Flow control arrangement for a wind turbine rotor blade
A rotor blade for a wind turbine is provided. The rotor blade includes an aerodynamic device for influencing the airflow flowing from the leading-edge section of the rotor blade to the trailing edge section of the rotor blade. The aerodynamic device is mounted at a surface of the rotor blade and includes a pneumatic or hydraulic actuator, such as a hose a cavity, of which the volume depends on the pressure of a fluid being present inside the pneumatic or hydraulic actuator. The rotor blade further includes a control unit for controlling the pressure of the fluid in the hose or the cavity of the aerodynamic device.
1. A rotor blade for a wind turbine, the rotor blade comprising:
an aerodynamic device for influencing an airflow flowing from the leading edge section of the rotor blade to the trailing edge section of the rotor blade, wherein the aerodynamic device is mounted at a surface of the rotor blade and comprises a pneumatic or hydraulic actuator of which the volume depends on the pressure of a fluid being present inside the pneumatic or hydraulic actuator, and
a control unit for controlling the pressure of the fluid in the pneumatic or hydraulic actuator of the aerodynamic device, wherein
the aerodynamic device is in a first configuration when no pressure application to the fluid in the pneumatic or hydraulic actuator is induced by the control unit,
the aerodynamic device is in a second configuration when the control unit induces the application of a positive or negative pressure to the fluid in the pneumatic or hydraulic actuator,
in the first configuration, at least a first section of the aerodynamic device protrudes away from the surface of the rotor blade into the airflow flowing from the leading edge section of the rotor blade to the trailing edge section of the rotor blade, and
in the second configuration, the first section is positioned closer to the surface of the rotor blade than in the first position.
2. The rotor blade according to claim 1 , wherein the lift of the rotor blade in the first configuration is smaller than the lift of the rotor blade in the second configuration.
3. The rotor blade according to claim 2 , wherein the aerodynamic device comprises a bending part made of flexible material which allows the change of configuration of the aerodynamic device from the first configuration to the second configuration and vice versa.
4. The rotor blade according to claim 3 , wherein the protrusion of the first section away from the surface of the rotor blade is caused, or at least supported, by pretensioning the bending part of the aerodynamic device.
5. The rotor blade according to claim 1 , wherein, in the second configuration of the aerodynamic device, the aerodynamic device is at least partially embedded into a shell of the rotor blade.
6. The rotor blade according to claim 1 , wherein the aerodynamic device extends in parallel to the length axis of the rotor blade.
7. The rotor blade according to claim 1 , wherein the aerodynamic device extends over at least ten percent of the length of the rotor blade.
8. The rotor blade according to claim 1 , wherein the aerodynamic device is placed between the leading edge of the rotor blade and fifty percent of the chord length of the rotor blade, as measured from the leading edge.
9. The rotor blade according to claim 1 , wherein the rotor blade further comprises a flow regulating unit for influencing the airflow flowing from the leading edge section of the rotor blade to the trailing edge section of the rotor blade.
10. The rotor blade according to claim 9 , wherein both the aerodynamic device and the flow regulating unit are mounted on the suction side of the rotor blade.
11. The rotor blade according to claim 9 , wherein the flow regulating unit is placed between the aerodynamic device and the trailing edge of the rotor blade.
12. The rotor blade according to claim 11 , wherein the chordwise distance between the aerodynamic device and the flow regulating unit is between ten percent and fifty percent of the chord length of the rotor blade.
13. The rotor blade according to claim 9 , wherein the flow regulating device is placed between the leading edge of the rotor blade and the aerodynamic device.
14. The rotor blade according to claim 13 , wherein the chordwise distance between the aerodynamic device and the flow regulating unit is between one percent and twenty percent of the chord length of the rotor blade.
15. The rotor blade according to claim 9 , wherein the aerodynamic device itself is equipped with the flow regulating unit.
16. The rotor blade according to claim 9 , wherein the flow regulating unit comprises a vortex generator.
17. A wind turbine for generating electricity comprising at least one rotor blade according to claim 1 .
18. The rotor blade according to claim 1 , wherein the pneumatic or hydraulic activator comprises at least one of a hose and a cavity.