Increasing fuel prices, carbon emissions and energy security are all key drivers in the search for alternative sources of energy. Tidal stream power is a relatively new area of research and development activity, aimed at harnessing the predictable nature of the tides. Multi-element wing profiles provide a competitive edge in mptorsports and are also a proven technology within aerospace, however their use within turbine design appears elusive. This thesis explores the use of multi-element profiles applied to vertical-axis tidal stream energy devices to determine if the additional complexity offers any significant advantage to turbine performance. A panel based method has been used to generate aerofoil performance data of standard profiles and multi-element profiles for a relative comparison of lift and drag coefficients. This data has then been applied to a cross-flow turbine model to assess the potential performance gain. Scale testing of models is used to validate results and the thesis includes the design and build of appropriate apparatus to facilitate this testing. Results demonstrate that the addition of a trailing edge plain flap increases the peak lift to drag ratio by 26% in comparison to a single blade of equivalent chord. The gains predicted for a turbine are in excess of this due to an increase in the tangential force vector, along with an increase in the range of angles which the blade is active for. A true performance comparison is difficult to achieve given the complexity of the downstream turbine behaviour.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:658060 |
| Date | January 2012 |
| Creators | Quayle, Stephen D. |
| Publisher | Lancaster University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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