Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760981
Title: Numerical investigation of cross-flow tidal turbine hydrodynamics
Author: Stringer, Robert
ISNI:       0000 0004 7432 6468
Awarding Body: University of Bath
Current Institution: University of Bath
Date of Award: 2018
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Abstract:
The challenge of tackling global climate change and our increasing reliance on power means that new and diverse renewable energy generation technologies are a necessity for the future. From a number of technologies reviewed at the outset, the cross-flow tidal turbine was chosen as the focus of the research. The numerical investigation begins by choosing to model flow around a circular cylinder as a challenging benchmarking and evaluation case to compare two potential solvers for the ongoing research, ANSYS CFX and OpenFOAM. A number of meshing strategies and solver limitations are extracted, forming a detailed guide on the topic of cylinder lift, drag and Strouhal frequency prediction in its own right. An introduction to cross-flow turbines follows, setting out turbine performance coefficients and a strategy to develop a robust numerical modelling environment with which to capture and evaluate hydrodynamic phenomena. The validation of a numerical model is undertaken by comparison with an experimentally tested lab scale turbine. The resultant numerical model is used to explore turbine performance with varying Reynolds number, concluding with a recommended minimum value for development purposes of Re = 350 × 103 to avoid scalability errors. Based on this limit a large scale numerical simulation of the turbine isconducted and evaluated in detail, in particular, a local flow sampling method is proposed and presented. The method captures flow conditions ahead of the turbine blade at all positions of motion allowing local velocities and angles of attack to be interrogated. The sampled flow conditions are used in the final chapter to construct a novel blade pitching strategy. The result is a highly effective optimisation method which increases peak turbine power coefficient by 20% for only two further case iterations of the numerical solution.
Supervisor: Hillis, Andrew ; Zang, Jun Sponsor: Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.760981  DOI: Not available
Keywords: Renewable Energy ; Tidal turbine ; CFD ; Numerical modelling ; Cross-flow ; Circular cylinders ; Optimisation
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