Sökning: "hydro"

Visar resultat 11 - 15 av 204 avhandlingar innehållade ordet hydro.

1. 11. System Perspectives on Hydro-Kinetic Energy Conversion

   Författare :Katarina Yuen; Mats Leijon; Chul Hee Jo; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tidal energy; permanent magnet; direct-drive; in-stream power converter; load control; vertical axis turbine; renewable energy; engineering science; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

   Sammanfattning : Free-flowing water currents such as tides and unregulated water courses could contribute to world electricity production given the emergence of robust technical solutions for extracting the energy. At Uppsala University, a concept for converting the energy in water currents to electricity using a vertical axis turbine with fixed blade-pitch and a direct-drive permanent magnet generator is studied. LÄS MER

3. 12. Ventilation Flow Field Characteristics of a Hydro-Generator Model- An experimental and Numerical Study

   Författare :Hamed Jamshidi; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Naphthalene Sublimation Technique; Hydro Power Generator; Ventilation; Experiment; CFD;

   Sammanfattning : Hydro-generators are complex machines used to convert the mechanical energy of the water turbine into electrical energy. Electromagnetic and mechanical losses accompany this energy conversion process which will cause heat generation and temperature increase. Cooling systems are needed to remove this excess heat from hydro-generators. LÄS MER

4. 13. Land-Sea Interactions in the Coastal-Marine System of the Baltic Sea under Hydro-Climatic Variability

   Författare :Yuanying Chen; Vladimir Cvetkovic; Carmen Prieto; Marco Marani; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Baltic Sea; nutrient loads; hydro-climatic variability; hydrodynamics; solute transport; water quality.; Land and Water Resources Engineering; Mark- och vattenteknik;

   Sammanfattning : This thesis investigates a few important component processes for understanding and quantifying eutrophication in the Baltic Sea, that include characterization of nutrient loadings from land, water flow in the sea under changing climate conditions and transport of solutes originating from different locations along the coast. Furthermore, this study aims to improve our understanding on how processes from land (the nutrient loading conditions) and the sea (transport dynamics and water quality) couple to determine the fate of nutrients in the sea and the water quality in a selected localized coastal area, the Himmerfjärden Bay. LÄS MER

5. 14. Hydro-Climatic Variability and Change in Central America : Supporting Risk Reduction Through Improved Analyses and Data

   Författare :Beatriz Quesada-Montano; Sven Halldin; Hugo G. Hidalgo; Ida K. Westerberg; Fredrik Wetterhall; Denis Hughes; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Central America; climate variability; disaster risk reduction; droughts; drought indices; floods; hydrological model; process constraints; statistical downscaling; uncertainty; ungauged basins; water resources.; Hydrology; Hydrologi;

   Sammanfattning : Floods and droughts are frequent in Central America and cause large social, economic and environmental impacts. A crucial step in disaster risk reduction is to have a good understanding of the causing mechanisms of extreme events and their spatio-temporal characteristics. LÄS MER

7. 15. Modeling and numerical simulation of hydro power flows

   Författare :John Bergström; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

   Sammanfattning : This work is about high precision numerical water flow simulations of hydro power related applications, and especially draft tube flows. Because of the accuracy requirements for these types of simulations (the efficiency of a hydro power turbine can be over 90%), the work has been devided into several steps; verification, validation and modeling. LÄS MER