Flow control method may increase turbine efficiency

Researchers from Syracuse University’s LC Smith College of Engineering and Computer Science (LCS) are testing new active flow control methods to increase the efficiency of large wind turbines under many different wind conditions.

Their approach first estimates the flow conditions over the blade surfaces from surface measurements, then uses the information in an intelligent controller to implement real-time actuation on the blades to control the airflow and increase the overall efficiency of the wind turbine system. The idea may also reduce excessive noise and vibration due to flow separation.

Initial simulation results show that flow control applied on the outboard side of the blade beyond the half radius could significantly enlarge the overall operational range of the wind turbine with the same rated power output, or considerably increase the rated output power for the same level of operational range.

In related research, scientists at the University of Minnesota are attempting to reduce the drag of a wind turbine’s blades, or the resistance felt by the turbine blades as they beat the air.

To do so, the team at the University of Minnesota’s Saint Anthony Falls Lab (SAFL) looked at the effect of creating triangular riblets scored into a coating on a blade’s surface. Through wind-tunnel tests of 2.5MW turbine airfoil surfaces and computer simulations, they have examined the grooves’ efficacy and believe that riblets will increase wind turbine efficiency by about three per cent.