Modeling of Wind Data and Aerodynamic Analysis of Vertical Axis Wind Turbines

  • Franklyn Kanyako

Student thesis: Master's Thesis

Abstract

The design of wind turbine blades in order to obtain maximum performance begins with the understanding of the aerodynamics forces on the blade. Darrieus Vertical Axis Wind Turbine (VAWT) aerodynamic performance prediction is a very complex task, since its blades move around the rotor axis in a three dimensional aerodynamic environment that lead to several flow phenomena, such as, dynamic stall, flow separation, flow wake deformations low efficiency and their natural inability to self-start. However VAWT present several advantages over Horizontal Axis Wind Turbine (HAWT), they are able to operate at lower wind speeds and are less sensitive to wind direction, which is ideal for low speed regions and urban environment. This thesis used the Blade Element Momentum (BEM) method and Double Multiple Stream Tube (DMST) model to develop a low fidelity performance analysis tool, with additional modification for both HAWT and Darrieus VAWT. 2-D Computational Fluid Dynamics (CFD) was performed using Unsteady Reynolds Average Navier Stokes (URAN) simulation to validate the low fidelity analysis tool for VAWT. The goal was to build to a fast low fidelity analysis tool that eliminates the need for costly experimental measurement for VAWT investigations. This includes the performance of different airfoils, appropriate turbine solidity for low wind environment. The measured wind data of Masdar city was used to investigate the economic feasibility of wind energy implementation in low wind urban environment. The power curves of two commercially available HAWTs, a large size 600 kW and small size 3.5 kW are coupled with the modeled data to account for the annual energy production and capacity factor. Considering the turbine efficiency to evaluate the cost of wind energy implementation, returns on investment are conducted accounting for capital cost, annuity, depreciation and operation and maintenance. The result shows that the BEM and DMST models are very capable tool for low solidity turbine investigation. The economic assessment based on the investment-return shows that the 3.5 kW have better capacity factor when compared to Vestas V44 but both are economically not a viable investment at Masdar due to low wind speed in the region.
Date of Award2014
Original languageAmerican English
SupervisorIsam Janajreh (Supervisor)

Keywords

  • Wind turbines; Wind power; Computational Fluid Dynamics.

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