Airfoils for Enhanced Wind Turbine and Cooling Tower Efficiency

Stage: Development
An important parameter for the design of wind turbine blades involves the optimal design of airfoils, the perpendicular cross-sections that span the entire length of the blade. These airfoils significantly impact the total performance of the blade and require a maximum thickness, Reynold’s number, and lift coefficient to mitigate the effects of drag and gravitational forces that reduce power output. Moreover, a blade with a high sensitivity to roughness, especially Horizontal Axis Wind Turbine (HAWT) blades, collects more dirt, bugs, and other airborne contaminants that adversely affect the maximum lift coefficient and total power output. Finally, airfoil induced noise, caused by effects such as inflow turbulence interaction, airfoil thickness, laminar separation bubbles, and boundary layer interaction, hinders the commercialization of both large and small wind turbines and can be mitigated through optimal airfoil design.


This novel airfoil design developed by NREL scientists is optimized for desirable aerodynamic performance and minimal airfoil induced noise for small and large wind turbines. This design involves two airfoil families suitable for horizontal axis wind turbines (HAWTs) and a variety of other wind turbine designs. Each airfoil family provides a high maximum lift coefficient, exhibits docile stalls, remains insensitive to roughness, and achieves a low profile drag. The first family of airfoils maintains maximum lift coefficients of approximately 1.0, 1.1, and 1.2 and Reynold’s numbers around 400,000, 400,000, and 250,000 respectively. The second family of airfoils is designed for use with large wind turbines and blades of 15 to 30 meters in length and has three separate airfoils. The first has a thickness of 21%, a maximum lift coefficient of 1.6, and a Reynold’s number of 4,000,000, the second has a thickness of 18% with a maximum lift coefficient of 1.5 and a Reynold’s number of 3,500,000, and the third maintains a thickness of 15%, a maximum lift coefficient of 1.4, and a Reynold’s number of 2,500,000.


To learn more about Airfoils for Enhanced Wind Turbine and Cooling Tower Efficiency, please contact Erin Beaumont at Erin.Beaumont@nrel.gov.

Applications and Industries

  • Wind Turbines
  • Cooling Tower Fans

Benefits

  • Reduced sensitivity to roughness
  • Enhanced performance and efficiency
  • Greater cost efficiency
  • Reduced operating noise