Georgia Tech and PAX Streamline win grant to reduce cost of wind turbines for generating electricity

A technology originally developed to increase lift in aircraft wings and simplify helicopter rotors could help reduce the cost of manufacturing and operating wind turbines.

01/19/2010


Supported by a $3 million grant from the Advanced ResearchProjects Agency-Energy -- the federal energy research and developmentorganization also known as ARPA-E -- a two-year research project aimed atadapting circulation control technology to wind turbine blades will beconducted by PAX Streamline, in collaboration with the Georgia Institute ofTechnology.nd speed.

Georgia Tech Wind Tunnel Research

Working in a Georgia Tech Research Institute wind tunnel on an unmanned aerial vehicle test, senior research engineers Rick Gaeta, left, and Gary Gray check a propeller that has been attached to a dynamometer for testing. Source: Georgia Tech.


Circulation control techniques use compressed air blown from

slots on the trailing edges of wings or hollow blades to change the aerodynamic

properties of those wings or blades.  In

aircraft, circulation control wings improve lift, allowing aircraft to fly at

much lower speeds -- and take off andland in much shorter distances.  In helicopter rotor blades, the technique --

also known as the "circulation control rotor" -- simplifies the rotor

and its control system and produces more lift.

"Our goal will be to make generation of electricity

from wind turbines less expensive by eliminating the need for the complex blade

shapes and mechanical control systems used in current turbines," said

Robert J. Englar, principal research engineer at the Georgia Tech ResearchInstitute (GTRI).  "Because these

new blades would operate effectively at lower wind speeds, we could potentially

open up new geographic areas to wind turbine use.  Together, these advances could significantly

expand the generation of electricity from wind power in the United States."

The ARPA-E project will apply the technique to controlling

the aerodynamic properties of wind turbine blades, which now must be made in

complicated shapes and controlled by complex control mechanisms to extract

optimal power from the wind. 

"The speed at which these turbines would begin to

operate will be much lower than with existing blades," said Englar.  "Places that wind maps have previously

indicated would not be suitable locations for wind turbines may now be

useful.  The blown technology should also

allow safe operation at higher wind speeds and in wind gusts that would cause

existing turbines to be shut down to prevent damage. "

Because they would produce more aerodynamic force, torque

and power than comparable blades, these blown structures being developed by

Georgia Tech and PAX could also allow a reduction in the size of the wind

turbines.

"If you need a specific amount of wind force and torque

generated by the wind turbine to generate electricity, we could get that force

and torque from a smaller blade area because we'd have more powerful lifting

surfaces," Englar explained. 

A major question awaiting study is how much energy will be

required to produce the compressed air the blown blades need to operate.  Preliminary studies done by Professor Lakshmi

Sankar in Georgia Tech's School of Aerospace Engineering suggest that wind

turbines with the blown blades could produce 30 to 40 percent more power than

conventional turbines at the same wind speed -- even when the energy required

to produce the compressed air is subtracted from the total energy production.

The new turbine blades will be developed at GTRI's low-speed

wind tunnel research facility located in Cobb

County, north of Atlanta. 

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- Edited by David Greenfield , editorial director
Control Engineering Sustainable Engineering
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