Search for dissertations about: "stall"

Showing result 1 - 5 of 45 swedish dissertations containing the word stall.

  2. 1. Vertical Axis Wind Turbines : Electrical System and Experimental Results

    Author : Jon Kjellin; Hans Bernhoff; Mats Leijon; Jonny Hylander; Uppsala universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; VAWT; H-rotor; start-up; all-electric control; Power Coefficient; stall; tip speed ratio; Renewable energy; Measurement systems; PM-generator;

    Abstract : The wind power research at the division of Electricity at Uppsala University is aimed towards increased understanding of vertical axis wind turbines. The considered type of wind turbine is an H-rotor with a directly driven synchronous generator operating at variable speed. READ MORE

  4. 2. Numerical simulation of viscous compressible flows applied to turbomachinery blade flutter

    Author : L. D. Gunnar Sidén; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; unsteady; flutter; turbine; aeroengine; turbomachinery; numerical method; oscillating; Navier-Stokes; finite volume; viscious; finite element; turbulent; fan; aeroelastic; vibration; compressor; stall;

    Abstract : .... READ MORE

  5. 3. Aerodynamics of Vertical Axis Wind Turbines : Development of Simulation Tools and Experiments

    Author : Eduard Dyachuk; Hans Bernhoff; Sandra Eriksson; Anders Goude; Mac Gaunaa; Uppsala universitet; []
    Keywords : wind power; vertical axis turbine; H-rotor; simulations; streamtube model; vortex model; dynamic stall; measurements; blade; force; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Abstract : This thesis combines measurements with the development of simulation tools for vertical axis wind turbines (VAWT). Numerical models of aerodynamic blade forces are developed and validated against experiments. The studies were made on VAWTs which were operated at open sites. READ MORE

  6. 4. Flow instabilities in centrifugal compressors at low mass flow rate

    Author : Elias Sundström; Mihai Mihaescu; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Centrifugal compressor; flow instabilities; rotational flows; rotating stall; surge; compressible Large Eddy Simulation; Engineering Mechanics; Teknisk mekanik;

    Abstract : A centrifugal compressor is a mechanical machine with purpose to convert kineticenergy from a rotating impeller wheel into the fluid medium by compressingit. One application involves supplying boost air pressure to downsized internalcombustion engines (ICE). READ MORE

  7. 5. Numerical investigation of the flow and instabilities at part-load and speed-no-load in an axial turbine

    Author : Jelle Kranenbarg; Michel Cervantes; Lisa Prahl Wittberg; Luleå tekniska universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Speed-no-load; vortical flow structures; flow instabilities; rotating stall; mitigation; independent guide vanes; axial turbine; swirling flow; off design operation; URANS; parametric study; blade clearance; head losses; diffusor; GEKO model; flow separation; hydraulic turbine; Strömningslära; Fluid Mechanics;

    Abstract : Global renewable energy requirements rapidly increase with the transition to a fossil-free society. As a result, intermittent energy resources, such as wind- and solar power, have become increasingly popular. However, their energy production varies over time, both in the short- and long term. READ MORE