Novel Cyclic Blade Pitching Mechanism for Wind and Tidal Energy Turbine Applications

A vertical axis drag-based turbine is proposed that allows for an improved performance by feathering its blades during recovery strokes to eliminate adverse blade forces. The turbine blades resemble flat plates and pitch by 90 ∘ between the two turbine strokes using a novel dual-cam mechanism. This...

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Bibliographic Details
Published inEnergies (Basel) Vol. 11; no. 12; p. 3328
Main Authors Prasad Rao, Jubilee, Diez, Francisco
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.12.2018
Subjects
Air flow
Alternative energy sources
Climate change
cyclic blade pitching
Depletion
drag-based wind turbines
Energy sources
Engineering
Fluids
Global warming
mathematical modeling
power performance testing
recovery stroke drag
Renewable energy sources
Renewable resources
Tidal energy
Turbines
vertical axis wind turbines
Wind power
wind tunnels
United States > US
China
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Summary:A vertical axis drag-based turbine is proposed that allows for an improved performance by feathering its blades during recovery strokes to eliminate adverse blade forces. The turbine blades resemble flat plates and pitch by 90 ∘ between the two turbine strokes using a novel dual-cam mechanism. This passive mechanism orients the blades vertically during the drive stroke for maximum effective area and horizontally for minimum effective area during the recovery stroke. This allows maximizing the positive drive stroke force and minimizing the recovery stroke losses, in turn maximizing the net energy capture and the turbine performance. It is called the cyclic pitch turbine, and a mathematical model is developed that predicts the turbine performance. It shows that the turbine is self-starting for all orientations and has a higher and more uniform static torque coefficient than the popular Savonius turbine. The dynamic analysis also indicates a higher performance, and the predicted values for torque and power coefficients match very closely with those from water channel and wind tunnel experiments on a prototype. Results of testing several blade shapes indicate that airfoil section blades with long and narrow continuous shapes that have less area towards the blade’s tip result in higher performance.
ISSN:1996-1073
1996-1073
DOI:10.3390/en11123328