초록 ▼

The invention relates to a method and a device for regulating the airflow around a blade of a windmill. The device comprise a spoiler, which is provided with a cavity. The spoiler is mounted to a surface of the blade in connection with an another flow regulating unit, and the spoiler can change the

The invention relates to a method and a device for regulating the airflow around a blade of a windmill. The device comprise a spoiler, which is provided with a cavity. The spoiler is mounted to a surface of the blade in connection with an another flow regulating unit, and the spoiler can change the airflow around the blade by assuming different forms. When the spoiler is in a deactivated form no particular changes of the airflow takes place, as the spoiler runs continually and follows the contour of the blade. When the spoiler is in an activated form the airflow, however, is changed in that the spoiler no longer follows the contours of the blade and creates a discontinuity or at least changes the profile of the blade in such way that the airflow conditions are changed. In particular the airflow conditions can be changed so the effect of the second flow regulating unit completely or partly is eliminated. The change of the form takes place by supplying a fluid, such as compressed air or hydraulic oil, to the cavity in the spoiler. The change of the airflow is an advantage in that is thus is possible to regulate the speed of rotation of the rotor, which the blade is mounted on.

대표청구항 ▼

The invention claimed is: 1. Method for regulating the airflow around a windmill blade, said method comprising a step, whereby a spoiler, mounted on the outer side of the blade, is activated and deactivated in order to create a first and respectively second airflow around the blade, characterised i

The invention claimed is: 1. Method for regulating the airflow around a windmill blade, said method comprising a step, whereby a spoiler, mounted on the outer side of the blade, is activated and deactivated in order to create a first and respectively second airflow around the blade, characterised in that said first airflow is used to suppress a flow regulation, which is established by a flow regulating unit, which is arranged in connection with the spoiler and in that said flow regulation eliminates an unintended spoiler effect of said spoiler in its deactivated state. 2. Method according to claim 1, characterised in that the flow regulation provides the aerodynamic profile with a higher lift coefficient or otherwise delays stall to first take place with a higher wind velocity. 3. Method according to claim 1 or claim 2, characterised in that the spoilers change of airflow around the blade changes the flow regulation established by a vortex generator. 4. Method according to any of the claims 1-3, characterised in that the change of airflow around the blade is regulated so that the power output from the windmill is maintained at a certain level in high wind. 5. Device for use when regulating the airflow around a windmill blade, where said device comprises at least one spoiler, which is made from a flexible material, provided with a least one cavity, and where the cavity in a deactivated form has a first volume and in an activated form has a second volume, and where the volume of the cavity can be changed from the deactivated form to the activated form by leading a fluid to the cavity, characterised in that said at least one spoiler is mounted on a surface of the blade, and that a flow regulating unit is provided associated with said at least one spoiler. 6. Device according to claim 5, characterised in that the spoiler constitutes a foil with a outer side, which is determined to face outwards in relation to the surface of the blade, and a inner side, which is determined to face inwards in relation to the surface of the blade, that said inner side of the foil is determined to be fastened to the surface of the blade, and that the cavity is formed between the outer side and the inner side of the foil. 7. Device according to claim 5 or claim 6, characterised in that the foil has a centre area, where the cavity is formed, and which has a thickness T, that said centre area converges against the edge areas, which have a thickness t, and that said thickness t is less than the thickness T. 8. Device according to any of the claims 5-7, characterised in that the centre area of the spoiler, when the spoiler assumes its deactivated form, has a outer side which converges continuously towards the edge areas, and that the centre area of the spoiler, when the spoiler assumes its activated form, at least provides a changed profile for the blade, preferably showing a discontinuity in relation to the surface of the blade. 9. Device according to any of the claims 5-8, characterised in that through the cavity between the outer side of the spoiler and the inner side of the spoiler there are formed reinforcing ribs, which are able to maintain a given minimum distance between the outer side and the inner side of the spoiler, when the device is in its deactivated form. 10. Device according to any of the claims 5-9, characterised in that through the cavity there are formed passageways extending in narrower channels in the cavity, and which runs between wider channels in the cavity, that said passageways are folded together, when the spoiler assumes its deactivated form, and that said passageways are enlarged, when the spoiler assumes its activated form. 11. Device according to any of the claims 5-10, characterised in that the spoiler is brought from its deactivated form to its activated form by filling the cavity with a given volume of fluid, preferably compressed air or another pressurised gas, alternatively hydraulic oil or another fluid. 12. Device according to claims 11, characterised in that the spoiler is brought from its activated form back to its deactivated form by emptying the cavity of fluid with aid from the airflow, which acts on the surface of the blade and on the outer side of the foil, and/or with aid from the centrifugal force acting the fluid. 13. Device according to any of the claims 5-12, characterised in that the spoiler is placed on the suction side of the blade on only a part of the blade. 14. Device according to 13, characterised in that the spoiler is placed in radial positions from innermost 0-30% to outermost 30-80% of the blade length. 15. Device according to 14, characterised in that the spoiler is placed immediate in front of a series of vortex generators with a height in the area of 3-50 mm. 16. Device according to any of the claims 5-15, characterised in that the spoiler is manufactured from rubber, alternatively manufactured from plastic, and preferably is manufactured from an extruded profile of silicone rubber and with a width of 50-250 mm.