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- Deglaire, Paul, 1978-
(författare)
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Analytical Aerodynamic Simulation Tools for Vertical Axis Wind Turbines
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wind power is a renewable energy source that is today the fastest growing solution to reduce CO2 emissions in the electric energy mix. Upwind horizontal axis wind turbine with three blades has been the preferred technical choice for more than two decades. This horizontal axis concept is today widely leading the market. The current PhD thesis will cover an alternative type of wind turbine with straight blades and rotating along the vertical axis. A brief overview of the main differences between the horizontal and vertical axis concept has been made. However the main focus of this thesis is the aerodynamics of the wind turbine blades. Making aerodynamically efficient turbines starts with efficient blades. Making efficient blades requires a good understanding of the physical phenomena and effective simulations tools to model them. The specific aerodynamics for straight bladed vertical axis turbine flow are reviewed together with the standard aerodynamic simulations tools that have been used in the past by blade and rotor designer. A reasonably fast (regarding computer power) and accurate (regarding comparison with experimental results) simulation method was still lacking in the field prior to the current work. This thesis aims at designing such a method. Analytical methods can be used to model complex flow if the geometry is simple. Therefore, a conformal mapping method is derived to transform any set of section into a set of standard circles. Then analytical procedures are generalized to simulate moving multibody sections in the complex vertical flows and forces experienced by the blades. Finally the fast semi analytical aerodynamic algorithm boosted by fast multipole methods to handle high number of vortices is coupled with a simple structural model of the rotor to investigate potential aeroelastic instabilities. Together with these advanced simulation tools, a standard double multiple streamtube model has been developed and used to design several straight bladed rotor ranging from 2 kW to 20 kW.
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- Deglaire, Paul, et al.
(författare)
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Conformal mapping and efficient boundary element method without, boundary elements for fast vortex particle simulations
- 2008
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Ingår i: European journal of mechanics. B, Fluids. - : Elsevier BV. - 0997-7546 .- 1873-7390. ; 27:2, s. 150-176
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a revitalization of conformal mapping methods applied to fluid flows in two dimensions is proposed. The present work addresses several important issues concerning their application for vortex particle flow solvers. Difficulties of past conformal based method are reviewed. One difficulty concerns the ability of a mapping procedure to represent complicated shapes. The present paper improves past algorithms to be able to map new shapes, including multiply connected domains. A new fast procedure allows transferring a set of points in the mapped simplified plane to the complicated domain and vice versa. After a mapping construction, it is demonstrated how basic exact solutions to potential flow problems with vortices can be put in a new form which provides a faster and more accurate computation than with distributed singularity methods.
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- Deglaire, Paul, et al.
(författare)
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Experimental results from a 12 kW vertical axis wind turbine with a direct driven PM synchronous generator
- 2007
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Experimental results from a three bladed vertical axis wind turbine with a direct driven PM synchronous generatorare presented. The H-rotor turbine, independent of wind direction, does not require any yaw mechanism.Furthermore, the variable speed, stall regulated turbine does not require pitch mechanism. The specifically designeddirectly driven generator eliminates the need for a gearbox. All electrical equipment, including generator, are placedon the ground. This reduces the weight that has to be supported by the structure and simplifies maintenance. Thus, theoverall strength of this concept is simplicity.The H-rotor has five meter long blades that are tapered at the tips. The aerodynamic torque is transferred to thegenerator via a 5.4 meter long drive shaft supported by a tower. A universal joint connects the drive shaft to thegenerator shaft, cancelling any transverse bending moments from the turbine on the generator. The generator acts as amotor to start up the turbine using a separate auxiliary winding. The turbine has a swept area of 30 m2 and is rated at12 kW in 12 m/s winds for 127 rpm.The turbine has been placed on a site where the wind resources have been extensively documented. The wind datarecord is more then ten years and includes data from various heights giving an accurate wind mapping of the area.The experimental aerodynamic power curve in turbulent wind conditions is presented. Considering the highlyturbulent wind conditions and the small size of the wind turbine these results are encouraging.
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- Kjellin, Jon, et al.
(författare)
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Power coefficient measurement on a 12 kW straight bladed vertical axis wind turbine
- 2011
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 36:11, s. 3050-3053
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Tidskriftsartikel (refereegranskat)abstract
- A 12 kW vertical axis H-rotor type wind turbine has been designed and constructed at Uppsala University. A measurement campaign has been performed to collect data to calculate the power coefficient using the method of bins. The measurement was performed at different constant rotational speeds on the turbine during varying wind speeds to observe the power coefficients dependence on tip speed ratio. The power coefficient peaked at 0.29 for a tip speed ratio equal to 3.3.
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- Yuen, Katarina, et al.
(författare)
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Matching a permanent magnet synchronous generator to a fixed pitch vertical axis turbine for marine current energy conversion
- 2009
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Ingår i: IEEE Journal of Oceanic Engineering. - 0364-9059 .- 1558-1691. ; 34:1, s. 24-31
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Tidskriftsartikel (refereegranskat)abstract
- Extracting energy from a free-flow marine current using a vertical axis fixed pitch turbine requires a generator that can handle varying speeds and loads, since such a turbine gives maximum power capture for a fixed tip speed ratio. A prototype of such a generator has been designed and constructed. In this paper, its variable speed and load operation is evaluated, both in terms of how the constructed generator performs in relation to simulations, and in terms of how the generator could perform with three different fixed pitch turbines. Measurements of root mean square (RMS) voltage and current differ 10% from simulations. Performance analysis with example turbines shows that the generator can match fixed tip speed ratio operation of several turbines for current speeds between 0.5 and 2.5 m/s.
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