Date of Award

1-1-2018

Document Type

Dissertation

Degree Name

Ph.D.

Department

Mechanical Engineering

First Advisor

Corinne S. Lengsfeld, Ph.D.

Keywords

Computational Fluid Dynamics, Wind energy, Wind farm land use, Wind farms, Wind turbine

Abstract

In this research, a computational system was designed to analyze and optimize the layout of wind farms under variable operational conditions. At first, a wind turbine computational fluid dynamic (CFD) model was developed covering the near wake. The near wake flow field was validated against near wake velocity data from the MEXICO experiment. The CFD simulation demonstrated that the tip speed ratio and the pitch angle greatly influence the near wake behavior, affecting the velocity deficit and the turbulence intensity profile in this region. The CFD model was extended to cover the far wake, aiming to become a computational tool applicable to propose a solution to the Wind Farm Layout Optimization Problem. The CFD model was then coupled to a MATLAB optimization routine, working in an automated way to find optimized solutions to maximize wind farm land use. The study concludes that it is possible to have a significant improvement on the use of land and output power production by staggering the first row of turbines away from the wake effects. The staggered configuration achieved 10% improvement in the use of land compared with an aligned configuration, both of them working under the same operational conditions. Additionally, control strategies can result in benefits for the wind farm: two cases studies showed improvements within 2.52% and 4.63% in the output power. The last study of this dissertation implemented different inlet velocity profiles to evaluate the impact of vertical wind shear on wake profiles. At the heights analyzed, different velocity inlet profiles did not result in significant changes to the wake of the wind turbine. The velocity deficit remained approximately the same for the three approaches (log law, HRRR and constant inlet) implemented in this work. The vertical wind shear might be more significant at higher altitude and for greater wind turbine diameters. Moreover, a transient model based on LES theory showed that there can be changes in the direction of propagation of the wake when velocity fluctuations are introduced to the model.

Provenance

Received from ProQuest

Rights holder

Rafael Valotta Rodrigues

File size

177 p.

File format

application/pdf

Language

en

Discipline

Energy

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