Numerical Study Of The Gurney Flap On The Aerodynamic Performance Of Wind Turbine Blades

With the development of society,the need for energy has increasedconstantly.For the worry about pollution to the world,developing and exploiting newenergy source,especially renewable energy sources,has been an urgent task for eachcountry.Wind energy,as one kind of renewable energy sources,which can be used inlarge scales,has been paid a lot of attention to,and has gained great development inrecent years.Improving the airfoil’s lift coefficient can effectively improve the lift of theblade under the condition of the same wind speed and equal blade area.Althoughpeople have tried a number of technical measures to increase the lift of the windturbine blade,but the easiest program to carry out is the Gurney flap.This paperreviews the status of the apply and research methods of Gurney flap in the windturbine,and using steady CFD numerical simulation method to study the Gurney flap.According to the U.S. National Renewable Energy Laboratory (NREL) S809airfoil,the two-dimensional CFD model S809airfoil and Gurney flap was establishedfor numerical simulation, The results verified the correctness and reliability of thesteady numerical calculation model.The results show that after adding a Gurneyflap,behind the flap an alternate shedding Karman vortex produced,which makes thefluid flows through the upper airfoil surface after Gurney flaps not only have noseparation,but speed increased,which also makes the airfoil suction enhanced,thusincrease the circulation of the airfoil and at most angle of attack the airfoil’s liftcoefficient have increased than the original,and the airfoil’s lift-drag ratio increasedin the low angle of attack.According to the national renewable energy laboratory(NREL) in the low speed wind tunnel Ames of two-blade fixed speed stall windturbine models,established wind turbine model,including blades,hub and Gurney flapfor three-dimensional CFD numerical simulation.Steady simulation results showthat,blade’s surface pressure distribution is more uniform if add Gurney flap at60%-80%R,and the pressure coefficient has also been significantly improved. Add aGurney flap that there can be significantly improved blade lift.