Turbines by an Accurate Eulerian and a Fast Lagrangian Evaluation Method

Directory of Open Access Journals (Sweden)

A. Panagiotopoulos

2015-01-01

Full Text Available The recent development of CFD has allowed the flow modeling in impulse hydro turbines that includes complex phenomena like free surface flow, multifluid interaction, and unsteady, time dependent flow. Some commercial and open-source CFD codes, which implement Eulerian methods, have been validated against experimental results showing satisfactory accuracy. Nevertheless, further improvement of accuracy is still a challenge, while the computational cost is very high and unaffordable for multiparametric design optimization of the turbine’s runner. In the present work a CFD Eulerian approach is applied at first, in order to simulate the flow in the runner of a Pelton turbine model installed at the laboratory. Then, a particulate method, the Fast Lagrangian Simulation (FLS, is used for the same case, which is much faster and hence potentially suitable for numerical design optimization, providing that it can achieve adequate accuracy. The results of both methods for various turbine operation conditions, as also for modified runner and bucket designs, are presented and discussed in the paper. In all examined cases the FLS method shows very good accuracy in predicting the hydraulic efficiency of the runner, although the computed flow evolution and the torque curve exhibit some systematic differences from the Eulerian results.

Understanding casing flow in Pelton turbines by numerical simulation

Science.gov (United States)

Rentschler, M.; Neuhauser, M.; Marongiu, J. C.; Parkinson, E.

2016-11-01

For rehabilitation projects of Pelton turbines, the flow in the casing may have an important influence on the overall performance of the machine. Water sheets returning on the jets or on the runner significantly reduce efficiency, and run-away speed depends on the flow in the casing. CFD simulations can provide a detailed insight into this type of flow, but these simulations are computationally intensive. As in general the volume of water in a Pelton turbine is small compared to the complete volume of the turbine housing, a single phase simulation greatly reduces the complexity of the simulation. In the present work a numerical tool based on the SPH-ALE meshless method is used to simulate the casing flow in a Pelton turbine. Using improved order schemes reduces the numerical viscosity. This is necessary to resolve the flow in the jet and on the casing wall, where the velocity differs by two orders of magnitude. The results are compared to flow visualizations and measurement in a hydraulic laboratory. Several rehabilitation projects proved the added value of understanding the flow in the Pelton casing. The flow simulation helps designing casing insert, not only to see their influence on the flow, but also to calculate the stress in the inserts. In some projects, the casing simulation leads to the understanding of unexpected behavior of the flow. One such example is presented where the backsplash of a deflector hit the runner, creating a reversed rotation of the runner.

Rotor optimization of a Francis type hydraulic turbine through the computer flow analysis (CFD); Optimizacion del rodete de una turbina hidraulica tipo Francis a traves del analisis computacional del flujo (CFD)

Energy Technology Data Exchange (ETDEWEB)

Rosado Tamariz, Erick

2007-06-15

In the analysis of fluid behavior through hydraulic turbines, two basic methodologies for flow analysis and optimization processes in turbines are used, which are: a) modeled of flow through the entire turbine (joint), or modeled one of each component separately, obtaining satisfactory results by both methodologies. The analysis of computational fluids dynamics (CFD) to geometries improved by means of finite volume method (FVM) with their corresponding initials and boundary conditions is made, to solve a system differential equations of second order that correspond to the flow around the dominion of runner blades; considering nonviscous flow and the implementation of the two equations models for the solution of the equations that govern the turbulent flow. Also, used parameterization techniques based in a parametric geometry an objective function and the diminution of cavitation. This work presents the optimization of a runner from a Francis hydro turbine for a 75 MW considering three different load conditions (75%, 85% and 100%) through CFD as a part of the hydraulic analysis for modernization of the actual condition of a power generation unit. Francis runner optimization is made, through a previous analysis of CFD by means of the FVM, considering the viscous effects of the fluid and the model of turbulence developed by Sparlart and Allmaras; modeling the wicket and runner separately. Later the generation of a parametric model of the runner is made and the simulation for the generation of data base is formed. Finally an objective function is considered to develop the optimal geometry of the runner blades. The results are presented in a graphic form in such a way, that it shows the distributions of pressure and speed around the blades runner, the geometrical and performance (efficiency and power) comparison between original and optimized model. [Spanish] En el analisis del comportamiento del fluido a traves de turbinas hidraulicas, se emplean dos metodologias

General overview of the AxialT project: A partnership for low head turbine developments

International Nuclear Information System (INIS)

Deschenes, C; Ciocan, G D; Henau, V De; Flemming, F; Qian, R; Huang, J; Koller, M; Vu, T; Naime, F A; Page, M

2010-01-01

An overview of the AxialT project is presented. Initiated in 2007 by the Consortium on Hydraulic Machines, the aim of this four years project is to contribute to the study of time-dependent hydraulic phenomena in a propeller turbine. The geometry of the entire turbine is generously shared by all partners. Numerical simulations carried out by all partners are confronted with experimental measurements carried out at the LAMH laboratory in Laval University. A mix of 2D LDA, 3D PIV and unsteady pressure measurements are adapted to yield precise measurements at eight strategic locations within the turbine and for nine operating points. Phase resolved analysis is performed wherever applicable. An illustration of potential analysis accessible with the database is shown for the identification of a vortex in the runner at part load.

Detection of cavitation in hydraulic turbines

Science.gov (United States)

Escaler, Xavier; Egusquiza, Eduard; Farhat, Mohamed; Avellan, François; Coussirat, Miguel

2006-05-01

An experimental investigation has been carried out in order to evaluate the detection of cavitation in actual hydraulic turbines. The methodology is based on the analysis of structural vibrations, acoustic emissions and hydrodynamic pressures measured in the machine. The proposed techniques have been checked in real prototypes suffering from different types of cavitation. In particular, one Kaplan, two Francis and one Pump-Turbine have been investigated in the field. Additionally, one Francis located in a laboratory has also been tested. First, a brief description of the general features of cavitation phenomenon is given as well as of the main types of cavitation occurring in hydraulic turbines. The work presented here is focused on the most important ones which are the leading edge cavitation due to its erosive power, the bubble cavitation because it affects the machine performance and the draft tube swirl that limits the operation stability. Cavitation detection is based on the previous understanding of the cavity dynamics and its location inside the machine. This knowledge has been gained from flow visualisations and measurements in laboratory devices such as a high-speed cavitation tunnel and a reduced scale turbine test rig. The main techniques are the study of the high frequency spectral content of the signals and of their amplitude demodulation for a given frequency band. Moreover, low frequency spectral content can also be used in certain cases. The results obtained for the various types of cavitation found in the selected machines are presented and discussed in detail in the paper. Conclusions are drawn about the best sensor, measuring location, signal processing and analysis for each type of cavitation, which serve to validate and to improve the detection techniques.

Simulations of Steady Cavitating Flow in a Small Francis Turbine

Directory of Open Access Journals (Sweden)

Ahmed Laouari

2016-01-01

Full Text Available The turbulent flow through a small horizontal Francis turbine is solved by means of Ansys-CFX at different operating points, with the determination of the hydrodynamic performance and the best efficiency point. The flow structures at different regimes reveal a large flow eddy in the runner and a swirl in the draft tube. The use of the mixture model for the cavity/liquid two-phase flow allowed studying the influence of cavitation on the hydrodynamic performance and revealed cavitation pockets near the trailing edge of the runner and a cavitation vortex rope in the draft tube. By maintaining a constant dimensionless head and a distributor vane opening while gradually increasing the cavitation number, the output power and efficiency reached a critical point and then had begun to stabilize. The cavitation number corresponding to the safety margin of cavitation is also predicted for this hydraulic turbine.

Investigation of the fluid-structure interaction of a high head Francis turbine using OpenFOAM and Code_Aster

Science.gov (United States)

Eichhorn, M.; Doujak, E.; Waldner, L.

2016-11-01

The increasing energy consumption and highly stressed power grids influence the operating conditions of turbines and pump turbines in the present situation. To provide or use energy as quick as possible, hydraulic turbines are operated more frequent and over longer periods of time in lower part load at off-design conditions. This leads to a more turbulent behavior and to higher requirements of the strength of stressed components (e.g. runner, guide or stay vanes). The modern advantages of computational capabilities regarding numerical investigations allow a precise prediction of appearing flow conditions and thereby induced strains in hydraulic machines. This paper focuses on the calculation of the unsteady pressure field of a high head Francis turbine with a specific speed of nq ≈ 24 min-1 and its impact on the structure at different operating conditions. In the first step, unsteady numerical flow simulations are performed with the open-source CFD software OpenFOAM. To obtain the appearing dynamic flow phenomena, the entire machine, consisting of the spiral casing, the stay vanes, the wicket gate, the runner and the draft tube, is taken into account. Additionally, a reduced model without the spiral casing and with a simplified inlet boundary is used. To evaluate the accuracy of the CFD simulations, operating parameters such as head and torque are compared with the results of site measurements carried out on the corresponding prototype machine. In the second part, the obtained pressure fields are used for a fluid-structure analysis with the open-source Finite Element software Code_Aster, to predict the static loads on the runner.

Numerical simulation of turbulence flow in a Kaplan turbine -Evaluation on turbine performance prediction accuracy-

International Nuclear Information System (INIS)

Ko, P; Kurosawa, S

2014-01-01

The understanding and accurate prediction of the flow behaviour related to cavitation and pressure fluctuation in a Kaplan turbine are important to the design work enhancing the turbine performance including the elongation of the operation life span and the improvement of turbine efficiency. In this paper, high accuracy turbine and cavitation performance prediction method based on entire flow passage for a Kaplan turbine is presented and evaluated. Two-phase flow field is predicted by solving Reynolds-Averaged Navier-Stokes equations expressed by volume of fluid method tracking the free surface and combined with Reynolds Stress model. The growth and collapse of cavitation bubbles are modelled by the modified Rayleigh-Plesset equation. The prediction accuracy is evaluated by comparing with the model test results of Ns 400 Kaplan model turbine. As a result that the experimentally measured data including turbine efficiency, cavitation performance, and pressure fluctuation are accurately predicted. Furthermore, the cavitation occurrence on the runner blade surface and the influence to the hydraulic loss of the flow passage are discussed. Evaluated prediction method for the turbine flow and performance is introduced to facilitate the future design and research works on Kaplan type turbine

Numerical simulation of turbulence flow in a Kaplan turbine -Evaluation on turbine performance prediction accuracy-

Science.gov (United States)

Ko, P.; Kurosawa, S.

2014-03-01

The understanding and accurate prediction of the flow behaviour related to cavitation and pressure fluctuation in a Kaplan turbine are important to the design work enhancing the turbine performance including the elongation of the operation life span and the improvement of turbine efficiency. In this paper, high accuracy turbine and cavitation performance prediction method based on entire flow passage for a Kaplan turbine is presented and evaluated. Two-phase flow field is predicted by solving Reynolds-Averaged Navier-Stokes equations expressed by volume of fluid method tracking the free surface and combined with Reynolds Stress model. The growth and collapse of cavitation bubbles are modelled by the modified Rayleigh-Plesset equation. The prediction accuracy is evaluated by comparing with the model test results of Ns 400 Kaplan model turbine. As a result that the experimentally measured data including turbine efficiency, cavitation performance, and pressure fluctuation are accurately predicted. Furthermore, the cavitation occurrence on the runner blade surface and the influence to the hydraulic loss of the flow passage are discussed. Evaluated prediction method for the turbine flow and performance is introduced to facilitate the future design and research works on Kaplan type turbine.

The swirl turbine

Science.gov (United States)

Haluza, M.; Pochylý, F.; Rudolf, P.

2012-11-01

In the article is introduced the new type of the turbine - swirl turbine. This turbine is based on opposite principle than Kaplan turbine. Euler equation is satisfied in the form gHηh = -u2vu2. From this equation is seen, that inflow of liquid into the runner is without rotation and on the outflow is a rotation of liquid opposite of rotation of runner. This turbine is suitable for small head and large discharge. Some constructional variants of this turbine are introduced in the article and theoretical aspects regarding losses in the draft tube. The theory is followed by computational simulations in Fluent and experiments using laser Doppler anemometry.

The swirl turbine

International Nuclear Information System (INIS)

Haluza, M; Pochylý, F; Rudolf, P

2012-01-01

In the article is introduced the new type of the turbine - swirl turbine. This turbine is based on opposite principle than Kaplan turbine. Euler equation is satisfied in the form gHη h = −u 2 v u2 . From this equation is seen, that inflow of liquid into the runner is without rotation and on the outflow is a rotation of liquid opposite of rotation of runner. This turbine is suitable for small head and large discharge. Some constructional variants of this turbine are introduced in the article and theoretical aspects regarding losses in the draft tube. The theory is followed by computational simulations in Fluent and experiments using laser Doppler anemometry.

A reference Pelton turbine - High speed visualization in the rotating frame

Science.gov (United States)

Solemslie, Bjørn W.; Dahlhaug, Ole G.

2016-11-01

To enable a detailed study the flow mechanisms effecting the flow within the reference Pelton runner designed at the Waterpower Laboratory (NTNLT) a flow visualization system has been developed. The system enables high speed filming of the hydraulic surface of a single bucket in the rotating frame of reference. It is built with an angular borescopes adapter entering the turbine along the rotational axis and a borescope embedded within a bucket. A stationary high speed camera located outside the turbine housing has been connected to the optical arrangement by a non-contact coupling. The view point of the system includes the whole hydraulic surface of one half of a bucket. The system has been designed to minimize the amount of vibrations and to ensure that the vibrations felt by the borescope are the same as those affecting the camera. The preliminary results captured with the system are promising and enable a detailed study of the flow within the turbine.

Research on the cavitation characteristic of Kaplan turbine under sediment flow condition

International Nuclear Information System (INIS)

Weili, L; Jinling, L; Xingqi, L; Yuan, L

2010-01-01

The sediment concentration in many rivers in our world is very high, and the Kaplan turbine running in these rivers are usually seriously abraded. Since the existence of sand, the probability of cavitation is greatly enhanced. Under the joint action and mutual promotion of cavitation and sand erosion, serious abrasion could be made, the hydraulic performance of the Kaplan turbine may be descended, and the safety and stability of turbine are greatly threatened. Therefore, it is very important and significant to investigate the cavitation characteristic of Kaplan turbine under sediment flow condition. In this paper, numerical simulation of cavitation characteristic in pure water and solid-liquid two-phase flow in Kaplan turbine was performed. The solid-liquid two-fluid model were adopted in the numerical simulation, and the pressure, velocity and particle concentration distributive regularity on turbine blade surface under different diameter and concentration was revealed. Particle trajectory model was used to investigate the region and degree of runner blade abrasion in different conditions. The results showed that serious sand abrasion could be found near the blade head and outlet in large flow rate working condition. Relatively slight abrasion may be found near blade flange in small flow rate working condition. The more the sediment concentration and the large the sand diameter, the serious the runner is abraded, and the greater the efficiency is decreased. further analysis of the combined effects of wear and abrasion was performed. The result shows that the cavitation in silt flow is more serious than in pure water. The runner cavitation performance become worse under high sand concentration and large particle diameter, and the efficiency decrease greatly with the increase of sediment concentration.

Research on the cavitation characteristic of Kaplan turbine under sediment flow condition

Energy Technology Data Exchange (ETDEWEB)

Weili, L; Jinling, L; Xingqi, L; Yuan, L, E-mail: liaoweili2004@163.co [Institute of Water Resources and Hydro-Electric Engineering, Xi' an University of Technology No.5 South Jinhua Road, Xi' an, Shaanxi, 710048 (China)

2010-08-15

The sediment concentration in many rivers in our world is very high, and the Kaplan turbine running in these rivers are usually seriously abraded. Since the existence of sand, the probability of cavitation is greatly enhanced. Under the joint action and mutual promotion of cavitation and sand erosion, serious abrasion could be made, the hydraulic performance of the Kaplan turbine may be descended, and the safety and stability of turbine are greatly threatened. Therefore, it is very important and significant to investigate the cavitation characteristic of Kaplan turbine under sediment flow condition. In this paper, numerical simulation of cavitation characteristic in pure water and solid-liquid two-phase flow in Kaplan turbine was performed. The solid-liquid two-fluid model were adopted in the numerical simulation, and the pressure, velocity and particle concentration distributive regularity on turbine blade surface under different diameter and concentration was revealed. Particle trajectory model was used to investigate the region and degree of runner blade abrasion in different conditions. The results showed that serious sand abrasion could be found near the blade head and outlet in large flow rate working condition. Relatively slight abrasion may be found near blade flange in small flow rate working condition. The more the sediment concentration and the large the sand diameter, the serious the runner is abraded, and the greater the efficiency is decreased. further analysis of the combined effects of wear and abrasion was performed. The result shows that the cavitation in silt flow is more serious than in pure water. The runner cavitation performance become worse under high sand concentration and large particle diameter, and the efficiency decrease greatly with the increase of sediment concentration.

Research on the cavitation characteristic of Kaplan turbine under sediment flow condition

Science.gov (United States)

Weili, L.; Jinling, L.; Xingqi, L.; Yuan, L.

2010-08-01

The sediment concentration in many rivers in our world is very high, and the Kaplan turbine running in these rivers are usually seriously abraded. Since the existence of sand, the probability of cavitation is greatly enhanced. Under the joint action and mutual promotion of cavitation and sand erosion, serious abrasion could be made, the hydraulic performance of the Kaplan turbine may be descended, and the safety and stability of turbine are greatly threatened. Therefore, it is very important and significant to investigate the cavitation characteristic of Kaplan turbine under sediment flow condition. In this paper, numerical simulation of cavitation characteristic in pure water and solid-liquid two-phase flow in Kaplan turbine was performed. The solid-liquid two-fluid model were adopted in the numerical simulation, and the pressure, velocity and particle concentration distributive regularity on turbine blade surface under different diameter and concentration was revealed. Particle trajectory model was used to investigate the region and degree of runner blade abrasion in different conditions. The results showed that serious sand abrasion could be found near the blade head and outlet in large flow rate working condition. Relatively slight abrasion may be found near blade flange in small flow rate working condition. The more the sediment concentration and the large the sand diameter, the serious the runner is abraded, and the greater the efficiency is decreased. further analysis of the combined effects of wear and abrasion was performed. The result shows that the cavitation in silt flow is more serious than in pure water. The runner cavitation performance become worse under high sand concentration and large particle diameter, and the efficiency decrease greatly with the increase of sediment concentration.

Validation of mathematical models for predicting the swirling flow and the vortex rope in a Francis turbine operated at partial discharge

DEFF Research Database (Denmark)

Kuibin, P.A.; Okulov, Valery; Susan-Resiga, R.F.

2010-01-01

recover all this information without actually computing the full three-dimensional unsteady flow in the hydraulic turbine. As a result, we provide valuable mathematical tools for assessing the turbine behaviour at off-design operating regimes in the early stages of runner design, with computational effort......The vortex rope in a hydro turbine draft tube is one the main and strong sources of pulsations in non-optimal modes of hydro turbine operation. We examine the case of a Francis turbine model operated at partial discharge, where a strong precessing vortex rope is developed in the discharge cone...... several orders of magnitude less than the current approaches of simulating the complex turbine flow....

Hydraulic pitch control system for wind turbines: Advanced modeling and verification of an hydraulic accumulator

DEFF Research Database (Denmark)

Irizar, Victor; Andreasen, Casper Schousboe

2017-01-01

Hydraulic pitch systems provide robust and reliable control of power and speed of modern wind turbines. During emergency stops, where the pitch of the blades has to be taken to a full stop position to avoid over speed situations, hydraulic accumulators play a crucial role. Their efficiency...... and capability of providing enough energy to rotate the blades is affected by thermal processes due to the compression and decompression of the gas chamber. This paper presents an in depth study of the thermodynamical processes involved in an hydraulic accumulator during operation, and how they affect the energy...

Hydraulic optimization of 'S' characteristics of the pump-turbine for Xianju pumped storage plant

International Nuclear Information System (INIS)

Liu, W C; Zheng, J S; Cheng, J; Shi, Q H

2012-01-01

The pump-turbine with a rated power capacity of 375MW each at Xianju pumped storage plant is the most powerful one under construction in China. In order to avoid the instability near no-load conditions, the hydraulic design of the pump-turbine has been optimized to improving the 'S' characteristic in the development of the model pump-turbine. This paper presents the cause of 'S' characteristic of a pump-turbine by CFD simulation of the internal flow. Based on the CFD analysis, the hydraulic design optimization of the pump-turbine was carried out to eliminate the 'S' characteristics of the machine at Xianju pumped storage plant and a big step for removing the 'S' characteristic of a pump-turbine has been obtained. The model test results demonstrate that the pump-turbine designed for Xianju pumped storage plant can smoothly operate near no-load conditions without an addition of misaligned guide vanes.

Development and industrial tests of the first LNG hydraulic turbine system in China

OpenAIRE

Jie Chen; Yihuai Hua; Qingbo Su; Xueli Wan; Zhenlin Li

2016-01-01

The cryogenic hydraulic turbine can be used to replace the conventional J–T valve for LNG or mixed refrigerant throttling and depressurization in a natural gas liquefaction plant. This advanced technology is not only to enhance the efficiency of the liquefaction plant, but to usher a new trend in the development of global liquefaction technologies. China has over 136 liquefaction plants, but the cryogenic hydraulic turbines have not been deployed in industrial utilization. In addition, these ...

An evaluation of a hubless inducer and a full flow hydraulic turbine driven inducer boost pump

Science.gov (United States)

Lindley, B. K.; Martinson, A. R.

1971-01-01

The purpose of the study was to compare the performance of several configurations of hubless inducers with a hydrodynamically similar conventional inducer and to demonstrate the performance of a full flow hydraulic turbine driven inducer boost pump using these inducers. A boost pump of this type consists of an inducer connected to a hydraulic turbine with a high speed rotor located in between. All the flow passes through the inducer, rotor, and hydraulic turbine, then into the main pump. The rotor, which is attached to the main pump shaft, provides the input power to drive the hydraulic turbine which, in turn, drives the inducer. The inducer, rotating at a lower speed, develops the necessary head to prevent rotor cavitation. The rotor speed is consistent with present main engine liquid hydrogen pump designs and the overall boost pump head rise is sufficient to provide adequate main pump suction head. This system would have the potential for operating at lower liquid hydrogen tank pressures.

77 FR 18801 - Notice of Application for Non-Capacity Amendment of License and Soliciting Comments, Motions To...

Science.gov (United States)

2012-03-28

... in November 2020. The proposed rehabilitation would increase the turbine hydraulic capacity by... MW pump-turbine/motor generator units at the Lewiston Pumped Storage Development by: (1) Installing new high efficiency turbine runners, replacing runner seals, replacing or modifying head covers; (2...

Design, Optimization and Analysis of Hydraulic Soft Yaw System for 5 MW Wind Turbine

DEFF Research Database (Denmark)

Stubkier, Søren; Pedersen, Henrik C.

2011-01-01

As wind turbines increase in size and the demands for lifetime also increases, new methods of load reduction needs to be examined. One method is to make the yaw system of the turbine soft/flexible and hence dampen the loads to the system, which is the focus of the current paper. The paper first p...... on the extrapolated loads, show that it is possible to construct a hydraulic soft yaw system, which is able to reduce the loads on the wind turbine significantly....... presents work previous done on this subject with focus on hydraulic yaw systems. By utilizing the HAWC2 aeroelastic code and an extended model of the NREL 5MW turbine combined with a simplified linear model of the turbine, the parameters of the soft yaw system are optimized. Results show that a significant...... reduction in fatigue and extreme loads to the yaw system and rotor shaft are possible, when utilizing the soft yaw drive concept compared to the original stiff yaw system. The physical demands of the hydraulic yaw system are furthermore examined for a life time of 20 years. The duty cycles, based...

Geometrical parameters effects on a runner-type wind turbine; Efectos de los parametros geometricos para una turbina eolica tipo rueda movil

Energy Technology Data Exchange (ETDEWEB)

Loreto, Ramon; Quintero, Freddy; Zambrano, Edgar [Universidad de Los Andes, Merida (Venezuela). Facultad de Ingenieria. Escuela de Mecanica

1995-07-01

The project consisted basically on wind tunnel testing of a Runner-Type wind turbine prototype. Testing was aimed at optimizing its performance by varying its geometry. Results are shown which relate geometry and efficiency as compared with Brace Research Institute of Mc Graw-Hill University of Montreal. (author)

Entropy production analysis of hysteresis characteristic of a pump-turbine model

International Nuclear Information System (INIS)

Li, Deyou; Wang, Hongjie; Qin, Yonglin; Han, Lei; Wei, Xianzhu; Qin, Daqing

2017-01-01

Highlights: • An interesting hysteresis phenomenon was analyzed using entropy production theory. • A function was used to calculate the entropy production in the wall region. • Generation mechanism of the hump and hysteresis characteristics was obtained. - Abstract: The hydraulic loss due to friction and unstable flow patterns in hydro-turbines causes a drop in their efficiency. The traditional method for analyzing the hydraulic loss is by evaluating the pressure drop, which has certain limitations and cannot determine the exact locations at which the high hydraulic loss occurs. In this study, entropy production theory was adopted to obtain a detailed distribution of the hydraulic loss in a pump-turbine in the pump mode. In the past, the wall effects of entropy production were not considered, which caused larger errors as compared with the method of pressure difference. First, a wall equation was proposed to calculate the hydraulic loss in the wall region. The comparison of hydraulic loss calculated by entropy production and pressure difference revealed a better result. Then, through the use of the entropy production theory, the performance characteristics were determined for a pump-turbine with 19 mm guide vane opening, and the variation in the entropy production was obtained. Recently, an interesting phenomenon, i.e., a hysteresis characteristic, was observed in the hump region in pump-turbines. Research shows that the hysteresis characteristic is a result of the Euler momentum and hydraulic loss; the hydraulic loss accounts for a major portion of the hysteresis characteristic. Finally, the hysteresis characteristic in the hump region was analyzed in detail through the entropy production. The results showed that the hump characteristic and the accompanying hysteresis phenomenon are caused by backflow at the runner inlet and the presence of separation vortices close to the hub and the shroud in the stay/guide vanes, which is dependent on the direction of

Fish-Friendly Hydropower Turbine Development & Deployment: Alden Turbine Preliminary Engineering and Model Testing

Energy Technology Data Exchange (ETDEWEB)

Foust, J. [Voith Hydro, Inc., York, PA (USA); Hecker, G. [Alden Research Laboratory, Inc., Holden, MA (USA); Li, S. [Alden Research Laboratory, Inc., Holden, MA (USA); Allen, G. [Alden Research Laboratory, Inc., Holden, MA (USA)

2011-10-01

The Alden turbine was developed through the U.S. Department of Energy's (DOE's) former Advanced Hydro Turbine Systems Program (1994-2006) and, more recently, through the Electric Power Research Institute (EPRI) and the DOE's Wind & Water Power Program. The primary goal of the engineering study described here was to provide a commercially competitive turbine design that would yield fish passage survival rates comparable to or better than the survival rates of bypassing or spilling flow. Although the turbine design was performed for site conditions corresponding to 92 ft (28 m) net head and a discharge of 1500 cfs (42.5 cms), the design can be modified for additional sites with differing operating conditions. During the turbine development, design modifications were identified for the spiral case, distributor (stay vanes and wicket gates), runner, and draft tube to improve turbine performance while maintaining features for high fish passage survival. Computational results for pressure change rates and shear within the runner passage were similar in the original and final turbine geometries, while predicted minimum pressures were higher for the final turbine. The final turbine geometry and resulting flow environments are expected to further enhance the fish passage characteristics of the turbine. Computational results for the final design were shown to improve turbine efficiencies by over 6% at the selected operating condition when compared to the original concept. Prior to the release of the hydraulic components for model fabrication, finite element analysis calculations were conducted for the stay vanes, wicket gates, and runner to verify that structural design criteria for stress and deflections were met. A physical model of the turbine was manufactured and tested with data collected for power and efficiency, cavitation limits, runaway speed, axial and radial thrust, pressure pulsations, and wicket gate torque. All parameters were observed to fall

Water hammer 2 phase analysis hydraulic system with a Kaplan turbine

OpenAIRE

Dudlik, A.; Koutnik, J.

2009-01-01

This investigation has been carried out for a case of sudden closing of a Kaplan turbine from a runaway operation. This work has been done at Fraunhofer UMSICHT, supported by VH. The runaway case has been selected as it is known that the discharge through a Kaplan turbine increases with its speed, and may reach up to twice the value of nominal discharge. The simulation model consists of: - penstock - Kaplan turbine (modelled with a valve characteristic) - draft tube All hydraulic pipe element...

Extensive use of computational fluid dynamics in the upgrading of hydraulic turbines

Energy Technology Data Exchange (ETDEWEB)

Sabourin, M.; De Henau, V. [GEC Alsthom Electromechanical Inc., Tracy, PQ (Canada); Eremeef, R. [GEC Alsthom Neyrpic, Grenoble (France)

1995-12-31

The use of computational fluid flow dynamics (CFD) and the Navier Stokes equations by GEC Alsthom for turbine rehabilitation were discussed. The process of runner rehabilitation was discussed from a fluid flow perspective, which accounts for the spiral case-distributor set and draft tube. The Kootenay turbine rehabilitation was described with regard to it spiral case and stay vane. The numerical analysis used to model upstream components was explained. The influence of draft tube effects was emphasized as an important efficiency factor. The differences between draft tubes at Sir Adam Beck 2 and La Grande 2 were discussed. Computational fluid flow modelling was claimed to have produced global performance enhancements in a reasonably short time, and at a reasonable cost. 6 refs., 6 figs., 4 tabs.

Dynamic stresses in a Francis model turbine at deep part load

Science.gov (United States)

Weber, Wilhelm; von Locquenghien, Florian; Conrad, Philipp; Koutnik, Jiri

2017-04-01

A comparison between numerically obtained dynamic stresses in a Francis model turbine at deep part load with experimental ones is presented. Due to the change in the electrical power mix to more content of new renewable energy sources, Francis turbines are forced to operate at deep part load in order to compensate stochastic nature of wind and solar power and to ensure grid stability. For the extension of the operating range towards deep part load improved understanding of the harsh flow conditions and their impact on material fatigue of hydraulic components is required in order to ensure long life time of the power unit. In this paper pressure loads on a model turbine runner from unsteady two-phase computational fluid dynamics simulation at deep part load are used for calculation of mechanical stresses by finite element analysis. Therewith, stress distribution over time is determined. Since only few runner rotations are simulated due to enormous numerical cost, more effort has to be spent to evaluation procedure in order to obtain objective results. By comparing the numerical results with measured strains accuracy of the whole simulation procedure is verified.

DETERMINATION OF HYDRAULIC TURBINE EFFICIENCY BY MEANS OF THE CURRENT METER METHOD

Directory of Open Access Journals (Sweden)

PURECE C.

2016-12-01

Full Text Available The paper presents methodology used for determining the efficiency of a low head Kaplan hydraulic turbine with short converging intake. The measurement method used was the current meters method, the only measurement method recommended by the IEC 41standard for flow measurement in this case. The paper also presents the methodology used for measuring the flow by means of the current meters method and the various procedures for calculating the flow. In the last part the paper presents the flow measurements carried out on the Fughiu HPP hydraulic turbines for determining the actual operating efficiency.

Selection of axial hydraulic turbines for low-head microhydropower plants

Science.gov (United States)

Šoukal, J.; Pochylý, F.; Varchola, M.; Parygin, A. G.; Volkov, A. V.; Khovanov, G. P.; Naumov, A. V.

2015-12-01

The creation of highly efficient hydroturbines for low-head microhydropower plants is considered. The use of uncontrolled (propeller) hydroturbines is a promising means of minimizing costs and the time for their recoupment. As an example, experimental results from Brno University of Technology are presented. The model axial hydraulic turbine produced by Czech specialists performs well. The rotor diameter of this turbine is 194 mm. In the design of the working rotor, ANSYS Fluent software is employed. Means of improving the efficiency of microhydropower plants by optimal selection of the turbine parameters in the early stages of design are outlined. The energy efficiency of the hydroturbine designed for use in a microhydropower plant may be assessed on the basis of the coefficient of energy utilization, which is a function of the total losses in all the pipeline elements and losses in the channel including the hydroturbine rotor. The limit on the coefficient of energy utilization in the pressure pipeline is the hydraulic analog of the Betz-Joukowsky limit, which is widely used in the design of wind generators. The proposed approach is experimentally verified at Moscow Power Engineering Institute. A model axial hydraulic turbine with four different rotors is designed for the research. The diameter of all four rotors is the same: 80 mm. The pipeline takes the form of a siphon. Working rotor R2, designed with parameter optimization, is characterized by the highest coefficient of energy utilization of the pressure pipeline and maximum efficiency. That confirms that the proposed approach is a promising means of maximizing the overall energy efficiency of the microhydropower plant.

Numerical investigation of hub clearance flow in a Kaplan turbine

Science.gov (United States)

Wu, H.; Feng, J. J.; Wu, G. K.; Luo, X. Q.

2012-11-01

In this paper, the flow field considering the hub clearance flow in a Kaplan turbine has been investigated through using the commercial CFD code ANSYS CFX based on high-quality structured grids generated by ANSYS ICEM CFD. The turbulence is simulated by k-ω based shear stress transport (SST) turbulence model together with automatic near wall treatments. Four kinds of simulations have been conducted for the runner geometry without hub clearance, with only the hub front clearance, with only the rear hub clearance, and with both front and rear clearance. The analysis of the obtained results is focused on the flow structure of the hub clearance flow, the effect on the turbine performance including hydraulic efficiency and cavitation performance, which can improve the understanding on the flow field in a Kaplan turbine.

Numerical investigation of hub clearance flow in a Kaplan turbine

International Nuclear Information System (INIS)

Wu, H; Feng, J J; Wu, G K; Luo, X Q

2012-01-01

In this paper, the flow field considering the hub clearance flow in a Kaplan turbine has been investigated through using the commercial CFD code ANSYS CFX based on high-quality structured grids generated by ANSYS ICEM CFD. The turbulence is simulated by k-ω based shear stress transport (SST) turbulence model together with automatic near wall treatments. Four kinds of simulations have been conducted for the runner geometry without hub clearance, with only the hub front clearance, with only the rear hub clearance, and with both front and rear clearance. The analysis of the obtained results is focused on the flow structure of the hub clearance flow, the effect on the turbine performance including hydraulic efficiency and cavitation performance, which can improve the understanding on the flow field in a Kaplan turbine.

Stability analysis for a delay differential equations model of a hydraulic turbine speed governor

Science.gov (United States)

Halanay, Andrei; Safta, Carmen A.; Dragoi, Constantin; Piraianu, Vlad F.

2017-01-01

The paper aims to study the dynamic behavior of a speed governor for a hydraulic turbine using a mathematical model. The nonlinear mathematical model proposed consists in a system of delay differential equations (DDE) to be compared with already established mathematical models of ordinary differential equations (ODE). A new kind of nonlinearity is introduced as a time delay. The delays can characterize different running conditions of the speed governor. For example, it is considered that spool displacement of hydraulic amplifier might be blocked due to oil impurities in the oil supply system and so the hydraulic amplifier has a time delay in comparison to the time control. Numerical simulations are presented in a comparative manner. A stability analysis of the hydraulic control system is performed, too. Conclusions of the dynamic behavior using the DDE model of a hydraulic turbine speed governor are useful in modeling and controlling hydropower plants.

Unsteady hydraulic simulation of the cavitating part load vortex rope in Francis turbines

Science.gov (United States)

Brammer, J.; Segoufin, C.; Duparchy, F.; Lowys, P. Y.; Favrel, A.; Avellan, F.

2017-04-01

For Francis turbines at part load operation a helical vortex rope is formed due to the swirling nature of the flow exiting the runner. This vortex creates pressure fluctuations which can lead to power swings, and the unsteady loading can lead to fatigue damage of the runner. In the case that the vortex rope cavitates there is the additional risk that hydro-acoustic resonance can occur. It is therefore important to be able to accurately simulate this phenomenon to address these issues. In this paper an unsteady, multi-phase CFD model was used to simulate two part-load operating points, for two different cavitation conditions. The simulation results were validated with test-rig data, and showed very good agreement. These results also served as an input for FEA calculations and fatigue analysis, which are presented in a separate study.

Bulb turbine operating at medium head: XIA JIANG case study

Science.gov (United States)

Loiseau, F.; Desrats, C.; Petit, P.; Liu, J.

2012-11-01

With lots of references for 4-blade bulb turbines, such as these of Wu Jin Xia (4 units - 36.1 MW per unit - 9.2 m rated head), Chang Zhou (15 units - 46.7 MW per unit - 9.5 m rated head) and Tong Wan (4 units - 46.2 MW per unit - 11 m rated head), ALSTOM Power Hydro is one of the major suppliers of bulb turbines operating under medium head for the Chinese market. ALSTOM Power Hydro has been awarded in November 2010 a contract by Jiang Xi Province Xia Jiang Water Control Project Headquarters to equip Xia Jiang's new hydropower plant. The power dam is located on the Gan Jiang river, at about 160 km away from Nan Chang town in South Eastern China. The supply will consist in 5 bulb units including the furniture of both the turbine and its generator, for a total capacity of 200 MW, under a rated net head of 8.6 m. The prototype turbine is a 7.8 m diameter runner, rotating at 71.4 rpm speed. For this project, ALSTOM has proposed a fully new design of 4-blade bulb runner. This paper outlines the main steps of the hydraulic development. First of all, a fine tuning of the blade geometry was performed to enhance the runner behaviour at high loads and low heads, so that to fulfill the demanding requirements of efficiencies and maximum output. The challenge was also to keep an excellent cavitation behaviour, especially at the outer blade diameter in order to avoid cavitation erosion on the prototype. The shape of the blade was optimized by using the latest tools in computational fluid dynamics. Steady state simulations of the distributor and the runner were performed, in order to simulate more accurately the pressure fields on the blade and the velocity distribution at the outlet of the runner. Moreover, draft tube computations have been performed close to the design point and at higher loads. Then, a model fully homologous with the prototype was manufactured and tested at ALSTOM's laboratory in Grenoble (France). The model test results confirmed the predicted ones: the

Extrapolation of dynamic load behaviour on hydroelectric turbine blades with cyclostationary modelling

Science.gov (United States)

Poirier, Marc; Gagnon, Martin; Tahan, Antoine; Coutu, André; Chamberland-lauzon, Joël

2017-01-01

In this paper, we present the application of cyclostationary modelling for the extrapolation of short stationary load strain samples measured in situ on hydraulic turbine blades. Long periods of measurements allow for a wide range of fluctuations representative of long-term reality to be considered. However, sampling over short periods limits the dynamic strain fluctuations available for analysis. The purpose of the technique presented here is therefore to generate a representative signal containing proper long term characteristics and expected spectrum starting with a much shorter signal period. The final objective is to obtain a strain history that can be used to estimate long-term fatigue behaviour of hydroelectric turbine runners.

Modern challenges for flow investigations in model hydraulic turbines on classical test rig

International Nuclear Information System (INIS)

Deschênes, C; Houde, S; Aeschlimann, V; Fraser, R; Ciocan, G D

2014-01-01

The BulbT project involved several investigations of flow phenomena in different parts of a model bulb turbine installed on the test rig of Laval University Laboratory. The aim is to create a comprehensive data base in order to increase the knowledge of the flow phenomena in this type of turbines and to validate or improve numerical flow simulation strategies. This validation being based on a kinematic comparison between experimental and numerical data, the project had to overcome challenges to facilitate the use of the experimental data for that purpose. Many parameters were checked, such as the test bench repeatability, the intrusiveness of a priori non-intrusive methods, the geometry of the runner and draft tube. This paper illustrates how some of those problematic were solved

Study on an Undershot Cross-Flow Water Turbine with Straight Blades

Directory of Open Access Journals (Sweden)

Yasuyuki Nishi

2015-01-01

Full Text Available Small-scale hydroelectric power generation has recently attracted considerable attention. The authors previously proposed an undershot cross-flow water turbine with a very low head suitable for application to open channels. The water turbine was of a cross-flow type and could be used in open channels with the undershot method, remarkably simplifying its design by eliminating guide vanes and the casing. The water turbine was fitted with curved blades (such as the runners of a typical cross-flow water turbine installed in tube channels. However, there was ambiguity as to how the blades’ shape influenced the turbine’s performance and flow field. To resolve this issue, the present study applies straight blades to an undershot cross-flow water turbine and examines the performance and flow field via experiments and numerical analyses. Results reveal that the output power and the turbine efficiency of the Straight Blades runner were greater than those of the Curved Blades runner regardless of the rotational speed. Compared with the Curved Blades runner, the output power and the turbine efficiency of the Straight Blades runner were improved by about 31.7% and about 67.1%, respectively.

Optimization Design and Performance Analysis of a Pit Turbine with Ultralow Head

Directory of Open Access Journals (Sweden)

Chunxia Yang

2014-04-01

Full Text Available A developed pit turbine with ultralow head was optimization designed under the design head of about 2 meters to achieve the goal of improving the turbine unit's efficiency. At the same time, the turbine's synthetic characteristic curve was drawn to predict the turbine's overall performance. Navier-Stokes equations and SIMPLEC algorithm were used for pit turbine's whole flow passage numerical simulation of the 3D, steady, incompressible, turbulent flow field. Through the CFD numerical simulation, the influence to ultralow head turbine's performance was analyzed by runner blade's different setting angles and guide vane's different axes. Considering the hydraulic performance of various methods, the best blade's setting angle and guide vane's axis were chosen. The results show that, the turbine unit has the best performance on efficiency, hydraulic loss, and so forth, with the blade's setting angle 23° and the angle 72° between the guide vane and the centerline of unit, meeting the power station's design requirements. The development pit turbine with ultralow head shows the highest efficiency of 87.6% under condition of design head of 2.1 meters and design discharge of 10 m3/s. The energy performance of pit turbine with ultralow head was researched by the model test of GD-WS-35 turbine. The model turbine's characteristic curve was drawn. The model turbine's high efficiency area is wide and the efficiency changes mildly. The numerical simulation results are essentially consistent with the model test results, while the former one is slightly higher than the latter one. The error range is ±3%.

A model for precessing helical vortex in the turbine discharge cone

International Nuclear Information System (INIS)

Kuibin, P A; University Politehnica Timişoara, Bv. Mihai Viteazu 1, RO-300222, Timişoara (Romania))" data-affiliation=" (Department of Hydraulic Machinery, University Politehnica Timişoara, Bv. Mihai Viteazu 1, RO-300222, Timişoara (Romania))" >Susan-Resiga, R F; Muntean, S

2014-01-01

The decelerated swirling flow in the discharge cone of hydraulic turbine develops various self-induced instabilities and associated low frequency phenomena when the turbine is operated far from the best efficiency regime. In particular, the precessing helical vortex ( v ortex rope ) developed at part-load regimes is notoriously difficult and expensive to be computed using full three-dimensional turbulent unsteady flow models. On the other hand, modern design and optimization techniques require robust, tractable and accurate a-priori assessment of the turbine flow unsteadiness level within a wide operating range before actually knowing the runner geometry details. This paper presents the development and validation of a quasi-analytical model of the vortex rope in the discharge cone. The first stage is the computing of the axisymmetrical swirling flow at runner outlet with input information related only to the operating point and to the blade outlet angle. Then, the swirling flow profile further downstream is computed in successive cross-sections through the discharge cone. The second stage is the reconstruction of the precessing vortex core parameters in successive cross-sections of the discharge cone. The final stage lies in assembling 3D unsteady flow field in the discharge cone. The end result is validated against both experimental and numerical data

Optimization Study of Shaft Tubular Turbine in a Bidirectional Tidal Power Station

Directory of Open Access Journals (Sweden)

Xinfeng Ge

2013-01-01

Full Text Available The shaft tubular turbine is a form of tidal power station which can provide bidirectional power. Efficiency is an important turbine performance indicator. To study the influence of runner design parameters on efficiency, a complete 3D flow-channel model of a shaft tubular turbine was developed, which contains the turbine runner, guide vanes, and flow passage and was integrated with hybrid grids calculated by steady-state calculation methods. Three aspects of the core component (turbine runner were optimized by numerical simulation. All the results were then verified by experiments. It was shown that curved-edge blades are much better than straight-edge blades; the optimal blade twist angle is 7°, and the optimal distance between the runner and the blades is 0.75–1.25 times the diameter of the runner. Moreover, the numerical simulation results matched the experimental data very well, which also verified the correctness of the optimal results.

Investigation of Self Yaw and its Potential using a Hydraulic Soft Yaw System for 5 MW Wind Turbine

DEFF Research Database (Denmark)

Stubkier, Søren; Pedersen, Henrik C.

2013-01-01

The focus of the current paper is on a hydraulic soft yaw system, designed to reduce the loading of the turbine structure, by absorbing wind guest via the hydraulic system, but which also enables the system to be used as a self-aligning yaw system. The system is analyzed with basis in the NREL 5-MW...... turbine, modeled in FAST, in which a new robust method for implementing Coulomb friction is utilized. Based on this model and a model of the hydraulic system, the influence of friction and wind speed is investigated in relation to the possibility to use the system as a self-aligning yaw system. Similarly...... the behavior of the hydraulic system is analyzed and it is concluded that the hydraulic yaw system allows selfyaw under normal operating conditions for the turbine. Self-yaw control is possible in wind speeds above 12 m/s when yaw friction is kept below 1 MNm....

A study on reliability of electro-hydraulic governor control system for large steam turbine in power plant

International Nuclear Information System (INIS)

Kang, Gu Hwa; Lee, Tae Hoon; Moon, Seung Jae; Lee, Jae Heon; Yoo, Ho Seon

2008-01-01

In this work, the right management procedure for hydraulic power oil will be discussed and suggested. A thermal power plant turbine should respond to the change of load status. However, to satisfy the frequency of alternating current, the revolution per minute should be kept constant. Therefore, by controlling the flow rate of the steam to the turbine, the governor satisfies the load variation without alternating the revolution per minutes of the turbine. To protect the governor, the hydraulic power unit should be managed carefully by controlling the quality and the flow rate of the oil

Development of low head Kaplan turbine for power station rehabilitation project

Science.gov (United States)

Lim, S. M.; Ohtake, N.; Kurosawa, S.; Suzuki, T.; Yamasaki, T.; Nishi, H.

2012-11-01

This paper presents the latest Kaplan turbine rehabilitation project for Funagira Power Station in Japan completed by J-POWER Group in collaboration with Toshiba Corporation. Area of rehabilitation was restricted to guide vane and runner. The main goal of the rehabilitation project was to expand the operating range of the existing turbine in terms of discharge and power with high operational stability, low noise as well as high cavitation performance. Computational Fluids Dynamics and model test were used to optimize the shape of guide vane and runner in development stage. Finally, field tests and runner inspection were carried out to confirm the performance of the new turbine. It was found that the new turbine has excellent performance in efficiency, power output, operational stability compared with existing turbine. Moreover, no sign of cavitation on the runner blade surface was observed after 5078 hours of operation near 100% load.

Development of low head Kaplan turbine for power station rehabilitation project

International Nuclear Information System (INIS)

Lim, S M; Ohtake, N; Kurosawa, S; Suzuki, T; Yamasaki, T; Nishi, H

2012-01-01

This paper presents the latest Kaplan turbine rehabilitation project for Funagira Power Station in Japan completed by J-POWER Group in collaboration with Toshiba Corporation. Area of rehabilitation was restricted to guide vane and runner. The main goal of the rehabilitation project was to expand the operating range of the existing turbine in terms of discharge and power with high operational stability, low noise as well as high cavitation performance. Computational Fluids Dynamics and model test were used to optimize the shape of guide vane and runner in development stage. Finally, field tests and runner inspection were carried out to confirm the performance of the new turbine. It was found that the new turbine has excellent performance in efficiency, power output, operational stability compared with existing turbine. Moreover, no sign of cavitation on the runner blade surface was observed after 5078 hours of operation near 100% load.

Bulb turbine operating at medium head: XIA JIANG case study

International Nuclear Information System (INIS)

Loiseau, F; Desrats, C; Petit, P; Liu, J

2012-01-01

With lots of references for 4-blade bulb turbines, such as these of Wu Jin Xia (4 units – 36.1 MW per unit – 9.2 m rated head), Chang Zhou (15 units – 46.7 MW per unit – 9.5 m rated head) and Tong Wan (4 units – 46.2 MW per unit – 11 m rated head), ALSTOM Power Hydro is one of the major suppliers of bulb turbines operating under medium head for the Chinese market. ALSTOM Power Hydro has been awarded in November 2010 a contract by Jiang Xi Province Xia Jiang Water Control Project Headquarters to equip Xia Jiang's new hydropower plant. The power dam is located on the Gan Jiang river, at about 160 km away from Nan Chang town in South Eastern China. The supply will consist in 5 bulb units including the furniture of both the turbine and its generator, for a total capacity of 200 MW, under a rated net head of 8.6 m. The prototype turbine is a 7.8 m diameter runner, rotating at 71.4 rpm speed. For this project, ALSTOM has proposed a fully new design of 4-blade bulb runner. This paper outlines the main steps of the hydraulic development. First of all, a fine tuning of the blade geometry was performed to enhance the runner behaviour at high loads and low heads, so that to fulfill the demanding requirements of efficiencies and maximum output. The challenge was also to keep an excellent cavitation behaviour, especially at the outer blade diameter in order to avoid cavitation erosion on the prototype. The shape of the blade was optimized by using the latest tools in computational fluid dynamics. Steady state simulations of the distributor and the runner were performed, in order to simulate more accurately the pressure fields on the blade and the velocity distribution at the outlet of the runner. Moreover, draft tube computations have been performed close to the design point and at higher loads. Then, a model fully homologous with the prototype was manufactured and tested at ALSTOM's laboratory in Grenoble (France). The model test results confirmed the predicted

Mitigation of pressure fluctuations in the discharge cone of hydraulic turbines using flow-feedback

International Nuclear Information System (INIS)

Tanasa, C; Susan-Resiga, R; Bosioc, A; Muntean, S

2010-01-01

Our previous experimental and numerical investigations of decelerated swirling flows in conical diffusers have demonstrated that water jet injection along the symmetry axis mitigates the pressure fluctuations associated with the precessing vortex rope. However, for swirling flows similar to Francis turbines operated at partial discharge, the jet becomes effective when the jet discharge is larger than 10% from the turbine discharge, leading to large volumetric losses when the jet is supplied from upstream the runner. As a result, we introduce in this paper a new approach for supplying the jet by using a fraction of the discharge collected downstream the conical diffuser. We present the technical implementation of this flow-feedback approach, and we investigated experimentally its capability in mitigating the pressure fluctuations generated by the precessing vortex rope. The main advantage of this flow-feedback approach is that is does not require additional energy to supply the jet and it does not decrease the turbine efficiency.

Analysis of the fault and malfunctioning of a 15 MW hydraulic turbine; Analisis de la falla y malfuncionamiento de una turbina hidraulica de 15 MW

Energy Technology Data Exchange (ETDEWEB)

Garcia I, Rafael; Perez R, Norberto [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2007-07-01

An historical case of the rehabilitation process of three hydraulic turbines with capacity of 15 MW each is presented. These units are used for the electrical generation, mainly to supply part of the central zone of the Mexican Republic. The turbo-generator units had been practically destroyed by catastrophic floods and only part of the equipment was rescued and rehabilitated for its operation. One of the three turbines presented serious operational problems, preventing its reliable operation evidenced by the excessive mechanical vibrations and heating of the bearing zone. This article presents the diagnosis of the possible causes of fault and the remedial actions taken. Strong misalignment problems of the runner with respect to its bearings and to the scroll case of the turbine are observed. In addition, during the inspection of the turbine runner and of the bearings it is observed that important frictions have existed, which increased the vibrations. It is shown that these frictions are not the cause of the problem but only one manifestation of the same. Finally some conclusions of the problem and their solution are presented. [Spanish] Se presenta un caso historico del proceso de rehabilitacion de tres turbinas hidraulicas con capacidad de 15 MW cada una. Dichas unidades son empleadas en la generacion electrica, principalmente para abastecer parte de la zona centro de la Republica Mexicana. Las unidades turbogeneradores habian sido practicamente destruidas por inundaciones catastroficas y solo parte del equipo fue rescatado y rehabilitado para su operacion. Una de las tres turbinas presento graves problemas de funcionamiento, impidiendo su operacion confiable, lo cual se manifestaba mediante vibraciones mecanicas excesivas y calentamiento en zona de chumaceras. En este articulo se presenta el diagnostico de las posibles causas de falla y las acciones correctivas tomadas. Se observan problemas fuertes de desalineamiento del rotor respecto a sus chumaceras y al

Numerical simulation of the two-phase flows in a hydraulic coupling by solving VOF model

International Nuclear Information System (INIS)

Luo, Y; Zuo, Z G; Liu, S H; Fan, H G; Zhuge, W L

2013-01-01

The flow in a partially filled hydraulic coupling is essentially a gas-liquid two-phase flow, in which the distribution of two phases has significant influence on its characteristics. The interfaces between the air and the liquid, and the circulating flows inside the hydraulic coupling can be simulated by solving the VOF two-phase model. In this paper, PISO algorithm and RNG k–ε turbulence model were employed to simulate the phase distribution and the flow field in a hydraulic coupling with 80% liquid fill. The results indicate that the flow forms a circulating movement on the torus section with decreasing speed ratio. In the pump impeller, the air phase mostly accumulates on the suction side of the blades, while liquid on the pressure side; in turbine runner, air locates in the middle of the flow passage. Flow separations appear near the blades and the enclosing boundaries of the hydraulic coupling

Numerical investigation of the air injection effect on the cavitating flow in Francis hydro turbine

Science.gov (United States)

Chirkov, D. V.; Shcherbakov, P. K.; Cherny, S. G.; Skorospelov, V. A.; Turuk, P. A.

2017-09-01

At full and over load operating points, some Francis turbines experience strong self-excited pressure and power oscillations. These oscillations are occuring due to the hydrodynamic instability of the cavitating fluid flow. In many cases, the amplitude of such pulsations may be reduced substantially during the turbine operation by the air injection/ admission below the runner. Such an effect is investigated numerically in the present work. To this end, the hybrid one-three-dimensional model of the flow of the mixture "liquid-vapor" in the duct of a hydroelectric power station, which was proposed previously by the present authors, is augmented by the second gaseous component — the noncondensable air. The boundary conditions and the numerical method for solving the equations of the model are described. To check the accuracy of computing the interface "liquid-gas", the numerical method was applied at first for solving the dam break problem. The algorithm was then used for modeling the flow in a hydraulic turbine with air injection below the runner. It is shown that with increasing flow rate of the injected air, the amplitude of pressure pulsations decreases. The mechanism of the flow structure alteration in the draft tube cone has been elucidated, which leads to flow stabilization at air injection.

Operation of a T63 Turbine Engine Using F24 Contaminated Skydrol 5 Hydraulic Fluid

Science.gov (United States)

2016-09-01

hydraulic fluids were originally developed by the Douglas Aircraft Company during the 1940s to reduce fire risk from leaking high pressure mineral oil...thermal load demands in modern hydraulic systems and reduced density to lower weight impact on the aircraft. Eastman Chemical is the current producer of...AFRL-RQ-WP-TM-2016-0155 OPERATION OF A T63 TURBINE ENGINE USING F24 CONTAMINATED SKYDROL 5 HYDRAULIC FLUID Matthew J. Wagner (AFRL/RQTM) James

Wind tunnel experiments to prove a hydraulic passive torque control concept for variable speed wind turbines

NARCIS (Netherlands)

Diepeveen, N.F.B.; Jarquin-Laguna, A.

2014-01-01

In this paper the results are presented of experiments to prove an innovative concept for passive torque control of variable speed wind turbines using fluid power technology. It is demonstrated that by correctly configuring the hydraulic drive train, the wind turbine rotor operates at or near

78 FR 69402 - Lock 7 Hydro Partners, LLC; Notice of Application for Amendment of License and Soliciting...

Science.gov (United States)

2013-11-19

... Commission approval to replace the turbine runner for generating unit No. 2. The runner replacement would increase the installed and hydraulic capacities of the unit by 170 kilowatts (kW) and 157 cubic feet per... and its hydraulic capacity from 2,229 cfs to 2,386 cfs. l. Locations of the Application: This filing...

A Summary of Environmentally Friendly Turbine Design Concepts

Energy Technology Data Exchange (ETDEWEB)

Odeh, Mufeed [United States Geological Survey - BRD, Turners Falls, MA (United States)

1999-07-01

The Advanced Hydropower Turbine System Program (AHTS) was created in 1994 by the U.S. Department of Energy, Electric Power Research Institute, and the Hydropower Research Foundation. The Program’s main goal is to develop “environmentally friendly” hydropower turbines. The Program’s first accomplishment was the development of conceptual designs of new environmentally friendly turbines. In order to do so, two contractors were competitively selected. The ARL/NREC team of engineers and biologists provided a conceptual design for a new turbine runner*. The new runner has the potential to generate hydroelectricity at close to 90% efficiency. The Voith team produced new fish-friendly design criteria for Kaplan and Francis turbines that can be incorporated in units during rehabilitation projects or in new hydroelectric facilities**. These include the use of advanced plant operation, minimum gap runners, placement of wicket gates behind stay vanes, among others. The Voith team will also provide design criteria on aerating Francis turbines to increase dissolved oxygen content. Detailed reviews of the available literature on fish mortality studies, causation of injuries to fish, and available biological design criteria that would assist in the design of fish-friendly turbines were performed. This review identified a need for more biological studies in order to develop performance criteria to assist turbine manufacturers in designing a more fish-friendly turbine.

Performance improvement of a cross-flow hydro turbine by air layer effect

International Nuclear Information System (INIS)

Choi, Y D; Yoon, H Y; Inagaki, M; Ooike, S; Kim, Y J; Lee, Y H

2010-01-01

The purpose of this study is not only to investigate the effects of air layer in the turbine chamber on the performance and internal flow of the cross-flow turbine, but also to suggest a newly developed air supply method. Field test is performed in order to measure the output power of the turbine by a new air supply method. CFD analysis on the performance and internal flow of the turbine is conducted by an unsteady state calculation using a two-phase flow model in order to embody the air layer effect on the turbine performance effectively.The result shows that air layer effect on the performance of the turbine is considerable. The air layer located in the turbine runner passage plays the role of preventing a shock loss at the runner axis and suppressing a recirculation flow in the runner. The location of air suction hole on the chamber wall is very important factor for the performance improvement. Moreover, the ratio between air from suction pipe and water from turbine inlet is also significant factor of the turbine performance.

Model and simulation of the hydraulic turbine speed regulator of the Atucha I nuclear power plant

International Nuclear Information System (INIS)

Copparoni, G.; Etchepareborda, A.; Urrutia, G.

1992-01-01

The hydraulics turbines of Atucha I Nuclear Power Plant takes advantage of condenser cooling water level difference between the plant and the river to recover about 2,5 MW e. It also supplies emergency power until diesel generators start up. Speed regulation is needed due to the transients that during this process occur. The purpose is to minimize the diesels start up time, and to avoid overshoots on the internal grid frequency. The hydraulic turbine, its speed regulator and the electric system associated with this transient have been modeled. The models and some simulation results are presented in this work. (author)

Decomposition of the swirling flow field downstream of Francis turbine runner

International Nuclear Information System (INIS)

Rudolf, P; Štefan, D

2012-01-01

Practical application of proper orthogonal decomposition (POD) is presented. Spatio-temporal behaviour of the coherent vortical structures in the draft tube of hydraulic turbine is studied for two partial load operating points. POD enables to identify the eigen modes, which compose the flow field and rank the modes according to their energy. Swirling flow fields are decomposed, which provides information about their streamwise and crosswise development and the energy transfer among modes. Presented methodology also assigns frequencies to the particular modes, which helps to identify the spectral properties of the flow with concrete mode shapes. Thus POD offers a complementary view to current time domain simulations or measurements.

Design and Experimental Validation of Hydraulic Yaw System for Multi MW Wind Turbine

DEFF Research Database (Denmark)

Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole

2013-01-01

market. A hydraulic yaw system is such a new technology, and so a mathematical model of the full scale system and test rig system is derived and compared to measurements from the system. This is done in order to have a validated model, which wind turbine manufacturers may use for test in their simulation......To comply with the increasing demands for life time and reliability of wind turbines as these grow in size, new measures needs to be taken in the design of wind turbines and components hereof. One critical point is the initial testing of the components and systems before they are implemented...... in an actual turbine. Full scale hardware testing is both extremely expensive and time consuming, and so the wind turbine industry moves more towards simulations when testing. In order to meet these demands it is necessary with valid models of systems in order to introduce new technologies to the wind turbine...

Control System on a Wind Turbine: Evaluation of Control Strategies for a Wind Turbine with Hydraulic Drive Train by Means of Aeroelastic Analysis

OpenAIRE

Frøyd, Lars

2009-01-01

The evolution of wind turbines are going towards floating offshore structures. To improve the stability of these turbines, the weight of the nacelle should be as low as possible. The company ChapDrive has developed a hydraulic drive train that gives the ability to move the generator to the base of the tower and to replace the traditional gearbox. To test the system, ChapDrive has constructed a prototype turbine which is located at Valsneset.This thesis describes the combined aero-elastic and...

VIBRATION ANALYSIS OF TURBINE BASED ON FLUID-STRUCTURE COUPLING

Institute of Scientific and Technical Information of China (English)

LIU Demin; LIU Xiaobing

2008-01-01

The vibration of a Francis turbine is analyzed with the additional quality matrix method based on fluid-structure coupling (FSC). Firstly, the vibration frequency and mode of blade and runner in air and water are calculated. Secondly, the influences to runner frequency domain by large flow, small flow and design flow working conditions are compared. Finally the influences to runner modes by centrifugal forces under three rotating speeds of 400 r/min, 500 r/min and 600 r/min are compared. The centrifugal force and small flow working condition have greatly influence on the vibration of small runner. With the increase of centrifugal force, the vibration frequency of the runner is sharply increased. Some order frequencies are even close to the runner natural frequency in the air. Because the low frequency vibration will severely damage the stability of the turbine, low frequency vibration of units should be avoided as soon as possible.

75 FR 57745 - FPL Energy Maine Hydro LLC; Notice of Application for Amendment of License and Soliciting...

Science.gov (United States)

2010-09-22

... Unit 3 of the project by rewinding the generator and replacing the turbine runner with a more efficient runner. The proposed upgrade would increase the installed and hydraulic capacities of the project by 5.7...

CFD simulation of pressure and discharge surge in Francis turbine at off-design conditions

International Nuclear Information System (INIS)

Chirkov, D; Avdyushenko, A; Panov, L; Bannikov, D; Cherny, S; Skorospelov, V; Pylev, I

2012-01-01

A hybrid 1D-3D CFD model is developed for the numerical simulation of pressure and discharge surge in hydraulic power plants. The most essential part – the turbine itself – is simulated directly using 3D unsteady equations of turbulent motion of fluid-vapor mixture, while the rest of the hydraulic system is simulated in frames of 1D hydro-acoustic model. Thus the model accounts for the main factors responsible for excitation and propagation of pressure and discharge waves in hydraulic power plant. Boundary conditions at penstock inlet and draft tube outlet are discussed in detail. Then simulations of dynamic behavior at part load and full load operating points are performed. It is shown that the numerical model is able to capture self-excited oscillations in full load conditions. The influence of penstock length and flow structure behind the runner are investigated. The presented approach seems to be a promising tool for prediction and investigation the dynamic behavior in hydraulic power plants.

Prediction Method for the Complete Characteristic Curves of a Francis Pump-Turbine

Directory of Open Access Journals (Sweden)

Wei Huang

2018-02-01

Full Text Available Complete characteristic curves of a pump-turbine are essential for simulating the hydraulic transients and designing pumped storage power plants but are often unavailable in the preliminary design stage. To solve this issue, a prediction method for the complete characteristics of a Francis pump-turbine was proposed. First, based on Euler equations and the velocity triangles at the runners, a mathematical model describing the complete characteristics of a Francis pump-turbine was derived. According to multiple sets of measured complete characteristic curves, explicit expressions for the characteristic parameters of characteristic operating point sets (COPs, as functions of a specific speed and guide vane opening, were then developed to determine the undetermined coefficients in the mathematical model. Ultimately, by combining the mathematical model with the regression analysis of COPs, the complete characteristic curves for an arbitrary specific speed were predicted. Moreover, a case study shows that the predicted characteristic curves are in good agreement with the measured data. The results obtained by 1D numerical simulation of the hydraulic transient process using the predicted characteristics deviate little from the measured characteristics. This method is effective and sufficient for a priori simulations before obtaining the measured characteristics and provides important support for the preliminary design of pumped storage power plants.

Sadhana | Indian Academy of Sciences

Indian Academy of Sciences (India)

Hydraulic turbines are operating at part load conditions depending on availability of hydraulic energy or to meet the grid requirements. The turbine experiences more fatigue during the part load operating conditions due to flow phenomena such as vortex breakdown in the draft tube and flow instability in the runner.

Verification of Kaplan turbine cam curves realization accuracy at power plant

Directory of Open Access Journals (Sweden)

Džepčeski Dane

2016-01-01

Full Text Available Sustainability of approximately constant value of Kaplan turbine efficiency, for relatively large net head changes, is a result of turbine runner variable geometry. Dependence of runner blades position change on guide vane opening represents the turbine cam curve. The cam curve realization accuracy is of great importance for the efficient and proper exploitation of turbines and consequently complete units. Due to the reasons mentioned above, special attention has been given to the tests designed for cam curves verification. The goal of this paper is to provide the description of the methodology and the results of the tests performed in the process of Kaplan turbine cam curves verification.

Utilization level utilizes more than the effectiveness; Nutzungsgrad nutzt mehr als Wirkungsgrad

Energy Technology Data Exchange (ETDEWEB)

Mueller, Martin [Hochschule Ulm (Germany); Treiber, Gerd [TWA Wasserkraft-Anlagenbau GmbH, Ilmtal (Germany); Linz, Hans-Dieter [Thueringer Fernwasserversorgung (TFW), Erfurt (Germany)

2013-02-01

By virtue of a damage at the turbine gear of the hydroelectric power plant Luisenthal of the Thuringian distant water supply, a new turbine runner had to be provided in order to achieve a better adjustment of the turbine to the new operating details. The maximum efficiency was nearly constant in the redesign of the runner of the Francis turbine. The progress of the efficiency with the hydraulic performance shows a flat optimum resulting in a utilisation level of nearly 14% being relevant for the operator.

Design of large Francis turbine using optimal methods

Science.gov (United States)

Flores, E.; Bornard, L.; Tomas, L.; Liu, J.; Couston, M.

2012-11-01

Among a high number of Francis turbine references all over the world, covering the whole market range of heads, Alstom has especially been involved in the development and equipment of the largest power plants in the world : Three Gorges (China -32×767 MW - 61 to 113 m), Itaipu (Brazil- 20x750 MW - 98.7m to 127m) and Xiangjiaba (China - 8x812 MW - 82.5m to 113.6m - in erection). Many new projects are under study to equip new power plants with Francis turbines in order to answer an increasing demand of renewable energy. In this context, Alstom Hydro is carrying out many developments to answer those needs, especially for jumbo units such the planned 1GW type units in China. The turbine design for such units requires specific care by using the state of the art in computation methods and the latest technologies in model testing as well as the maximum feedback from operation of Jumbo plants already in operation. We present in this paper how a large Francis turbine can be designed using specific design methods, including the global and local optimization methods. The design of the spiral case, the tandem cascade profiles, the runner and the draft tube are designed with optimization loops involving a blade design tool, an automatic meshing software and a Navier-Stokes solver, piloted by a genetic algorithm. These automated optimization methods, presented in different papers over the last decade, are nowadays widely used, thanks to the growing computation capacity of the HPC clusters: the intensive use of such optimization methods at the turbine design stage allows to reach very high level of performances, while the hydraulic flow characteristics are carefully studied over the whole water passage to avoid any unexpected hydraulic phenomena.

Design of large Francis turbine using optimal methods

International Nuclear Information System (INIS)

Flores, E; Bornard, L; Tomas, L; Couston, M; Liu, J

2012-01-01

Among a high number of Francis turbine references all over the world, covering the whole market range of heads, Alstom has especially been involved in the development and equipment of the largest power plants in the world : Three Gorges (China −32×767 MW - 61 to 113 m), Itaipu (Brazil- 20x750 MW - 98.7m to 127m) and Xiangjiaba (China - 8x812 MW - 82.5m to 113.6m - in erection). Many new projects are under study to equip new power plants with Francis turbines in order to answer an increasing demand of renewable energy. In this context, Alstom Hydro is carrying out many developments to answer those needs, especially for jumbo units such the planned 1GW type units in China. The turbine design for such units requires specific care by using the state of the art in computation methods and the latest technologies in model testing as well as the maximum feedback from operation of Jumbo plants already in operation. We present in this paper how a large Francis turbine can be designed using specific design methods, including the global and local optimization methods. The design of the spiral case, the tandem cascade profiles, the runner and the draft tube are designed with optimization loops involving a blade design tool, an automatic meshing software and a Navier-Stokes solver, piloted by a genetic algorithm. These automated optimization methods, presented in different papers over the last decade, are nowadays widely used, thanks to the growing computation capacity of the HPC clusters: the intensive use of such optimization methods at the turbine design stage allows to reach very high level of performances, while the hydraulic flow characteristics are carefully studied over the whole water passage to avoid any unexpected hydraulic phenomena.

Fish passage through hydropower turbines: Simulating blade strike using the discrete element method

International Nuclear Information System (INIS)

Richmond, M C; Romero-Gomez, P

2014-01-01

Among the hazardous hydraulic conditions affecting anadromous and resident fish during their passage though hydro-turbines two common physical processes can lead to injury and mortality: collisions/blade-strike and rapid decompression. Several methods are currently available to evaluate these stressors in installed turbines, e.g. using live fish or autonomous sensor devices, and in reduced-scale physical models, e.g. registering collisions from plastic beads. However, a priori estimates with computational modeling approaches applied early in the process of turbine design can facilitate the development of fish-friendly turbines. In the present study, we evaluated the frequency of blade strike and rapid pressure change by modeling potential fish trajectories with the Discrete Element Method (DEM) applied to fish-like composite particles. In the DEM approach, particles are subjected to realistic hydraulic conditions simulated with computational fluid dynamics (CFD), and particle-structure interactions-representing fish collisions with turbine components such as blades-are explicitly recorded and accounted for in the calculation of particle trajectories. We conducted transient CFD simulations by setting the runner in motion and allowing for unsteady turbulence using detached eddy simulation (DES), as compared to the conventional practice of simulating the system in steady state (which was also done here for comparison). While both schemes yielded comparable bulk hydraulic performance values, transient conditions exhibited an improvement in describing flow temporal and spatial variability. We released streamtraces (in the steady flow solution) and DEM particles (transient solution) at the same locations where sensor fish (SF) were released in previous field studies of the advanced turbine unit. The streamtrace- based results showed a better agreement with SF data than the DEM-based nadir pressures did because the former accounted for the turbulent dispersion at the

Expected load spectra of prototype Francis turbines in low-load operation using numerical simulations and site measurements

Science.gov (United States)

Eichhorn, M.; Taruffi, A.; Bauer, C.

2017-04-01

The operators of hydropower plants are forced to extend the existing operating ranges of their hydraulic machines to remain competitive on the energy market due to the rising amount of wind and solar power. Faster response times and a higher flexibility towards part- and low-load conditions enable a better electric grid control and assure therefore an economic operation of the power plant. The occurring disadvantage is a higher dynamic excitation of affected machine components, especially Francis turbine runners, due to pressure pulsations induced by unsteady flow phenomena (e.g. draft tube vortex ropes). Therefore, fatigue analysis becomes more important even in the design phase of the hydraulic machines to evaluate the static and dynamic load in different operating conditions and to reduce maintenance costs. An approach including a one-way coupled fluid-structure interaction has been already developed using unsteady CFD simulations and transient FEM computations. This is now applied on two Francis turbines with different specific speeds and power ranges, to obtain the load spectra of both machines. The results are compared to strain gauge measurements on the according Francis turbines to validate the overall procedure.

Computational and experimental study of effects of sediment shape on erosion of hydraulic turbines

International Nuclear Information System (INIS)

Poudel, L; Thapa, B; Shrestha, B P; Thapa, B S; Shrestha, K P; Shrestha, N K

2012-01-01

Hard particles as Quartz and Feldspar are present in large amount in most of the rivers across the Himalayan basins. In run-off-river hydro power plants these particles find way to turbine and cause its components to erode. Loss of turbine material due to the erosion and subsequent change in flow pattern induce several operational and maintenance problems in the power plants. Reduction in overall efficiency, vibrations and reduced life of turbine components are the major effects of sediment erosion of hydraulic turbines. Sediment erosion of hydraulic turbines is a complex phenomenon and depends upon several factors. One of the most influencing parameter is the characteristics of sediment particles. Quantity of sediment particles, which are harder than the turbine material, is one of the bases to indicate erosion potential of a particular site. Research findings have indicated that shape and size of the hard particles together with velocity of impact play a major role to decide the mode and rate of erosion in turbine components. It is not a common practice in Himalayan basins to conduct a detail study of sediment characteristics as a part of feasibility study for hydropower projects. Lack of scientifically verified procedures and guidelines to conduct the sediment analysis to estimate its erosion potential is one of the reasons to overlook this important part of feasibility study. Present study has been conducted by implementing computational tools to characterize the sediment particles with respect to their shape and size. Experimental studies have also been done to analyze the effects of different combinations of shape and size of hard particles on turbine material. Efforts have also been given to develop standard procedures to conduct similar study to compare erosion potential between different hydropower sites. Digital image processing software and sieve analyzer have been utilized to extract shape and size of sediment particles from the erosion sensitive power

Design, analysis and control of hydraulic soft yaw system for 5MW wind turbine

DEFF Research Database (Denmark)

Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole

2012-01-01

by active control of a hydraulic yaw system. The control is based on a non-linear and linear model derived based on a concept yaw system for the NREL 5MW wind turbine. The control strategies show a reduction in pressure pulsations under load and it is concluded that the strategie including high......As wind turbines increase in size and the demands for lifetime also increases, new methods of load reduction needs to be examined. One method is to make the yaw system of the turbine soft/flexible and wereby dampen the loads to the system. This paper presents work done on dampening of these loads...

The application of hydraulics in the 2,000 kW wind turbine generator

Science.gov (United States)

Onufreiczuk, S.

1978-01-01

A 2000 kW turbine generator using hydraulic power in two of its control systems is being built under the management of NASA Lewis Research Center. The hydraulic systems providing the control torques and forces for the yaw and blade pitch control systems are discussed. The yaw-drive-system hydraulic supply provides the power for positioning the nacelle so that the rotary axis is kept in line with the direction of the prevailing wind, as well as pressure to the yaw and high speed shaft brakes. The pitch-change-mechanism hydraulic system provides the actuation to the pitch change mechanism and permits feathering of the blades during an emergency situation. It operates in conjunction with the overall windmill computer system, with the feather control permitting slewing control flow to pass from the servo valve to the actuators without restriction.

Degradation of phosphate ester hydraulic fluid in power station turbines investigated by a three-magnet unilateral magnet array.

Science.gov (United States)

Guo, Pan; He, Wei; García-Naranjo, Juan C

2014-04-14

A three-magnet array unilateral NMR sensor with a homogeneous sensitive spot was employed for assessing aging of the turbine oils used in two different power stations. The Carr-Purcell-Meiboom-Gill (CPMG) sequence and Inversion Recovery-prepared CPMG were employed for measuring the ¹H-NMR transverse and longitudinal relaxation times of turbine oils with different service status. Two signal components with different lifetimes were obtained by processing the transverse relaxation curves with a numeric program based on the Inverse Laplace Transformation. The long lifetime components of the transverse relaxation time T₂eff and longitudinal relaxation time T₁ were chosen to monitor the hydraulic fluid aging. The results demonstrate that an increase of the service time of the turbine oils clearly results in a decrease of T₂eff,long and T₁,long. This indicates that the T₂eff,long and T₁,long relaxation times, obtained from the unilateral magnetic resonance measurements, can be applied as indices for degradation of the hydraulic fluid in power station turbines.

Cavitation erosion - corrosion behaviour of ASTM A27 runner steel in natural river water

International Nuclear Information System (INIS)

Tôn-Thât, L

2014-01-01

Cavitation erosion is still one of the most important degradation modes in hydraulic turbine runners. Part of researches in this field focuses on finding new materials, coatings and surface treatments to improve the resistance properties of runners to this phenomenon. However, only few studies are focused on the deleterious effect of the environment. Actually, in some cases a synergistic effect between cavitation erosion mechanisms and corrosion kinetics can establish and increase erosion rate. In the present study, the cavitation erosion-corrosion behaviour of ASTM A27 steel in natural river water is investigated. This paper state the approach which has been used to enlighten the synergy between both phenomena. For this, a 20 kHz vibratory test according ASTM G32 standard is coupled to an electrochemical cell to be able to follow the different corrosion parameters during the tests to get evidence of the damaging mechanism. Moreover, mass losses have been followed during the exposure time. The classical degradation parameters (cumulative weight loss and erosion rate) are determined. Furthermore, a particular effort has been implemented to determine the evolution of surface damages in terms of pitting, surface cracking, material removal and surface corrosion. For this, scanning electron microscopy has been used to link the microstructure to the material removal mechanisms

Multiobjective Optimization of a Counterrotating Type Pump-Turbine Unit Operated at Turbine Mode

Directory of Open Access Journals (Sweden)

Jin-Hyuk Kim

2014-05-01

Full Text Available A multiobjective optimization for improving the turbine output and efficiency of a counterrotating type pump-turbine unit operated at turbine mode was carried out in this work. The blade geometry of both the runners was optimized using a hybrid multiobjective evolutionary algorithm coupled with a surrogate model. Three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model were discretized by finite volume approximations and solved on hexahedral grids to analyze the flow in the pump-turbine unit. As major hydrodynamic performance parameters, the turbine output and efficiency were selected as objective functions with two design variables related to the hub profiles of both the runner blades. These objectives were numerically assessed at twelve design points selected by Latin hypercube sampling in the design space. Response surface approximation models for the objectives were constructed based on the objective function values at the design points. A fast nondominated sorting genetic algorithm for the local search coupled with the response surface approximation models was applied to determine the global Pareto-optimal solutions. The trade-off between the two objectives was determined and described with respect to the Pareto-optimal solutions. The results of this work showed that the turbine outputs and efficiencies of optimized pump-turbine units were simultaneously improved in comparison to the reference unit.

Wind tunnel experiments to prove a hydraulic passive rotor speed control concept for variable speed wind turbines (poster)

NARCIS (Netherlands)

Diepeveen, N.F.B.; Jarquin Laguna, A.

2012-01-01

As alternative to geared and direct drive solutions, fluid power drive trains are being developed by several institutions around the world. The common configuration is where the wind turbine rotor is coupled to a hydraulic pump. The pump is connected through a high pressure line to a hydraulic motor

To Examine effect of Flow Zone Generation Techniques for Numerical Flow Analysis in Hydraulic Turbine

International Nuclear Information System (INIS)

Hussain, M.; Khan, J.A.

2004-01-01

A numerical study of flow in distributor of Francis Turbine is carried out by using two different techniques of flow zone generation. Distributor of GAMM Francis Turbine is used for present calculation. In present work, flow is assumed to be periodic around the distributor in steady state conditions, therefore computational domain consists of only one blade channel (one stay vane and one guide vane). The distributor computational domain is bounded up stream by cylindrical and downstream by conical patches. The first one corresponds to the spiral casing outflow section, while the second one is considered to be the distributor outlet or runner inlet. Upper and lower surfaces are generated by the revolution of hub and shroud edges. Single connected and multiple connected techniques are considered to generate distributor flow zone for numerical flow analysis of GAMM Francis turbine. The tetrahedral meshes are generated in both the flow zones. Same boundary conditions are applied for both the equivalent flow zones. The three dimensional, laminar flow analysis for both the distributor flow zones of the GAMM Francis turbine operating at the best efficiency point is performed. Gambit and G- Turbo are used as a preprocessor while calculations are done by using Fluent. Finally, numerical results obtained on the distributor outlet are compared with the available experimental data to validate the two different methodologies and examine their accuracy. (author)

On the upper part load vortex rope in Francis turbine: Experimental investigation

International Nuclear Information System (INIS)

Nicolet, C; Zobeiri, A; Maruzewski, P; Avellan, F

2010-01-01

The swirling flow developing in Francis turbine draft tube under part load operation leads to pressure fluctuations usually in the range of 0.2 to 0.4 times the runner rotational frequency resulting from the so-called vortex breakdown. For low cavitation number, the flow features a cavitation vortex rope animated with precession motion. Under given conditions, these pressure fluctuations may lead to undesirable pressure fluctuations in the entire hydraulic system and also produce active power oscillations. For the upper part load range, between 0.7 and 0.85 times the best efficiency discharge, pressure fluctuations may appear in a higher frequency range of 2 to 4 times the runner rotational speed and feature modulations with vortex rope precession. It has been pointed out that for this particular operating point, the vortex rope features elliptical cross section and is animated of a self-rotation. This paper presents an experimental investigation focusing on this peculiar phenomenon, defined as the upper part load vortex rope. The experimental investigation is carried out on a high specific speed Francis turbine scale model installed on a test rig of the EPFL Laboratory for Hydraulic Machines. The selected operating point corresponds to a discharge of 0.83 times the best efficiency discharge. Observations of the cavitation vortex carried out with high speed camera have been recorded and synchronized with pressure fluctuations measurements at the draft tube cone. First, the vortex rope self rotation frequency is evidenced and the related frequency is deduced. Then, the influence of the sigma cavitation number on vortex rope shape and pressure fluctuations is presented. The waterfall diagram of the pressure fluctuations evidences resonance effects with the hydraulic circuit. The time evolution of the vortex rope volume is compared with pressure fluctuations time evolution using image processing. Finally, the influence of the Froude number on the vortex rope shape and

On the upper part load vortex rope in Francis turbine: Experimental investigation

Energy Technology Data Exchange (ETDEWEB)

Nicolet, C [Power Vision Engineering sarl Ch. des Champs-Courbes 1, CH-1024 Ecublens (Switzerland); Zobeiri, A; Maruzewski, P; Avellan, F, E-mail: christophe.nicolet@powervision-eng.c [Laboratory for Hydraulic Machines, Ecole polytechnique federale de Lausanne, EPFL Av. de Cour 33bis, CH-1007 Lausanne (Switzerland)

2010-08-15

The swirling flow developing in Francis turbine draft tube under part load operation leads to pressure fluctuations usually in the range of 0.2 to 0.4 times the runner rotational frequency resulting from the so-called vortex breakdown. For low cavitation number, the flow features a cavitation vortex rope animated with precession motion. Under given conditions, these pressure fluctuations may lead to undesirable pressure fluctuations in the entire hydraulic system and also produce active power oscillations. For the upper part load range, between 0.7 and 0.85 times the best efficiency discharge, pressure fluctuations may appear in a higher frequency range of 2 to 4 times the runner rotational speed and feature modulations with vortex rope precession. It has been pointed out that for this particular operating point, the vortex rope features elliptical cross section and is animated of a self-rotation. This paper presents an experimental investigation focusing on this peculiar phenomenon, defined as the upper part load vortex rope. The experimental investigation is carried out on a high specific speed Francis turbine scale model installed on a test rig of the EPFL Laboratory for Hydraulic Machines. The selected operating point corresponds to a discharge of 0.83 times the best efficiency discharge. Observations of the cavitation vortex carried out with high speed camera have been recorded and synchronized with pressure fluctuations measurements at the draft tube cone. First, the vortex rope self rotation frequency is evidenced and the related frequency is deduced. Then, the influence of the sigma cavitation number on vortex rope shape and pressure fluctuations is presented. The waterfall diagram of the pressure fluctuations evidences resonance effects with the hydraulic circuit. The time evolution of the vortex rope volume is compared with pressure fluctuations time evolution using image processing. Finally, the influence of the Froude number on the vortex rope shape and

On the upper part load vortex rope in Francis turbine: Experimental investigation

Science.gov (United States)

Nicolet, C.; Zobeiri, A.; Maruzewski, P.; Avellan, F.

2010-08-01

The swirling flow developing in Francis turbine draft tube under part load operation leads to pressure fluctuations usually in the range of 0.2 to 0.4 times the runner rotational frequency resulting from the so-called vortex breakdown. For low cavitation number, the flow features a cavitation vortex rope animated with precession motion. Under given conditions, these pressure fluctuations may lead to undesirable pressure fluctuations in the entire hydraulic system and also produce active power oscillations. For the upper part load range, between 0.7 and 0.85 times the best efficiency discharge, pressure fluctuations may appear in a higher frequency range of 2 to 4 times the runner rotational speed and feature modulations with vortex rope precession. It has been pointed out that for this particular operating point, the vortex rope features elliptical cross section and is animated of a self-rotation. This paper presents an experimental investigation focusing on this peculiar phenomenon, defined as the upper part load vortex rope. The experimental investigation is carried out on a high specific speed Francis turbine scale model installed on a test rig of the EPFL Laboratory for Hydraulic Machines. The selected operating point corresponds to a discharge of 0.83 times the best efficiency discharge. Observations of the cavitation vortex carried out with high speed camera have been recorded and synchronized with pressure fluctuations measurements at the draft tube cone. First, the vortex rope self rotation frequency is evidenced and the related frequency is deduced. Then, the influence of the sigma cavitation number on vortex rope shape and pressure fluctuations is presented. The waterfall diagram of the pressure fluctuations evidences resonance effects with the hydraulic circuit. The time evolution of the vortex rope volume is compared with pressure fluctuations time evolution using image processing. Finally, the influence of the Froude number on the vortex rope shape and

Experiences with environmentally adapted Kaplan runners; Erfarenheter med miljoeanpassade Kaplanloephjul

Energy Technology Data Exchange (ETDEWEB)

Ukonsaari; Jan

2012-08-15

This study concerns environmentally adapted Kaplan runners, which have no oil for lubricating the blade regulation mechanisms and bearings. The runners are water or air filled with self lubricated bearings. Recent design also includes regulation system pressure increase and servo motor placement below runner centre and environmentally adapted synthetic ester as hydraulic fluid. These together with power output increase and efficiency optimization are suspected sources of poor runner function. Of 37 runners 43 % have had some kind of problem and 30 % bearing or mechanism related ones. When the axial blade bearing problems are excluded the problems occurred at 16 %. Deeper look into the design of newer runners shows that only bronze based runner hubs is significantly more problem dense regarding regulation mechanisms (50 %). Hidden figures of increased runner regulation forces are suspected. All problems cannot be explained and the young machines limit the experiences. The working group's opinion and bring ups of historical and present examples during the work show evidence that the old oil filled runners function is far from perfect, nor the life length. The future is not with oil filled runner hubs. Main parts of the discovered problems have been solved and can be resolved by thorough design analysis. One future concern is what effects the recent design changes will cause due to increase demand for power output changes including the number of starts and stops. That is why the working group's recommendation is to put joint effort into material fatigue and in which a first step is to identify the real forces the runners are exposed to.

Overview of autoventing turbine technology development project

International Nuclear Information System (INIS)

Waldrop, W.R.

1991-01-01

This paper reports on low concentrations of dissolved oxygen (DO) in the discharge of hydro plants which represents one of the most significant environmental concerns confronting the hydropower industry. This is especially of concern to utilities attempting to relicense older plants and to build new facilities. One method which shows promise is the autoventing turbine (AVT). The concept of an AVT involves air to be aspirated into the water as it passes through the turbine whenever concentrations of DO are less than desired. Because of this simple and natural process of aeration, the AVT promises to be more cost efficient and reliable than any of the other techniques. This has been demonstrated through experimentation at TVA's Norris Dam. An applied research project is being conducted to develop experimental and numerical methods to allow for reliable design and deployment of this new environmentally improved hydroturbine. TVA is providing overall coordination for this research which is being performed cooperatively with the U.S. Army Corps of Engineers, the U.S. Bureau of Reclamation, and the Iowa Institute of Hydraulic Research. This applied research project is fully integrated with a scale model test program jointly supported and conducted by TVA and Voith Hydro to test alternative locations for venting air into replacement turbine runners for Norris Dam

Use of cooling ponds and hydraulic turbines to save SRP energy consumption

International Nuclear Information System (INIS)

Price, J.B.

1980-01-01

A substantial amount of energy can be saved by using cooling ponds to supply C and K reactors with cooling water. Hydraulic turbines between the reactor and the cooling pond can recover some of the power used to pump cooling water to the reactors. Cooling ponds would also reduce effluent temperature in the swamps adjacent to the Savannah River. Cooling ponds are evaluated in this memorandum

EVALUASI UNJUK KERJA TURBIN AIR PELTON TERBUAT DARI KAYU DAN BAMBU SEBAGAI PEMBANGKIT LISTRIK RAMAH LINGKUNGAN UNTUK PEDESAAN (Performance Evaluation of Hydraulic Pelton Turbine Made of Wood and Bamboo as Environmentally Friendly Electric Generation

Directory of Open Access Journals (Sweden)

Samsul Kamal

2013-07-01

Full Text Available ABSTRAK Pemanfaatan energi air di Indonesia, khususnya untuk pembangkit listrik skala kecil di pedesaan masih perlu diprioritaskan untuk ditingkatkan dalam program memperoleh energi bersih yang ramah lingkungan. Pemanfaatan tersebut masih terkendala oleh biaya investasi yang relatif tinggi serta teknologi yang sesuai. Pemerintah mendorong pemanfaatan energi baru dan terbarukan melalui program Desa Mandiri Energi dengan menggunakan potensi dan sumber daya yang tersedia di pedesaan. Kajian ini bertujuan untuk mengevaluasi unjuk kerja turbin air Pelton untuk pembangkit listrik skala kecil dengan sudu terbuat dari bambu dan roda turbin dari kayu. Data yang terkumpul menunjukkan bahwa efisiensi pembangkitan mampu mencapai sekitar 28% untuk debit aliran 28 liter/detik dan tinggi jatuh efektif 7 m menggunakan nosel berpenampang empat persegi panjang. Walaupun dari aspek teknik dan lingkungan penggunaan bambu sebagai sudu turbin adalah baik dan sesuai untuk digunakan di pedesaan, namun unjuk kerja yang diperoleh masih perlu ditingkatkan dibanding dengan umumnya turbin Pelton yang terbuat dari logam. Hal ini diperkirakan karena bentuk alamiah lengkung bambu yang tidak optimum untuk sudu serta bentuk penampang nosel yang masih harus disesuaikan.   ABSTRACT The use of hydroenergy in Indonesia, especially for small electric generation in rural areas is still to be priority increased in a program to find a clean and environmentally friendly energy.  The use is still limited by relatively high investation cost and appropriate technology. Government has pushed the use of new and renewable energy through the Village Self-Relliant Energy Supply Program by using potential and available resources in the village. The objective of this study is to evaluate the performance of a hydraulic Pelton turbine for small electric generation with the buckets are made of bamboo and the runner is made of wood. Data collected from the study show that the efficiency of the

Comprehensive experimental and numerical analysis of instability phenomena in pump turbines

International Nuclear Information System (INIS)

Gentner, Ch; Sallaberger, M; Widmer, Ch; Bobach, B-J; Jaberg, H; Schiffer, J; Senn, F; Guggenberger, M

2014-01-01

The changes in the electricity market have led to changed requirements for the operation of pump turbines. Utilities need to change fast and frequently between pumping and generating modes and increasingly want to operate at off-design conditions for extended periods. Operation of the units in instable areas of the machine characteristic is not acceptable and may lead to self-excited vibration of the hydraulic system. In turbine operation of pump turbines unstable behaviour can occur at low load off-design operation close to runaway conditions (S-shape of the turbine characteristic). This type of instability may impede the synchronization of the machine in turbine mode and thus increase start-up and switch over times. A pronounced S-shaped instability can also lead to significant drop of discharge in the event of load rejection. Low pressure on the suction side and in the tail-race tunnel could cause dangerous separation of the water column. Understanding the flow features that lead to the instable behaviour of pump turbines is a prerequisite to the design of machines that can fulfil the growing requirements relating to operational flexibility. Flow simulation in these instability zones is demanding due to the complex and highly unsteady flow patterns. Only unsteady simulation methods are able to reproduce the governing physical effects in these operating regions. ANDRITZ HYDRO has been investigating the stability behaviour of pump turbines in turbine operation in cooperation with several universities using simulation and measurements. In order to validate the results of flow simulation of unstable operating points, the Graz University of Technology (Austria) performed detailed experimental investigations. Within the scope of a long term research project, the operating characteristics of several pump turbine runners have been measured and flow patterns in the pump turbine at speed no load and runaway have been examined by 2D Laser particle image velocimetry (PIV

Hydraulic Darrieus turbines efficiency for free fluid flow conditions versus power farms conditions

Energy Technology Data Exchange (ETDEWEB)

Antheaume, Sylvain [Electricite de France, Recherche et Developpement, Laboratoire National d' Hydraulique et Environnement, 6 Quai Watier, 78400 Chatou (France); Maitre, Thierry; Achard, Jean-Luc [Laboratoire des Ecoulements Geophysiques et Industriels, BP 53, 38041 Grenoble (France)

2008-10-15

The present study deals with the efficiency of cross flow water current turbine for free stream conditions versus power farm conditions. In the first part, a single turbine for free fluid flow conditions is considered. The simulations are carried out with a new in house code which couples a Navier-Stokes computation of the outer flow field with a description of the inner flow field around the turbine. The latter is based on experimental results of a Darrieus wind turbine in an unbounded domain. This code is applied for the description of a hydraulic turbine. In the second part, the interest of piling up several turbines on the same axis of rotation to make a tower is investigated. Not only is it profitable because only one alternator is needed but the simulations demonstrate the advantage of the tower configuration for the efficiency. The tower is then inserted into a cluster of several lined up towers which makes a barge. Simulations show that the average barge efficiency rises as the distance between towers is decreased and as the number of towers is increased within the row. Thereby, the efficiency of a single isolated turbine is greatly increased when set both into a tower and into a cluster of several towers corresponding to possible power farm arrangements. (author)

Experimental Investigation of Inter-Blade Vortices in a Model Francis Turbine

Science.gov (United States)

LIU, Demin; LIU, Xiaobing; ZHAO, Yongzhi

2017-07-01

The inter-blade vortex in a Francis turbine becomes one of the main hydraulic factors that are likely to cause blade erosion at deep part load operating conditions. However, the causes and the mechanism of inter-blade vortex are still under investigation according to present researches. Thus the causes of inter-blade vortex and the effect of different hydraulic parameters on the inter-blade vortex are investigated experimentally. The whole life cycle of the inter-blade vortex is observed by a high speed camera. The test results illustrate the whole life cycle of the inter-blade vortex from generation to separation and even to fading. It is observed that the inter-blade vortex becomes stronger with the decreasing of flow and head, which leads to pressure fluctuation. Meanwhile, the pressure fluctuations in the vane-less area and the draft tube section become stronger when inter-blade vortices exist in the blade channel. The turbine will be damaged if operating in the inter-blade vortex zone, so its operating range must be far away from that zone. This paper reveals the main cause of the inter-blade vortex which is the larger incidence angle between the inflow angle and the blade angle on the leading edge of the runner at deep part load operating conditions.

Improvements of a Kaplan type small turbine: Forbedre og vidreutvikle en Kaplan småturbin

OpenAIRE

Fjærvold, Lars

2012-01-01

The goal with this master thesis was to establish Hill diagrams and improve a Kaplan turbine intended for use in Afghanistan. The turbine efficiency has been tested in setting 1 and 2. Turbine efficiency in setting 3 and 4 could not be tested because the runner blades interfere with the housing making it impossible to rotate the turbine. The efficiency was tested with an effective pressure head ranging from 2 to 8 meters. Best efficiency point was not reached because of limitations in the te...

Modernization of the turbine control technique and the turbine hydraulics aimed to improved maneuverability in the load range, system safety and plant availability, plant transparency for diagnosis and long-term performance

International Nuclear Information System (INIS)

Baran, Detlef

2012-01-01

In the contribution H.Mauell GmbH presents modernization projects for the nuclear power plants Tihange-3 and Doel-4. The project volume included control technique and the turbine hydraulics for the steam turbo generating set including turbine auxiliary devices and two turbine feeding pumps. The modernizations were successfully completed in 2010 and 2011, respectively. The nuclear power plants are trouble-free operated.

76 FR 7831 - Grand River Dam Authority; Notice of Application for Amendment of License and Soliciting Comments...

Science.gov (United States)

2011-02-11

... turbine runners and replacing the generator frame, stator core and windings. Each of the project's turbine... capacity would increase by 5,000 kW from 27,000 kW to 32,000 kW. The total maximum hydraulic capacity of...

Tests Performed on Hydraulic Turbines at Commissioning or after Capital Repairs. Part II. Tests Performed on a 6.5 MW Kaplan Turbine

Directory of Open Access Journals (Sweden)

Adrian Cuzmoş

2015-07-01

Full Text Available The paper presents the tests performed on a hydraulic turbine on commissioning, the devices, test methods and the results obtained from the respective tests, as well as the conclusions and recommendations resulted from these tests. This kind of tests can be performed for the verification of guarantees.

Novel Repair Technique for Life-Extension of Hydraulic Turbine Components in Hydroelectric Power Stations

Science.gov (United States)

Hiramatsu, Yoichi; Ishii, Jun; Funato, Kazuhiro

A significant number of hydraulic turbines operated in Japan were installed in the first half of the 20th century. Today, aging degradation and flaws are observed in these turbine equipments. So far, Japanese engineers have applied NDI technology of Ultrasonic Testing (UT) to detect the flaws, and after empirical evaluation of the remaining life they decided an adequate moment to replace the equipments. Since the replacement requires a large-scale field site works and high-cost, one of the solutions for life-extension of the equipments is introduction of repair services. We have been working in order to enhance the accuracy of results during the detection of flaws and flaws dimensioning, in particular focusing on the techniques of Tip-echo, TOFD and Phased-Array UT, accompanied by the conventional UT. These NDI methods made possible to recognize the entire image of surface and embedded flaws with complicated geometry. Then, we have developed an evaluation system of these flaws based on the theory of crack propagation, of the logic of crack growth driven by the stress-intensity factor of the crack tip front. The sophisticated evaluation system is constituted by a hand-made software and database of stress-intensity factor. Based on these elemental technologies, we propose a technique of repair welding to provide a life-extension of hydraulic turbine components.

Erosion estimation of guide vane end clearance in hydraulic turbines with sediment water flow

Science.gov (United States)

Han, Wei; Kang, Jingbo; Wang, Jie; Peng, Guoyi; Li, Lianyuan; Su, Min

2018-04-01

The end surface of guide vane or head cover is one of the most serious parts of sediment erosion for high-head hydraulic turbines. In order to investigate the relationship between erosion depth of wall surface and the characteristic parameter of erosion, an estimative method including a simplified flow model and a modificatory erosion calculative function is proposed in this paper. The flow between the end surfaces of guide vane and head cover is simplified as a clearance flow around a circular cylinder with a backward facing step. Erosion characteristic parameter of csws3 is calculated with the mixture model for multiphase flow and the renormalization group (RNG) k-𝜀 turbulence model under the actual working conditions, based on which, erosion depths of guide vane and head cover end surfaces are estimated with a modification of erosion coefficient K. The estimation results agree well with the actual situation. It is shown that the estimative method is reasonable for erosion prediction of guide vane and can provide a significant reference to determine the optimal maintenance cycle for hydraulic turbine in the future.

Hydraulic Yaw System

DEFF Research Database (Denmark)

Stubkier, Søren; Pedersen, Henrik C.; Mørkholt, M.

a hydraulic soft yaw system, which is able to reduce the loads on the wind turbine significantly. A full scale hydraulic yaw test rig is available for experiments and tests. The test rig is presented as well as the system schematics of the hydraulic yaw system....... the HAWC2 aeroelastic code and an extended model of the NREL 5MW turbine combined with a simplified linear model of the turbine, the parameters of the soft yaw system are optimized to reduce loading in critical components. Results shows that a significant reduction in fatigue and extreme loads to the yaw...... system and rotor shaft when utilizing the soft yaw drive concept compared to the original stiff yaw system. The physical demands of the hydraulic yaw system are furthermore examined for a life time of 20 years. Based on the extrapolated loads, the duty cycles show that it is possible to construct...

Hydro-abrasive erosion on coated Pelton runners: Partial calibration of the IEC model based on measurements in HPP Fieschertal

Science.gov (United States)

Felix, D.; Abgottspon, A.; Albayrak, I.; Boes, R. M.

2016-11-01

At medium- and high-head hydropower plants (HPPs) on sediment-laden rivers, hydro-abrasive erosion on hydraulic turbines is a major economic issue. For optimization of such HPPs, there is an interest in equations to predict erosion depths. Such a semi-empirical equation suitable for engineering practice is proposed in the relevant guideline of the International Electrotechnical Commission (IEC 62364). However, for Pelton turbines no numerical values of the model's calibration parameters have been available yet. In the scope of a research project at the high-head HPP Fieschertal, Switzerland, the particle load and the erosion on the buckets of two hard-coated 32 MW-Pelton runners have been measured since 2012. Based on three years of field data, the numerical values of a group of calibration parameters of the IEC erosion model were determined for five application cases: (i) reduction of splitter height, (ii) increase of splitter width and (iii) increase of cut-out depth due to erosion of mainly base material, as well as erosion of coating on (iv) the splitter crests and (v) inside the buckets. Further laboratory and field investigations are recommended to quantify the effects of individual parameters as well as to improve, generalize and validate erosion models for uncoated and coated Pelton turbines.

Meritev izkoristka in nastavitev krmilnih parametrov kaplanove turbine z dolgim cevnim sistemom s primerjalno metodo: Measurement of relative turbine efficiency and adjustment of governing parameters on long penstock Kaplan turbine with comparative method:

OpenAIRE

Trebše, Andrej J.

2004-01-01

The paper deals with efficiency measurement of Kaplan turbine with relative method (index test) and adjustment of operating of runner and guide vane governing system. At certain longer penstocks the looses in conduit at turbineload operation change the net head. On basis of model test on Kaplan turbine and relative turbine efficiency measurement on prototype the turbine governing system was optimized in accordance with comparative method. Prispevek obravnava meritev izkoristka kaplanove tu...

Development of a 5kw Francis Turbine Runner Using Computation ...

African Journals Online (AJOL)

First Lady

energy obtained is known as hydro-electric power which is one of the cheapest forms ... Turgo) used for hydropower generation (Sabourin et al., 1996). The Awba ... Function of draft tube is to convert unused kinetic energy at the exit of runner.

Investigation of distributor vane jets to decrease the unsteady load on hydro turbine runner blades

Science.gov (United States)

Lewis, B. J.; Cimbala, J. M.; Wouden, A. M.

2012-11-01

As the runner blades of a Francis hydroturbine pass though the wakes created from the wicket gates, they experience a significant change in absolute velocity, flow angle, and pressure. The concept of adding jets to the trailing edge of the wicket gates is proposed as a method for reducing the dynamic load on the hydroturbine runner blades. Computational experiments show a decrease in velocity variation experienced by the runner blade with the addition of the jets. The decrease in velocity variation resulted in a 43% decrease in global torque variation at the runner passing frequency. However, an increased variation was observed at the wicket gate passing frequency. Also, a 5.7% increase in average global torque was observed with the addition of blowing from the trailing-edge of the wicket gates.

Investigation of distributor vane jets to decrease the unsteady load on hydro turbine runner blades

International Nuclear Information System (INIS)

Lewis, B J; Cimbala, J M; Wouden, A M

2012-01-01

As the runner blades of a Francis hydroturbine pass though the wakes created from the wicket gates, they experience a significant change in absolute velocity, flow angle, and pressure. The concept of adding jets to the trailing edge of the wicket gates is proposed as a method for reducing the dynamic load on the hydroturbine runner blades. Computational experiments show a decrease in velocity variation experienced by the runner blade with the addition of the jets. The decrease in velocity variation resulted in a 43% decrease in global torque variation at the runner passing frequency. However, an increased variation was observed at the wicket gate passing frequency. Also, a 5.7% increase in average global torque was observed with the addition of blowing from the trailing-edge of the wicket gates.

Major historical developments in the design of water wheels and Francis hydroturbines

International Nuclear Information System (INIS)

Lewis, B J; Cimbala, J M; Wouden, A M

2014-01-01

The first record of water wheels dates back to ancient Greece. Over the next several centuries the technology spread all over the world. The process of arriving at the design of the modern Francis runner lasted from 1848 to approximately 1920. Though the modern Francis runner has little resemblance to the original turbines designed by James B. Francis in 1848, it became know as the Francis turbine around 1920, in honor of his many contributions to hydraulic engineering analysis and design. The modern Francis turbine is the most widely used turbine design today, particularly for medium head and large flow rate situations, and can achieve over 95% efficiency

System design and optimization study of axial flow turbine applied in ...

Indian Academy of Sciences (India)

between parameters of the turbine and flows, three different types of turbines with ... and the water are run through a multi-stage hydro-turbine for producing electricity. ... to optimize the runner blade shape of a tubular turbine. ..... Ranade V V, Perrard M, Le Sauze N, Xuereb C and Bertrand J 2001 Trailing vortices of Rushton ...

Using genetic algorithm to define the governor parameters of a hydraulic turbine

International Nuclear Information System (INIS)

Andrade, J G P; Ribeiro, L C L J; Junior, E L

2010-01-01

There are several governor architectures, but in general, all of them are designed to maintain the controlled variable fluctuations within acceptable range. The Proportional, Integral and Derivative (PID) governor is one of the types used to regulate a hydraulic turbine, in which the deviation of the variable controlled is corrected through earnings proportional, integral and derivative. For a definition of the governor parameters and its stability analysis there are several methods that in general can be classified into a time domain and frequency domain. The frequency domain method, based on the control theory, have ease application, expeditious manner of obtaining the parameters, but the physical phenomena involved are linearized. However the time domain methods are more difficult to be applied, but have the advantage of being able to take into account the non-linearities presents in physical phenomena. Despite the time-domain method offers advantages, it does not provides a structured way to optimize the parameters of the governor, since the parameters are obtained through simulations with adopted values. This paper presents a methodology to obtain the turbine governor appropriate parameters through a hybrid model (simulation and optimization model), based on method of characteristic to the hydraulic simulation (time domain) and Genetic Algorithm (GA) to obtain appropriate values. Examples are presented showing the application of the proposed methodology.

Using genetic algorithm to define the governor parameters of a hydraulic turbine

Energy Technology Data Exchange (ETDEWEB)

Andrade, J G P; Ribeiro, L C L J [School of Technology, UNICAMP Rua Paschoal Marmo, 1888, Limeira, Postal Code:13484-332 (Brazil); Junior, E L, E-mail: josegeraldo@ft.unicamp.b [School of Civil Engineering, Architecture and Urbanism, UNICAMP Avenida Albert Einstein, 951, Campinas, Postal Code: 13083-852 (Brazil)

2010-08-15

There are several governor architectures, but in general, all of them are designed to maintain the controlled variable fluctuations within acceptable range. The Proportional, Integral and Derivative (PID) governor is one of the types used to regulate a hydraulic turbine, in which the deviation of the variable controlled is corrected through earnings proportional, integral and derivative. For a definition of the governor parameters and its stability analysis there are several methods that in general can be classified into a time domain and frequency domain. The frequency domain method, based on the control theory, have ease application, expeditious manner of obtaining the parameters, but the physical phenomena involved are linearized. However the time domain methods are more difficult to be applied, but have the advantage of being able to take into account the non-linearities presents in physical phenomena. Despite the time-domain method offers advantages, it does not provides a structured way to optimize the parameters of the governor, since the parameters are obtained through simulations with adopted values. This paper presents a methodology to obtain the turbine governor appropriate parameters through a hybrid model (simulation and optimization model), based on method of characteristic to the hydraulic simulation (time domain) and Genetic Algorithm (GA) to obtain appropriate values. Examples are presented showing the application of the proposed methodology.

Cost of enlarged operating zone for an existing Francis runner

Science.gov (United States)

Monette, Christine; Marmont, Hugues; Chamberland-Lauzon, Joël; Skagerstrand, Anders; Coutu, André; Carlevi, Jens

2016-11-01

Traditionally, hydro power plants have been operated close to best efficiency point, the more stable operating condition for which they have been designed. However, because of changes in the electricity market, many hydro power plants operators wish to operate their machines differently to fulfil those new market needs. New operating conditions can include whole range operation, many start/stops, extensive low load operation, synchronous condenser mode and power/frequency regulation. Many of these new operating conditions may impose more severe fatigue damage than the traditional base load operation close to best efficiency point. Under these conditions, the fatigue life of the runner may be significantly reduced and reparation or replacement cost might occur sooner than expected. In order to design reliable Francis runners for those new challenging operating scenarios, Andritz Hydro has developed various proprietary tools and design rules. These are used within Andritz Hydro to design mechanically robust Francis runners for the operating scenarios fulfilling customer's specifications. To estimate residual life under different operating scenarios of an existing runner designed years ago for best efficiency base load operation, Andritz Hydro's design rules and tools would necessarily lead to conservative results. While the geometry of a new runner can be modified to fulfil all conservative mechanical design rules, the predicted fatigue life of an existing runner under off-design operating conditions may appear rather short because of the conservative safety factor included in the calculations. The most precise and reliable way to calculate residual life of an existing runner under different operating scenarios is to perform a strain gauge measurement campaign on the runner. This paper presents the runner strain gage measurement campaign of a mid-head Francis turbine over all the operating conditions available during the test, the analysis of the measurement signals

Studies of field test procedures in hydraulic turbines for SHP; Estudos de procedimentos de ensaios de campo em turbinas hidraulicas para PCH

Energy Technology Data Exchange (ETDEWEB)

Justino, Lucimary Aparecida

2006-07-01

A supply contract of equipment for Small Hydro Power, contain the power and turbine efficiency guarantees and can contain adds guarantees referring to a rotation and pressure variation, runaway speed and cavitations test. To the determination about the hydraulics turbines performance for contractual guarantees are realized the field acceptance test, that are methods quite a lot used for enterprises like tools to prove the contractual guarantees in substitution to model test, that showed a cost extremely high. In the field acceptance test are measures of some values that added to the others, possibility obtain the turbine efficiency. In the small hydro power, the turbine efficiency represents the hydraulic power percentage that is subject to be transformed in electrical power. In the turbine purchase, the manufacturer has to guarantee the efficiency specified if it is become down to expected, the damages are enormous, then the importance to exist precise methods and reliable for your measurement. The method accuracy of the discharge measurement that has, between another problems, the calibration and installation, that influence hard the value of the efficiency obtained. This work shows the different methodologies about discharge measurement in hydraulic turbines, that can be apply in Small Hydro Power field tests and shows too the procedures used that in specifics cases of small hydro, without quality damage, the site tests could be executed the form that the guarantees will be approve with compatible cots with the investment done. As an example for said above, are show two cases in small hydro where did realized field acceptance tests to assure the contractual guarantees. (author)

Characteristics of reversible-pump turbines

Energy Technology Data Exchange (ETDEWEB)

Olimstad, Grunde

2012-07-01

The primary goal for this PhD project has been to investigate instability of reversible-pump turbines (RPTs) as a phenomenon and to find remedies to solve it. The instability occurs for turbines with s-shaped characteristics, unfavourable waterway and limited rotating inertia. It is only observed for certain operation pints at either high speed or low load. These correspond to ether high values of Ned or low values of Qed. The work done in this PhD thesis can be divided in to the three following categories. Investigate and understand the behaviour of a pump turbine: A model was designed in order to investigate the pump turbine behaviour related to its characteristics. This model was manufactured and measurements were performed in the laboratory. By using throttling valves or torque as input the full s-shaped characteristics was measured. When neither of these techniques is used, the laboratory system has unstable operation points which result in hysteresis behaviour. Global behaviour of the RPT in power plant system was investigated through analytical stability analysis and dynamic system simulations. The latter included both rigid and elastic representation of the water column. Turbine internal flow: The flow inside the runner was investigated by computer simulations (CFD). Two-dimensional analysis was used to study the inlet part of the runner. This showed that a vortex forming at the inlet is one of the causes for the unstable operation range. Measurements at different pressure levels showed that the characteristics were dependent on the Reynolds number at high Ned values in turbine mode. This means that the similarity of flows is not sufficiently described by constant Qed and Ned values at this part of the characteristics. Design modifications: The root of the stability problem was considered to be the runners geometric design at the inlet in turbine mode. Therefore different design parameters were investigated to find relations to the characteristics. Methods

Siphon-based turbine - Demonstration project: hydropower plant at a paper factory in Perlen, Switzerland; Demonstrationsprojekt Saugheber - Turbinen. Wasserturbinenanlage Papierfabrik Perlen (WTA-PF)

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

This final report for the Swiss Federal Office of Energy (SFOE) describes the demonstration project that concerned the re-activation and refurbishing of a very low-head hydropower installation. The functional principles of the siphon-turbine used are explained and the potential for its use at many low-head sites examined. The authors are of the opinion that innovative technology and simple mechanical concepts could be used to reactivate out-of-use hydropower plant or be used to refurbish existing plant to provide increased efficiency and reliability. Various other points that are to be considered when planning the refurbishment of a hydropower plant such as retaining mechanical and hydraulic symmetry in the plant are listed and concepts for reducing operating costs are discussed. Figures on the three runner-regulated turbines installed in Perlen are quoted.

Evaluation of the dynamic behavior of a Pelton runner based on strain gauge measurements

Science.gov (United States)

Mack, Reiner; Probst, Christian

2016-11-01

A reliable mechanical design of Pelton runners is very important in the layout of new installations and modernizations. Especially in horizontal machines, where the housing is not embedded into concrete, a rupture of a runner bucket can have severe consequences. Even if a crack in the runner is detected on time, the outage time that follows the malfunction of the runner is shortening the return of investment. It is a fact that stresses caused by the runner rotation and the jet forces are superposed by high frequent dynamic stresses. In case of resonance it even can be the dominating effect that is limiting the lifetime of a runner. Therefore a clear understanding of the dynamic mechanisms is essential for a safe runner design. This paper describes the evaluation of the dynamic behavior of a Pelton runner installed in a model turbine based on strain gauge measurements. Equipped with strain gauges at the root area of the buckets, the time responses of the strains under the influence of various operational parameters were measured. As a result basic theories for the jet bucket excitation were verified and the influence of the water mass was detected by evaluating the frequency shift in case of resonance. Furthermore, the influence of the individual bucket masses onto the dynamic behaviour for different mode shapes got measured.

Fundamental investigations for a OWC-tidal power plant with a conventional hydraulic turbine; Basisuntersuchungen fuer ein OWC-Wellenenergiekraftwerk mit konventioneller Hydroturbine. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Graw, K.U.; Lengricht, J.; Schimmels, S.

2001-07-01

At the present the OWC-tidal power plant is the most forward-looking way of converting tidal energy into usable electric power. Current research works focus on the dimensions of the structures in terms of occurring loads, the minimisation of hydraulic losses and the development of new turbine-generator types. The development of all air-turbine systems, which have been investigated so far, is considered as problematic and the commercialisation is likely to be a hindrance. Based on international research results an inventory tata of available hydraulic turbines is supposed to be gathered and fundamental investigations are supposed to check, if the application of conventional hydraulic turbines are an energetic progress in the OWC-tidal power plant. In order to considerably increase the efficiency compared to current developments, small-scale investigations at a physical model are supposed to show if and how a hydraulic turbine can be realised in a OWC-tidal power plant and how a concept of flow rectification as well as a flow-optimised form of inflow and outflow chambers can be achieved. (orig.) [German] Das OWC-Wellenenergiekraftwerk ist der zur Zeit zukunftstraechtigste Typ zur Umwandlung von Wellenenergie in nutzbaren Strom. Die laufenden Forschungsarbeiten beschaeftigen sich insbesondere mit der Dimensionierung der Strukturen hinsichtlich auftretender Belastungen, der Minimierung der hydraulischen Verluste und der Entwicklung von neuartigen Turbinen-Generatoren-Typen. Die Entwicklung aller bisher untersuchten Luftturbinensysteme wird jedoch als problematisch und die Kommerzialisierung hindernd angesehen. Aufbauend auf den internationalen Forschungsergebnissen sollen eine Bestandaufnahme der verfuegbaren Hydroturbinen durchgefuehrt und mit Baisuntersuchungen geprueft werden, ob ein Einsatz konventionaller Hydroturbinen im OWC-Wellenenergiekraftwerk eine energetische Weiterentwicklung darstellen kann. Um den Wirkungsgrad gegenueber derzeitigen Entwicklungen

Repair of a Kaplan blade sealing surface without dismantling the turbine; Instandsetzung einer Kaplanschaufel-Dichtflaeche ohne Turbinendemontage

Energy Technology Data Exchange (ETDEWEB)

Drygas, A.; Bauer, K. [E.ON Wasserkraft GmbH, Landshut (Germany)

2008-07-01

In spite of aiming at minimum maintenance costs, runners of Kaplan turbines need to be kept in good repair. Besides preserving their main function as an energy converter, ecological reasons have to be considered as well. The latter aspect accounts for fully functional, safe seals of the pivot-mounted Kaplan runner blades. Advanced wear of the sealing surfaces may require mechanical processing, which formerly called for a costly dismantling of the runner. A newly developed and patented processing device now allows for machining the worn out sealing surfaces without dismantling the runner, thus reducing costs considerably. The device was first successfully applied to a Kaplan turbine runner with a diameter of 5.35 m. The device, so far designed for grinding, will be enhanced for lathing, in order to obtain a process even more efficient when combining lathing and grinding. (orig.)

Hydro-abrasive erosion of hydraulic turbines caused by sediment - a century of research and development

Science.gov (United States)

Felix, D.; Albayrak, I.; Abgottspon, A.; Boes, R. M.

2016-11-01

Hydro-abrasive erosion of hydraulic turbines is an economically important issue due to maintenance costs and production losses, in particular at high- and medium-head run-of- river hydropower plants (HPPs) on sediment laden rivers. In this paper, research and development in this field over the last century are reviewed. Facilities for sediment exclusion, typically sand traps, as well as turbine design and materials have been improved considerably. Since the 1980s, hard-coatings have been applied on Francis and Pelton turbine parts of erosion-prone HPPs and became state-of-the-art. These measures have led to increased times between overhauls and smaller efficiency reductions. Analytical, laboratory and field investigations have contributed to a better processes understanding and quantification of sediment-related effects on turbines. More recently, progress has been made in numerical modelling of turbine erosion. To calibrate, validate and further develop prediction models, more measurements from both physical model tests in laboratories and real-scale data from HPPs are required. Significant improvements to mitigate hydro-abrasive erosion have been achieved so far and development is ongoing. A good collaboration between turbine manufacturers, HPP operators, measuring equipment suppliers, engineering consultants, and research institutes is required. This contributes to the energy- and cost-efficient use of the worldwide hydropower potential.

Numerical prediction for effects of guide vane blade numbers on hydraulic turbine performance

International Nuclear Information System (INIS)

Shi, F X; Yang, J H; Wang, X H; Li, C E

2013-01-01

Using unstructured hybrid grid technique and SIMPLEC algorithm,a general three-dimensional simulation based on Reynolds Navier- stocks in multiple reference frames and the RNG k-ε turbulence model, is presented for the reversal centrifugal pump (PAT) with a guide vane. Four different schemes are designed by a change of the number of guide vane blade of PAT. The inner flow field in every scheme is simulated, accordingly, the external characteristic and static pressure distribution in flow field in PAT is obtained. The results obtained show that the efficiency can be improved by adding a guide vane for the PAT, besides, the high efficiency area is wider than before. Guide blade numbers changed, external characteristics of turbine changed, and the external characteristic changed. The optimal value is existent for the guide vane blade number, which has a great impact on the distribution of pressure in runner inlet

3D Numerical Simulation versus Experimental Assessment of Pressure Pulsations Using a Passive Method for Swirling Flow Control in Conical Diffusers of Hydraulic Turbines

Science.gov (United States)

TANASA, C.; MUNTEAN, S.; CIOCAN, T.; SUSAN-RESIGA, R. F.

2016-11-01

The hydraulic turbines operated at partial discharge (especially hydraulic turbines with fixed blades, i.e. Francis turbine), developing a swirling flow in the conical diffuser of draft tube. As a result, the helical vortex breakdown, also known in the literature as “precessing vortex rope” is developed. A passive method to mitigate the pressure pulsations associated to the vortex rope in the draft tube cone of hydraulic turbines is presented in this paper. The method involves the development of a progressive and controlled throttling (shutter), of the flow cross section at the bottom of the conical diffuser. The adjustable cross section is made on the basis of the shutter-opening of circular diaphragms, while maintaining in all positions the circular cross-sectional shape, centred on the axis of the turbine. The stagnant region and the pressure pulsations associated to the vortex rope are mitigated when it is controlled with the turbine operating regime. Consequently, the severe flow deceleration and corresponding central stagnant are diminished with an efficient mitigation of the precessing helical vortex. Four cases (one without diaphragm and three with diaphragm), are numerically and experimentally investigated, respectively. The present paper focuses on a 3D turbulent swirling flow simulation in order to evaluate the control method. Numerical results are compared against measured pressure recovery coefficient and Fourier spectra. The results prove the vortex rope mitigation and its associated pressure pulsations when employing the diaphragm.

Mathematical, numerical and experimental analysis of the swirling flow at a Kaplan runner outlet

International Nuclear Information System (INIS)

Muntean, S; Ciocan, T; Susan-Resiga, R F; Cervantes, M; Nilsson, H

2012-01-01

The paper presents a novel mathematical model for a-priori computation of the swirling flow at Kaplan runners outlet. The model is an extension of the initial version developed by Susan-Resiga et al [1], to include the contributions of non-negligible radial velocity and of the variable rothalpy. Simple analytical expressions are derived for these additional data from three-dimensional numerical simulations of the Kaplan turbine. The final results, i.e. velocity components profiles, are validated against experimental data at two operating points, with the same Kaplan runner blades opening, but variable discharge.

Mathematical, numerical and experimental analysis of the swirling flow at a Kaplan runner outlet

Science.gov (United States)

Muntean, S.; Ciocan, T.; Susan-Resiga, R. F.; Cervantes, M.; Nilsson, H.

2012-11-01

The paper presents a novel mathematical model for a-priori computation of the swirling flow at Kaplan runners outlet. The model is an extension of the initial version developed by Susan-Resiga et al [1], to include the contributions of non-negligible radial velocity and of the variable rothalpy. Simple analytical expressions are derived for these additional data from three-dimensional numerical simulations of the Kaplan turbine. The final results, i.e. velocity components profiles, are validated against experimental data at two operating points, with the same Kaplan runner blades opening, but variable discharge.

Prediction of hydraulic force and momentum on pelton turbine jet deflector based on cfd simulation

International Nuclear Information System (INIS)

Popovski, Boro

2015-01-01

The numerical simulation of three-dimensional turbulent flow through the jet-distributor, free stream jet and deflector of Pelton Turbine is presented in this work. The calculations are performed using the CFD package Ansys CFX (Navie-Stokes equations and the k-omega SST turbulent model). A traditional definition for calculation of hydraulic forces and momentum on the jet deflector and a method for experimental evaluation are described. The steps for flow modelling, mesh (grid) generation, as well as the results obtained from the numerical simulation of the flow and stress deformation calculations of the jet-deflector are presented. This work corresponds with the actual approach of methods development for flow simulation and calculations of Pelton Turbines. The kinematic and dynamic parameters are calculated based on CFD simulations. The results of the calculations represents reliable tool in the procedure of development and construction of Pelton Turbines. (author)

77 FR 281 - Green Mountain Power Corporation; Notice of Application Accepted for Filing, Soliciting Comments...

Science.gov (United States)

2012-01-04

... recommendations filed. k. Description of Request: The licensee in 2009 replaced the project's turbine runner with... changed the project's generating capacity but the hydraulic capacity of the unit increased by 14 percent...

Development of the water-lubricated thrust bearing of the hydraulic turbine generator

International Nuclear Information System (INIS)

Inoue, K; Deguchi, K; Okude, K; Fujimoto, R

2012-01-01

In hydropower plant, a large quantities of turbine oil is used as machine control pressure oil and lubricating oil. If the oil leak out from hydropower plant, it flows into a river. And such oil spill has an adverse effect on natural environment because the oil does not degrade easily. Therefore the KANSAI and Hitachi Mitsubishi Hydro developed the water-lubricated thrust bearing for vertical type hydraulic turbine generator. The water-lubricated bearing has advantages in risk avoidance of river pollution because it does not need oil. For proceeding the development of the water-lubricated thrust bearing, we studied following items. The first is the examination of the trial products of water lubricating liquid. The second is the study of bearing structure which can satisfy bearing performance such as temperature characteristic and so on. The third is the mock-up testing for actual application in the future. As a result, it was found that the water-lubricated thrust bearing was technically applicable to actual equipments.

Model with Peach Bottom Turbine trip and thermal-Hydraulic code TRACE V5P3

International Nuclear Information System (INIS)

Mesado, C.; Miro, R.; Barrachina, T.; Verdu, G.

2014-01-01

This work is the continuation of the work presented previously in the thirty-ninth meeting annual of the Spanish Nuclear society. The semi-automatic translation of the Thermo-hydraulic model TRAC-BF1 Peach Bottom Turbine Trip to TRACE was presented in such work. This article is intended to validate the model obtained in TRACE, why compare the model results result from the translation with the Benchmark results: NEA/OECD BWR Peach Bottom Turbine Trip (PBTT), in particular is of the extreme scenario 2 of exercise 3, in which there is SCRAM in the reactor. Among other data present in the (transitional) Benchmark , are: total power, axial profile of power, pressure Dome, total reactivity and its components. (Author)

Investigation Of Cross-Flow Model Water Turbine

International Nuclear Information System (INIS)

Obretenov, V.S.

1998-01-01

The research is made with the basic objective of constructing effective stream section of cross-flow turbine. In the research project are presented the results from experimental testing of the cross-flow turbine with various runner. nozzles and draft tubes. The rotational and universal characteristics of the turbine are presented. The experimental results have been analyzed.The results from the research give the possibility to make clear some important aspects of the working process with the cross-flow turbines. The characteristics derived from these tests prove that the stream section of the tested cross-flow turbine can be used as a model in the construction of cross-flow turbines for power electric stations with small capacity

Analysis of vorticity dynamics for hump characteristics of a pump turbine model

Energy Technology Data Exchange (ETDEWEB)

Li, Deyou; Gong, Ruzhi; Wang, Hongjie; Han, Lei; Wei, Xianzhu; Qin, Daqing [School of Energy Science and Engineering, Harbin Institute of Technology, Harbin (China)

2016-08-15

Conventional parameters based on CFD methodology for the investigation on hump characteristics of a pump turbine cannot reflect the dynamic interaction mechanism between the runner and the fluid. This research presents a dynamic interaction mechanism of a pump turbine operating in the hump region. First, vorticity dynamic parameters were obtained based on the theory of vorticity dynamics. Second, 3-D unsteady flow simulations were performed in a full pump turbine model using the SST k-ω turbulence model, and numerical results have a good agreement with the experiments. Then, analysis was carried out to determine the relation between the vorticity dynamic parameters and hump characteristics. The results indicate that the theory of vorticity dynamics has an advantage in evaluating the dynamic performance of a pump turbine. The energy transfer between the runner and the fluid is through vorticity dynamic parameters-pressure and friction terms, in which the pressure term accounts for the most. Furthermore, vortex generation mainly results from the skin friction. Combining vorticity dynamic analysis with the method of Q-criterion indicates that hump characteristics are related to the reduction of the surface normal pressure work and vortex motion on the suction surfaces close to the leading edges in the runner, and the increase of skin friction work in the stay-guide vanes.

Analysis of load reduction possibilities using a hydraulic soft yaw system for a 5-MW turbine and its sensitivity to yaw-bearing friction

DEFF Research Database (Denmark)

Stubkier, S.; Pedersen, H. C.; Jonkman, J. M.

2014-01-01

With the increasing size of wind turbines and with increasing lifetime demands, new methods for load reduction in the turbines need to be examined. One method is to make the yaw system of the turbine flexible, thereby dampening the loads to the system. This paper presents a hydraulic soft yaw...... concept and investigates the effect this has on critical loads in the turbine. To analyze the system, a novel friction model is developed and implemented for the yaw system using the NREL 5-MW turbine in the aerodynamic code FAST. Based on this model, the influence of friction is investigated...

Measurement of pressure pulsations in Francis turbines

Energy Technology Data Exchange (ETDEWEB)

Kobro, Einar

2010-11-15

The work presented in this thesis involves preparation and execution of measurements on Francis runners. The measurements were performed by means of onboard measuring equipment both in model runners and full-scale prototype runners. Also, analysis of the measured data, and the discussion of the results, is presented. The measurements resulted in large data sets. These data sets were used by the author to investigate the dynamic pressure and strain in the runners. The results of the analysis can be used as input in future turbine design. Andritz Hydro AG has used the data for verification of their numerical simulation tools. In connection with the refurbishment of Tokke power plant, two model runners were made available for onboard pressure measurements. To investigate the dynamic pressure in these runners, methods for integration of pressure transducers in the runner blades needed to be developed. After initial difficulties during the preparation, successful measurements were obtained from both model runners. At Tokke power plant, both the original and replacement runners were made accessible for onboard pressure and strain gauge measurements. On the original Kvaerner Brug AS runner, the test was prepared and performed by the author. This test failed, due to water intrusion in the logging chain. The second test was performed on the Andritz Hydro AG replacement runner. This test was prepared and performed by the author in close cooperation with Andritz Hydro AG, and the results were successful. The analysis results from both model and prototype runners show that the wake leaving the guide vanes is the most severe source of dynamic pressure in the runner. The draft tube vortex rope pulsation propagates upstream the runner, but does not appear as a significant frequency in the runner strain measurements. (Author)

Performance and safety of hydraulic turbines

International Nuclear Information System (INIS)

Brekke, H

2010-01-01

The first part of the paper contains the choice of small turbines for run of the river power plants. Then a discussion is given on the optimization of the performance of different types of large turbines. Finally a discussion on the safety and necessary maintenance of turbines is given with special attention to bolt connections.

The effects of improvement of the main shaft on the operating conditions of the Agnew turbine

Energy Technology Data Exchange (ETDEWEB)

Yassi, Y. [Iranian Research Organization for Science and Technology (IROST), Tehran (Iran)

2009-10-15

Agnew turbine is a 45 axial flow Kaplan type micro hydro. The turbine was designed by an ex-lecturer of the Univ. of Glasgow, to operate without guide vanes. Later due to a joint research program between the Iranian Research Organization for Science and Technology (IROST) and the Univ. of Glasgow it was developed to operate under low head and limited flow potentials in Iran. The original design of the main shaft of the turbine was supported by a bearing housing consisting of three bearings outside the main casing, leaving the rest of the shaft, hub and the runner without any supports inside the turbine.Later a suitable support near the runner and inside the casing was designed and installed. Standard turbine tests showed considerable improvements in operating characteristics of the turbine due to these design modifications. This paper presents details of these improvements and the related outcomes. (author)

The effects of improvement of the main shaft on the operating conditions of the Agnew turbine

International Nuclear Information System (INIS)

Yassi, Y.

2009-01-01

Agnew turbine is a 45 deg. axial flow Kaplan type micro hydro. The turbine was designed by an ex-lecturer of the University of Glasgow, to operate without guide vanes. Later due to a joint research program between the Iranian Research Organization for Science and Technology (IROST) and the University of Glasgow it was developed to operate under low head and limited flow potentials in Iran. The original design of the main shaft of the turbine was supported by a bearing housing consisting of three bearings outside the main casing, leaving the rest of the shaft, hub and the runner without any supports inside the turbine .Later a suitable support near the runner and inside the casing was designed and installed. Standard turbine tests showed considerable improvements in operating characteristics of the turbine due to these design modifications. This paper presents details of these improvements and the related outcomes.

The impact of inlet angle and outlet angle of guide vane on pump in reversal based hydraulic turbine performance

International Nuclear Information System (INIS)

Shi, F X; Yang, J H; Wang, X H; Zhang, R H; Li, C E

2012-01-01

In this paper, in order to research the impact of inlet angle and outlet angle of guide vane on hydraulic turbine performance, a centrifugal pump in reversal is adopted as turbine. A numerical simulation method is adopted for researching outer performance and flow field of turbine. The results show: inlet angle has a crucial role to turbine, to the same flow, there is a noticeable decline for the efficiency and head of turbine with the inlet angle increases. At the best efficiency point(EFP),to a same inlet angle, when the inlet angle greater than inlet angle, velocity circulation in guide vane outlet decreases, which lead the efficiency of turbine to reduce, Contrarily, the efficiency rises. With the increase of inlet angle and outlet angle, the EFP moves to the big flow area and the uniformity of pressure distribution becomes worse. The paper indicates that the inlet angle and outlet angle have great impact on the turbine performance, and the best combination exists for the inlet angle and outlet angle of the guide vane.

Analysis of the malfunctioning and failure of a 15 MW hydraulic turbine; Analisis de malfuncionamiento y de falla de una turbina hidraulica de 15 MW

Energy Technology Data Exchange (ETDEWEB)

Garcia Illescas, R.; Perez Rodriguez, N. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2007-11-15

A case history is presented of the rehabilitation process of three hydraulic turbines with a capacity of 15 MW each one. Such units are used for electric power generation, mainly to supply part of the center zone of the Mexican Republic. The turbo-generator units had been practically destroyed by catastrophic floods and only part of the equipment was recovered and reconditioned for its operation. One of the three turbines presented serious functioning problems preventing its reliable operation that was evidenced by excessive mechanical vibrations and heating in the bearing zone. This paper presents the diagnosis of the possible causes of failure and the corrective measures taken. Serious rotor misalignment problems were observed respect to its bearings and the turbine scroll. Additionally, during the inspection of the turbine runner and of the bearing it was observed that important friction have existed, which incremented the vibrations. It is shown that such rubbings are not the cause of the problem but only a manifestation of the same. Finally some of the conclusions and their solution are presented. [Spanish] Se presenta un caso historico del proceso de rehabilitacion de tres turbinas hidraulicas con capacidad de 15 MW cada una. Dichas unidades son empleadas en la generacion electrica, principalmente para abastecer parte de la zona centro de la republica mexicana. Las unidades turbogeneradores habian sido practicamente destruidas por inundaciones catastroficas y solo parte del equipo fue rescatado y rehabilitado para su operacion. Una de las tres turbinas presento graves problemas de funcionamiento, impidiendo su operacion confiable, lo cual se manifestaba mediante vibraciones mecanicas excesivas y calentamiento en zona de chumaceras. En este articulo se presenta el diagnostico de las posibles causas de falla y las acciones correctivas tomandas. Se observan problemas fuertes de desalineamiento del rotor respecto a sus chumaceras y al caracol de la turbina

Pelton turbines

CERN Document Server

Zhang, Zhengji

2016-01-01

This book concerns the theoretical foundations of hydromechanics of Pelton turbines from the engineering viewpoint. For reference purposes, all relevant flow processes and hydraulic aspects in a Pelton turbine have been analyzed completely and systematically. The analyses especially include the quantification of all possible losses existing in the Pelton turbine and the indication of most available potential for further enhancing the system efficiency. As a guideline the book therefore supports further developments of Pelton turbines with regard to their hydraulic designs and optimizations. It is thus suitable for the development and design engineers as well as those working in the field of turbo machinery. Many laws described in the book can also be directly used to simplify aspects of computational fluid dynamics (CFD) or to develop new computational methods. The well-executed examples help better understand the related flow mechanics.

On the physical mechanisms governing self-excited pressure surge in Francis turbines

International Nuclear Information System (INIS)

Müller, A; Favrel, A; Landry, C; Yamamoto, K; Avellan, F

2014-01-01

The required operating range for hydraulic machines is continually extended in an effort to integrate renewable energy sources with unsteady power outputs into the existing electrical grid. The off-design operation however brings forth unfavorable flow patterns in the machine, causing dynamic problems involving cavitation, which may represent a limiting factor to the energy production. In Francis turbines it is observed that the self-excited oscillation of a vortex rope in the draft tube cone prevents the delivery of maximum power when required. This phenomenon is referred to as full load pressure surge and has been the object of extensive research during the past decades. Several contributions deepened its understanding through measurement and simulation of the local flow properties and the global stability parameters. The draft tube pressure level and the runner outlet swirl are identified as key variables in the modelling of the vortex rope dynamics. Recently, a cyclic appearance of blade cavitation has been observed at overload conditions in a multiphase numerical simulation coupling the runner and the draft tube. From the analysis of the simulation it becomes obvious that the cyclic appearance of blade cavitation has a direct effect on the runner outlet swirl, thus introducing an additional interaction mechanism that is not accounted for in formerly published models. For the presented work, the results of this numerical study are confirmed experimentally on a reduced scale model of a Francis turbine. Several wall pressure measurements in the draft tube cone are performed, together with high speed visualizations of the vortex rope and the blade cavitation. The flow swirl is calculated based on Laser Doppler Velocimetry measurements. A possible mechanism explaining the coupling between the self-excited pressure and vortex rope oscillation and the cyclic appearance of the blade cavitation is proposed. Furthermore, the streamwise propagation speed of the flow

Study on performance and flow field of an undershot cross-flow water turbine comprising different number of blades

Science.gov (United States)

Nishi, Yasuyuki; Hatano, Kentaro; Inagaki, Terumi

2017-10-01

Recently, small hydroelectric generators have gained attention as a further development in water turbine technology for ultra low head drops in open channels. The authors have evaluated the application of cross-flow water turbines in open channels as an undershot type after removing the casings and guide vanes to substantially simplify these water turbines. However, because undershot cross-flow water turbines are designed on the basis of cross-flow water turbine runners used in typical pipelines, it remains unclear whether the number of blades has an effect on the performance or flow fields. Thus, in this research, experiments and numerical analyses are employed to study the performance and flow fields of undershot cross-flow water turbines with varying number of blades. The findings show that the turbine output and torque are lower, the fluctuation is significantly higher, and the turbine efficiency is higher for runners with 8 blades as opposed to those with 24 blades.

Highly reliable electro-hydraulic control system

International Nuclear Information System (INIS)

Mande, Morima; Hiyama, Hiroshi; Takahashi, Makoto

1984-01-01

The unscheduled shutdown of nuclear power stations disturbs power system, and exerts large influence on power generation cost due to the lowering of capacity ratio; therefore, high reliability is required for the control system of nuclear power stations. Toshiba Corp. has exerted effort to improve the reliability of the control system of power stations, and in this report, the electro-hydraulic control system for the turbines of nuclear power stations is described. The main functions of the electro-hydraulic control system are the control of main steam pressure with steam regulation valves and turbine bypass valves, the control of turbine speed and load, the prevention of turbine overspeed, the protection of turbines and so on. The system is composed of pressure sensors and a speed sensor, the control board containing the electronic circuits for control computation and protective sequence, the oil cylinders, servo valves and opening detectors of the valves for control, a high pressure oil hydraulic machine and piping, the operating panel and so on. The main features are the adoption of tripling intermediate value selection method, the multiplying of protection sensors and the adoption of 2 out of 3 trip logic, the multiplying of power sources, the improvement of the reliability of electronic circuit hardware and oil hydraulic system. (Kako, I.)

Technologies for evaluating fish passage through turbines

Energy Technology Data Exchange (ETDEWEB)

Weiland, Mark A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carlson, Thomas J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2003-10-01

This study evaluated the feasibility of two types of technologies to observe fish and near neutrally buoyant drogues as they move through hydropower turbines. Existing or reasonably modified light-emitting and ultrasonic technologies were used to observe flow patterns, the response of fish to flow, and interactions between fish and turbine structures with good spatial and temporal accuracy. This information can be used to assess the biological benefits of turbine design features such as reductions in gaps at the tips and hub of turbine runner blades, reshaping wicket gates and stay vanes, modifications to draft tube splitter piers, and design changes that enhance egress through the powerhouse and tailrace.

Dynamical study of the Darrieus-type turbine runners by using finite element method; Estudo da dinamica de turbinas hidraulicas mare-motrizes do tipo Darrieus atraves do metodo dos elementos finitos

Energy Technology Data Exchange (ETDEWEB)

Sena, Manoel Jose dos Santos; Mesquita, Andre Luiz Amarante [Para Univ., Belem, PA (Brazil). Dept. de Engenharia Mecanica. Grupo de Turbomaquinas]. E-mail: gtdem@ufpa.br

2000-07-01

The purpose of this work is describe the implementation of a finite element model for dynamic response analysis of Darrieus-type turbine runners. A fluid-structure coupling is be used to put in evidence some aspects of the rotor-water interaction. The rotating system fixed to the rotor will be used when writing the equations governing the system. A procedure using the ANSYS Parametric Design Language is discussed and some results obtained for the free-free configuration are shown. (author)

HydroHillChart – Pelton module. Software used to Calculate the Hill Chart of the Pelton Hydraulic Turbines

OpenAIRE

Dorian Nedelcu; Adelina Bostan; Florin Peris-Bendu

2015-01-01

The paper presents the HydroHillChart - Pelton module application, used to calculate the hill chart of the Pelton hydraulic turbine models, by processing the data measured on the stand. In addition, the tools offered by the application such as: interface, menu, input data, numerical and graphical results, etc. are described.

LDV survey of cavitation and resonance effect on the precessing vortex rope dynamics in the draft tube of Francis turbines

Science.gov (United States)

Favrel, A.; Müller, A.; Landry, C.; Yamamoto, K.; Avellan, F.

2016-11-01

The large-scale penetration of the electrical grid by intermittent renewable energy sources requires a continuous operating range extension of hydropower plants. This causes the formation of unfavourable flow patterns in the draft tube of turbines and pump-turbines. At partial load operation, a precessing cavitation vortex rope is formed at the Francis turbine runner outlet, acting as an excitation source for the hydraulic system. In case of resonance, the resulting high-amplitude pressure pulsations can put at risk the stability of the machine and of the electrical grid to which it is connected. It is therefore crucial to understand and accurately simulate the underlying physical mechanisms in such conditions. However, the exact impact of cavitation and hydro-acoustic resonance on the flow velocity fluctuations in the draft tube remains to be established. The flow discharge pulsations expected to occur in the draft tube in resonance conditions have for instance never been verified experimentally. In this study, two-component Laser Doppler Velocimetry is used to investigate the axial and tangential velocity fluctuations at the runner outlet of a reduced scale physical model of a Francis turbine. The investigation is performed for a discharge equal to 64 % of the nominal value and three different pressure levels in the draft tube, including resonance and cavitation-free conditions. Based on the convective pressure fluctuations induced by the vortex precession, the periodical velocity fluctuations over one typical precession period are recovered by phase averaging. The impact of cavitation and hydro-acoustic resonance on both axial and tangential velocity fluctuations in terms of amplitude and phase shift is highlighted for the first time. It is shown that the occurrence of resonance does not have significant effects on the draft tube velocity fields, suggesting that the synchronous axial velocity fluctuations are surprisingly negligible compared to the velocity

A performance study on a direct drive hydro turbine for wave energy converter

International Nuclear Information System (INIS)

Choi, Young Do; Kim, Chang Goo; Kim, You Taek; Lee, Young Ho; Song, Jung Il

2010-01-01

Clean and renewable energy technologies using ocean energy give us non-polluting alternatives to fossil-fueled power plants as a countermeasure against global warming and growing demand for electrical energy. Among the ocean energy resources, wave power takes a growing interest because of its enormous amount of potential energy in the world. Therefore, various types of wave power systems to capture the energy of ocean waves have been developed. However, a suitable turbine type is not yet normalized because of relatively low efficiency of the turbine systems. The purpose of this study is to investigate the performance of a newly developed direct drive hydro turbine (DDT), which will be built in a caisson for a wave power plant. Experiment and CFD analysis are conducted to clarify the turbine performance and internal flow characteristics. The results show that the DDT obtains fairly good turbine efficiency in cases with and without wave conditions. Most of the output power is generated at the runner passage of Stage 2. Relatively larger amount of the decreased tangential velocity at Stage 2 produces more angular momentum than that at Stage 1 and thus, the larger angular momentum at the Stage 2 makes a greater contribution to the generation of total output power in comparison with that at Stage 1. Large vortex existing in the upper-left region of the runner passage forms a large recirculation region in the runner passage, and the recirculating flow consumes the output power at Region 2

A performance study on a direct drive hydro turbine for wave energy converter

Energy Technology Data Exchange (ETDEWEB)

Choi, Young Do [Mokpo National University, Muan (Korea, Republic of); Kim, Chang Goo; Kim, You Taek; Lee, Young Ho [Korea Maritime University, Busan (Korea, Republic of); Song, Jung Il [Changwon National University, Changwon (Korea, Republic of)

2010-11-15

Clean and renewable energy technologies using ocean energy give us non-polluting alternatives to fossil-fueled power plants as a countermeasure against global warming and growing demand for electrical energy. Among the ocean energy resources, wave power takes a growing interest because of its enormous amount of potential energy in the world. Therefore, various types of wave power systems to capture the energy of ocean waves have been developed. However, a suitable turbine type is not yet normalized because of relatively low efficiency of the turbine systems. The purpose of this study is to investigate the performance of a newly developed direct drive hydro turbine (DDT), which will be built in a caisson for a wave power plant. Experiment and CFD analysis are conducted to clarify the turbine performance and internal flow characteristics. The results show that the DDT obtains fairly good turbine efficiency in cases with and without wave conditions. Most of the output power is generated at the runner passage of Stage 2. Relatively larger amount of the decreased tangential velocity at Stage 2 produces more angular momentum than that at Stage 1 and thus, the larger angular momentum at the Stage 2 makes a greater contribution to the generation of total output power in comparison with that at Stage 1. Large vortex existing in the upper-left region of the runner passage forms a large recirculation region in the runner passage, and the recirculating flow consumes the output power at Region 2

Research on the flow field of undershot cross-flow water turbines using experiments and numerical analysis

International Nuclear Information System (INIS)

Nishi, Y; Inagaki, T; Li, Y; Omiya, R; Hatano, K

2014-01-01

The purpose of this research is to develop a water turbine appropriate for low-head open channels in order to effectively utilize the unused hydropower energy of rivers and agricultural waterways. The application of the cross-flow runner to open channels as an undershot water turbine has come under consideration and, to this end, a significant simplification was attained by removing the casings. However, the flow field of undershot cross-flow water turbines possesses free surfaces. This means that with the variation in the rotational speed, the water depth around the runner will change and flow field itself is significantly altered. Thus it is necessary to clearly understand the flow fields with free surfaces in order to improve the performance of this turbine. In this research, the performance of this turbine and the flow field were studied through experiments and numerical analysis. The experimental results on the performance of this turbine and the flow field were consistent with the numerical analysis. In addition, the inlet and outlet regions at the first and second stages of this water turbine were clarified

Velocity and pressure measurements in guide vane clearance gap of a low specific speed Francis turbine

Science.gov (United States)

Thapa, B. S.; Dahlhaug, O. G.; Thapa, B.

2016-11-01

In Francis turbine, a small clearance gap between the guide vanes and the cover plates is usually required to pivot guide vanes as a part of governing system. Deflection of cover plates and erosion of mating surfaces causes this gap to increase from its design value. The clearance gap induces the secondary flow in the distributor system. This effects the main flow at the runner inlet, which causes losses in efficiency and instability. A guide vane cascade of a low specific speed Francis turbine has been developed for experimental investigations. The test setup is able to produce similar velocity distributions at the runner inlet as that of a reference prototype turbine. The setup is designed for particle image velocimetry (PIV) measurements from the position of stay vane outlet to the position of runner inlet. In this study, velocity and pressure measurements are conducted with 2 mm clearance gap on one side of guide vane. Leakage flow is observed and measured together with pressure measurements. It is concluded that the leakage flow behaves as a jet and mixes with the main flow in cross-wise direction and forms a vortex filament. This causes non-uniform inlet flow conditions at runner blades.

Sensor-Based Optimized Control of the Full Load Instability in Large Hydraulic Turbines

Directory of Open Access Journals (Sweden)

Alexandre Presas

2018-03-01

Full Text Available Hydropower plants are of paramount importance for the integration of intermittent renewable energy sources in the power grid. In order to match the energy generated and consumed, Large hydraulic turbines have to work under off-design conditions, which may lead to dangerous unstable operating points involving the hydraulic, mechanical and electrical system. Under these conditions, the stability of the grid and the safety of the power plant itself can be compromised. For many Francis Turbines one of these critical points, that usually limits the maximum output power, is the full load instability. Therefore, these machines usually work far away from this unstable point, reducing the effective operating range of the unit. In order to extend the operating range of the machine, working closer to this point with a reasonable safety margin, it is of paramount importance to monitor and to control relevant parameters of the unit, which have to be obtained with an accurate sensor acquisition strategy. Within the framework of a large EU project, field tests in a large Francis Turbine located in Canada (rated power of 444 MW have been performed. Many different sensors were used to monitor several working parameters of the unit for all its operating range. Particularly for these tests, more than 80 signals, including ten type of different sensors and several operating signals that define the operating point of the unit, were simultaneously acquired. The present study, focuses on the optimization of the acquisition strategy, which includes type, number, location, acquisition frequency of the sensors and corresponding signal analysis to detect the full load instability and to prevent the unit from reaching this point. A systematic approach to determine this strategy has been followed. It has been found that some indicators obtained with different types of sensors are linearly correlated with the oscillating power. The optimized strategy has been determined

Sensor-Based Optimized Control of the Full Load Instability in Large Hydraulic Turbines.

Science.gov (United States)

Presas, Alexandre; Valentin, David; Egusquiza, Mònica; Valero, Carme; Egusquiza, Eduard

2018-03-30

Hydropower plants are of paramount importance for the integration of intermittent renewable energy sources in the power grid. In order to match the energy generated and consumed, Large hydraulic turbines have to work under off-design conditions, which may lead to dangerous unstable operating points involving the hydraulic, mechanical and electrical system. Under these conditions, the stability of the grid and the safety of the power plant itself can be compromised. For many Francis Turbines one of these critical points, that usually limits the maximum output power, is the full load instability. Therefore, these machines usually work far away from this unstable point, reducing the effective operating range of the unit. In order to extend the operating range of the machine, working closer to this point with a reasonable safety margin, it is of paramount importance to monitor and to control relevant parameters of the unit, which have to be obtained with an accurate sensor acquisition strategy. Within the framework of a large EU project, field tests in a large Francis Turbine located in Canada (rated power of 444 MW) have been performed. Many different sensors were used to monitor several working parameters of the unit for all its operating range. Particularly for these tests, more than 80 signals, including ten type of different sensors and several operating signals that define the operating point of the unit, were simultaneously acquired. The present study, focuses on the optimization of the acquisition strategy, which includes type, number, location, acquisition frequency of the sensors and corresponding signal analysis to detect the full load instability and to prevent the unit from reaching this point. A systematic approach to determine this strategy has been followed. It has been found that some indicators obtained with different types of sensors are linearly correlated with the oscillating power. The optimized strategy has been determined based on the

HydroHillChart – Pelton module. Software used to Calculate the Hill Chart of the Pelton Hydraulic Turbines

Directory of Open Access Journals (Sweden)

Dorian Nedelcu

2015-07-01

Full Text Available The paper presents the HydroHillChart - Pelton module application, used to calculate the hill chart of the Pelton hydraulic turbine models, by processing the data measured on the stand. In addition, the tools offered by the application such as: interface, menu, input data, numerical and graphical results, etc. are described.

Preventive maintenance basis: Volume 37 -- Main turbine EHC hydraulics. Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1998-11-01

US nuclear power plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This document provides a program of preventive maintenance tasks suitable for application to the main turbine EHC hydraulic fluid and associated components. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used in conjunction with material from other sources, to develop a complete PM program or to improve an existing program

Compressible simulation of rotor-stator interaction in pump-turbines

International Nuclear Information System (INIS)

Yan, J; Koutnik, J; Seidel, U; Huebner, B

2010-01-01

This work investigates the influence of water compressibility on pressure pulsations induced by rotor-stator interaction (RSI) in hydraulic machinery, using the commercial CFD solver ANSYS-CFX. A pipe flow example with harmonic velocity excitation at the inlet plane is simulated using different grid densities and time step sizes. Results are compared with a validated code for hydraulic networks (SIMSEN). Subsequently, the solution procedure is applied to a simplified 2.5-dimensional pump-turbine configuration in model scale with an adapted speed of sound. Pressure fluctuations are compared with numerical and experimental data based on prototype scale. The good agreement indicates that the scaling of acoustic effects with an adapted speed of sound works well. Finally, the procedure is applied to a 3-dimensional pump configuration in model scale. Pressure fluctuations are compared with results from prototype measurements. Compared to incompressible computations, compressible simulations provide similar pressure fluctuations in vaneless space, but pressure fluctuations in spiral case and penstock may be much higher. With respect to pressure fluctuation amplitudes along the centerline of runner channels, incompressible solutions exhibit a linear decrease while compressible solutions exhibit sinusoidal distributions with maximum values at half the channel length, coinciding with analytical solutions of one-dimensional acoustics.

Extension of Operating Range in Pump-Turbines. Influence of Head and Load

Directory of Open Access Journals (Sweden)

Carme Valero

2017-12-01

Full Text Available Due to the increasing share of new renewable energies like wind and solar in the generation of electricity the need for power regulation and energy storage is becoming of paramount importance. One of the systems to store huge amounts of energy is pumped storage using reversible hydropower units. The machines used in these power plants are pump-turbines, which can operate as a pump and as a turbine. The surplus of electrical energy during low consumption hours can be converted into potential hydraulic energy by pumping water to a higher level. The stored energy can be converted into electricity again by operating the runner as a turbine. Due to new regulation requirements machines have to extend the operating range in order to match energy generation with consumption for the grid stability. In this paper the consequences of extending the operating range in existing pump-turbines have been studied. For that purpose, the data obtained after two years of condition monitoring were analyzed. Vibrations and pressure fluctuations of two pump-turbines of 85 MW each have been studied during pump and turbine operation. For turbine operation the effects of extending the operating range from the standard range of 45–85 MW to and increased range of 20–85 MW were analyzed. The change in vibration levels and signatures at very low load are presented with the identification of the phenomena that occur under these conditions. The influence of head in the vibration behavior is also presented. The appearance of fluid instabilities generated at part load that may produce power swing is also presented. Finally, the effect of head on the vibration levels for pump operation is shown and analyzed.

Concept Evaluation for Hydraulic Yaw System

DEFF Research Database (Denmark)

Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole

2013-01-01

The yaw system is the subsystem on a wind turbine which ensures that the rotor plane of the turbine always is facing the wind direction. Studies from [1] show that a soft yaw system may be utilized to dampen the loads in the wind turbine structure. The soft yaw system operates much like...... investigation. Loads and yaw demands are based on the IEC 61400-1 standard for wind turbine design, and the loads for this examination are extrapolated from the HAWC2 aeroelastic design code. The concepts are based on a 5 MW off-shore turbine....... a suspension system on a car, leading the loads away from the turbine structure. However, to realize a soft hydraulic yaw system a new design concept must be found. As a part of the development of the new concept a preliminary concept evaluation has been conducted, evaluating seven different hydraulic yaw...

Dynamic Model of Kaplan Turbine Regulating System Suitable for Power System Analysis

OpenAIRE

Zhao, Jie; Wang, Li; Liu, Dichen; Wang, Jun; Zhao, Yu; Liu, Tian; Wang, Haoyu

2015-01-01

Accurate modeling of Kaplan turbine regulating system is of great significance for grid security and stability analysis. In this paper, Kaplan turbine regulating system model is divided into the governor system model, the blade control system model, and the turbine and water diversion system model. The Kaplan turbine has its particularity, and the on-cam relationship between the wicket gate opening and the runner blade angle under a certain water head on the whole range was obtained by high-o...

The cross flow turbine (Michell - Banki) as option for small hydroelectric power plants; A turbina de fluxo cruzado (Michell - Banki) como opcao para centrais hidraulicas de pequeno porte

Energy Technology Data Exchange (ETDEWEB)

Mello Junior, Antonio Goncalves de

2000-07-01

Several types of hydraulic turbines can be used in small hydroelectric power plant, as Pelton, Francis, Turgo, Kaplan, Propeller, Banki, etc. In Brazil the more used are Francis and Kaplan followed by Pelton. The usage of the other types is almost unknown, mainly the Turgo turbine. The cross flow turbine, also known by the names of Michell-Banki, Banki, and Michell-Ossberger is defined as an action turbine that can be applicable to falls from 1 to 200 m and flows from 0,025 to 13 m{sup 3}/s. With the technical evolution mainly in the last two decades by traditional firms like Ossberger Turbinenfabrik and new firms like CINK, that turbine can reach diameters of rotors of 1,0 m with width of 2,6 m and to develop capacity up to 2,000 k W, with efficiency near 90%. The main evolutions are concentrated in modifications presented in the injector of the turbine by several manufacturers, and the use of new materials in the blades of the runner, shafts, bearings and the use of the draft tube. Case study shows the technical and economical implications using a cross flow turbine in comparison to a Francis turbine and a Kaplan. The conclusions will be reported after technical and economical viability analysis among the three types of turbines. (author)

The Hill Chart Calculation for Pelton Runner Models using the HydroHillChart - Pelton Module Software

Directory of Open Access Journals (Sweden)

Adelina Bostan

2015-07-01

Full Text Available The Pelton turbines industrial design is based on the hill chart characteristics obtained by measuring the models. Primary data measurements used to obtain the hill chart can be processed graphically, by hand or by using graphic programs respectively CAD programs; the HydroHillChart - Pelton module software is a specialized tool in achieving the hill chart, using interpolation cubic spline functions. Thereby, based on measurements of several models of Pelton turbines, a computerized library, used to design industrial Pelton turbines can be created. The paper presents the universal characteristics calculated by using the HydroHillChart - Pelton module software for a series of Pelton runners.

Classification of the operating conditions of a Kaplan turbine according to its impact in the structural integrity of the runner; Clasificacion de las condiciones de operacion de una turbina Kaplan de acuerdo a su impacto en la integridad estructural del rodete

Energy Technology Data Exchange (ETDEWEB)

Palacios, Luis M; Bautista, Eder A; Espitia, J Ernesto [Instituto Tecnologico de Pachuca, Pachuca, Hidalgo (Mexico); Mazur C, Zdzislaw [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2007-11-15

Each one of the operating conditions of the turbine according to the impact they have in the structural integrity of the runner is evaluated. By means of CFD (Computational Fluid Dynamics) analysis the pressure that the working fluid exerts on the blade for the turbine operating conditions is obtained. The oscillating disturbances induced by the flow, the angular velocity of the runner and the cavitation effect have been considered. The value of maximum stress for each one of the operating conditions is related to its respective values of cavitation. With this information those operating conditions that induce the greater values of stress and represent greater wears away in the runner are determined. This way, it is possible to avoid the more severe operating conditions and if this is not possible, lineaments of redesign are established to obtain more favorable operating conditions for the runner. [Spanish] Se evaluan y clasifican cada una de las condiciones de operacion de la turbina de acuerdo al impacto que tienen en la integridad estructural del rodete. Mediante analisis de CFD (Computacional Fluid Dynamics) se obtiene la presion que el fluido de trabajo ejerce sobre el alabe para las condiciones de operacion de la turbina. Se han considerado las perturbaciones oscilatorias inducidas por el flujo, la velocidad angular del rodete y el efecto de la cavitacion. Se relacionan los valores de esfuerzo maximo para cada una de las condiciones de operacion con sus respectivos valores de cavitacion. Con esta informacion se determinan aquellas condiciones de operacion que inducen los mayores valores de esfuerzo y representan mayor desgaste en el rodete. De esta manera, es posible evitar las condiciones de operacion mas severas, y si esto no es posible, se establecen lineamientos de rediseno para obtener condiciones de operacion mas favorables para el rodete.

Kaplan turbine tip vortex cavitation - analysis and prevention

Science.gov (United States)

Motycak, L.; Skotak, A.; Kupcik, R.

2012-11-01

The work is focused on one type of Kaplan turbine runner cavitation - a tip vortex cavitation. For detailed description of the tip vortex, the CFD analysis is used. On the basis of this analysis it is possible to estimate the intensity of cavitating vortex core, danger of possible blade surface and runner chamber cavitation pitting. In the paper, the ways how to avoid the pitting effect of the tip vortex are described. In order to prevent the blade surface against pitting, the following possibilities as the change of geometry of the runner blade, dimension of tip clearance and finally the installation of the anti-cavitation lips are discussed. The knowledge of the shape and intensity of the tip vortex helps to design the anti-cavitation lips more sophistically. After all, the results of the model tests of the Kaplan runner with or without anti-cavitation lips and the results of the CFD analysis are compared.

Experimental determination of unsteady flow forces on turbine blades by hydraulic analogy; Determination experimentale, par analogie hydraulique, des efforts instationnaires sur les aubages d`une turbine

Energy Technology Data Exchange (ETDEWEB)

Verdonk, G. [GEC Alsthom Rateau, 93 - La Courneuve (France); Naudin, M. [Framatome Thermodyn, 71 - Le Creusot (France); Pluviose, M. [CNAM, 75 - Paris (France); Sankale, H. [CETIM, 44 - Nantes (France)

1998-06-01

The blades of turbomachinery undergo unsteady flow forces, created principally by the presence of a series of stator or diffuser blades prior to a series of rotor blades. The stage geometry is the main factor which defines the magnitude of these forces. The influence of both geometric and thermodynamic parameters is currently being analysed using a model representing the turbine blades and by applying the hydraulic analogy technique. The study is being conducted at CETIM in Nantes amongst a working group including manufacturers, research organisms, and technical center. Work is in progress and initial results have proved sufficiently encouraging for presentation at the forthcoming Symposium on multidisciplinary turbomachinery issues organised by the Societe Francaise des Mecaniciens. The study should eventually facilitate the optimisation of rotor blade dimensioning for total and partial injection turbine applications and furthermore to reduce the risk of blade failure. Following quantitative study, results obtained for a given geometry of total injection turbine are presented in this paper. (authors) 16 refs.

Study of the use of a micro hydro in knockdown container completed with a cylindrical form housing of francis hydraulic turbine to support the development program of energy self-sustainability for remote and isolated areas in Indonesia

Directory of Open Access Journals (Sweden)

Kamal Samsul

2017-01-01

It shows that the implementation of the unit in a remote area has reduced the total site construction time by 1/3 compared to the predicted one with conventional unit. The performance of the Francis turbine with cylindrical form housing has shown comparable with the conventional one which has volute form housing. The superiority was even more pronounced by introducing a deflection insert in its input flow channel. The insertion was capable to create more distributed flow into the runner. Efficiency of the turbine up to 80% was performed in this research. Local manufacture for turbine usually use many craft work and welding to built a volute form housing for the Francis turbine. The cylindrical form housing here has also proven significantly in reducing the time and price for the turbine manufacturing process.

Numerical simulation of cavitation flow characteristic on Pelton turbine bucket surface

Science.gov (United States)

Zeng, C. J.; Xiao, Y. X.; Zhu, W.; Yao, Y. Y.; Wang, Z. W.

2015-01-01

The internal flow in the rotating bucket of Pelton turbine is free water sheet flow with moving boundary. The runner operates under atmospheric and the cavitation in the bucket is still a controversial problem. While more and more field practice proved that there exists cavitation in the Pelton turbine bucket and the cavitation erosion may occur at the worst which will damage the bucket. So a well prediction about the cavitation flow on the bucket surface of Pelton turbine and the followed cavitation erosion characteristic can effectively guide the optimization of Pelton runner bucket and the stable operation of unit. This paper will investigate the appropriate numerical model and method for the unsteady 3D water-air-vapour multiphase cavitation flow which may occur on the Pelton bucket surface. The computational domain will include the nozzle pipe flow, semi-free surface jet and runner domain. Via comparing the numerical results of different turbulence, cavity and multiphase models, this paper will determine the suitable numerical model and method for the simulation of cavitation on the Pelton bucket surface. In order to investigate the conditions corresponding to the cavitation phenomena on the bucket surface, this paper will adopt the suitable model to simulate the various operational conditions of different water head and needle travel. Then, the characteristics of cavitation flow the development process of cavitation will be analysed in in great detail.

Numerical simulation of cavitation flow characteristic on Pelton turbine bucket surface

International Nuclear Information System (INIS)

Zeng, C J; Xiao, Y X; Zhu, W; Yao, Y Y; Wang, Z W

2015-01-01

The internal flow in the rotating bucket of Pelton turbine is free water sheet flow with moving boundary. The runner operates under atmospheric and the cavitation in the bucket is still a controversial problem. While more and more field practice proved that there exists cavitation in the Pelton turbine bucket and the cavitation erosion may occur at the worst which will damage the bucket. So a well prediction about the cavitation flow on the bucket surface of Pelton turbine and the followed cavitation erosion characteristic can effectively guide the optimization of Pelton runner bucket and the stable operation of unit. This paper will investigate the appropriate numerical model and method for the unsteady 3D water-air-vapour multiphase cavitation flow which may occur on the Pelton bucket surface. The computational domain will include the nozzle pipe flow, semi-free surface jet and runner domain. Via comparing the numerical results of different turbulence, cavity and multiphase models, this paper will determine the suitable numerical model and method for the simulation of cavitation on the Pelton bucket surface. In order to investigate the conditions corresponding to the cavitation phenomena on the bucket surface, this paper will adopt the suitable model to simulate the various operational conditions of different water head and needle travel. Then, the characteristics of cavitation flow the development process of cavitation will be analysed in in great detail

Draft tube flow phenomena across the bulb turbine hill chart

International Nuclear Information System (INIS)

Duquesne, P; Fraser, R; Maciel, Y; Aeschlimann, V; Deschênes, C

2014-01-01

In the framework of the BulbT project launched by the Consortium on Hydraulic Machines and the LAMH (Hydraulic Machine Laboratory of Laval University) in 2011, an intensive campaign to identify flow phenomena in the draft tube of a model bulb turbine has been done. A special focus was put on the draft tube component since it has a particular importance for recuperation in low head turbines. Particular operating points were chosen to analyse flow phenomena in this component. For each of these operating points, power, efficiency and pressure were measured following the IEC 60193 standard. Visualizations, unsteady wall pressure and efficiency measurements were performed in this component. The unsteady wall pressure was monitored at seven locations in the draft tube. The frequency content of each pressure signal was analyzed in order to characterize the flow phenomena across the efficiency hill chart. Visualizations were recorded with a high speed camera using tufts and cavitation bubbles as markers. The predominant detected phenomena were mapped and categorized in relation to the efficiency hill charts obtained for three runner blade openings. At partial load, the vortex rope was detected and characterized. An inflection in the partial load efficiency curves was found to be related to complex vortex rope instabilities. For overload conditions, the efficiency curves present a sharp drop after the best efficiency point, corresponding to an inflection on the power curves. This break off is more severe towards the highest blade openings. It is correlated to a flow separation at the wall of the draft tube. Also, due to the separation occurring in these conditions, a hysteresis effect was observed on the efficiency curves

Experimental and numerical examination of the unsteady flow in an axial turbine; Experimentelle und numerische Untersuchung der instationaeren Stroemung in einer Axialturbine

Energy Technology Data Exchange (ETDEWEB)

Gentner, C.

2000-07-01

The periodic instationary flow in guidevanes and runner of an axial hydraulic turbine is examined experimentally and numerically. The study is carried out at three different points of operation. The experimental study comprises the measurement of the velocity of the flow at midspan using a single channel Laser Doppler Velocimeter and the acquisition of the ozillating pressure at several locations in the casing. The unsteady numerical examination is carried out in a two dimensional plane at midspan of the runnerblades. The interaction between guidevanes and runner is taken into account by exchanging the flow properties at the adjoining edges of the two calculation grids. Further the influence of the tip clearance flow on the characteristics of the turbine is studied numerically by means of a three dimensional steady state calculation. The comparison of the results of measurement and calculation shows the abilities and the limitations of the applied numerical method. Moreover the results are helpful for the optimisation of the turbine with regard to higher efficiency and reduced cavitation. (orig.) [German] Die periodisch instationaere Stroemung in Leit- und Laufrad einer hydraulischen Axialturbine zur Druckentspannung in Rohrleitungssystemen wird fuer drei Betriebspunkte experimentell und rechnerisch untersucht. Die experimentelle Untersuchung umfasst die zeitaufgeloeste Messung der Stroemungsgeschwindigkeiten mit einem Laser-Doppler-Velozimeter im Mittelschnitt und die Erfassung des periodisch schwankenden Drucks an mehreren Punkten an der Gehaeusewand. Die instationaere numerische Untersuchung erfolgt in einem zweidimensionalen Zylinderschnitt im mittleren Durchmesser der Laufschaufeln. Die Wechselwirkung zwischen Leit- und Laufrad wird druch den Austausch der Stroemungsgroessen mittels eines Kopplungsalgorithmus an der Stossflaeche zwischen den zwei gegeneinander bewegten Berechnungsgittern erfasst. Darueber hinaus wird in einer dreidimensionalen stationaeren

Performance and Flow Field of a Gravitation Vortex Type Water Turbine

OpenAIRE

Nishi, Yasuyuki; Inagaki, Terumi

2017-01-01

A gravitation vortex type water turbine, which mainly comprises a runner and a tank, generates electricity by introducing a flow of water into the tank and using the gravitation vortex generated when the water drains from the bottom of the tank. This water turbine is capable of generating electricity using a low head and a low flow rate with relatively simple structure. However, because its flow field has a free surface, this water turbine is extremely complicated, and thus its relevance to p...

Digital electro-hydraulic control system for nuclear turbine

International Nuclear Information System (INIS)

Yokota, Yutaka; Tone, Youichi; Ozono, Jiro

1985-01-01

The unit capacity of steam turbines for nuclear power generation is very large, accordingly their unexpected stop disturbs power system, and the lowering of their capacity ratio exerts large influence on power generation cost. Therefore, very high reliability is required for turbine EHC controllers which directly control the turbines for nuclear power generation. In order to meet such requirement, Toshiba Corp. has developed high reliability type analog tripled turbine EHC controllers, and delivered them to No. 3 plant in the Fukushima No. 2 Nuclear Power Station and No. 1 plant in the Kashiwazaki Kariwa Nuclear Power Station, Tokyo Electric Power Co., Inc. At present, the trial operation is under way. The development of digital EHC controllers was begun in 1976, and through the digital EHC for a test turbine and that for a small turbine, the digital EHC controllers for the turbines for nuclear power generation were developed. In this paper, the function, constitution, features and maintenance of the digital tripled EHC controllers for the turbines for nuclear power generation, the application of new technology to them, and the confirmation of the control function by simulation are reported. (Kako, I.)

Parameters identification of hydraulic turbine governing system using improved gravitational search algorithm

Energy Technology Data Exchange (ETDEWEB)

Chaoshun Li; Jianzhong Zhou [College of Hydroelectric Digitization Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2011-01-15

Parameter identification of hydraulic turbine governing system (HTGS) is crucial in precise modeling of hydropower plant and provides support for the analysis of stability of power system. In this paper, a newly developed optimization algorithm, called gravitational search algorithm (GSA), is introduced and applied in parameter identification of HTGS, and the GSA is improved by combination of the search strategy of particle swarm optimization. Furthermore, a new weighted objective function is proposed in the identification frame. The improved gravitational search algorithm (IGSA), together with genetic algorithm, particle swarm optimization and GSA, is employed in parameter identification experiments and the procedure is validated by comparing experimental and simulated results. Consequently, IGSA is shown to locate more precise parameter values than the compared methods with higher efficiency. (author)

Parameters identification of hydraulic turbine governing system using improved gravitational search algorithm

International Nuclear Information System (INIS)

Li Chaoshun; Zhou Jianzhong

2011-01-01

Parameter identification of hydraulic turbine governing system (HTGS) is crucial in precise modeling of hydropower plant and provides support for the analysis of stability of power system. In this paper, a newly developed optimization algorithm, called gravitational search algorithm (GSA), is introduced and applied in parameter identification of HTGS, and the GSA is improved by combination of the search strategy of particle swarm optimization. Furthermore, a new weighted objective function is proposed in the identification frame. The improved gravitational search algorithm (IGSA), together with genetic algorithm, particle swarm optimization and GSA, is employed in parameter identification experiments and the procedure is validated by comparing experimental and simulated results. Consequently, IGSA is shown to locate more precise parameter values than the compared methods with higher efficiency.

Improvement of hydro-turbine draft tube efficiency using vortex generator

Directory of Open Access Journals (Sweden)

Xiaoqing Tian

2015-07-01

Full Text Available Computational fluid dynamics simulation was employed in a hydraulic turbine (from inlet tube to draft tube. The calculated turbine efficiencies were compared with measured results, and the relative error is 1.12%. In order to improve the efficiency of the hydraulic turbine, 15 kinds of vortex generators were installed at the vortex development section of the draft tube, and all of them were simulated using the same method. Based on the turbine efficiencies, distribution of streamlines, velocities, and pressures in the draft tube, an optimal draft tube was found, which can increase the efficiency of this hydraulic turbine more than 1.5%. The efficiency of turbine with the optimal draft tube, draft tube with four pairs of middle-sized vortex generator, and draft tube without vortex generator under different heads of turbine (5–14 m was calculated, and it was verified that these two kinds of draft tubes can increase the efficiency of this turbine in every situation.

46 CFR 112.50-3 - Hydraulic starting.

Science.gov (United States)

2010-10-01

... POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets § 112.50-3 Hydraulic starting. A hydraulic starting system must meet the following: (a) The hydraulic starting system must be a... 46 Shipping 4 2010-10-01 2010-10-01 false Hydraulic starting. 112.50-3 Section 112.50-3 Shipping...

Kaplan turbine tip vortex cavitation – analysis and prevention

International Nuclear Information System (INIS)

Motycak, L; Skotak, A; Kupcik, R

2012-01-01

The work is focused on one type of Kaplan turbine runner cavitation – a tip vortex cavitation. For detailed description of the tip vortex, the CFD analysis is used. On the basis of this analysis it is possible to estimate the intensity of cavitating vortex core, danger of possible blade surface and runner chamber cavitation pitting. In the paper, the ways how to avoid the pitting effect of the tip vortex are described. In order to prevent the blade surface against pitting, the following possibilities as the change of geometry of the runner blade, dimension of tip clearance and finally the installation of the anti-cavitation lips are discussed. The knowledge of the shape and intensity of the tip vortex helps to design the anti-cavitation lips more sophistically. After all, the results of the model tests of the Kaplan runner with or without anti-cavitation lips and the results of the CFD analysis are compared.

Nonlinear Dynamical Analysis of Hydraulic Turbine Governing Systems with Nonelastic Water Hammer Effect

Directory of Open Access Journals (Sweden)

Junyi Li

2014-01-01

Full Text Available A nonlinear mathematical model for hydroturbine governing system (HTGS has been proposed. All essential components of HTGS, that is, conduit system, turbine, generator, and hydraulic servo system, are considered in the model. Using the proposed model, the existence and stability of Hopf bifurcation of an example HTGS are investigated. In addition, chaotic characteristics of the system with different system parameters are studied extensively and presented in the form of bifurcation diagrams, time waveforms, phase space trajectories, Lyapunov exponent, chaotic attractors, and Poincare maps. Good correlation can be found between the model predictions and theoretical analysis. The simulation results provide a reasonable explanation for the sustained oscillation phenomenon commonly seen in operation of hydroelectric generating set.

14 CFR 33.72 - Hydraulic actuating systems.

Science.gov (United States)

2010-01-01

... AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.72 Hydraulic actuating systems. Each hydraulic actuating system must function properly under all conditions in which the... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hydraulic actuating systems. 33.72 Section...

Hydro turbines: An introduction

International Nuclear Information System (INIS)

Gordon, J.L.

1993-01-01

The various types of hydraulic turbines currently used in hydroelectric power plants are described. The descriptions are intended for use by non-engineers who are concerned with fish passage and fish mortality at a hydro power facility. Terminology used in the hydro industry is explained. Since the extent of cavitation is one of the factors affecting mortality rates of fish passing through hydraulic turbines, an equation is introduced which measures the extent of cavitation likely to be experienced in a turbine. An example of how the cavitation index can be calculated is provided for two typical power plants. The relation between certain parameters of power plant operation and the extent of cavitation, and therefore of fish mortality, is illustrated. 2 refs., 14 figs

Functional Problems and Maintenance Operations of Hydraulic Turbines

Directory of Open Access Journals (Sweden)

Liliana Topliceanu

2016-02-01

Full Text Available The exploitation in good conditions of the hydroelectric power plant imposes a rigorous maintenance of equipment and operating facilities, primarily of the turbine. The efficiency of the turbine is strongly affected by any defects which could occur during the operation. The paper makes a synthesis of the most frequent failures which have occurred during the functioning of Kaplan turbines plant and the required maintenance plan that has to be adopted. The maintenance rules for the optimal working of these turbines are also emphasized.

Hydraulic Soft Yaw System Load Reduction and Prototype Results

DEFF Research Database (Denmark)

Stubkier, Søren; Pedersen, Henrik C.; Markussen, Kristian

2013-01-01

Introducing a hydraulic soft yaw concept for wind turbines leads to significant load reductions in the wind turbine structure. The soft yaw system operates as a shock absorption system on a car, hence absorbing the loading from turbulent wind conditions instead of leading them into the stiff wind...... turbine structure. Results presented shows fatigue reductions of up to 40% and ultimate load reduction of up to 19%. The ultimate load reduction increases even more when the over load protection system in the hydraulic soft yaw system is introduced and results show how the exact extreme load cut off...... operates. Further it is analyzed how the soft yaw system influence the power production of the turbine. It is shown that the influence is minimal, but at larger yaw errors the effect is possitive. Due to the implemeted functions in the hydraulic soft yaw system such as even load distribution on the pinions...

CFD based draft tube hydraulic design optimization

International Nuclear Information System (INIS)

McNabb, J; Murry, N; Mullins, B F; Devals, C; Kyriacou, S A

2014-01-01

The draft tube design of a hydraulic turbine, particularly in low to medium head applications, plays an important role in determining the efficiency and power characteristics of the overall machine, since an important proportion of the available energy, being in kinetic form leaving the runner, needs to be recovered by the draft tube into static head. For large units, these efficiency and power characteristics can equate to large sums of money when considering the anticipated selling price of the energy produced over the machine's life-cycle. This same draft tube design is also a key factor in determining the overall civil costs of the powerhouse, primarily in excavation and concreting, which can amount to similar orders of magnitude as the price of the energy produced. Therefore, there is a need to find the optimum compromise between these two conflicting requirements. In this paper, an elaborate approach is described for dealing with this optimization problem. First, the draft tube's detailed geometry is defined as a function of a comprehensive set of design parameters (about 20 of which a subset is allowed to vary during the optimization process) and are then used in a non-uniform rational B-spline based geometric modeller to fully define the wetted surfaces geometry. Since the performance of the draft tube is largely governed by 3D viscous effects, such as boundary layer separation from the walls and swirling flow characteristics, which in turn governs the portion of the available kinetic energy which will be converted into pressure, a full 3D meshing and Navier-Stokes analysis is performed for each design. What makes this even more challenging is the fact that the inlet velocity distribution to the draft tube is governed by the runner at each of the various operating conditions that are of interest for the exploitation of the powerhouse. In order to determine these inlet conditions, a combined steady-state runner and an initial draft tube analysis

CFD based draft tube hydraulic design optimization

Science.gov (United States)

McNabb, J.; Devals, C.; Kyriacou, S. A.; Murry, N.; Mullins, B. F.

2014-03-01

The draft tube design of a hydraulic turbine, particularly in low to medium head applications, plays an important role in determining the efficiency and power characteristics of the overall machine, since an important proportion of the available energy, being in kinetic form leaving the runner, needs to be recovered by the draft tube into static head. For large units, these efficiency and power characteristics can equate to large sums of money when considering the anticipated selling price of the energy produced over the machine's life-cycle. This same draft tube design is also a key factor in determining the overall civil costs of the powerhouse, primarily in excavation and concreting, which can amount to similar orders of magnitude as the price of the energy produced. Therefore, there is a need to find the optimum compromise between these two conflicting requirements. In this paper, an elaborate approach is described for dealing with this optimization problem. First, the draft tube's detailed geometry is defined as a function of a comprehensive set of design parameters (about 20 of which a subset is allowed to vary during the optimization process) and are then used in a non-uniform rational B-spline based geometric modeller to fully define the wetted surfaces geometry. Since the performance of the draft tube is largely governed by 3D viscous effects, such as boundary layer separation from the walls and swirling flow characteristics, which in turn governs the portion of the available kinetic energy which will be converted into pressure, a full 3D meshing and Navier-Stokes analysis is performed for each design. What makes this even more challenging is the fact that the inlet velocity distribution to the draft tube is governed by the runner at each of the various operating conditions that are of interest for the exploitation of the powerhouse. In order to determine these inlet conditions, a combined steady-state runner and an initial draft tube analysis, using a

The comparative analysis of model and prototype test results of Bulb turbine

International Nuclear Information System (INIS)

Benisek, M; Bozic, I; Ignjatovic, B

2010-01-01

This paper presents the problem of the hydropower plant oblique water inflow and its influence on the turbines operation. Oblique water inflow on the low head hydropower plant with bulb turbines influences turbine characteristics. The characteristics change occurs due to swirl incidence in the turbine inlet which spreads to the guide vanes inlet. Downstream, the flow conditions change is caused in the turbine runner in relation to the flow conditions without swirl inflow. Special attention is paid to the phenomenon of swirl flow incidence in the turbine conduit. With the aim of presenting and analyzing the oblique water inflow consequences on the hydropower plant operation, the existing turbine model tests results, performed in the laboratories, and the in situ prototype testing results have been used.

Counter rotating type hydroelectric unit suitable for tidal power station

International Nuclear Information System (INIS)

Kanemoto, T; Suzuki, T

2010-01-01

The counter rotating type hydroelectric unit, which is composed of the axial flow type tandem runners and the peculiar generator with double rotational armatures,was proposed to utilize effectively the tidal power. In the unit, the front and the rear runners counter drive the inner and the outer armatures of the generator, respectively. Besides, the flow direction at the rear runner outlet must coincide with the flow direction at the front runner inlet, because the angular momentum through the rear runner must coincides with that through the front runner. That is, the flow runs in the axial direction at the rear runner outlet while the axial inflow at the front runner inlet. Such operations are suitable for working at the seashore with rising and falling tidal flows, and the unit may be able to take place of the traditional bulb type turbines. The tandem runners were operated at the on-cam conditions, in keeping the induced frequency constant. The output and the hydraulic efficiency are affected by the adjustment of the front and the blade setting angles. The both optimum angles giving the maximum output and/or efficiency were presented at the various discharges/heads. To promote more the tidal power generation by this type unit, the runners were also modified so as to be suitable for both rising and falling flows. The hydraulic performances are acceptable while the output is determined mainly by the trailing edge profiles of the runner blades.

The possibility to increase the rated output as a result of index tests performed in Iron Gates II- Romania

Energy Technology Data Exchange (ETDEWEB)

Novac, D; Pantelimon, D [Hidroelectrica - SH Portile de Fier, Str. I.G. Bibicescu Nr.2, Drobeta Turnu Severin, RO - 220103 (Romania); Popescu, E, E-mail: dragos.novac@hidroelectrica.r [Hidroelectrica Bucuresti, Str. C-tin Nacu Nr.3, Bucuresti, RO - 020995 (Romania)

2010-08-15

The Index Tests have been used for many years to obtain the optimized cam correlation between wicket gates and runner blades for double regulated turbines (Kaplan, bulb). The cam is based on homologous model tests and is verified by site measurements, as model tests generally do not reproduce the exact intake configuration. Index Tests have also a considerable importance for checking of the relative efficiency curve of all type of turbines and can demonstrate if the prototype efficiency curve at plant condition has the shape expected from the test of the homologues model. During the Index Tests measurements the influence of all losses at multiple points of turbine operation can be proved. This publication deals with an overview on the Index Tests made after modernization of large bulb units in Iron Gates II - Romania. These field tests, together with the comparative, fully homologous tests for the new hydraulic shape of the runner blades have confirmed the smooth operational behavior and the guaranteed performance. Over the whole 'guaranteed operating range' for H = 8m, the characteristic of the Kaplan curve (enveloping curve to the propeller curves), agreed very well to the predicted efficiency curve from the hydraulic prototype hill chart. The new cam correlation have been determined for different head and realised in the governor, normally based on model tests. The guaranteed, maximum turbine output for H = 7,8m is specified with 32, 5 MW. The maximum measured turbine output during the Index Tests on cam operation was 35,704 MW at the net head of 7,836 m. This corresponds to 35,458 MW for the specified head H= 7, 8 m. All these important improvements ensure a significant increase of annual energy production without any change of the civil construction and without increasing the runner diameter. Also the possibility to increase the turbine rated output is evident.

The possibility to increase the rated output as a result of index tests performed in Iron Gates II- Romania

Science.gov (United States)

Novac, D.; Pantelimon, D.; Popescu, E.

2010-08-01

The Index Tests have been used for many years to obtain the optimized cam corellation between wicket gates and runner blades for double regulated turbines (Kaplan, bulb). The cam is based on homologous model tests and is verified by site measurements, as model tests generally do not reproduce the exact intake configuration. Index Tests have also a considerable importance for checking of the relative efficiency curve of all type of turbines and can demonstrate if the prototype efficiency curve at plant condition has the shape expected from the test of the homologues model. During the Index Tests measurements the influence of all losses at multiple points of turbine operation can be proved. This publication deals with an overview on the Index Tests made after modernization of large bulb units in Iron Gates II - Romania. These field tests, together with the comparative, fully homologous tests for the new hydraulic shape of the runner blades have confirmed the smooth operational behavior and the guaranteed performance. Over the whole "guaranteed operating range" for H = 8m, the characteristic of the Kaplan curve (enveloping curve to the proppeler curves), agreed very well to the predicted efficiency curve from the hydraulic prototype hill chart. The new cam correlation have been determined for different head and realised in the governor, normally based on model tests. The guaranteed, maximum turbine output for H = 7,8m is specified with 32, 5 MW. The maximum measured turbine output during the Index Tests on cam operation was 35,704 MW at the net head of 7,836 m. This coresponds to 35,458 MW for the specified head H= 7, 8 m. All these important improvements ensure a significant increase of annual energy production without any change of the civil construction and without increasing the runner diameter. Also the possibility to increase the turbine rated output is evident.

The possibility to increase the rated output as a result of index tests performed in Iron Gates II- Romania

International Nuclear Information System (INIS)

Novac, D; Pantelimon, D; Popescu, E

2010-01-01

The Index Tests have been used for many years to obtain the optimized cam correlation between wicket gates and runner blades for double regulated turbines (Kaplan, bulb). The cam is based on homologous model tests and is verified by site measurements, as model tests generally do not reproduce the exact intake configuration. Index Tests have also a considerable importance for checking of the relative efficiency curve of all type of turbines and can demonstrate if the prototype efficiency curve at plant condition has the shape expected from the test of the homologues model. During the Index Tests measurements the influence of all losses at multiple points of turbine operation can be proved. This publication deals with an overview on the Index Tests made after modernization of large bulb units in Iron Gates II - Romania. These field tests, together with the comparative, fully homologous tests for the new hydraulic shape of the runner blades have confirmed the smooth operational behavior and the guaranteed performance. Over the whole 'guaranteed operating range' for H = 8m, the characteristic of the Kaplan curve (enveloping curve to the propeller curves), agreed very well to the predicted efficiency curve from the hydraulic prototype hill chart. The new cam correlation have been determined for different head and realised in the governor, normally based on model tests. The guaranteed, maximum turbine output for H = 7,8m is specified with 32, 5 MW. The maximum measured turbine output during the Index Tests on cam operation was 35,704 MW at the net head of 7,836 m. This corresponds to 35,458 MW for the specified head H= 7, 8 m. All these important improvements ensure a significant increase of annual energy production without any change of the civil construction and without increasing the runner diameter. Also the possibility to increase the turbine rated output is evident.

CFD Analysis of The Hydraulic Turbine Draft Tube to Improve System Efficiency

Directory of Open Access Journals (Sweden)

Chakrabarty Spandan

2016-01-01

Full Text Available Demand of the power is increasing day by day with the development of the science and technology. Development of the renewable energy sector has become essential issue at the present situation due to the limited source of the non-renewable energy. Hydro energy power generation sector is superior over the other renewable sector due to the high efficiency, ability to continuous generation and low generation cost. In India a great amount of the power generation is taken care by the hydro power system but still some more potential have unexplored. The efficiency improvement of the hydro turbine system can be done for the new installation or installed system by the improvement in component level. The system can be installed by the state of the art equipment, like modern inlet guide vane (IGV control system, improved design of the runner, IGV system, draft tube, penstock to reduce the loss, hence improve the efficiency. The energy recovery in the draft tube depends on the design of draft tube. In the present work the optimized design of the draft tube shape through computational fluid dynamics (CFD simulation has been carried out in ANSYS FLUENT platform. The design objective of the draft tube is to reduce the flow loss and improve the energy recovery, hence to improve the efficiency.

Control system for NPP powerfull turbines

International Nuclear Information System (INIS)

Osipenko, V.D.; Rozhanskij, V.E.; Rokhlenko, V.Yu.

1985-01-01

A control system for NPP 1000 MW turbines safety is described. The turbine safety system has a hydraulic drive to actuate in case of increasipg of rotational speed of a turbine rotor and an electrohydraulic drce to operate in case of pressure reduction in the lubrication system, axial displacement deviation, etc. The system is highly reliable due to application of a safety system without slide valves and long-term operation of hydraulic controls in guarding conditions; the system epsures multifunctional control with high accuracy and speed due to application of the intricate electronic part, high speed of response with a limited use of high pressure oil due to application of two-pressure pumps, pneumohydraulic accumulators and oil discharge valves. Steady-state serviceability of the system is maintained by devices for valve cooling dawn. A shockless change from electrohydraulic to hydraulic control channels is provided

HydroHillChart – Francis module. Software used to Calculate the Hill Chart of the Francis Hydraulic Turbines

Directory of Open Access Journals (Sweden)

Dorian Nedelcu

2015-07-01

Full Text Available The paper presents the Hydro Hill Chart - Francis module application, used to calculate the hill chart of the Pelton, Francis and Kaplan hydraulic turbine models, by processing the data measured on the stand. After describing the interface and menu, the input data is graphically presented and the universal characteristic for measuring scenarios ao=const. and n11=const is calculated. Finally, the two calculated hill charts are compared through a graphical superimposition of the isolines.

Nonlinear dynamic analysis and robust controller design for Francis hydraulic turbine regulating system with a straight-tube surge tank

Science.gov (United States)

Liang, Ji; Yuan, Xiaohui; Yuan, Yanbin; Chen, Zhihuan; Li, Yuanzheng

2017-02-01

The safety and stability of hydraulic turbine regulating system (HTRS) in hydropower plants become increasingly important since the rapid development and the broad application of hydro energy technology. In this paper, a novel mathematical model of Francis hydraulic turbine regulating system with a straight-tube surge tank based on a few state-space equations is introduced to study the dynamic behaviors of the HTRS system, where the existence of possible unstable oscillations of this model is studied extensively and presented in the forms of the bifurcation diagram, time waveform plot, phase trajectories, and power spectrum. To eliminate these undesirable behaviors, a specified fuzzy sliding mode controller is designed. In this hybrid controller, the sliding mode control law makes full use of the proposed model to guarantee the robust control in the presence of system uncertainties, while the fuzzy system is applied to approximate the proper gains of the switching control in sliding mode technique to reduce the chattering effect, and particle swarm optimization is developed to search the optimal gains of the controller. Numerical simulations are presented to verify the effectiveness of the designed controller, and the results show that the performances of the nonlinear HTRS system assisted with the proposed controller is much better than that with the commonly used optimal PID controller.

Numerical Simulations of Vortex Shedding in Hydraulic Turbines

Science.gov (United States)

Dorney, Daniel; Marcu, Bogdan

2004-01-01

Turbomachines for rocket propulsion applications operate with many different working fluids and flow conditions. Oxidizer boost turbines often operate in liquid oxygen, resulting in an incompressible flow field. Vortex shedding from airfoils in this flow environment can have adverse effects on both turbine performance and durability. In this study the effects of vortex shedding in a low-pressure oxidizer turbine are investigated. Benchmark results are also presented for vortex shedding behind a circular cylinder. The predicted results are compared with available experimental data.

Statistical safety evaluation of BWR turbine trip scenario using coupled neutron kinetics and thermal hydraulics analysis code SKETCH-INS/TRACE5.0

International Nuclear Information System (INIS)

Ichikawa, Ryoko; Masuhara, Yasuhiro; Kasahara, Fumio

2012-01-01

The Best Estimate Plus Uncertainty (BEPU) method has been prepared for the regulatory cross-check analysis at Japan Nuclear Energy Safety Organization (JNES) on base of the three-dimensional neutron-kinetics/thermal-hydraulics coupled code SKETCH-INS/TRACE5.0. In the preparation, TRACE5.0 is verified against the large-scale thermal-hydraulic tests carried out with NUPEC facility. These tests were focused on the pressure drop of steam-liquid two phase flow and void fraction distribution. From the comparison of the experimental data with other codes (RELAP5/MOD3.3 and TRAC-BF1), TRACE5.0 was judged better than other codes. It was confirmed that TRACE5.0 has high reliability for thermal hydraulics behavior and are used as a best-estimate code for the statistical safety evaluation. Next, the coupled code SKETCH-INS/TRACE5.0 was applied to turbine trip tests performed at the Peach Bottom-2 BWR4 Plant. The turbine trip event shows the rapid power peak due to the voids collapse with the pressure increase. The analyzed peak value of core power is better simulated than the previous version SKETCH-INS/TRAC-BF1. And the statistical safety evaluation using SKETCH-INS/TRACE5.0 was applied to the loss of load transient for examining the influence of the choice of sampling method. (author)

Hydraulic Evaluation and Optimisation of T. Basses Wave Turbine

DEFF Research Database (Denmark)

Frigaard, Peter; Kofoed, Jens Peter

The present study investigates designs of the wing profiles and layouts of the wave turbine in order to optimize the design. Furthermore, the overall power production capability of the device has been estimated for the selected wing profiles and turbine layout.......The present study investigates designs of the wing profiles and layouts of the wave turbine in order to optimize the design. Furthermore, the overall power production capability of the device has been estimated for the selected wing profiles and turbine layout....

Turbine related fish mortality

International Nuclear Information System (INIS)

Eicher, G.J.

1993-01-01

A literature review was conducted to assess the factors affecting turbine-related fish mortality. The mechanics of fish passage through a turbine is outlined, and various turbine related stresses are described, including pressure and shear effects, hydraulic head, turbine efficiency, and tailwater level. The methodologies used in determining the effects of fish passage are evaluated. The necessity of adequate controls in each test is noted. It is concluded that mortality is the result of several factors such as hardiness of study fish, fish size, concentrations of dissolved gases, and amounts of cavitation. Comparisons between Francis and Kaplan turbines indicate little difference in percent mortality. 27 refs., 5 figs

Fatigue Analysis of an Outer Bearing Bush of a Kaplan Turbine

Directory of Open Access Journals (Sweden)

Doina Frunzaverde

2011-01-01

Full Text Available The paper presents the fatigue analysis of an outer bearing bush of aKaplan turbine. This outer bush, together with an inner one, bear thepin lever - trunion - blade subassembly of the runner blade operatingmechanism. For modeling and simulation, SolidWorks software is used.

The comparison between the acquisition vibration data obtained by different types of transducers for hydraulic turbine head cover

Science.gov (United States)

Li, Youping; Lu, Jinsong; Cheng, Jian; Yin, Yongzhen; Wang, Jianlan

2017-04-01

Based on the summaries of the rules about the vibration measurement for hydro-generator sets with respect to relevant standards, the key issues of the vibration measurement, such as measurement modes, the transducer selection are illustrated. In addition, the problems existing in vibration measurement are pointed out. The actual acquisition data of head cover vertical vibration respectively obtained by seismic transducer and eddy current transducer in site hydraulic turbine performance tests during the rising of the reservoir upstream level in a certain hydraulic power plant are compared. The difference of the data obtained by the two types of transducers and the potential reasons are presented. The application conditions of seismic transducer and eddy current transducer for hydro-generator set vibration measurement are given based on the analysis. Research subjects that should be focused on about the topic discussed in this paper are suggested.

Hydraulic turbines uses for rural electric generation

International Nuclear Information System (INIS)

Genta, J.; Nunes, V.

1994-01-01

The micro turbines use for electric generation either in autonomous systems or in connection to the national net is presented like an alternative whose viability has been studied in the Agreement taken place between the UTE Administracion Nacional de Usinas y transmisiones Electricas y la Facultad de Ingenieria. The Agreement S tudy for the Installation of Micro turbines that initially considered areas far from the national electric net it extended then to near areas to the same one to analyze the cogeneration alternative. They were considered smaller and bigger powers than 1 MW and up to 5MW. For the whole study range a methodology is described of calculate primary, starting from a minimum of field information that allows a first estimate of viability of a certain place and the selection of the turbine type, for a later detailed study

TG 220 MW hydraulic control system diagnostics

International Nuclear Information System (INIS)

Svabcik, A.

1996-01-01

The TG power output control system comprises a hydraulic and an electronic part. TG speed, power output or the main steam header pressure (HPK) depend on the steam flow at the turbine inlet. The steam admission into the turbine is controlled by four control valves and one by-pass valve in case of the HP part and by four capture flap valves in case of the LP part. The task of the SKODA K-220 MW turbine protection and control systems is to provide both the turbine speed and power output control to the setpoint value. Diagnostic measurements were aimed at getting an overview of both technical and functional states of all power output control elements. Principally, it can be stated that some deficiencies of a design nature originating from the manufacturer's factory were revealed and some other deficiencies related to hydraulic control elements functionality were identified more closely by the new method. 5 figs

TG 220 MW hydraulic control system diagnostics

Energy Technology Data Exchange (ETDEWEB)

Svabcik, A [Atomova Elektraren Bohunice, Jaslovske Bohunice (Slovakia)

1997-12-31

The TG power output control system comprises a hydraulic and an electronic part. TG speed, power output or the main steam header pressure (HPK) depend on the steam flow at the turbine inlet. The steam admission into the turbine is controlled by four control valves and one by-pass valve in case of the HP part and by four capture flap valves in case of the LP part. The task of the SKODA K-220 MW turbine protection and control systems is to provide both the turbine speed and power output control to the setpoint value. Diagnostic measurements were aimed at getting an overview of both technical and functional states of all power output control elements. Principally, it can be stated that some deficiencies of a design nature originating from the manufacturer`s factory were revealed and some other deficiencies related to hydraulic control elements functionality were identified more closely by the new method. 5 figs.

Experimental Study on Abrasive Waterjet Polishing of Hydraulic Turbine Blades

International Nuclear Information System (INIS)

Khakpour, H; Birglenl, L; Tahan, A; Paquet, F

2014-01-01

In this paper, an experimental investigation is implemented on the abrasive waterjet polishing technique to evaluate its capability in polishing of surfaces and edges of hydraulic turbine blades. For this, the properties of this method are studied and the main parameters affecting its performance are determined. Then, an experimental test-rig is designed, manufactured and tested to be used in this study. This test-rig can be used to polish linear and planar areas on the surface of the desired workpieces. Considering the number of parameters and their levels, the Taguchi method is used to design the preliminary experiments. All experiments are then implemented according to the Taguchi L 18 orthogonal array. The signal-to-noise ratios obtained from the results of these experiments are used to determine the importance of the controlled polishing parameters on the final quality of the polished surface. The evaluations on these ratios reveal that the nozzle angle and the nozzle diameter have the most important impact on the results. The outcomes of these experiments can be used as a basis to design a more precise set of experiments in which the optimal values of each parameter can be estimated

Sensitivity analysis of a Pelton hydropower station based on a novel approach of turbine torque

International Nuclear Information System (INIS)

Xu, Beibei; Yan, Donglin; Chen, Diyi; Gao, Xiang; Wu, Changzhi

2017-01-01

Highlights: • A novel approach of the turbine torque is proposed. • A unify model is capable of the dynamic characteristics of Pelton hydropower stations. • Sensitivity analysis from hydraulic parameters, mechanic parameters and electric parameters are performed. • Numerical simulations show the sensitivity ranges of the above three parameters. - Abstract: Hydraulic turbine generator units with long-running operation may cause the values of hydraulic, mechanic or electric parameters changing gradually, which brings a new challenge, namely that whether the operating stability of these units will be changed in the next thirty or forty years. This paper is an attempt to seek a relatively unified model for sensitivity analysis from three aspects: hydraulic parameters (turbine flow and turbine head), mechanic parameters (axis coordinates and axial misalignment) and electric parameters (generator speed and excitation current). First, a novel approach of the Pelton turbine torque is proposed, which can make connections between the hydraulic turbine governing system and the shafting system of the hydro-turbine generator unit. Moreover, the correctness of this approach is verified by comparing with other three models of hydropower stations. Second, this latter is analyzed to obtain the sensitivity of electric parameter (excitation current), the mechanic parameters (axial misalignment, upper guide bearing rigidity, lower guide bearing rigidity, and turbine guide bearing rigidity) on hydraulic parameters on the operating stability of the unit. In addition to this, some critical values and ranges are proposed. Finally, these results can provide some bases for the design and stable operation of Peltonhydropower stations.

Analysis of the pump-turbine S characteristics using the detached eddy simulation method

Science.gov (United States)

Sun, Hui; Xiao, Ruofu; Wang, Fujun; Xiao, Yexiang; Liu, Weichao

2015-01-01

Current research on pump-turbine units is focused on the unstable operation at off-design conditions, with the characteristic curves in generating mode being S-shaped. Unlike in the traditional water turbines, pump-turbine operation along the S-shaped curve can lead to difficulties during load rejection with unusual increases in the water pressure, which leads to machine vibrations. This paper describes both model tests and numerical simulations. A reduced scale model of a low specific speed pump-turbine was used for the performance tests, with comparisons to computational fluid dynamics(CFD) results. Predictions using the detached eddy simulation(DES) turbulence model, which is a combined Reynolds averaged Naviers-Stokes(RANS) and large eddy simulation(LES) model, are compared with the two-equation turbulence mode results. The external characteristics as well as the internal flow are for various guide vane openings to understand the unsteady flow along the so called S characteristics of a pump-turbine. Comparison of the experimental data with the CFD results for various conditions and times shows that DES model gives better agreement with experimental data than the two-equation turbulence model. For low flow conditions, the centrifugal forces and the large incident angle create large vortices between the guide vanes and the runner inlet in the runner passage, which is the main factor leading to the S-shaped characteristics. The turbulence model used here gives more accurate simulations of the internal flow characteristics of the pump-turbine and a more detailed force analysis which shows the mechanisms controlling of the S characteristics.

Fatigue Analysis of the Piston Rod in a Kaplan Turbine Based on Crack Propagation under Unsteady Hydraulic Loads

International Nuclear Information System (INIS)

Liu, X; Luo, Y Y; Wang, Z W

2014-01-01

As an important component of the blade-control system in Kaplan turbines, piston rods are subjected to fluctuating forces transferred by the turbines blades from hydraulic pressure oscillations. Damage due to unsteady hydraulic loads might generate unexpected down time and high repair cost. In one running hydropower plant, the fracture failure of the piston rod was found twice at the same location. With the transient dynamic analysis, the retainer ring structure of the piston rod existed a relative high stress concentration. This predicted position of the stress concentration agreed well with the actual fracture position in the plant. However, the local strain approach was not able to explain why this position broke frequently. Since traditional structural fatigue analyses use a local stress strain approach to assess structural integrity, do not consider the effect of flaws which can significantly degrade structural life. Using linear elastic fracture mechanism (LEFM) approaches that include the effect of flaws is becoming common practice in many industries. In this research, a case involving a small semi-ellipse crack was taken into account at the stress concentration area, crack growth progress was calculated by FEM. The relationship between crack length and remaining life was obtained. The crack propagation path approximately agreed with the actual fracture section. The results showed that presence of the crack had significantly changed the local stress and strain distributions of the piston rod compared with non-flaw assumption

Fatigue Analysis of the Piston Rod in a Kaplan Turbine Based on Crack Propagation under Unsteady Hydraulic Loads

Science.gov (United States)

Liu, X.; Y Luo, Y.; Wang, Z. W.

2014-03-01

As an important component of the blade-control system in Kaplan turbines, piston rods are subjected to fluctuating forces transferred by the turbines blades from hydraulic pressure oscillations. Damage due to unsteady hydraulic loads might generate unexpected down time and high repair cost. In one running hydropower plant, the fracture failure of the piston rod was found twice at the same location. With the transient dynamic analysis, the retainer ring structure of the piston rod existed a relative high stress concentration. This predicted position of the stress concentration agreed well with the actual fracture position in the plant. However, the local strain approach was not able to explain why this position broke frequently. Since traditional structural fatigue analyses use a local stress strain approach to assess structural integrity, do not consider the effect of flaws which can significantly degrade structural life. Using linear elastic fracture mechanism (LEFM) approaches that include the effect of flaws is becoming common practice in many industries. In this research, a case involving a small semi-ellipse crack was taken into account at the stress concentration area, crack growth progress was calculated by FEM. The relationship between crack length and remaining life was obtained. The crack propagation path approximately agreed with the actual fracture section. The results showed that presence of the crack had significantly changed the local stress and strain distributions of the piston rod compared with non-flaw assumption.

Gastrointestinal disturbances in marathon runners.

Science.gov (United States)

Riddoch, C; Trinick, T

1988-06-01

The purpose of this survey was to investigate the prevalence of running-induced gastrointestinal (GI) disturbances in marathon runners. A questionnaire was completed by 471 of the estimated 1,750 competitors in the 1986 Belfast City Marathon. Eighty-three per cent of respondents indicated that they occasionally or frequently suffered one or more GI disturbances during or immediately after running. The urge to have a bowel movement (53%) and diarrhoea (38%) were the most common symptoms, especially among female runners (74% and 68% respectively). Upper GI tract symptoms were experienced more by women than men (p less than 0.05) and more by younger runners than older runners (p less than 0.01). Women also suffered more lower GI tract symptoms than men (p less than 0.05) with younger runners showing a similar trend. Both upper and lower tract symptoms were more common during a "hard" run than an "easy" run (p less than 0.01) and were equally as common both during and after running. Of those runners who suffered GI disturbances, 72% thought that running was the cause and 29% believed their performance to be adversely affected. There was no consensus among sufferers as to the causes of symptoms and a wide variety of "remedies" were suggested. GI disturbances are common amongst long-distance runners and their aetiology is unknown. Medical practitioners should be aware of this when dealing with patients who run.

Flow-Induced Instabilities in Pump-Turbines in China

Directory of Open Access Journals (Sweden)

Zhigang Zuo

2017-08-01

Full Text Available The stability of pump-turbines is of great importance to the operation of pumped storage power (PSP stations. Both hydraulic instabilities and operational instabilities have been reported in PSP stations in China. In order to provide a reference to the engineers and scientists working on pump-turbines, this paper summarizes the hydraulic instabilities and performance characteristics that promote the operational instabilities encountered in pump-turbine operations in China. Definitions, analytical methods, numerical and experimental studies, and main results are clarified. Precautions and countermeasures are also provided based on a literature review. The gaps between present studies and the need for engineering practice are pointed out.

Robust Control Analysis of Hydraulic Turbine Speed

Science.gov (United States)

Jekan, P.; Subramani, C.

2018-04-01

An effective control strategy for the hydro-turbine governor in time scenario is adjective for this paper. Considering the complex dynamic characteristic and the uncertainty of the hydro-turbine governor model and taking the static and dynamic performance of the governing system as the ultimate goal, the designed logic combined the classical PID control theory with artificial intelligence used to obtain the desired output. The used controller will be a variable control techniques, therefore, its parameters can be adaptively adjusted according to the information about the control error signal.

A new bladeless hydraulic turbine

Czech Academy of Sciences Publication Activity Database

Beran, V.; Sedláček, M.; Maršík, František

2013-01-01

Roč. 104, APR 2013 (2013), s. 978-983 ISSN 0306-2619 R&D Projects: GA ČR GAP201/10/0357 Institutional research plan: CEZ:AV0Z20760514 Institutional support: RVO:61388998 Keywords : rolling turbine * low head hydro power * stability of flow Subject RIV: BK - Fluid Dynamics Impact factor: 5.261, year: 2013 http://dx.doi.org/10.1016/j.apenergy.2012.12.016

Numerical investigation for one bad-behaved flow in a Pelton turbine

International Nuclear Information System (INIS)

Wei, X Z; Yang, K; Wang, H J; Gong, R Z; Li, D Y

2015-01-01

The gas-liquid two-phase flow in pelton turbines is very complicated, there are many kinds of bad-behaved flow in pelton turbines. In this paper, CFD numerical simulation for the pelton turbine was conducted using VOF two-phase model. One kind of bad-behaved flow caused by the two jets was captured, and the bad-behaved flow was analysed by torque on buckets. It can be concluded that the angle between the two jets and the value of ratio of runner diameter and jet diameter are important parameters for the bad-behaved flow. Furthermore, the reason why the efficiency of some multi-jet type turbines is very low can be well explained by the analysis of bad-behaved flow. Finally, some suggestions for improvement were also provided in present paper

Numerical investigation for one bad-behaved flow in a Pelton turbine

Science.gov (United States)

Wei, X. Z.; Yang, K.; Wang, H. J.; Gong, R. Z.; Li, D. Y.

2015-01-01

The gas-liquid two-phase flow in pelton turbines is very complicated, there are many kinds of bad-behaved flow in pelton turbines. In this paper, CFD numerical simulation for the pelton turbine was conducted using VOF two-phase model. One kind of bad-behaved flow caused by the two jets was captured, and the bad-behaved flow was analysed by torque on buckets. It can be concluded that the angle between the two jets and the value of ratio of runner diameter and jet diameter are important parameters for the bad-behaved flow. Furthermore, the reason why the efficiency of some multi-jet type turbines is very low can be well explained by the analysis of bad-behaved flow. Finally, some suggestions for improvement were also provided in present paper.

Development of New Micro Hydropower Turbine

OpenAIRE

Dousith, Phommachanh; Kurokawa, Junichi; Matsui, Jun; Choi, Young-Do

2005-01-01

There is a huge of available hydropower potential in the water supply system (WSS) that has been abandoned．Each time when we use a water faucet, the power of 10 to 80 watts is dissipated．In fact, this dissipated energy can be converted to useful energy by hydraulic turbine. Presently, there is not suitable turbine to use in WSS. Therefore, the new type turbine is needed to explore. In this study, Positive Displacement Turbine (PDT) is proposed. The main objective of this study is to develop n...

Erosion of Pelton buckets and changes in turbine efficiency measured in the HPP Fieschertal

Science.gov (United States)

Abgottspon, A.; Staubli, T.; Felix, D.

2016-11-01

Geometrical changes and material loss of Pelton turbine runners as well as changes in turbine efficiency were measured at HPP Fieschertal in Valais, Switzerland. The HPP is equipped with two horizontal axis Pelton units, with each 32 MW nominal power, 7.5 m3/s design discharge, 515 m head and two injectors. The injectors and the buckets are hard-coated. Hydro-abrasive erosion was quantified based on repeated measurements on two runner buckets using (i) 3d-scanning and (ii) a coating thickness gauge. Changes in efficiency were measured by applying the sliding needle procedure. In addition to these periodically performed measurements, efficiency was also continuously monitored. The highest erosion rate was measured during the first half of the sediment season 2012 including a major sediment transport event. Because the runner was not fully reconditioned at the beginning of this season, progressive damages occurred. After the event, a splitter width of 10 mm was measured, corresponding to 1.5 % of the inner bucket width. The cut-outs were eroded by up to 9 mm towards the axis. The efficiency reductions ranged from 1 % in the year with the major sediment transport event to insignificant differences in 2014, when the sediment load was small and only little hydro-abrasive erosion occurred.

State of the art-hydraulic yaw systems for wind turbines

DEFF Research Database (Denmark)

Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole

2011-01-01

This paper addresses the yawing systems of Horizontal Axis Wind Turbines (HAWT’s). HAWT’s represents close to all of the commercial large wind turbines sold today and must be considered state-of-the art within wind turbine technology. Two choices exists when considering components for the active ...

Hydraulic analysis and optimization design in Guri rehabilitation project

Science.gov (United States)

Cheng, H.; Zhou, L. J.; Gong, L.; Wang, Z. N.; Wen, Q.; Zhao, Y. Z.; Wang, Y. L.

2016-11-01

Recently Dongfang was awarded the contract for rehabilitation of 6 units in Guri power plant, the biggest hydro power project in Venezuela. The rehabilitation includes, but not limited to, the extension of output capacity by about 50% and enhancement of efficiency level. To achieve the targets the runner and the guide vanes will be replaced by the newly optimized designs. In addition, the out-of-date stay vanes with straight plate shape will be modified into proper profiles after considering the application feasibility in field. The runner and vane profiles were optimized by using state-of-the-art flow simulation techniques. And the hydraulic performances were confirmed by the following model tests. This paper describes the flow analysis during the optimization procedure and the comparison between various technical concepts.

Fish passage assessment of an advanced hydropower turbine and conventional turbine using blade-strike modeling

Energy Technology Data Exchange (ETDEWEB)

Deng, Z.; Carlson, T. J.; Dauble, D. D.; Ploskey, G. R. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

2011-07-01

Hydropower is the largest renewable energy source in the world. However, in the Columbia and Snake River basins, several species of Pacific salmon and steelhead have been listed for protection under the Endangered Species Act due to significant declines of fish population. Dam operators and design engineers are thus faced with the task of making hydroelectric facilities more fish friendly through changes in hydro-turbine design and operation. Public Utility District No. 2 of Grant County, Washington, applied for relicensing from the U.S. Federal Energy Regulatory Commission to replace the 10 turbines at Wanapum Dam with advanced hydropower turbines that were designed to increase power generation and improve fish passage conditions. We applied both deterministic and stochastic blade-strike models to compare fish passage performance of the newly installed advanced turbine to an existing turbine. Modeled probabilities were compared to the results of a large-scale live-fish survival study and a Sensor Fish study under the same operational parameters. Overall, injury rates predicted by the deterministic model were higher than experimental rates of injury, while those predicted by the stochastic model were in close agreement with experimental results. Fish orientation at the time of entry into the plane of the leading edges of the turbine runner blades was an important factor contributing to uncertainty in modeled results. The advanced design turbine had slightly higher modeled injury rates than the existing turbine design; however, no statistical evidence suggested significant differences in blade-strike injuries between the two turbines, thus the hypothesis that direct fish survival rate through the advanced hydropower turbine is equal to or higher than that for fish passing through the conventional turbine could not be rejected. (authors)

Fish Passage Assessment of an Advanced Hydropower Turbine and Conventional Turbine Using Blade-Strike Modeling

Directory of Open Access Journals (Sweden)

Zhiqun Deng

2011-01-01

Full Text Available Hydropower is the largest renewable energy source in the world. However, in the Columbia and Snake River basins, several species of Pacific salmon and steelhead have been listed for protection under the Endangered Species Act due to significant declines of fish population. Dam operators and design engineers are thus faced with the task of making hydroelectric facilities more fish friendly through changes in hydro-turbine design and operation. Public Utility District No. 2 of Grant County, Washington, applied for relicensing from the U.S. Federal Energy Regulatory Commission to replace the 10 turbines at Wanapum Dam with advanced hydropower turbines that were designed to increase power generation and improve fish passage conditions. We applied both deterministic and stochastic blade-strike models to compare fish passage performance of the newly installed advanced turbine to an existing turbine. Modeled probabilities were compared to the results of a large-scale live-fish survival study and a Sensor Fish study under the same operational parameters. Overall, injury rates predicted by the deterministic model were higher than experimental rates of injury, while those predicted by the stochastic model were in close agreement with experimental results. Fish orientation at the time of entry into the plane of the leading edges of the turbine runner blades was an important factor contributing to uncertainty in modeled results. The advanced design turbine had slightly higher modeled injury rates than the existing turbine design; however, no statistical evidence suggested significant differences in blade-strike injuries between the two turbines, thus the hypothesis that direct fish survival rate through the advanced hydropower turbine is equal to or higher than that for fish passing through the conventional turbine could not be rejected.

3D fluid-structure modelling and vibration analysis for fault diagnosis of Francis turbine using multiple ANN and multiple ANFIS

Science.gov (United States)

Saeed, R. A.; Galybin, A. N.; Popov, V.

2013-01-01

This paper discusses condition monitoring and fault diagnosis in Francis turbine based on integration of numerical modelling with several different artificial intelligence (AI) techniques. In this study, a numerical approach for fluid-structure (turbine runner) analysis is presented. The results of numerical analysis provide frequency response functions (FRFs) data sets along x-, y- and z-directions under different operating load and different position and size of faults in the structure. To extract features and reduce the dimensionality of the obtained FRF data, the principal component analysis (PCA) has been applied. Subsequently, the extracted features are formulated and fed into multiple artificial neural networks (ANN) and multiple adaptive neuro-fuzzy inference systems (ANFIS) in order to identify the size and position of the damage in the runner and estimate the turbine operating conditions. The results demonstrated the effectiveness of this approach and provide satisfactory accuracy even when the input data are corrupted with certain level of noise.

Numerical investigation of tip clearance cavitation in Kaplan runners

Science.gov (United States)

Nikiforova, K.; Semenov, G.; Kuznetsov, I.; Spiridonov, E.

2016-11-01

There is a gap between the Kaplan runner blade and the shroud that makes for a special kind of cavitation: cavitation in the tip leakage flow. Two types of cavitation caused by the presence of clearance gap are known: tip vortex cavitation that appears at the core of the rolled up vortex on the blade suction side and tip clearance cavitation that appears precisely in the gap between the blade tip edge and the shroud. In the context of this work numerical investigation of the model Kaplan runner has been performed taking into account variable tip clearance for several cavitation regimes. The focus is put on investigation of structure and origination of mechanism of cavitation in the tip leakage flow. Calculations have been performed with the help of 3-D unsteady numerical model for two-phase medium. Modeling of turbulent flow in this work has been carried out using full equations of Navier-Stokes averaged by Reynolds with correction for streamline curvature and system rotation. For description of this medium (liquid-vapor) simplification of Euler approach is used; it is based on the model of interpenetrating continuums, within the bounds of this two- phase medium considered as a quasi-homogeneous mixture with the common velocity field and continuous distribution of density for both phases. As a result, engineering techniques for calculation of cavitation conditioned by existence of tip clearance in model turbine runner have been developed. The detailed visualization of the flow was carried out and vortex structure on the suction side of the blade was reproduced. The range of frequency with maximum value of pulsation was assigned and maximum energy frequency was defined; it is based on spectral analysis of the obtained data. Comparison between numerical computation results and experimental data has been also performed. The location of cavitation zone has a good agreement with experiment for all analyzed regimes.

Graphene in turbine blades

Science.gov (United States)

Das, D. K.; Swain, P. K.; Sahoo, S.

2016-07-01

Graphene, the two-dimensional (2D) nanomaterial, draws interest of several researchers due to its many superior properties. It has extensive applications in numerous fields. A turbine is a hydraulic machine which extracts energy from a fluid and converts it into useful work. Recently, Gudukeya and Madanhire have tried to increase the efficiency of Pelton turbine. Beucher et al. have also tried the same by reducing friction between fluid and turbine blades. In this paper, we study the advantages of using graphene as a coating on Pelton turbine blades. It is found that the efficiency of turbines increases, running and maintenance cost is reduced with more power output. By the application of graphene in pipes, cavitation will be reduced, durability of pipes will increase, operation and maintenance cost of water power plants will be less.

Hydro-acoustic resonance behavior in presence of a precessing vortex rope: observation of a lock-in phenomenon at part load Francis turbine operation

International Nuclear Information System (INIS)

Favrel, A; Landry, C; Müller, A; Yamamoto, K; Avellan, F

2014-01-01

Francis turbines operating at part load condition experience the development of a cavitating helical vortex rope in the draft tube cone at the runner outlet. The precession movement of this vortex rope induces local convective pressure fluctuations and a synchronous pressure pulsation acting as a forced excitation for the hydraulic system, propagating in the entire system. In the draft tube, synchronous pressure fluctuations with a frequency different to the precession frequency may also be observed in presence of cavitation. In the case of a matching between the precession frequency and the synchronous surge frequency, hydro-acoustic resonance occurs in the draft tube inducing high pressure fluctuations throughout the entire hydraulic system, causing torque and power pulsations. The risk of such resonances limits the possible extension of the Francis turbine operating range. A more precise knowledge of the phenomenon occurring at such resonance conditions and prediction capabilities of the induced pressure pulsations needs therefore to be developed. This paper proposes a detailed study of the occurrence of hydro-acoustic resonance for one particular part load operating point featuring a well-developed precessing vortex rope and corresponding to 64% of the BEP. It focuses particularly on the evolution of the local interaction between the pressure fluctuations at the precession frequency and the synchronous surge mode passing through the resonance condition. For this purpose, an experimental investigation is performed on a reduced scale model of a Francis turbine, including pressure fluctuation measurements in the draft tube and in the upstream piping system. Changing the pressure level in the draft tube, resonance occurrences are highlighted for different Froude numbers. The evolution of the hydro-acoustic response of the system suggests that a lock-in effect between the excitation frequency and the natural frequency may occur at low Froude number, inducing a hydro

Design optimization of hydraulic turbine draft tube based on CFD and DOE method

Science.gov (United States)

Nam, Mun chol; Dechun, Ba; Xiangji, Yue; Mingri, Jin

2018-03-01

In order to improve performance of the hydraulic turbine draft tube in its design process, the optimization for draft tube is performed based on multi-disciplinary collaborative design optimization platform by combining the computation fluid dynamic (CFD) and the design of experiment (DOE) in this paper. The geometrical design variables are considered as the median section in the draft tube and the cross section in its exit diffuser and objective function is to maximize the pressure recovery factor (Cp). Sample matrixes required for the shape optimization of the draft tube are generated by optimal Latin hypercube (OLH) method of the DOE technique and their performances are evaluated through computational fluid dynamic (CFD) numerical simulation. Subsequently the main effect analysis and the sensitivity analysis of the geometrical parameters of the draft tube are accomplished. Then, the design optimization of the geometrical design variables is determined using the response surface method. The optimization result of the draft tube shows a marked performance improvement over the original.

Mathematical simulation of fluid flow and analysis of flow pattern in the flow path of low-head Kaplan turbine

Directory of Open Access Journals (Sweden)

A. V. Rusanov

2016-12-01

Full Text Available The results of numerical investigation of spatial flow of viscous incompressible fluid in flow part of Kaplan turbine PL20 Kremenchug HPP at optimum setting angle of runner blade φb = 15° and at maximum setting angle φb = 35° are shown. The flow simulation has been carried out on basis of numerical integration of the Reynolds equations with an additional term containing artificial compressibility. The differential two-parameter model of Menter (SST has been applied to take into account turbulent effects. Numerical integration of the equations is carried out using an implicit quasi-monotone Godunov type scheme of second - order accuracy in space and time. The calculations have been conducted with the help of the software system IPMFlow. The analysis of fluid flow in the flow part elements is shown and the values of hydraulic losses and local cavitation coefficient have been obtained. Comparison of calculated and experimental results has been carried out.

Unsteady numerical simulation of the flow in the U9 Kaplan turbine model

International Nuclear Information System (INIS)

Javadi, Ardalan; Nilsson, Håkan

2014-01-01

The Reynolds-averaged Navier-Stokes equations with the RNG k-ε turbulence model closure are utilized to simulate the unsteady turbulent flow throughout the whole flow passage of the U9 Kaplan turbine model. The U9 Kaplan turbine model comprises 20 stationary guide vanes and 6 rotating blades (696.3 RPM), working at best efficiency load (0.71 m 3 /s). The computations are conducted using a general finite volume method, using the OpenFOAM CFD code. A dynamic mesh is used together with a sliding GGI interface to include the effect of the rotating runner. The clearance is included in the guide vane. The hub and tip clearances are also included in the runner. An analysis is conducted of the unsteady behavior of the flow field, the pressure fluctuation in the draft tube, and the coherent structures of the flow. The tangential and axial velocity distributions at three sections in the draft tube are compared against LDV measurements. The numerical result is in reasonable agreement with the experimental data, and the important flow physics close to the hub in the draft tube is captured. The hub and tip vortices and an on-axis forced vortex are captured. The numerical results show that the frequency of the forced vortex in 1/5 of the runner rotation

Unsteady numerical simulation of the flow in the U9 Kaplan turbine model

Science.gov (United States)

Javadi, Ardalan; Nilsson, Håkan

2014-03-01

The Reynolds-averaged Navier-Stokes equations with the RNG k-ε turbulence model closure are utilized to simulate the unsteady turbulent flow throughout the whole flow passage of the U9 Kaplan turbine model. The U9 Kaplan turbine model comprises 20 stationary guide vanes and 6 rotating blades (696.3 RPM), working at best efficiency load (0.71 m3/s). The computations are conducted using a general finite volume method, using the OpenFOAM CFD code. A dynamic mesh is used together with a sliding GGI interface to include the effect of the rotating runner. The clearance is included in the guide vane. The hub and tip clearances are also included in the runner. An analysis is conducted of the unsteady behavior of the flow field, the pressure fluctuation in the draft tube, and the coherent structures of the flow. The tangential and axial velocity distributions at three sections in the draft tube are compared against LDV measurements. The numerical result is in reasonable agreement with the experimental data, and the important flow physics close to the hub in the draft tube is captured. The hub and tip vortices and an on-axis forced vortex are captured. The numerical results show that the frequency of the forced vortex in 1/5 of the runner rotation.

Trabecular bone in the calcaneus of runners.

Science.gov (United States)

Best, Andrew; Holt, Brigitte; Troy, Karen; Hamill, Joseph

2017-01-01

Trabecular bone of the human calcaneus is subjected to extreme repetitive forces during endurance running and should adapt in response to this strain. To assess possible bone functional adaptation in the posterior region of the calcaneus, we recruited forefoot-striking runners (n = 6), rearfoot-striking runners (n = 6), and non-runners (n = 6), all males aged 20-41 for this institutionally approved study. Foot strike pattern was confirmed for each runner using a motion capture system. We obtained high resolution peripheral computed tomography scans of the posterior calcaneus for both runners and non-runners. No statistically significant differences were found between runners and nonrunners or forefoot strikers and rearfoot strikers. Mean trabecular thickness and mineral density were greatest in forefoot runners with strong effect sizes (forefoot strikers, likely an artifact of greater running volume and earlier onset of running in this subgroup; thus, individuals with the greatest summative loading stimulus had, after body mass adjustment, the thickest trabeculae. Further study with larger sample sizes is necessary to elucidate the role of footstrike on calcaneal trabecular structure. To our knowledge, intraspecific body mass correlations with measures of trabecular robusticity have not been reported elsewhere. We hypothesize that early adoption of running and years of sustained moderate volume running stimulate bone modeling in trabeculae of the posterior calcaneus.

Researches regarding primary control in hydraulic systems

OpenAIRE

Tița Irina; Mardare Irina

2017-01-01

The technology in wind turbines has developed very rapidly but there are still a lot that can be improved also regarding new technologies. One example is wind turbine with hydraulic transmission. At the beginning low power wind turbines are in view. First of all the wind energy is meant to be used by isolated users for household and garden equipment or pumping water. Later, if results will be as expected, and wind potential satisfactory, such systems could be connected to electric grid. In ou...

Dynamic Model of Kaplan Turbine Regulating System Suitable for Power System Analysis

Directory of Open Access Journals (Sweden)

Jie Zhao

2015-01-01

Full Text Available Accurate modeling of Kaplan turbine regulating system is of great significance for grid security and stability analysis. In this paper, Kaplan turbine regulating system model is divided into the governor system model, the blade control system model, and the turbine and water diversion system model. The Kaplan turbine has its particularity, and the on-cam relationship between the wicket gate opening and the runner blade angle under a certain water head on the whole range was obtained by high-order curve fitting method. Progressively the linearized Kaplan turbine model, improved ideal Kaplan turbine model, and nonlinear Kaplan turbine model were developed. The nonlinear Kaplan turbine model considered the correction function of the blade angle on the turbine power, thereby improving the model simulation accuracy. The model parameters were calculated or obtained by the improved particle swarm optimization (IPSO algorithm. For the blade control system model, the default blade servomotor time constant given by value of one simplified the modeling and experimental work. Further studies combined with measured test data verified the established model accuracy and laid a foundation for further research into the influence of Kaplan turbine connecting to the grid.

Tapering strategies in elite British endurance runners.

Science.gov (United States)

Spilsbury, Kate L; Fudge, Barry W; Ingham, Stephen A; Faulkner, Steve H; Nimmo, Myra A

2015-01-01

The aim of the study was to explore pre-competition training practices of elite endurance runners. Training details from elite British middle distance (MD; 800 m and 1500 m), long distance (LD; 3000 m steeplechase to 10,000 m) and marathon (MAR) runners were collected by survey for 7 days in a regular training (RT) phase and throughout a pre-competition taper. Taper duration was [median (interquartile range)] 6 (3) days in MD, 6 (1) days in LD and 14 (8) days in MAR runners. Continuous running volume was reduced to 70 (16)%, 71 (24)% and 53 (12)% of regular levels in MD, LD and MAR runners, respectively (P training (MD; 53 (45)%, LD; 67 (23)%, MAR; 64 (34)%, P training intensity was above race speed in LD and MAR runners (112 (27)% and 114 (3)%, respectively, P training undertaken prior to the taper in elite endurance runners is predictive of the tapering strategy implemented before competition.

Energy balance of hydro-aggregate with Pelton water turbine

International Nuclear Information System (INIS)

Obretenov, V.

2005-01-01

One of the major tasks in the field of hydraulic power engineering refers to machines and equipment modernization in the hydropower plants and pumped storage power plants commissioned more than 20 years ago. The increase of hydraulic units operation efficiency will allow in a number of cases to substantially reduce the specific water consumption and to drive the output of electric energy up. In these cases it is crucial to find out the operational efficiency of individual system elements and to precisely focus the modernization endeavours on such elements where the energy losses go beyond all admissible limits. Besides, the determination of the energy losses in the hydro energy turbo system will allow valid defining of hydraulic units operational scope. This work treats the methods of balance study of a hydraulic unit with Peiton water turbine. The experimental results of the balance study of Belmeken pumped storage power plant hydraulic unit No 5 under turbine operational mode are presented

Advanced Performance Hydraulic Wind Energy

Science.gov (United States)

Jones, Jack A.; Bruce, Allan; Lam, Adrienne S.

2013-01-01

The Jet Propulsion Laboratory, California Institute of Technology, has developed a novel advanced hydraulic wind energy design, which has up to 23% performance improvement over conventional wind turbine and conventional hydraulic wind energy systems with 5 m/sec winds. It also has significant cost advantages with levelized costs equal to coal (after carbon tax rebate). The design is equally applicable to tidal energy systems and has passed preliminary laboratory proof-of-performance tests, as funded by the Department of Energy.

Analysis of the OECD/NRC BWR Turbine Trip Transient Benchmark with the Coupled Thermal-Hydraulics and Neutronics Code TRAC-M/PARCS

International Nuclear Information System (INIS)

Lee, Deokjung; Downar, Thomas J.; Ulses, Anthony; Akdeniz, Bedirhan; Ivanov, Kostadin N.

2004-01-01

An analysis of the Peach Bottom Unit 2 Turbine Trip 2 (TT2) experiment has been performed using the U.S. Nuclear Regulatory Commission coupled thermal-hydraulics and neutronics code TRAC-M/PARCS. The objective of the analysis was to assess the performance of TRAC-M/PARCS on a BWR transient with significance in two-phase flow and spatial variations of the neutron flux. TRAC-M/PARCS results are found to be in good agreement with measured plant data for both steady-state and transient phases of the benchmark. Additional analyses of four fictitious extreme scenarios are performed to provide a basis for code-to-code comparisons and comprehensive testing of the thermal-hydraulics/neutronics coupling. The obtained results of sensitivity studies on the effect of direct moderator heating on transient simulation indicate the importance of this modeling aspect

Counter-rotating type axial flow pump unit in turbine mode for micro grid system

International Nuclear Information System (INIS)

Kasahara, R; Takano, G; Komaki, K; Murakami, T; Kanemoto, T

2012-01-01

Traditional type pumped storage system contributes to adjust the electric power unbalance between day and night, in general. This serial research proposes the hybrid power system combined the wind power unit with the pump-turbine unit, to provide the constant output for the grid system, even at the suddenly fluctuating/turbulent wind. In the pumping mode, the pump should operate unsteadily at not only the normal but also the partial discharge. The operation may be unstable in the rising portion of the head characteristics at the lower discharge, and/or bring the cavitation at the low suction head. To simultaneously overcome both weak points, the authors have proposed a superior pump unit that is composed of counter-rotating type impellers and a peculiar motor with double rotational armatures. This paper discusses the operation at the turbine mode of the above unit. It is concluded with the numerical simulations that this type unit can be also operated acceptably at the turbine mode, because the unit works so as to coincide the angular momentum change through the front runners/impellers with that thorough the rear runners/impellers, namely to take the axial flow at not only the inlet but also the outlet without the guide vanes.

Trabecular bone in the calcaneus of runners.

Directory of Open Access Journals (Sweden)

Andrew Best

Full Text Available Trabecular bone of the human calcaneus is subjected to extreme repetitive forces during endurance running and should adapt in response to this strain. To assess possible bone functional adaptation in the posterior region of the calcaneus, we recruited forefoot-striking runners (n = 6, rearfoot-striking runners (n = 6, and non-runners (n = 6, all males aged 20-41 for this institutionally approved study. Foot strike pattern was confirmed for each runner using a motion capture system. We obtained high resolution peripheral computed tomography scans of the posterior calcaneus for both runners and non-runners. No statistically significant differences were found between runners and nonrunners or forefoot strikers and rearfoot strikers. Mean trabecular thickness and mineral density were greatest in forefoot runners with strong effect sizes (<0.80. Trabecular thickness was positively correlated with weekly running distance (r2 = 0.417, p<0.05 and years running (r2 = 0.339, p<0.05 and negatively correlated with age at onset of running (r2 = 0.515, p<0.01 Trabecular thickness, mineral density and bone volume ratio of nonrunners were highly correlated with body mass (r2 = 0.824, p<0.05 and nonrunners were significantly heavier than runners (p<0.05. Adjusting for body mass revealed significantly thicker trabeculae in the posterior calcaneus of forefoot strikers, likely an artifact of greater running volume and earlier onset of running in this subgroup; thus, individuals with the greatest summative loading stimulus had, after body mass adjustment, the thickest trabeculae. Further study with larger sample sizes is necessary to elucidate the role of footstrike on calcaneal trabecular structure. To our knowledge, intraspecific body mass correlations with measures of trabecular robusticity have not been reported elsewhere. We hypothesize that early adoption of running and years of sustained moderate volume running stimulate bone modeling in trabeculae of the

Fat intake and injury in female runners.

Science.gov (United States)

Gerlach, Kristen E; Burton, Harold W; Dorn, Joan M; Leddy, John J; Horvath, Peter J

2008-01-03

Our purpose was to determine the relationship between energy intake, energy availability, dietary fat and lower extremity injury in adult female runners. We hypothesized that runners who develop overuse running-related injuries have lower energy intakes, lower energy availability and lower fat intake compared to non-injured runners. Eighty-six female subjects, running a minimum of 20 miles/week, completed a food frequency questionnaire and informed us about injury incidence over the next year. Injured runners had significantly lower intakes of total fat (63 +/- 20 vs. 80 +/- 50 g/d) and percentage of kilocalories from fat (27 +/- 5 vs. 30 +/- 8 %) compared with non-injured runners. A logistic regression analysis found that fat intake was the best dietary predictor, correctly identifying 64% of future injuries. Lower energy intake and lower energy availability approached, but did not reach, a significant association with overuse injury in this study. Fat intake is likely associated with injury risk in female runners. By documenting these associations, better strategies can be developed to reduce running injuries in women.

Runaway transient simulation of a model Kaplan turbine

Energy Technology Data Exchange (ETDEWEB)

Liu, S; Liu, D; Wu, Y [State Key Laboratory of Hydroscience and Engineering, Department of Thermal Eng., Tsinghua University, Beijing, 100084 (China); Zhou, D [Water Conservancy and Hydropower Eng., Hohai University, Nanjing. 210098 (China); Nishi, M, E-mail: liushuhong@tsinghua.edu.c [Kyushu Inst. Tech. Senior Academy, Kitakyushu, 804-8550 (Japan)

2010-08-15

The runaway transient is a typical transient process of a hydro power unit, where the rotational speed of a turbine runner rapidly increases up to the runaway speed under a working head as the guide vanes cannot be closed due to some reason at the load rejection. In the present paper, the characteristics of the runaway transient of a model Kaplan turbine having ns = 479(m-kW) is simulated by using a time-dependent CFD technique where equation of rotational motion of runner, continuity equation and unsteady RANS equations with RNG k-{epsilon} turbulence model are solved iteratively. In the calculation, unstructured mesh is used to the whole flow passage, which consists of several sub-domains: entrance, casing, stay vanes + guide vanes, guide section, runner and draft tube. And variable speed sliding mesh technique is used to exchange interface flow information between moving part and stationary part, and three-dimensional unstructured dynamic mesh technique is also adopted to ensure mesh quality. Two cases were treated in the simulation of runaway transient characteristics after load rejection: one is the rated operating condition as the initial condition, and the other is the condition at the maximum head. Regarding the runaway speed, the experimental speed is 1.45 times the initial speed and the calculation is 1.47 times the initial for the former case. In the latter case, the experiment and the calculation are 1.67 times and 1.69 times respectively. From these results, it is recognized that satisfactorily prediction will be possible by using the present numerical method. Further, numerical results show that the swirl in the draft-tube flow becomes stronger in the latter part of the transient process so that a vortex rope will occur in the draft tube and its precession will cause the pressure fluctuations which sometimes affect the stability of hydro power system considerably.

Runaway transient simulation of a model Kaplan turbine

Science.gov (United States)

Liu, S.; Zhou, D.; Liu, D.; Wu, Y.; Nishi, M.

2010-08-01

The runaway transient is a typical transient process of a hydro power unit, where the rotational speed of a turbine runner rapidly increases up to the runaway speed under a working head as the guide vanes cannot be closed due to some reason at the load rejection. In the present paper, the characteristics of the runaway transient of a model Kaplan turbine having ns = 479(m-kW) is simulated by using a time-dependent CFD technique where equation of rotational motion of runner, continuity equation and unsteady RANS equations with RNG k-epsilon turbulence model are solved iteratively. In the calculation, unstructured mesh is used to the whole flow passage, which consists of several sub-domains: entrance, casing, stay vanes + guide vanes, guide section, runner and draft tube. And variable speed sliding mesh technique is used to exchange interface flow information between moving part and stationary part, and three-dimensional unstructured dynamic mesh technique is also adopted to ensure mesh quality. Two cases were treated in the simulation of runaway transient characteristics after load rejection: one is the rated operating condition as the initial condition, and the other is the condition at the maximum head. Regarding the runaway speed, the experimental speed is 1.45 times the initial speed and the calculation is 1.47 times the initial for the former case. In the latter case, the experiment and the calculation are 1.67 times and 1.69 times respectively. From these results, it is recognized that satisfactorily prediction will be possible by using the present numerical method. Further, numerical results show that the swirl in the draft-tube flow becomes stronger in the latter part of the transient process so that a vortex rope will occur in the draft tube and its precession will cause the pressure fluctuations which sometimes affect the stability of hydro power system considerably.

Runaway transient simulation of a model Kaplan turbine

International Nuclear Information System (INIS)

Liu, S; Liu, D; Wu, Y; Zhou, D; Nishi, M

2010-01-01

The runaway transient is a typical transient process of a hydro power unit, where the rotational speed of a turbine runner rapidly increases up to the runaway speed under a working head as the guide vanes cannot be closed due to some reason at the load rejection. In the present paper, the characteristics of the runaway transient of a model Kaplan turbine having ns = 479(m-kW) is simulated by using a time-dependent CFD technique where equation of rotational motion of runner, continuity equation and unsteady RANS equations with RNG k-ε turbulence model are solved iteratively. In the calculation, unstructured mesh is used to the whole flow passage, which consists of several sub-domains: entrance, casing, stay vanes + guide vanes, guide section, runner and draft tube. And variable speed sliding mesh technique is used to exchange interface flow information between moving part and stationary part, and three-dimensional unstructured dynamic mesh technique is also adopted to ensure mesh quality. Two cases were treated in the simulation of runaway transient characteristics after load rejection: one is the rated operating condition as the initial condition, and the other is the condition at the maximum head. Regarding the runaway speed, the experimental speed is 1.45 times the initial speed and the calculation is 1.47 times the initial for the former case. In the latter case, the experiment and the calculation are 1.67 times and 1.69 times respectively. From these results, it is recognized that satisfactorily prediction will be possible by using the present numerical method. Further, numerical results show that the swirl in the draft-tube flow becomes stronger in the latter part of the transient process so that a vortex rope will occur in the draft tube and its precession will cause the pressure fluctuations which sometimes affect the stability of hydro power system considerably.

Optimization of Hydraulic Machinery Bladings by Multilevel CFD Techniques

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Thum Susanne

2005-01-01

Full Text Available The numerical design optimization for complex hydraulic machinery bladings requires a high number of design parameters and the use of a precise CFD solver yielding high computational costs. To reduce the CPU time needed, a multilevel CFD method has been developed. First of all, the 3D blade geometry is parametrized by means of a geometric design tool to reduce the number of design parameters. To keep geometric accuracy, a special B-spline modification technique has been developed. On the first optimization level, a quasi-3D Euler code (EQ3D is applied. To guarantee a sufficiently accurate result, the code is calibrated by a Navier-Stokes recalculation of the initial design and can be recalibrated after a number of optimization steps by another Navier-Stokes computation. After having got a convergent solution, the optimization process is repeated on the second level using a full 3D Euler code yielding a more accurate flow prediction. Finally, a 3D Navier-Stokes code is applied on the third level to search for the optimum optimorum by means of a fine-tuning of the geometrical parameters. To show the potential of the developed optimization system, the runner blading of a water turbine having a specific speed n q = 41 1 / min was optimized applying the multilevel approach.

A full three dimensional Navier-Stokes numerical simulation of flow field inside a power plant Kaplan turbine using some model test turbine hill chart points

Science.gov (United States)

Hosseinalipour, S. M.; Raja, A.; Hajikhani, S.

2012-06-01

A full three dimensional Navier - Stokes numerical simulation has been performed for performance analysis of a Kaplan turbine which is installed in one of the Irans south dams. No simplifications have been enforced in the simulation. The numerical results have been evaluated using some integral parameters such as the turbine efficiency via comparing the results with existing experimental data from the prototype Hill chart. In part of this study the numerical simulations were performed in order to calculate the prototype turbine efficiencies in some specific points which comes from the scaling up of the model efficiency that are available in the model experimental Hill chart. The results are very promising which shows the good ability of the numerical techniques for resolving the flow characteristics in these kind of complex geometries. A parametric study regarding the evaluation of turbine performance in three different runner angles of the prototype is also performed and the results are cited in this paper.

Proceedings of the 1991 national conference on hydraulic engineering

International Nuclear Information System (INIS)

Shane, R.M.

1991-01-01

This book contains the proceedings of the 1991 National Conference of Hydraulic Engineering. The conference was held in conjunction with the International Symposium on Ground Water and a Software Exchange that facilitated exchange of information on recent software developments of interest to hydraulic engineers. Also included in the program were three mini-symposia on the Exclusive Economic Zone, Data Acquisition, and Appropriate Technology. Topics include sedimentation; appropriate technology; exclusive economic zone hydraulics; hydraulic data acquisition and display; innovative hydraulic structures and water quality applications of hydraulic research, including the hydraulics of aerating turbines; wetlands; hydraulic and hydrologic extremes; highway drainage; overtopping protection of dams; spillway design; coastal and estuarine hydraulics; scale models; computation hydraulics; GIS and expert system applications; watershed response to rainfall; probabilistic approaches; and flood control investigations

Performance of a direct drive hydro turbine for wave power generation

Energy Technology Data Exchange (ETDEWEB)

Lee, Y-H; Kim, C-G [Division of Mechanical and Information Engineering, Korea Maritime University Dongsam-dong 1, Youngdo-ku, Busan, 606-791 (Korea, Republic of); Choi, Y-D; Kim, I-S [Department of Mechanical Engineering, Mokpo National University Muan-ro 560, Chunggye-myun, Jeonnam, 534-729 (Korea, Republic of); Hwang, Y-C, E-mail: lyh@hhu.ac.k [R and D Institute, Shinhan Precision Co. Ltd. Gomo-ri 313, Jinle-myun, Kimhae, 621-881 (Korea, Republic of)

2010-08-15

Clean and renewable energy technologies using ocean energy give us non-polluting alternatives to fossil-fueled power plants as a countermeasure against the global warming and growing demand for electrical energy. Among the ocean energy resources, wave power takes a growing interest because of its enormous amount of potential energy in the world. Therefore, various types of wave power system to capture the energy of ocean waves have been developed. However, suitable turbine type is not normalized yet because of relatively low efficiency of the turbine systems. The purpose of this study is to investigate the performance of a newly developed direct drive hydro turbine (DDT), which will be built in a caisson for wave power plant. Experiment and CFD analysis are conducted to clarify the turbine performance and internal flow characteristics. The results show that the DDT obtains fairly good turbine efficiency in both cases of with wave and no wave conditions. As the turbine performance is influenced considerably by the wave condition, designed point of the turbine should be determined according to the wave condition at an expected installation site. Most of the output power generates at the runner passage of the Stage 2.

Numerical study of similarity in prototype and model pumped turbines

International Nuclear Information System (INIS)

Li, Z J; Wang, Z W; Bi, H L

2014-01-01

Similarity study of prototype and model pumped turbines are performed by numerical simulation and the partial discharge case is analysed in detail. It is found out that in the RSI (rotor-stator interaction) region where the flow is convectively accelerated with minor flow separation, a high level of similarity in flow patterns and pressure fluctuation appear with relative pressure fluctuation amplitude of model turbine slightly higher than that of prototype turbine. As for the condition in the runner where the flow is convectively accelerated with severe separation, similarity fades substantially due to different topology of flow separation and vortex formation brought by distinctive Reynolds numbers of the two turbines. In the draft tube where the flow is diffusively decelerated, similarity becomes debilitated owing to different vortex rope formation impacted by Reynolds number. It is noted that the pressure fluctuation amplitude and characteristic frequency of model turbine are larger than those of prototype turbine. The differences in pressure fluctuation characteristics are discussed theoretically through dimensionless Navier-Stokes equation. The above conclusions are all made based on simulation without regard to the penstock response and resonance

LDA measurements in the Francis-99 draft tube cone

International Nuclear Information System (INIS)

Sundstrom, L R J; Amiri, K; Cervantes, M J; Bergan, C; Dahlhaug, O G

2014-01-01

Velocity measurements were performed in the draft tube cone of a 1:5.1 scaled model of the Tokke hydropower plant, Norway; also known as the Francis-99 model. Results from the laser Doppler anemometry measurements undertaken at three operating points will be used as validation data for an upcoming workshop on the state of the art of Francis turbine numerical simulation. With the turbine operating at the best efficiency point, a sensitivity analysis of the flow parameters head, flow rate and runner rotational speed shows that the effects on the dimensionless velocity profiles are small as long as n ED and Q ED are held constant. The results indicate a well-functioning turbine at the best efficiency point and high load. At the part load operating point, a vortex breakdown occurs which distorts the velocity profiles and significantly lowers the turbine's hydraulic efficiency. Frequency spectrums of each LDA signal at part load reveals a peak which is asynchronous to that of the runner angular speed. The peaks might be related to the precession of a rotating vortex rope but the characteristics of the LDA signals are different compared to previous studies involving rotating vortex ropes

Unsteady flow simulations of Pelton turbine at different rotational speeds

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Minsuk Choi

2015-11-01

Full Text Available This article presents numerical simulations of a small Pelton turbine suitable for desalination system. A commercial flow solver was adopted to resolve difficulties in the numerical simulation for Pelton turbine such as the relative motion of the turbine runner to the injector and two-phase flow of water and air. To decrease the numerical diffusion of the water jet, a new topology with only hexagonal mesh was suggested for the computational mesh around the complex geometry of a bucket. The predicted flow coefficient, net head coefficient, and overall efficiency showed a good agreement with the experimental data. Based on the validation of the numerical results, the pattern of wet area on the bucket inner surface has been analyzed at different rotational speeds, and an attempt to find the connection between rotational speeds, torque, and efficiency has been made.

Effect of size and concentration of silt particles on erosion of Pelton turbine buckets

Energy Technology Data Exchange (ETDEWEB)

Padhy, M.K.; Saini, R.P. [Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, Roorkee (India)

2009-10-15

Erosive wear of hydro turbine runners depends upon different parameters such as size, hardness and concentration of silt particles, velocity of flow, properties of the base material of the turbine components and operating hours of the turbine. Various researchers have conducted experiments to study the effect of these parameters on erosive wear. Most of these experiments were on small-size samples at different types of test rigs to simulate the flow conditions in turbines, however actual flow conditions and the phenomenon of erosive wear are too complex to simulate. Under the present study, effect of these parameters on erosion in actual conditions has been investigated experimentally. An extensive experimental study has been carried out on a small scale Pelton turbine. Based on the experimental data collected for different parameters, correlations have been developed for wear rate of Pelton turbine buckets as a function of critical parameters, i.e., size and concentration of silt particles and jet velocity. (author)

Fat intake and injury in female runners

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Leddy John J

2008-01-01

Full Text Available Abstract Background Our purpose was to determine the relationship between energy intake, energy availability, dietary fat and lower extremity injury in adult female runners. We hypothesized that runners who develop overuse running-related injuries have lower energy intakes, lower energy availability and lower fat intake compared to non-injured runners. Methods Eighty-six female subjects, running a minimum of 20 miles/week, completed a food frequency questionnaire and informed us about injury incidence over the next year. Results Injured runners had significantly lower intakes of total fat (63 ± 20 vs. 80 ± 50 g/d and percentage of kilocalories from fat (27 ± 5 vs. 30 ± 8 % compared with non-injured runners. A logistic regression analysis found that fat intake was the best dietary predictor, correctly identifying 64% of future injuries. Lower energy intake and lower energy availability approached, but did not reach, a significant association with overuse injury in this study. Conclusion Fat intake is likely associated with injury risk in female runners. By documenting these associations, better strategies can be developed to reduce running injuries in women.

Very Low Head Turbine Deployment in Canada

International Nuclear Information System (INIS)

Kemp, P; Williams, C; Sasseville, Remi; Anderson, N

2014-01-01

The Very Low Head (VLH) turbine is a recent turbine technology developed in Europe for low head sites in the 1.4 - 4.2 m range. The VLH turbine is primarily targeted for installation at existing hydraulic structures to provide a low impact, low cost, yet highly efficient solution. Over 35 VLH turbines have been successfully installed in Europe and the first VLH deployment for North America is underway at Wasdell Falls in Ontario, Canada. Deployment opportunities abound in Canada with an estimated 80,000 existing structures within North America for possible low-head hydro development. There are several new considerations and challenges for the deployment of the VLH turbine technology in Canada in adapting to the hydraulic, environmental, electrical and social requirements. Several studies were completed to determine suitable approaches and design modifications to mitigate risk and confirm turbine performance. Diverse types of existing weirs and spillways pose certain hydraulic design challenges. Physical and numerical modelling of the VLH deployment alternatives provided for performance optimization. For this application, studies characterizing the influence of upstream obstacles using water tunnel model testing as well as full-scale prototype flow dynamics testing were completed. A Cold Climate Adaptation Package (CCA) was developed to allow year-round turbine operation in ice covered rivers. The CCA package facilitates turbine extraction and accommodates ice forces, frazil ice, ad-freezing and cold temperatures that are not present at the European sites. The Permanent Magnet Generator (PMG) presents some unique challenges in meeting Canadian utility interconnection requirements. Specific attention to the frequency driver control and protection requirements resulted in a driver design with greater over-voltage capability for the PMG as well as other key attributes. Environmental studies in Europe included fish friendliness testing comprised of multiple in

Very Low Head Turbine Deployment in Canada

Science.gov (United States)

Kemp, P.; Williams, C.; Sasseville, Remi; Anderson, N.

2014-03-01

The Very Low Head (VLH) turbine is a recent turbine technology developed in Europe for low head sites in the 1.4 - 4.2 m range. The VLH turbine is primarily targeted for installation at existing hydraulic structures to provide a low impact, low cost, yet highly efficient solution. Over 35 VLH turbines have been successfully installed in Europe and the first VLH deployment for North America is underway at Wasdell Falls in Ontario, Canada. Deployment opportunities abound in Canada with an estimated 80,000 existing structures within North America for possible low-head hydro development. There are several new considerations and challenges for the deployment of the VLH turbine technology in Canada in adapting to the hydraulic, environmental, electrical and social requirements. Several studies were completed to determine suitable approaches and design modifications to mitigate risk and confirm turbine performance. Diverse types of existing weirs and spillways pose certain hydraulic design challenges. Physical and numerical modelling of the VLH deployment alternatives provided for performance optimization. For this application, studies characterizing the influence of upstream obstacles using water tunnel model testing as well as full-scale prototype flow dynamics testing were completed. A Cold Climate Adaptation Package (CCA) was developed to allow year-round turbine operation in ice covered rivers. The CCA package facilitates turbine extraction and accommodates ice forces, frazil ice, ad-freezing and cold temperatures that are not present at the European sites. The Permanent Magnet Generator (PMG) presents some unique challenges in meeting Canadian utility interconnection requirements. Specific attention to the frequency driver control and protection requirements resulted in a driver design with greater over-voltage capability for the PMG as well as other key attributes. Environmental studies in Europe included fish friendliness testing comprised of multiple in

Runner's Knee

Science.gov (United States)

... require a lot of knee bending, such as biking, jumping, or skiing. Runner's knee happens when the ... is out of alignment, activities like running or biking can wear down the cartilage of the kneecap ( ...

Improvement of automatic control systems of high-power turbines of PAO tubroatom for nuclear power plants

Science.gov (United States)

Shvetsov, V. L.; Babaev, I. N.

2017-09-01

The main technical solutions applied by PAO Turboatom used as the compensatory measures at the increase of the period of nonstop operation of nuclear power plants' (NPP) turbines with VVER-1000 type reactors up to 18 months are (1) replacing the standard hydraulic speed controller with an electronic one, (2) introduction of overclocking protection, (3) modernization of units of stop-control valves of high pressures, (4) installation of locking dampers on the receiver tubes of turbines of the first and second modification, and (5) improving the quality of repairs by reviewing the requirements for their implementation. The introduction of complex diagnostics of a control system on the basis of automatic treatment of results of registration of working parameters of the turbine is allocated as a separate prospective direction. Using an electronic controller of speed makes it possible to simplify the procedure of its inclusion in work at the failure of an electro-hydraulic system of control and vice versa. The regimes of maintaining the turbine rotor speed, steam pressure on the outlet of turbine, and the positions of main servomotors were introduced into the functions of the electronic controller. An electronic controller of speed includes its own electro-hydraulic transducer, turbine rotor speed sensor, and sensors of the position of main servomotors. Into the functions of electro- hydraulic control system and electronic speed controller, the function of overclocking protection, which determines the formation of commands for stopping the turbine at the exceeding of both the defined level of rotation speed and the defined combination of achieved rotation speed and angular acceleration of rotor, was introduced. To simplify the correction of forces acting on the control valve cups, the design of the cups was changed, and it has the profiled inserts. The solutions proposed were implemented on K-1100-60/1500-2M turbines of Rostov NPP. From the composition of control system

PERANCANGAN MODEL AIR ALIRAN SILANG (CROSS FLOW TURBINE DENGAN HEAD 2 m DAN DEBIT 0,03 m3/s

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Ridwan Ridwan

2017-01-01

Full Text Available Pembangkit listrik tenaga mikrohidro merupakan pembangkit listrik skala kecil yang menggunakan air sebagai penggeraknya dan penggerak mula adalah turbin. Sistem pembangkit ini sangat tepat digunakan di pedesaan karena sistem ini mudah dibuat, menghasilkan daya listrik yang cukup besar dan biaya pembuatan yang lebih relatif murah. Atas dasar diatas maka perlu dirancang suatu turbin yang mendukung sistem pembangkit ini, diantaranya adalah Turbin Aliran Silang. Untuk merancang sebuah turbin air agar tidak terjadi kesalahan dalam perancangan (seperti hal-nya biaya pembuatannya maka dilakukan perancangan prototipenya. Sebuah prototipe Turbin Aliran Silang dirancang dalam kegiatan tugas akhir ini dengan debit (Q = 0,03  m3/s, head (H = 2 m dengan efisiensi 0,80. Spesifikasi teknik utama dari hasil perancangan turbin adalah diameter runner (D = 0,195 m dengan putaran turbin 281,39 rpm daya keluaran efektif sebesar 470,4 W.

Runners with Patellofemoral Pain Exhibit Greater Peak Patella Cartilage Stress Compared to Pain-Free Runners.

Science.gov (United States)

Liao, Tzu-Chieh; Keyak, Joyce H; Powers, Christopher M

2018-02-27

The purpose of this study is to determine whether recreational runners with patellofemoral pain (PFP) exhibit greater peak patella cartilage stress compared to pain-free runners. A secondary purpose was to determine the kinematic and/or kinetic predictors of peak patella cartilage stress during running. Twenty-two female recreational runners participated (12 with PFP and 10 pain-free controls). Patella cartilage stress profiles were quantified using subject-specific finite element models simulating the maximum knee flexion angle during stance phase of running. Input parameters to the finite element model included subject-specific patellofemoral joint geometry, quadriceps muscle forces, and lower extremity kinematics in the frontal and transverse planes. Tibiofemoral joint kinematics and kinetics were quantified to determine the best predictor of stress using stepwise regression analysis. Compared to the pain-free runners, those with PFP exhibited greater peak hydrostatic pressure (PFP vs. control, 21.2 ± 5.6 MPa vs. 16.5 ± 4.6 MPa) and maximum shear stress (11.3 ± 4.6 MPa vs. 8.7 ± 2.3 MPa). Knee external rotation was the best predictor of peak hydrostatic pressure and peak maximum shear stress (38% and 25% of variances, respectively) followed by the knee extensor moment (21% and 25% of variances, respectively). Runners with PFP exhibit greater peak patella cartilage stress during running compared to pain-free individuals. The combination of knee external rotation and a high knee extensor moment best predicted elevated peak stress during running.

The Influence of runner system on production of injection molds

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Janostik Vaclav

2016-01-01

Full Text Available This experimental study describes the influence of runner system on rheological properties during the injection molding process. Economic effects on the amount of production are discussed as well. Autodesk Moldflow Synergy 2016 (Moldflow was used for the study of the injection process. Three suggestions of the runner system, cold runner system, hot runner system and the combination of cold–hot runner system have been promoted. These three variants underwent the rheological and economic analysis. As a result, recommendations for the application of the runner system for the required amount of production have been suggested

Monitoring of Rotor-Stator Interaction in Pump-Turbine Using Vibrations Measured with On-Board Sensors Rotating with Shaft

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Cristian G. Rodriguez

2014-01-01

Full Text Available Current trends in design of pump-turbines have led into higher rotor-stator interaction (RSI loads over impeller-runner. These dynamic loads are of special interest having produced catastrophic failures in pump-turbines. Determining RSI characteristics facilitates the proposal of actions that will prevent these failures. Pressure measurements all around the perimeter of the impeller-runner are appropriate to monitor and detect RSI characteristics. Unfortunately most installed pump-turbines are not manufactured with in-built pressure sensors in appropriate positions to monitor RSI. For this reason, vibration measurements are the preferred method to monitor RSI in industry. Usually vibrations are measured in two perpendicular radial directions in bearings where valuable information could be lost due to bearing response. In this work, in order to avoid the effect of bearing response on measurement, two vibration sensors are installed rotating with the shaft. The RSI characteristics obtained with pressure measurements were compared to those determined using vibration measurements. The RSI characteristics obtained with pressure measurements were also determined using vibrations measured rotating with shaft. These RSI characteristics were not possible to be determined using the vibrations measured in guide bearing. Finally, it is recommended to measure vibrations rotating with shaft to detect RSI characteristics in installed pump-turbines as a more practical and reliable method to monitor RSI characteristics.

The flow field investigations of no load conditions in axial flow fixed-blade turbine

Science.gov (United States)

Yang, J.; Gao, L.; Wang, Z. W.; Zhou, X. Z.; Xu, H. X.

2014-03-01

During the start-up process, the strong instabilities happened at no load operation in a low head axial flow fixed-blade turbine, with strong pressure pulsation and vibration. The rated speed can not reach until guide vane opening to some extent, and stable operation could not be maintained under the rated speed at some head, which had a negative impact on the grid-connected operation of the unit. In order to find the reason of this phenomenon, the unsteady flow field of the whole flow passage at no load conditions was carried out to analyze the detailed fluid field characteristics including the pressure pulsation and force imposed on the runner under three typical heads. The main hydraulic cause of no load conditions instability was described. It is recommended that the power station should try to reduce the no-load running time and go into the high load operation as soon as possible when connected to grid at the rated head. Following the recommendations, the plant operation practice proved the unstable degree of the unit was reduced greatly during start up and connect to the power grid.

Design of hydraulic recuperation unit

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Jandourek Pavel

2016-01-01

Full Text Available This article deals with design and measurement of hydraulic recuperation unit. Recuperation unit consist of radial turbine and axial pump, which are coupled on the same shaft. Speed of shaft with impellers are 6000 1/min. For economic reasons, is design of recuperation unit performed using commercially manufactured propellers.

Master equation and runaway speed of the Francis turbine

Science.gov (United States)

Zhang, Zh.

2018-04-01

The master equation of the Francis turbine is derived based on the combination of the angular momentum (Euler) and the energy laws. It relates the geometrical design of the impeller and the regulation settings (guide vane angle and rotational speed) to the discharge and the power output. The master equation, thus, enables the complete characteristics of a given Francis turbine to be easily computed. While applying the energy law, both the shock loss at the impeller inlet and the swirling loss at the impeller exit are taken into account. These are main losses which occur at both the partial load and the overloads and, thus, dominantly influence the characteristics of the Francis turbine. They also totally govern the discharge of the water through the impeller when the impeller is found in the standstill. The computations have been performed for the discharge, the hydraulic torque and the hydraulic efficiency. They were also compared with the available measurements on a model turbine. Excellent agreement has been achieved. The computations also enable the runaway speed of the Francis turbine and the related discharge to be determined as a function of the setting angle of the guide vanes.

The Design of High Efficiency Crossflow Hydro Turbines: A Review and Extension

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Ram Adhikari

2018-01-01

Full Text Available Efficiency is a critical consideration in the design of hydro turbines. The crossflow turbine is the cheapest and easiest hydro turbine to manufacture and so is commonly used in remote power systems for developing countries. A longstanding problem for practical crossflow turbines is their lower maximum efficiency compared to their more advanced counterparts, such as Pelton and Francis turbines. This paper reviews the experimental and computational studies relevant to the design of high efficiency crossflow turbines. We concentrate on the studies that have contributed to designs with efficiencies in the range of 88–90%. Many recent studies have been conducted on turbines of low maximum efficiency, which we believe is due to misunderstanding of design principles for achieving high efficiencies. We synthesize the key results of experimental and computational fluid dynamics studies to highlight the key fundamental design principles for achieving efficiencies of about 90%, as well as future research and development areas to further improve the maximum efficiency. The main finding of this review is that the total conversion of head into kinetic energy in the nozzle and the matching of nozzle and runner designs are the two main design requirements for the design of high efficiency turbines.

Wicket gate trailing-edge blowing: A method for improving off-design hydroturbine performance by adjusting the runner inlet swirl angle

International Nuclear Information System (INIS)

Lewis, B J; Cimbala, J M; Wouden, A M

2014-01-01

At their best efficiency point (BEP), hydroturbines operate at very high efficiency. However, with the ever-increasing penetration of alternative electricity generation, it has become common to operate hydroturbines at off-design conditions in order to maintain stability in the electric power grid. This paper demonstrates a method for improving hydroturbine performance during off-design operation by injecting water through slots at the trailing edges of the wicket gates. The injected water causes a change in bulk flow direction at the inlet of the runner. This change in flow angle from the wicket gate trailing-edge jets provides the capability of independently varying the flow rate and swirl angle through the runner, which in current designs are both determined by the wicket gate opening angle. When properly tuned, altering the flow angle results in a significant improvement in turbine efficiency during off-design operation

Wicket gate trailing-edge blowing: A method for improving off-design hydroturbine performance by adjusting the runner inlet swirl angle

Science.gov (United States)

Lewis, B. J.; Cimbala, J. M.; Wouden, A. M.

2014-03-01

At their best efficiency point (BEP), hydroturbines operate at very high efficiency. However, with the ever-increasing penetration of alternative electricity generation, it has become common to operate hydroturbines at off-design conditions in order to maintain stability in the electric power grid. This paper demonstrates a method for improving hydroturbine performance during off-design operation by injecting water through slots at the trailing edges of the wicket gates. The injected water causes a change in bulk flow direction at the inlet of the runner. This change in flow angle from the wicket gate trailing-edge jets provides the capability of independently varying the flow rate and swirl angle through the runner, which in current designs are both determined by the wicket gate opening angle. When properly tuned, altering the flow angle results in a significant improvement in turbine efficiency during off-design operation.

Increasing hydro turbine operation range and efficiencies using water injection in draft tubes

Energy Technology Data Exchange (ETDEWEB)

Francke, Haakon Hjort

2010-09-15

It is a well known fact that most Francis turbines, because of the fixed blade design, faces challenges when running at partial load operation. Especially in the operating range below approximately 50 % of the rated output, it is common to observe severe pressure pulsations and surge in the draft tube. These pressure fluctuations are believed to be related to the swirling flow exiting the runner. By using water jets in the draft tube cone directed towards the swirling flow, the swirl strength is believed to be reduced and thereby also the pressure fluctuations produced by the swirl. This system thus has a potential of increasing the turbine operating range. The system can be activated when needed, and will not affect the turbine when running at its best efficiency point.Based on the main hypothesis, a simplified swirl rig was designed and constructed in order to investigate the nozzle influence on the swirling flow and on the pressure pulsations in a simplified environment. To expand the understanding of the nozzle performance in a Francis turbine, experiments were conducted in a model turbine with a prototype of movable nozzles. To establish a link between laboratory nozzle measurements and full scale nozzle measurements, field measurements were carried out on full scale Francis turbines running at partial discharge. For this purpose the turbines installed at Skarsfjord Power Station and Skibotn Power Station were used, where full scale nozzle injection systems were installed. The test results suggested that the concept of water injection worked, but not unconditionally. A reduction in pressure fluctuations was achieved both in laboratory and field experiments, as well as a noticeable reduction regarding fluctuations in the shaft run-out at Skibotn. In addition, water injection gave a surprisingly positive effect at overload conditions in the model turbine, even though the nozzle angle was directed in the same direction as the overload swirl. Ideally, the results

Infectious episodes in runners before and after a roadrace.

Science.gov (United States)

Nieman, D C; Johanssen, L M; Lee, J W

1989-09-01

Various researchers have implied that regular and moderate exercise training may improve the ability of the immune system to protect the host from infection. In contrast, acute, maximal, and exhaustive exercise may have negative effects of the immune system. This study compared the incidence of infectious episodes in 273 runners during a two month training period prior to a 5 K, 10 K, or half-marathon race. In addition, the effect of the race experience on infectious episodes was studied. Twenty-five percent of the runners training more than 15 miles per week reported at least one infectious episode as compared with 34.3% of runners training less than 15 miles per week (p = 0.09). Only 6.8% of the runners preparing for the half-marathon race reported becoming sick with the flu versus 17.9% of the 5 K and 10 K runners (p = 0.067). During the week following the roadrace, runners did not report an increase in infectious episodes as compared to the week prior to the race. These trends suggest that runners with a more serious commitment to regular exercise may experience less infectious episodes than recreational runners because of both direct and indirect affects on immunosurveillance. In addition, the stressful race experience does not appear to increase risk of acquiring an acute respiratory infection.

PERFORMANCE OPTIMIZATION OF AN ORGANIC MUD AGITATOR SCREW

Directory of Open Access Journals (Sweden)

Mircea Dimitrie CAZACU

2009-11-01

Full Text Available Due to the special performances obtained by means of the optimisation method applied to the axial runners of run-of-river hydraulic turbines and of wind turbines, as well as in the case of the screws for boat propulsion, perfected by the first of the authors [1] - [10], in this work one extend the application of this method at the case of an organic mud agitator screw for fermentation and biogas production. One presents the obtaining of the bio liquid circulation minimal velocity in the two possible cases [3]: extracting the fluid velocity from the peripheral force exerted by the runner, as well as from the mechanical power consumed for its driving. After the obtaining of the optimal relative peripheral angle one determines also the optimal incidence angles of the profile for other blade radii. This method permits in the same time to find the optimal profile, using the multitude of the profile characteristics, experimentally studied.

The main features of control and operation of steam turbines at nuclear power plants

International Nuclear Information System (INIS)

Czinkoczky, B.

1981-01-01

The output and speed control of steam turbines at nuclear power plants as well as the combination of both controls are reviewed and evaluated. At the same time the tasks of unit control at nuclear power plants, the control of steady main steam pressure and medium pressure of primary circuit, further the connection of reactor and turbine controls and the self-controlling properties of pressurized water reactor are dealt with. Hydraulic and electro-hydraulic speed control, the connection of cach-up dampers and speed control and the application of electro-hydraulic signal converters are discussed. The accomplishment of protection is also described. (author)

Experimental investigation of the turbine instability of a pump-turbine during synchronization

International Nuclear Information System (INIS)

Guggenberger, M; Senn, F; Schiffer, J; Jaberg, H; Gentner, C; Sallaberger, M; Widmer, C

2014-01-01

Although the technology of pump-turbines is generally well known the operation is still affected by flow phenomena that are quite complex and not fully understood. One of these phenomena is the S-shape instability which occurs in turbine mode at low load operation, close to runaway conditions. The instability results in an S-shape of the turbine characteristics and complicates the synchronization of the machine. Numerical investigations performed in the past indicated that the occurrence of turbine instabilities is connected with the appearance of rotor-stator interactions, and backflow regions in the vane less space between guide vane and impeller. This paper presents the results and conclusions of experimental investigations of pump-turbine instabilities carried out to find a practical explanation for the flow phenomena responsible for the appearance of the S-shaped characteristics. In the scope of a joint research project with Andritz Hydro, the Institute for Hydraulic Fluidmachinery at Graz University of Technology optimized an existing 4-quadrant test rig for an experimental investigation at off design conditions featuring the possibility for adjusting stable operation of instabilities. All the experimental investigations were based on IEC60193-standard using a pump turbine model provided by Andritz Hydro AG. In addition to the standard measurements of flow rate, head and efficiency the interaction between model and its hydraulic environment were analysed by dynamic pressure sensors. Additional pressure sensors integrated in the guide vane apparatus were used to investigate pressure distributions in the model. Particle Image Velocimetry (PIV) allowed the measurement of the velocity field in the vane less space between impeller and guide vanes and in the environment of two single guide vanes. The experimental investigations were focused on operation points in the S-shape region of the characteristics. For each operation point 190 double images for 20 rotor

Proceedings of transient thermal-hydraulics and coupled vessel and piping system responses 1991

International Nuclear Information System (INIS)

Wang, G.Y.; Shin, Y.W.; Moody, F.J.

1991-01-01

This book reports on transient thermal-hydraulics and coupled vessel and piping system responses. Topics covered include: nuclear power plant containment designs; analysis of control rods; gate closure of hydraulic turbines; and shock wave solutions for steam water mixtures in piping systems

A reference Pelton turbine design

International Nuclear Information System (INIS)

Solemslie, B W; Dahlhaug, O G

2012-01-01

The designs of hydraulic turbines are usually close kept corporation secrets. Therefore, the possibility of innovation and co-operation between different academic institutions regarding a specific turbine geometry is difficult. A Ph.D.-project at the Waterpower Laboratory, NTNU, aim to design several model Pelton turbines where all measurements, simulations, the design strategy, design software in addition to the physical model will be available to the public. In the following paper a short description of the methods and the test rig that are to be utilized in the project are described. The design will be based on empirical data and NURBS will be used as the descriptive method for the turbine geometry. In addition CFX and SPH simulations will be included in the design process. Each turbine designed and produced in connection to this project will be based on the experience and knowledge gained from the previous designs. The first design will be based on the philosophy to keep a near constant relative velocity through the bucket.

A reference Pelton turbine design

Science.gov (United States)

Solemslie, B. W.; Dahlhaug, O. G.

2012-09-01

The designs of hydraulic turbines are usually close kept corporation secrets. Therefore, the possibility of innovation and co-operation between different academic institutions regarding a specific turbine geometry is difficult. A Ph.D.-project at the Waterpower Laboratory, NTNU, aim to design several model Pelton turbines where all measurements, simulations, the design strategy, design software in addition to the physical model will be available to the public. In the following paper a short description of the methods and the test rig that are to be utilized in the project are described. The design will be based on empirical data and NURBS will be used as the descriptive method for the turbine geometry. In addition CFX and SPH simulations will be included in the design process. Each turbine designed and produced in connection to this project will be based on the experience and knowledge gained from the previous designs. The first design will be based on the philosophy to keep a near constant relative velocity through the bucket.

Running, Being, and Beijing—An Existential Exploration of a Runner Identity

DEFF Research Database (Denmark)

Ronkainen, Noora; Harrison, Marlen Elliot; Ryba, Tatiana

2014-01-01

In this research, we explore the negotiation of a conflicted runner identity in a Finnish runner's short-term migration to Beijing, China. We examine the historical and cultural construction of the runner identity and discuss the current discourses that constitute the modern runner subjectivities...... and migration studies as well as practical considerations for the use of autoethnography in psychological research and practice.......In this research, we explore the negotiation of a conflicted runner identity in a Finnish runner's short-term migration to Beijing, China. We examine the historical and cultural construction of the runner identity and discuss the current discourses that constitute the modern runner subjectivities....... From there, we continue with a Heideggerian existential-phenomenological analysis of the ‘boundary situation’ when the project of competitive running is challenged due to environmental and cultural barriers in the migration. Our empirical inquiry is based on the first author's autoethnographic account...

Experimental Hydro-Mechanical Characterization of Full Load Pressure Surge in Francis Turbines

Science.gov (United States)

Müller, A.; Favrel, A.; Landry, C.; Yamamoto, K.; Avellan, F.

2017-04-01

Full load pressure surge limits the operating range of hydro-electric generating units by causing significant power output swings and by compromising the safety of the plant. It appears during the off-design operation of hydraulic machines, which is increasingly required to regulate the broad integration of volatile renewable energy sources into the existing power network. The underlying causes and governing physical mechanisms of this instability were investigated in the frame of a large European research project and this paper documents the main findings from two experimental campaigns on a reduced scale model of a Francis turbine. The multi-phase flow in the draft tube is characterized by Particle Image Velocimetry, Laser Doppler Velocimetry and high-speed visualizations, along with synchronized measurements of the relevant hydro-mechanical quantities. The final result is a comprehensive overview of how the unsteady draft tube flow and the mechanical torque on the runner shaft behave during one mean period of the pressure oscillation, thus defining the unstable fluid-structure interaction responsible for the power swings. A discussion of the root cause is initiated, based on the state of the art. Finally, the latest results will enable a validation of recent RANS flow simulations used for determining the key parameters of hydro-acoustic stability models.

Hydroscoop - Bulletin of the small-scale hydraulic laboratory MHyLab; Hydroscoop - Bulletin d'information MHyLab laboratoire de petite hydraulique

Energy Technology Data Exchange (ETDEWEB)

Denis, V.

2009-07-01

This is issue Nr. 5 of the news bulletin of MHyLab, the small-scale hydraulic laboratory in Montcherand, Switzerland. The history of MHyLab development is recalled. The objective of the laboratory is given: the laboratory development of efficient and reliable turbines for the entire small-scale hydraulic range (power: 10 to 2000 kW, flow rate: 0.01 to 10 m{sup 3}/s, hydraulic head: 1 m up to more than 700 m). The first period (1997-2001) was devoted to Pelton turbines for high heads (60 to 70 m) and the second (2001-2009) to Kaplan turbines for low and very low heads (1 to 30 m). In the third period (beginning 2008) diagonal turbines for medium heads (25 to 100 m) are being developed. MHyLab designed, modelled and tested all these different types. The small-scale hydraulic market developed unexpectedly quickly. The potential of small-scale hydraulics in the Canton of Vaud, western Switzerland is presented. Three implemented projects are reported on as examples for MHyLab activities on the market place. The MHyLab staff is presented.

CFD Modelling of a Pump as Turbine (PAT with Rounded Leading Edge Impellers for Micro Hydro Systems

Directory of Open Access Journals (Sweden)

Ismail Mohd Azlan

2017-01-01

Full Text Available A Pump as Turbine (PAT is one of micro hydro system components that is used to substitute a commercially available turbine due to its wide availability and low acquisition cost. However, PAT have high hydraulic losses due to differences in pump-turbine operation and hydraulic design. The fluid flowing inside the PAT is subjected to hydraulic losses due to the longer flow passage and unmatched fluid flow within the wall boundaries. This paper presents the effect of rounding the impeller leading edges of the pump on turbine performance. A CFD model of a PAT was designed to simulate virtual performance for the analysis. The aim of this study is to observe the internal hydraulic performance resulting from the changes in the performance characteristics. Highest efficiency was recorded at 17.0 l/s, an increase of 0.18%. The simulation results reveal that there is an improvement in hydraulic performance at overflow operation. The velocity vector visualization shows that there is a reduction in wake and consequently less flow separation along impeller flow passages. However, adjusting the sensitive impeller inlet geometry will also alter the velocity inlet vector and consequently change the velocity triangles for the turbo machinery system.