Tidal Energy is one of the growing renewable energy technologies that is aimed at tackling global energy challenges. The Horizontal Axis Tidal Turbine (HATT) is an in-stream Tidal Energy Converter (TEC) which extracts kinetic energy from tidal flows. These tidal turbines face many reliability challenges due to their complexity, harsh operating environment and low accessibility. One of the component contributing significantly to the reliability of a TEC is the bearing supporting the rotating shaft within the nacelle. The reliability assessment of this component is essential during the design process and before their eventual deployments. This work is describes shaft bearing reliability assessment procedures. In recent years, the Offshore Renewable Energy (ORE) Catapult’s National Renewable Energy Centre has developed a dedicated multi axis test facility for full scale testing of tidal turbine nacelles and components (i.e. Nautilus). This work presents a methodology for testing tidal turbine shaft bearings in a representative manner in the full scale nacelle test rig, Nautilus. Two aspects are considered, namely the damage assessment and the damage replication in an accelerated manner. The damage assessment process considers the global loading on the shaft bearing and a Rigid Dynamics (RD) model has been applied to identify the local bearing loads. Local loads are converted to stress enabling the identification of stress-life relationship and bearing damage. The damage replication process is aimed to evaluate the 20 year damage and the Acceleration by Phase-shift (AbP) method has been developed to accelerate the cumulative damage. The AbP method enables the assessment of performance characteristics of shaft bearings in a laboratory environment, reducing failure rates, validate performance in a cost effective manner by reduced testing times. Within this work, novel processes for shaft bearing reliability assessments and demonstration are suggested and it concludes with the presentation of a recommended test plan for carrying out accelerated tests on a full scale bearing.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:732654 |
| Date | January 2016 |
| Creators | Karikari-Boateng, Kwaku Ampea |
| Contributors | Johanning, Lars ; Ng, Chong ; Mueller, Markus ; Nigel, Barltrop |
| Publisher | University of Exeter |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10871/31210 |
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