Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.631387
Title: Optimization of a CFD based design of a straight blade vertical axis wind turbine (SB-VAWT)
Author: Almohammadi, Khaled Mohammad
ISNI:       0000 0004 5356 0511
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2014
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Abstract:
Enhancing the extraction of the wind energy in urban regions using micro and small wind turbines becomes a necessity with the increasing power consumption. The focus of this thesis is to optimize micro and small SB-VAWT performance by analysing CFD techniques, several modelling characteristics and design parameters where the performance is measured by the power coefficient. In this thesis, the SB-VAWT is optimized by employing sophisticated optimization techniques, namely such as the GA and the NLPQL, which are employed on response surfaces created from several design sampling methods. The optimization is based on three parameters, namely, camber, thickness and chord. A novel airfoil geometry has been introduced. The new airfoil geometry increases the power coefficient by about 42% at the optimized tip speed ratio and increases the peak of the turbine power coefficient by 4% at a low tip speed ratio. However, it was necessary to assess the computational process by examining the mesh and the computational method in order to ensure that the optimized design of the SB-VAWT is only resulting from the optimization process. Therefore, several physical phenomena have been investigate including the dynamic stall, laminar-turbulent transition and laminar bubbles. Also, several computational techniques and schemes have been critically analysed. Further, several mesh independency techniques have been implemented and it was found that the fitting method may be suitable for SB-VAWTs due to the presence of oscillations in the convergence of the power coefficient which may be caused by the presence of dynamic stall, laminar-turbulent transition and laminar bubbles. The physics of these flow conditions are only captured when the transitional model is employed. The optimization of the SB-VAWT in this thesis is based on a 2D model. It was found that the 2D model produce a results similar to the 3D model at mid span of the turbine blade. Therefore, the 2D model of the turbine sufficiently represents the flow physics around the blades qualitatively, and thus the 2D model is employed for the optimization of the SB-VAWT.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.631387  DOI: Not available
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