Flow deflection device of a wind turbine

1. A rotor blade of a wind turbine, wherein the rotor blade comprises

a flow deflection device for influencing an airflow flowing from a leading edge section of the rotor blade to a trailing edge section of the rotor blade,

wherein the flow deflection device passively changes its configuration depending on the bending of the rotor blade,

wherein the airflow is influenced such that load on the rotor blade is reduced,

wherein the flow deflection device comprises a base plate disposed atop and secured to a surface of the rotor blade, and a lid comprising a first surface portion and a second surface portion, the lid disposed atop and secured to the base plate, and

wherein the first surface portion and the second surface portion fold up when bending of the rotor blade is above a pre-determined threshold bending value, thereby forming a gap between the base plate and the first and the second surface portions, such that the first and the second surface portions form a ramp that guides the airflow away from the surface of the rotor blade.

2. The rotor blade according to claim 1 ,

wherein the flow deflection device is arranged on a suction side of the rotor blade.

3. The rotor blade according to claim 2 ,

wherein the flow deflection device is arranged upstream with regard to a vortex generator mounted to the surface of the rotor blade.

4. The rotor blade according to claim 2 ,

wherein the flow deflection device is a part of a retrofit kit for an existing rotor blade of a wind turbine.

5. The rotor blade according to claim 1 ,

wherein the flow deflection device continuously changes its configuration depending on the bending of the rotor blade.

6. A method to reduce load on a rotor blade of a wind turbine, wherein an airflow flowing from a leading edge section of the rotor blade to a trailing edge section of the rotor blade is passively influenced by a flow deflection device, the method comprising:

inducing a change of the configuration of the flow deflection device by bending of the rotor blade, and

influencing the airflow with the flow deflection device such that the load on the rotor blade is reduced,

wherein the flow deflection device comprises a base plate disposed atop and secured to a surface of the rotor blade, and a first surface portion and a second surface portion both disposed atop and secured to the base plate, and

wherein the first surface portion and the second surface portion fold up when bending of the rotor blade is above a pre-determined threshold bending value, thereby forming a gap between the base plate and the first and the second surface portions, such that the first and the second surface portions form a ramp that guides the airflow away from the surface of the rotor blade.

7. The method according to claim 6 ,

wherein the flow deflection device is retrofitted to the wind turbine.

8. The method according to claim 6 ,

wherein, the flow deflection device continuously changes its configuration depending on the bending of the rotor blade.

9. A rotor blade of a wind turbine, wherein the rotor blade comprises:

a flow deflecting device comprising a base plate disposed atop and secured to a surface of the rotor blade, and a lid disposed atop the base plate;

wherein during deflection of the rotor blade the lid translates relative to the base plate to an unstowed configuration;

wherein in the unstowed configuration airflow is redirected to reduce a load on the rotor blade; and

wherein the lid comprises two panels, each panel individually secured to the base plate at a first end and not secured to the base plate at a second end, wherein the translation comprises the second ends moving relative to the base plate and apart from each other, thereby forming a flow channel therebetween into which the airflow is redirected.

10. A rotor blade of a wind turbine, wherein the rotor blade comprises:

a flow deflecting device comprising a base plate disposed atop and secured to a surface of the rotor blade, and a lid disposed atop the base plate;

wherein during deflection of the rotor blade the lid translates relative to the base plate to an unstowed configuration;

wherein in the unstowed configuration airflow is redirected to reduce a load on the rotor blade; and

wherein the lid is secured to the base plate in two locations, wherein the two locations are separated by a region of the lid, wherein the translation comprises the region lifting off the base plate to form a ramp that redirects the airflow.

11. The rotor blade of claim 10 , wherein the base plate conforms to a curvature of the surface of the rotor blade during the deflection.