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Visar resultat 1 - 5 av 300 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Fluid Mechanics of Vertical Axis Turbines : Simulations and Model Development

   Författare :Anders Goude; Olov Ågren; Carlos Simão Ferreira; Uppsala universitet; []
   Nyckelord :Wind power; Marine current power; Vertical axis turbine; Wind farm; Channel flow; Simulations; Vortex model; Streamtube model; Control system; Graphics processing unit; CUDA; Fast multipole method; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

   Sammanfattning : Two computationally fast fluid mechanical models for vertical axis turbines are the streamtube and the vortex model. The streamtube model is the fastest, allowing three-dimensional modeling of the turbine, but lacks a proper time-dependent description of the flow through the turbine. LÄS MER

3. 2. Turbine Outlet Guide Vane Flows

   Författare :Johan Hjärne; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spalart-Allmaras model; k-ω SST model; linear cascade; secondary flows; turbine exhaust casing; RSM; k-ε realizable model; turbine rear frame; engine mount bump; tail bearing housing; Outlet guide vane;

   Sammanfattning : New design goals on modern jet engines often leads to more highly loaded turbines with fewer stages in order to save weight and cost. This gives higher swirl angles into the outlet guide vane (OGV), implying a more difficult aerodynamic design. LÄS MER

4. 3. Calibration and Reduction of Large-Scale Dynamic Models - Application to Wind Turbine Blades

   Författare :Majid Khorsand Vakilzadeh; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; maximum likelihood estimator; model reduction; finite element model calibration; Bayesian model calibration; Verification and validation; wind turbine blade; logarithmic least square estimator; large-scale dynamics model; SWPTC;

   Sammanfattning : This thesis investigates the validity of structural dynamics models of wind turbine blades. An outlook on methods for model calibration to make models valid for their intended use is presented in the thesis. The intention is to make the models valid for robust predictions. The model validity is here assessed to be of hierarchical dual level. LÄS MER

5. 4. Flow Control and Shape Optimization of Intermediate Turbine Ducts for Turbofan Engines

   Författare :Fredrik Wallin; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; response surface methodology; intermediate turbine duct; vortex generators; turbine intermediate case; endwall contouring; turbine center frame; body-force model; shape optimization; mid-turbine frame; flow control;

   Sammanfattning : Demands on improved efficiency, reduced emissions and lowered noise levels cause a strive towards high by-pass ratios of commercial turbofan engines. This results in an increased radial offset between the high- and low-pressure turbines. Thus the design of the intermediate turbine duct connecting the two turbines becomes more challenging. LÄS MER

7. 5. Evaluation, Experience and Potential of Gas Turbine Based Cycles with Humidification

   Författare :Torbjörn Lindquist; Kraftverksteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Model Validation; Recuperator; Flue Gas Condensation; Humidification; Gas Turbine; Advanced Thermodynamic Cycles; HAT; Humid Air Turbine; Evaporative Gas Turbine Cycle; EvGT; Operating Experience; EvGT Pilot Plant; Thermal engineering; applied thermodynamics; Termisk teknik; termodynamik;

   Sammanfattning : Gas turbines, in simple and combined cycle, are common and economically profitable on the power generating market today. Several new cycles have been proposed as future competing technologies, but all studies about these cycles have, so far, been paperwork. LÄS MER