Electricity has been proved to be a crucial factor to achieve an economic and social development in emergent countries and is seen as a necessity to deplete the world’s poverty. As energy resources are getting scarce, a higher implementation of renewable electricity generation, such as hydropower, is a necessity. Hydrokinetic turbines, which use slow flowing water as a source of energy, are to be installed in the Amazonas River in Colombia. The Amazon River has high amount of sediment and flowing objects due to the large quantity of vegetation in the area. This leaves the turbine exposed to a higher degree of erosion on the blades and a higher risk of getting clogged. The efficiency will decrease and the turbine will have an impending risk of getting damaged. By adapting the hydrokinetic turbine for the conditions prevailing in the Amazon basin, the efficiency can be improved and a longer lifetime for the turbine is given. A field study was conducted to attain the velocity and amount of sediment in the Amazon River through measurements. The collected data was analyzed and used as input values during simulations of a turbine model by the Computational Fluid Dynamics program COMSOL. Areas on the turbine exposed to the water with a high velocity, and containing a high concentration of sediment, were examined and proposals for protection were given. Also the necessity and consequences of installing a protective grate in front of the turbine were investigated. The turbine will be exposed to almost a factor of 12 000 higher erosive wear in the Amazon River than in Swedish water as of the higher amount of sediment. The investigation states that areas on the tip of the blade’s rear side and the area close to the rotating center are most exposed to erosion and will be in need of protection in form of a harder surface. A grate will be necessary to provide a longer lifetime for the turbine, but will result in a decreased power output from the turbine by up to 46 %. / Elektricitet har bevisats vara en viktig komponent för en ekonomisk och social utveckling i utvecklingsländer och ses därför som en nödvändighet för att minska fattigdomen i världen. Energikällorna är dock hårt utnyttjade och en högre andel förnyelsebar elektrisk generering, genom bland annat vattenkraft, är en nödvändighet. Hydrokinetiska turbiner, vilka producerar el på långsamt flödande vatten, ska implementeras i Amazonfloden i Colombia. Amazonfloden har en hög andel sediment samt flytande objekt i floden på grund av den höga andel vegetation i området. Detta ger en ökad erosion på bladen samt risk för igentäppning av turbinen efter implementering. En lägre effektivitet samt hög risk för skada på turbinerna erhålls. Genom att adaptera den hydrokinetiska turbinen för förhållanden som råder i Amazonasfloden kan verkningsgraden förbättras och en längre livslängd på turbinen kan erhållas. En fältstudie utfördes där mätningar över vattenhastigheter, mängd sediment samt större objekt i floden genomfördes och analyserades. Data användes sedan som indata vid simuleringar över en uppbyggd modell av turbinen i Computational Fluid Dynamics-programmet COMSOL Multiphysics. Områden på turbinen utsatta för sedimentfullt vatten med en högre hastighet undersöktes och skyddsåtgärder föreslogs. Även behovet av ett skyddande galler framför turbinen granskades. Det visades att turbinen kommer utsättas för nästintill en faktor på 12 000 högre erosion i Amazonasfloden jämfört med i svenska vatten. Undersökningen visar att yttersta delarna av bladets baksida samt ett område nära det roterande centret är i behov av ett extra skydd i form av en hårdare yta. Ett galler kan bli nödvändigt för att uppnå en längre livstid för turbinen, men resulterar i en sänkt elproduktion med upp till 46 %.

Magistrantūros studijų baigiamasis darbas 52 lapai, 30 paveikslų, 4 lentelės, 41 literatūros šaltiniai. PAGRINDINIAI ŽODŽIAI: Hidrokinetinė energija, turbinos, nepatvankinė technologija, hidroelektrinė. Tiriamojo darbo objektas: Nepatvankinių technologijų panaudojimas upių hidrokinetinės energijos gavybai. Tiriamojo darbo tikslas: Įvertinti nepatvankinių energijos gavybos technologijų ir aplinkosaugos priemonių integracinius suderinamumus. Tiriamojo darbo uždaviniai: 1. Apžvelgti hidrokinetinės energijos panaudojimo taikant nepatvankines technologijas patirtį užsienio šalyse. 2. Apžvelgti hidrokinetinės energijos taikant nepatvankines technologijas panaudojimo siekius Lietuvoje. 3. Išanalizuoti nepatvankinių technologijų schemas. 4. Išanalizuoti nepatvankinių technologijų poveikį vandens ekosistemoms. 5. Įvertinti galimas nepatvankinių technologijų poveikio vandens ekosistemoms sumažinimo priemones. Tiriamojo darbo metodika: literatūros apžvalgos skyrius rašomas referatyviai, analizuojant mokslinius šaltinius. Duomenys tyrimui renkami analizuojant lietuvišką ir užsienio literatūrą, patentus, schemas, didžiausią dėmesį atkreipiant į nepatvankines energijos gavybos technologijas ir jų poveikį aplinkai. Tiriamojo darbo rezultatai: 1. Literatūros analizėje apžvelgta hidrokinetinės energijos panaudojimo taikant nepatvankines technologijas patirtis Lietuvoje, bei užsienyje. 2. Išanalizuotos nepatvankinių technologijų schemos, bei nepatvankinių technologijų poveikis... [toliau žr. visą tekstą] / The final master work consisting of 52 sheets, 30 images, 4 tables, 41 sources of literature. Key words: hydrokinetic energy, turbines, non-affluent technology, hydroelectric power plant. The object of this work: use of non – affluent technologies in extracting hydrokinetic energy out of the rivers. Main goal of this work: estimate the compatibility between non – affluent energy extracting technologies and tools of environment control integrity. Tasks of this work: 1. Overview of the hydrokinetic energy use abroad applying non – affluent technologies. 2. Overview of the hydrokinetic energy implementation and goals into Lithuanian market. 3. Analyses of the schemes about non – affluent technologies. 4. Analyze the impact of non-affluent technologies to eco systems. 5. Estimate the possible tools for decreasing impact of the non-affluent technologies to water eco systems. Methodology of this work: Literature overview charter is written abstractly analyzing scholarly sources. Data for the research was collected by analyzing Lithuanian and foreign literature, licenses, schemes considering non-affluent energy extraction technologies and their impact to the environment. The results of the work: 1. In literature analysis overviewed the experience of the hydrokinetic energy use applying non-affluent technologies in Lithuania and abroad. 2. Analyzed the schemes of the non – affluent technologies and their impact to the eco systems. 3. Estimating the tools for decreasing impact of the... [to full text]

The flow velocity in a river is three-dimensional (3D), turbulent, and varies in time and space. Capturing this variability in field measurements to support studies of river processes has proven particularly challenging. While originally developed to measure discharge, boat-mounted acoustic Doppler current profilers (ADCP) are increasingly used in field studies to quantify flow features including mean velocity, boundary shear stress, and sediment motion. Two survey procedures are typically employed with an ADCP. Moving-vessel (MV) measurements provide spatially-rich velocity data while temporally-rich data are obtained with fixed-vessel (FV) procedures. Given the relative ease of MV measurements, recent work has focused on developing MV procedures that produce comparable results to FV measurements. At the present, results of this work are inconclusive. Additionally, there is a lack of reported data and procedures for FV measurements. This work seeks to develop techniques to present 3D velocity data obtained in natural rivers in a unified framework. This framework is based on a stream-fitted coordinate system defined by the flow direction at a cross section and allows for 3D velocity to be decomposed into streamwise, spanwise, and vertical components. Procedures are developed to assure that the velocity profiles measured at fixed locations are (1) not negatively impacted by the inevitable motion of the ADCP, (2) statistically stationary, and (3) of sufficient record length to determine the mean velocity. The coordinate system allows time-averaged velocity from FV procedures to be compared with spatially-averaged velocity from MV vessels. Significant differences are found between the two survey procedures, particularly for secondary velocity components. Ultimately, integrating results of the two survey procedures leads to an improved representation of the mean flow field. The techniques are applied to data obtained on a study reach on the lower Roanoke River, located in eastern North Carolina. / Ph. D.