Kaplan turbines are a type of hydropower turbine with adjustable runner blades. This allows the turbine to alter its power output while maintaining a relatively high efficiency over a wide range of power levels. But these frequent blade angel adjustments exposes the turbines internal mechanism to wear and the possibility of fatigue failure. A Kaplan turbine, and the regulating mechanism inside it, usually has an expected service life, but depending on how the turbine is operated its actual lifespan could potentially either exceed or fall short of this expected service life. The objective of this thesis was to create a tool to evaluate the fatigue damage and fatigue life of the components in the Kaplan runner's regulating mechanism. This thesis was mainly focused on two components that are found in practically all Kaplan runner regulating mechanism. One of these components is the "crank", which is the part that rotates with the runner blades, and on which the runner blades are often directly attached. The other component is the link, that attaches the cranks to the crosshead, which is the part that is moved with hydraulics axially inside the runner. The reason for this is that these components have been found to be among the most susceptible to fatigue damage in the regulating mechanism. The tool was realized in the form of a program with a graphical user interface. It was programmed in Matlab's AppDesigner, and has a direct connection to the OSIsoft PI database. This program lets the user enter dimensions of the mechanism's components manually, and reads data such as load and runner blade angle directly from PI. The program also features different options the user can select depending on the design of the mechanism's components. Load and angular data is retrieved from a selected time period. The program evaluates the fatigue life of the components using stress based fatigue evaluation. The stresses and stress concentrations in the components are calculated using mathematical formulas. Most of these formulas were gathered from literature, but a formula describing the stress concentration in the crank was experimentally developed during the thesis. This formula was developed based on FEM-simulations carried out in the program Ansys. The finished product is a program that relatively quickly lets the user evaluate the fatigue lifespan of the link and crank in a given turbine, based on measurement data and dimensions entered by the user. The program is computationally fast as it utilizes mathematical expressions to numerically calculate the maximum stresses in the components, instead of FEM-analysis. The program can be run on any computer a standalone program as it has been compiled to an executable file for ease of use.

In the near future hydropower will be used to regulate intermittent energy sources, shallow water ways can then occur in close proximity to the power plants, where the bottom often consists of stones in a similar length scale as the water depth. The idea of this project, which has been initiated by Vattenfall R\&D, is to compare experimental measurements in a laboratory environment with numerical simulations with CFD, this to find a way to represent roughness structures where there is low relative submergence. For the measurements in the lab, gravel were attached to the bottom of a flume and the water depth were measured for different flow rates and a CFD model were calibrated against the measurement data. A conversion of the Manning coefficient, originating from experimental measurements to equivalent Sand-grain size used in the CFD to model the roughness has been proposed and has shown good predictions of the maximum water depth. To capture the entire flow field, it is not enough to just model the friction from the roughness, it needs to be resolved and it may be necessary to consider the influence by form drag.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24888号 / 工博第5168号 / 新制||工||1987(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 角 哲也, 教授 田中 賢治, 准教授 竹林 洋史 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(地域研究) / 甲第24015号 / 地博第294号 / 新制||地||113(附属図書館) / 京都大学大学院アジア・アフリカ地域研究研究科東南アジア地域研究専攻 / (主査)教授 三重野 文晴, 教授 河野 泰之, 准教授 小坂 康之, 教授 水野 広祐 / 学位規則第4条第1項該当 / Doctor of Area Studies / Kyoto University / DGAM

This study analyses the environmental and health benefits associated with the use of renewable energy sources, focusing on the costs and savings involved. The research employs a comprehensive cost-benefit analysis approach, comparing the costs associated with generating energy from a 10 megawatts solar energy power plant versus a 10 megawatt hydropower plant. The data used in this research was gathered from a variety of sources, including government reports, academic studies, and industry publications. The analysis ensued a positive net benefit for both power plants, while the economic useful life of developing and implementing the solar plant is shorter, the long-term benefits of these technology outweighs that of the hydro power plant. The data indicates that renewable energy technologies can significantly reduce greenhouse gas emissions and air pollution, leading to substantial improvements in public health and environmental quality. Overall, this research indicates that investing in renewable energy sources is not only an environmentally responsible choice, but also a viable decision for the society.

<p>This thesis proposes the design and documents analysis for a Modular River Current Energy Converter (MRCEC) to improve the efficiency of hydrokinetic turbine power systems. The MRCEC can produce electricity from low-velocity river flow with increased energy affordability and availability. The MRCEC, for the scope of this thesis, consists of the hydroturbine and maintenance systems. The turbine in the MRCEC system is a cross-flow cycloidal turbine that yields a high power coefficient (0.515) through a novel pitch variance mechanism involving a 3D cam that adapts to varying river flow conditions to maximize operational efficiencies. The cycloidal turbine is a four-section three-blade turbine that uses a unique hydrofoil profile designed for the MRCEC. The cycloidal turbine is housed in a frame supported by a flotation system to harness energy from near-surface currents. The flotation system, in turn, is connected to the service dock which houses the mooring, debris blockage, and maintenance systems. The mooring system allows the MRCEC to be fixed at the working site while allowing for self-adjustment with varying river depths. The debris blockage system prevents debris carried by the river from interfering with an operational hydroturbine. The maintenance system enables the installation, operation, and maintenance functions by integrating a flipping mechanism to invert the turbine for transportation and maintenance purposes. Mechanisms of these systems are designed to appropriate standards, then simulated to validate functionality at all stages of installation, operation, and maintenance.</p>

Submitted by Jordan (jordanbiblio@gmail.com) on 2017-03-13T16:16:56Z No. of bitstreams: 1 DISS_2015_Antonio Carlos Coelho da Silva.pdf: 2821968 bytes, checksum: fcd2e727317e1f78374149a461864c21 (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2017-03-14T15:59:26Z (GMT) No. of bitstreams: 1 DISS_2015_Antonio Carlos Coelho da Silva.pdf: 2821968 bytes, checksum: fcd2e727317e1f78374149a461864c21 (MD5) / Made available in DSpace on 2017-03-14T15:59:26Z (GMT). No. of bitstreams: 1 DISS_2015_Antonio Carlos Coelho da Silva.pdf: 2821968 bytes, checksum: fcd2e727317e1f78374149a461864c21 (MD5) Previous issue date: 2015-02-25 / A maior planície inundável do mundo, o Pantanal, tem como seu principal contribuinte formador o Rio Paraguai. Em sua Região Hidrográfica foram instaladas cinco hidrelétricas e cinquenta e oito Pequenas Centrais Hidrelétricas (PDHs). No Rio Jauru, afluente importante do Rio Paraguai, uma sequência de 6hidrelétricas foi construída no gradiente longitudinal do rio. Neste estudo, que visou identificar e analisar os impactos sobre a hidrologia e qualidade da água do Rio Jauru, devido à operação em cascata das hidrelétricas, foi considerado não apenas o impacto individual produzido por cada hidrelétrica, mas também, o resultado de seus impactos de forma integrada. Foram analisados 12 parâmetros formadores da qualidade de água do rio em, diversos pontos no longitudinal do rio, a montante e a jusante das hidrelétricas. Também foram analisados 32 parâmetros hidrológicos utilizando o através do software IHA. Alterações na hidrologia e na qualidade da água após a instalação das usinas hidrelétricas foram verificadas. Os resultados deste estudo questionam a teoria que pequenas centrais hidrelétricas provocam pouco impacto ambiental no rio. / The Paraguay River is the major tributary of the largest floodplain in the world, the Pantanal. Itsbasincontains five hydropower plants and fifty-eight small hydro power plants. In the Jauru River, an important tributary of the Paraguay River, a cascade of six hydropower plants was built along the longitudinal gradient of the river. The present study aimed at identifying and analyzing the impacts on the hydrology and water quality of the Jauru River caused by the cascade hydropower plants, considering not only the individual impact produced by each one but also the combination of their impacts together. We analyzed 12 parameters indicating water quality of the river, data from several sites along the longitudinal axis of the river, upstream and downstream of the reservoirs lakes. Also, 32 hydrological parameters were examined with the aid of the software IHA. Changes in hydrology and water quality were found after the installation of the hydropower plants. Our results question the assertion that small hydropower plants have little environmental impact on the river.

Climate change is altering hydrological processes with varying degrees in various regions of the world. This research work investigates the possible impacts of climate change on water resource and Hydropower production potential in central and southern Africa. The Congo, Zambezi and Kwanza, Shire, Kafue and Kabompo basins that lie in central and southern Africa are used as case studies. The review of climate change impact studies shows that there are few studies on impacts of climate change on hydropower production. Most of these studies were carried out in Europe and north America and very few in Asia, south America and Africa. The few studies indicate that southern Africa would experience reduction in precipitation and runoff, consequently reductions in hydropower production. There are no standard methods of assessing the resulting impacts. Two approaches were used to assess the impacts of climate change on water resources and hydropower. One approach is lumping changes on country or regional level and use the mean climate changes on mean annual flows as the basis for regional changes in hydropower production. This is done to get an overall picture of the changes on global and regional level. The second approach is a detailed assessment process in which downscaling, hydrological modelling and hydropower simulations are carried out. The possible future climate scenarios for the region of central and southern Africa depicted that some areas where precipitation are likely to have increases while other, precipitation will reduce. The region northern Zambia and southern Congo showed increases while the northern Congo basin showed reductions. Further south in southern African region, there is a tendency of decreases in precipitation. To the west, in Angola, inland showed increases while towards the coast highlighted some decreases in precipitation. On a global scale, hydropower is likely to experience slight changes (0.08%) due to climate change by 2050. Africa is projected for a slight decrease (0.05%), Asia with an increase of 0.27%, Europe a reduction up to 0.16% while America is projected to have an increase of 0.05%. In the eastern African region, it was shown that hydropower production is likely to increase by 0.59%, the central with 0.22% and the western with a 0.03%. The southern, and northern African regions were projected to have reductions of 0.83% and 0.48% respectively. The basins with increases in flow projections have a slight increase on hydropower production but not proportional to the increase in precipitation. The basins with decreases had even high change as the reduction was further increased by evaporation losses. The hydropower production potential of most of southern African basins is likely to decrease in the future due to the impact of climate change while the central African region shows an increasing trend. The hydropower system in these regions will be affected consequently. The hydropower production changes will vary from basin to basin in these regions. The Zambezi, Kafue and Shire river basins have negative changes while the Congo, Kwanza and Kabompo river basins have positive changes. The hydropower production potential in the Zambezi basin decreases by 9 - 34%. The hydropower production potential in the Kafue basin decreases by 8 - 34% and the Shire basin decreases by 7 - 14 %. The southern region will become drier with shorter rainy seasons. The central region will become wetter with increased runoff. The hydropower production potential in the Congo basin reduces slightly and then increases by 4% by the end of the century. The hydropower production potential in the Kwanza basin decreases by 3% and then increases by 10% towards the end of the century and the Kabompo basin production increases by 6 - 18%. It can be concluded that in the central African region hydropower production will, in general, increase while the southern African region, hydropower production will decrease. In summary, the analysis has shown that the southern African region is expected to experience decreases in rainfall and increases in temperature. This will result in reduced runoff. However the northern part of southern Africa is expected to remain relatively the same with slight increase, moving northwards towards the central African region where mainly increases have been registered. The southern African region is likely to experience reductions up to 5 - 20% while the central African region is likely to experience an increase in runoff in the range of 1 - 5%. Lack of data was observed as a critical limiting factor in modelling in the central and southern Africa region. The designs, plans and operations based on poor hydrological data severely compromise performance and decrease efficiency of systems. Climate change is expected to change these risks. The normal extrapolations of historical data will be less reliable as the past will become an increasingly poor predictor of the future. Better (observed) data is recommended in future assessments and if not better tools and methods for data collection/ should be used. Future designs, plans and operations should include and aspect of climate change, if the region is to benefit from the climate change impacts.

Cette thèse porte sur l’étude des microcentrales hydroélectriques à vis d’Archimède. Il s’agit dans ces travaux de proposer une solution alternative à l’hydroélectricité à petite échelle, en exploitant les ressources inutilisées telles que les petites rivières ou les cours d’eau. Ces microcentrales inversent le principe de fonctionnement de la pompe à vis d’Archimède. Elles exploitent la puissance hydraulique disponible dans les usines hydroélectriques de très basses chutes. A partir de l’état de l’art, un modèle numérique est établi pour estimer les rendements, la production d’énergie et la rentabilité pour un fonctionnement à vitesse variable des microcentrales hydroélectriques à vis d’Archimède. Les différents résultats théoriques et de simulation ont été validés expérimentalement sur le prototype de l’INSA de Strasbourg, développé dans le cadre de cette thèse. Enfin, des actions sont menées sur le prototype expérimental afin de maximiser le transfert d’énergie et de limiter les pertes. Pour finir, une stratégie MPPT (Maximum Power Point Tacking) très spécifique est développée et est actuellement en cours d’implémentation. / This work focuses on a small hydro plant which uses the Archimedes screw. This is an alternative solution to smallscale hydropower as it employs unused resources such as small rivers or streams. Archimedes screw plants reverse the pump use principle and employ the available stream power for energy production in very low head application. Based on the state-of-the-art, a numerical model is established to estimate efficiencies, energy production and profitability of variable speed operations for a small hydro plant using Archimedes screw. Several theoretical results and simulations are proposed. We validated them experimentally on the prototype of INSA Strasbourg, developed within the framework of this thesis. Finally, actions carried out on the experimental prototype led to maximizing the transfer of energy and limiting losses. Then a very specific MPPT (Maximum Power Point Tracking) control strategy is developed and is currently being implemented.

Hydropower systems often contain complex river systems which cause the simulations and analyses of a hydropower operation to be computationally heavy. The complex river system is referred to as something called a Detailed model. By creating a simpler model, denoted the Equivalent model, the computational issue could be circumvented. The purpose of this Equivalent model is to emulate the results of the Detailed model. This thesis computes the Equivalent model for a large hydropower system using Particle Swarm Optimisation- algorithm, then evaluates the Equivalent model performance. Simulations are performed on ten rivers in Sweden, representing four trading areas for one year, October 2017 – September 2018. Furthermore, the year is divided into Quarterly and Seasonal periods, to investigate whether the Equivalent model changes over time. The Equivalent model performance is evaluated based on the relative power difference and computational time compared to the Detailed model. The relative power difference is 4%23% between Equivalent and Detailed models, depending on the period and trading area, with the computational time can be reduced by more than 90%. Furthermore, the Equivalent model changes over time, suggesting that when the year is divided appropriately, the Equivalent model could perform better. The relative power difference results indicate that the Equivalent model performance can still be improved by dividing the periods more appropriately, other than Quarterly or Seasonal. Nevertheless, the results provide a satisfactory Equivalent model, based on the faster computation time and a reasonable relative power difference. Finally, the Equivalent model could be used as a foundation for further analyses and simulations. / Vattenkraftsystem består ofta av komplexa älvsystem som gör att simuleringar och analyser av vattenkraftens operation blir beräkningsmässigt tunga. Det komplexa älvsystem kallas en Detaljeraded modell. Genom att skapa en enklare modell, betecknas som en Ekvivalent modell, beräkningsproblemen kan kringgås. Syftet med denna Ekvivalenta modell är att emulera resultaten av den komplexa Detaljerade modellen. Detta examensarbete beräknar den Ekvivalenta modellen för ett stort vattenkraftssystem med hjälp av Particle Swarm Optimisation- algorithmen, och utvärderar modellprestandan hos Ekvivalenten. Simuleringar utförs på tio älvar i Sverige, som representerar fyra handelsområden under ett år, från oktober 2017 september 2018. Dessutom är året uppdelat i kvartals- och säsongsperioder för att undersöka om den Ekvivalenta modellen förändras över tid. Denna Ekvivalenta modell utvärderas baserat på den relativa effektskillnaden och beräkningstiden jämfört med den Detaljerade modellen. Den relativa effektskillnaden är 4% 23% mellan de Ekvivalenta och Detaljerade modellerna, beroende på period och handelsområde, och beräkningstiden minskas med mer än 90%. Vidare ändras Ekvivalenta modellen över tiden, vilket tyder på att när året delas upp på rätt sätt kan den Ekvivalenta modellen prestera ännu bättre. De relativa effektskillnaderna indikerar att vissa perioder fortfarande kan förbättras genom att dela upp perioden mer korrekt. Trots allt, förser resultanten en tillfredsställande Ekvivalent modell som har en mer effektiv beräkningstid och rimliga effektskillnader. Slutligen skulle den Ekvivalenta modellen kunna användas som en grund för ytterligare analyser och simuleringar.