Adaptive Geometry Wind Turbine Blades for Increased Performance and Load Reduction

Open Access
Author:
Albanese, Leonardo Charles
Graduate Program:
Aerospace Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
  • Farhan Gandhi, Thesis Advisor
  • Farhan S Gandhi, Thesis Advisor
  • Susan W Stewart, Thesis Advisor
Keywords:
  • Adaptable Structures
  • Wind Turbines
Abstract:
Wind energy is becoming an integral part of many nations’ plans for achieving goals on renewable energy production. With wind turbines working to efficiently capture energy at different wind speeds, rotor morphing could potentially increase energy capture over wind speeds up to the rated speed. This study examines what the optimal geometry might look like at different wind speeds below the rated speed, how it might differ from one speed to another, and the increase in power and annual energy production that could be realized with the optimal geometry at each wind speed. A second study is shown that examines possible ways geometry changes used together could result in lower root bending moments while maintaining or increasing power output. Using a blade-element theory based analysis and conducting simulations on the 1.5 MW WindPACT turbine and the 5MW NREL concept offshore turbine, variations in blade twist, collective pitch, chord, radius, and airfoil characteristics were considered. The results indicate that there are negligible benefits to changing blade collective pitch, twist, chord, and airfoil characteristics. Only radius increase has a dominant effect, with 20% increase in radius resulting in power increase of over 45% at 8 and 10 m/s and much higher percentage increases at lower speeds, for both turbines (as the power in the wind increases in proportion to the radius squared). The increase in annual energy production is in the range of 20%. However, a larger radius increases blade loading. In regards to reducing blade loading while maintaining power output, it is seen that it is possible for the 1.5MW WindPACT turbine to decrease root bending moments by over 15% with combinations in pitch and chord changes at the rated speed with negligible changes in power output.