München, Techn. Universiẗat, Diss., 2004.

The concept of added hydrodynamic properties such as added mass is of importance in modern hydropower development, mainly for rotor dynamic calculations. Added mass could result in reduced natural frequencies and altered mode compared to existing simulation models. It is of importance to quantify added mass but also added damping to make the simulation models more accurate. Experiments are conducted on a model Kaplan turbine, D = 0,5 m, and a steel cube, S = 0,2 m, for linear vibrations in still water confined in a cylindrical tank. The experiments are conducted in air and water for evaluation of added forces. The vibrations are generated with an electrodynamic vibration exciter with a frequency range of approximately 1-10 Hz with amplitudes 0,5-3 mm. The experiments were repeated to check test rig reliability. Each individual working point [frequency, amplitude] were in total tested 40 times in 15 s intervals. The added mass was found to be function of acceleration for the model Kaplan with an increase in added mass from 10 % at 4 m/s2 to 35 % at 0,5 m/s2. The damping forces was at best measured at ±30 %, making added damping calculations unreliable. The cube experiments resulted in small differences between water and air. Cube results must be interpreted with caution due to test rig uncertainties.

As a consequence of increasing wind power installations in the Nordic grid the last years, the need for regulating power has become larger. In the Nordic grid, regulating power is mainly provided by hydro power. One part of the regulating power is called frequency control, which ensures that the grid frequency is stable and close to 50 Hz. However, setting the turbine into frequency controlled operation may cause stress and wear of the components in the mechanical control system. Frequency controlling implies large and frequent servo forces and longer travelling distance of the sliding bearings in the Kaplan turbine. Based on one selected Kaplan turbine, Selsfors G1, measurements and MATLAB calculations have been performed in order to determine forces and movements of the linkage system. With these forces and movements as input, stresses and fatigue have been determined as well as sliding distances, bearing pressures and wear of bearings during a typical lifetime of 40 years. The results indicate that no severe wear exists on the bearings during 40 years of service. This is valid for Selsfors G1, where self-lubricating greaseless Orkot bearings are installed. The wear is much smaller than the largest allowed bearing clearance, as long as the bearings are mounted correctly and free from dirt and oil. For turbines with grease or oil lubricated bearings, the result might differ. The highest average stresses have been recorded in the links in the runner. A very simple Finite Element Analysis has been made for the links, to estimate risk of fatigue. The stresses are much lower compared to the fatigue limit, and thus the risk of fatigue is considered very small. In situations where wear and large load changes after all are problems, a change in the turbine regulator settings is recommended. A dead band reduces the sliding distances of the bearings and the amount of load changes remarkably, but causes on the other hand lower turbine efficiency and worse quality of the frequency control.

In order to reach climate and environmental goals, Sweden is increasing the implementation of intermittent renewable energy sources such as wind and solar power to the electricity grid. The increase of intermittent energy sources is rising power regulation requirement towards hydropower, which increasingly exposes the hydraulic turbines to high loads and fluctuating hydraulic forces. These conditions affect the turbine’s structural and rotor dynamic behavior, leading to fatigue in turbine components. Identifying the parameters that affect the dynamics of the water turbine is an essential part of analyzing and, if possible, avoiding these situations. Furthermore, accurate rotor dynamic models are necessary to design for a robust hydropower unit and improve the estimate of wear on turbine components. Added parameters (added mass, polar moment of inertia, and damping) are hydrodynamic effects occurring due to interaction between structural vibrations and surrounding fluid. Added parameters can modify the turbine’s natural frequencies and consequently its dynamic behavior. Therefore, it is of interest to study and quantify the impact of these parameters on the turbine for accurate rotor dynamic modeling and turbine design. The added parameters have been investigated by conducting experiments on a model Kaplan runner, for which the project has been divided into two consecutive parts. First, experiments were performed in a test rig, in which the runner was excited in a lateral movement to determine added mass and linear damping. Secondly, experiments were performed in a test rig similar to the first, except the runner was excited in a torsional movement to determine added polar moment of inertia and torsional damping. Force and displacement have been measured during both movements, with the runner placed in air and thereafter in quiescent water. The added parameters were quantified by comparing measurements conducted with the runner in air against those conducted in water. By varying the excitation frequency and amplitude, added parameters have been analyzed against excitation frequency, velocity, and acceleration to determine dependent variables. The dimensionless added mass ratio, γma, was investigated within a range of acceleration of 0.07m/s2 to 5.00 m/s2 and in an excitation frequency of 2-9 Hz. Results exhibited a frequency-dependent added mass ratio, leading to a mass addition variation of 1.00-1.49 times the test rig mass with a mean γma of 1.22. Similarly, the dimensionless added polar moment of inertia, γIp, was investigated within a range of angular acceleration between 2.4 rad/s2 to 29.6 rad/s2 and in an excitation frequency range of 2-10 Hz. The mean added polar inertia ratio, γIp, was obtained as 1.09 times the polar moment of inertia of the test rig, corresponding to an increase in polar inertia of about 9%, compared to the total dry polar inertia of the test rig. Results showed that the added polar inertia ratio varied by approximately 1.8% within the studied frequency range. Thus, no frequency dependence could be determined. Due to measurement uncertainties and limitations of the test rigs, added linear damping and torsional damping could not be determined in either of the existing test rigs (lateral and torsional movement).

This diploma thesis describes design of a new shape of the draft tube for small hydro Katovice with maintaining built dimension. First part of this thesis is devoted to the formulation of the problem, description of basic function of the draft tube, its efficiency and other formulas. In the second part of this thesis the analysis is made for original design supported by CFD calculation. Furthermore a new design of the draft tube is made with comparison of original draft tube.

This master’s thesis solving the issue of planning and management of Kaplan turbine modernization project. The first chapter deals with the basic definition of project management concepts, methods, techniques and tools used in project planning and management. This information forms theoretical basis for the following two chapters, which represent the company in which the turbine modernization project itself will be implemented in the future. The second chapter contains analyzes of external and internal environment of the company and the project. On their basis the third chapter creates a specific proposal for project solution. Results and conclusions of the master’s thesis will allow a better and more detailed understanding of Kaplan turbine modernization implementation project and all associated critical points or potential risks. The work can be beneficial not only for project managers, but also for company management, investors, other companies in the field of engineering and wide audience.

The aim of the present master’s thesis is to explore the feasibility of small hydropower plant for cur-rent hydro energetic potential of the weir on Ohře river, located in the city of Terezín in Ústecký re-gion, Czech Republic. The target of the thesis itself was to design minimally two variants of constructional and technological part. Due to requirements related to maintaining of all functions of the weir construction was decided to design small hydropower plant completely under the water surface, with flap mounted to the roof of the hydropower plant. Part of the thesis was also an economical assessment of designed hydropower project.

La présence de structures de vapeur dans la machine peut provoquer des dommages structurels et altérer les performances de la turbine. Ainsi, l’étude de la cavitation dans les machines hydrauliques est d’un très grand intérêt pour les industriels. Parmi les turbines hydrauliques, les turbines Kaplan sont réputées pour leur flexibilité. En effet, l’ouverture des directrices et la position des aubes de la roue peuvent être régulées en continu pendant l’utilisation de la machine, optimisant son rendement sur une large plage de fonctionnement. En contrepartie, Cela implique la présence de jeux entre les parties fixes et mobiles des turbines Kaplanà qui conduit à des structures de cavitation supplémentaires à ce niveau des machines. Dans ce contexte, l’objectif principal de cette thèse est de développer une méthodologie numérique capable de prédire et de caractériser la cavitation dans des turbines Kaplan et son impact sur les performances de la machine. Dans cette thèse, un modèle réduit de turbine Kaplan à 5 pales a été analysé. Les équations RANS/URANS ont été résolues,modélisant l’écoulement cavitant à l’aide d’une approche homogène et d’une loi d’état de type barotrope. Tout d’abord, la méthodologie a été définie pour des conditions de fonctionnement optimales, puis elle a été testée également sur un point de fonctionnement à forte charge. La méthode numérique de prédiction de la cavitation qui a été développée a pu être validée à l’aide de données expérimentales. Les prédictions numériques des performances et de l’évolution des structures de vapeur obtenues en appliquant la nouvelle stratégie de calcul de la cavitation sont en très bon accord quantitatif et qualitatif avec les données expérimentales. Une fois que la méthodologie numérique a été définie, des analyses approfondies de l’évolution des écoulements cavitants dans la machine ont été effectuées. L’approche développée apparaît très fiable, robuste et précise. / The presence of cavitation phenomena in hydraulic machines cause several structural damages and alter the machine performances. Hence, the investigation of the cavitation in hydraulic turbine is of great industrial interest. Amongthe hydraulic turbine, Kaplan turbine are known for their flexibility. The guide vane opening and the runner blade position can be continuously regulated during machine operation maximizing the efficiency for a large range of operating conditions. This implies the presence of shroud and hub gaps that leads to additional cavitation structures in the runner. In this context, the principal aim of this thesis is the development of a numerical methodology able to predict and characterize the cavitation in Kaplan turbine and its impact on the machine performance. The analysis refers to a scale model of a 5-blades Kaplan turbine. RANS/URANS equations have been solved modeling the cavitating flow by using a homogeneous approach and a barotropic state law. The methodology have been defined for optimal operating conditions and, after has been tested also on the full load operating point. Experimental data have been used to validate the developed numerical method of cavitation prediction. The numerical predictions of the performances and the vapor structures obtained by applying the new cavitation calculations strategy are in very good quantitative and qualitative agreement with the available experimental data. Once the numerical methodology has been defined in-deep analyses of the cavitating flow evolution in the machine have been performed. The developed approach appears to be very reliable, robust and precise.

The aim of this dissertation is to prepare a study of a small hydroelectric power plant as part of the Přelouč navigation level II. The preparation deals with one of the possible variants for the layout design of given constructions. The layout design of a weir with an adjacent lock chamber which secures navigability for the stretch of the Elbe River located between the river kilometers 949,23 and 951,20 near the city of Přelouč in the Pardubice District is also included in the study. The introduction chapter contains the assessment of the environment, which is followed by the specification of the exact placement of the constructions. In the following chapter, a particular type of the hydroelectric power plant machinery is designed based on the available hydrological information and gradient conditions. The final chapter contains the design of the constructional technological layout of an machine room in the form of a technical report and drawing documentation.

The diploma thesis should identify inconsistencies of the small hydraulic power plant Katovice. The fountain water turbine is now running in slower delivery because the original Francis high speed turbine achieved much smaller flow than a Kaplan type turbine. The aim of the thesis is a project of a spiral case and a distributor for the Kaplan turbine, which should work in higher flow and should be run in its optimum. This project will serve as a base for construction of distributor and spiral case for the small hydraulic power plant Katovice.