Tip air receptor
Disclosed is a tip section for a wind turbine blade. The tip section comprises an intermediary blade section comprising a first shell part forming a first side of the intermediary blade section and a second shell part forming a second side of the intermediary blade section, the intermediary blade section having a leading edge and a trailing edge and extending from an intermediary blade section first end to an intermediary blade section second end; a tip part forming an end of the tip section and having been rigidly attached to the intermediary blade section first end, the tip part having an outer surface comprising a metal area; and a number of one or more superficial metal strips extending along an outer surface of the intermediary blade section. A wind turbine blade with such a tip section and the manufacturing of such a wind turbine blade is also disclosed.
1. A replaceable wind turbine blade tip section ( 301 , 302 , 303 , 1301 ) for a wind turbine blade, the replaceable wind turbine blade section ( 301 , 302 , 303 , 1301 ) being configured for attachment to a main blade section, the replaceable wind turbine blade section ( 301 , 302 , 303 , 1301 ) comprising:
an intermediary blade section ( 310 ) comprising a first shell part ( 310 a ) forming a first side of the intermediary blade section ( 310 ) and a second shell part ( 310 b ) forming a second side of the intermediary blade section ( 310 ), the intermediary blade section ( 310 ) having a leading edge ( 18 ) and a trailing edge ( 20 ) and extending from an intermediary blade section first end ( 321 ) to an intermediary blade section second end ( 322 ),
a tip part ( 312 ) forming an end of the tip section ( 301 , 302 , 303 , 1301 ) and having been rigidly attached to the intermediary blade section first end ( 321 ), the tip part ( 312 ) having an outer surface comprising a metal area,
a number of one or more superficial metal strips ( 314 a , 314 b ) extending along an outer surface of the intermediary blade section ( 310 ), wherein each of the one or more superficial metal strips ( 314 a , 314 b ) has a first end connected to the metal area of the tip part ( 312 ), and a second end configured for electrical connection to a downconductor cable ( 351 , 352 , 353 ) of the main blade section.
2. The replaceable wind turbine blade tip section in accordance with claim 1 , wherein at least one of the superficial metal strips ( 314 a , 314 b ) is arranged at a distance from the leading edge ( 18 ) and the trailing edge ( 20 ).
3. The replaceable wind turbine blade tip section in accordance with claim 1 , wherein at least one of the superficial metal strips ( 314 a , 314 b ) is placed near a thickest portion of the intermediary blade section ( 310 ).
4. The replaceable wind turbine blade tip section in accordance with claim 1 , wherein a chordwise position of a centerline of at least one of the superficial metal strips ( 314 a , 314 b ) lies in the range x=0.2 to x=0.7, where x is the chordwise airfoil coordinate and x=0 coincides with the leading edge ( 18 ) and x=1 coincides with the trailing edge ( 20 ).
5. The replaceable wind turbine blade tip section in accordance with claim 1 , wherein the one or more superficial metal strips ( 314 a , 314 b ) are substantially parallel to a longitudinal axis of the intermediary blade section ( 310 ).
6. The replaceable wind turbine blade tip section in accordance with claim 1 , wherein the one or more superficial metal strips ( 314 a , 314 b ) are arranged in recesses in the first and second shell parts ( 310 a , 310 b ) to achieve a flush surface around the one or more superficial metal strips ( 314 a , 314 b ).
7. The replaceable wind turbine blade tip section in accordance with claim 1 , further comprising:
a downconductor coupler ( 316 ) arranged inside the intermediary blade section ( 310 ), the tip part ( 312 ) being electrically connected to the downconductor coupler ( 316 ) only via the one or more superficial metal strips ( 314 a , 314 b ).
8. A method of manufacturing a wind turbine blade having a root end and a tip end, comprising:
providing a first blade part ( 330 ) having an airfoil region, a root end connectable to a wind turbine hub, and a first end ( 323 , 1305 ) opposite the root end,
providing the replaceable wind turbine blade tip section ( 301 , 302 , 303 , 1301 ) in accordance with claim 7 , and
rigidly joining the first end ( 323 , 1305 ) of the first blade part ( 330 ) to the intermediary blade section second end ( 322 ).
9. The method in accordance with claim 8 , further comprising surrounding the downconductor coupler ( 316 ) with a non-conductive material.
10. The replaceable wind turbine blade tip section in accordance with claim 7 , wherein the downconductor coupler ( 316 ) comprises a metal piece that extends to an outer surface of the first shell part ( 310 a ) and is electrically connected to exactly one of the number of one or more superficial metal strips ( 314 a , 314 b ).
11. The replaceable wind turbine blade tip section in accordance with claim 7 , wherein the number of superficial metal strips ( 314 a , 314 b ) is exactly two, wherein a first metal strip of the two superficial metal strips ( 314 a , 314 b ) is arranged on the first side of the intermediary blade section ( 310 ), and a second metal strip of the two superficial metal strips ( 314 a , 314 b ) is arranged on the second side of the intermediary blade section ( 310 ).
12. The replaceable wind turbine blade tip section in accordance with claim 11 , wherein the downconductor coupler ( 316 ) comprises a metal piece that extends to an outer surface of the first shell part ( 310 a ) where it is electrically connected to the first metal strip, and the metal piece of the downconductor coupler ( 316 ) further extends to an outer surface of the second shell part ( 310 b ) where it is electrically connected to the second metal strip.
13. The replaceable wind turbine blade tip section in accordance with claim 1 , wherein a length, Lint, of the intermediary blade section ( 310 ) is in the range 15-100 cm.
14. The replaceable wind turbine blade tip section in accordance with claim 1 , wherein the tip part ( 312 ) is made of copper or a copper alloy.
15. The replaceable wind turbine blade tip section in accordance with claim 1 , wherein a length, Lstrip, of all of the superficial metal strips ( 314 a , 314 b ) is in the range 20-110 cm, a width, W, of all of the superficial metal strips ( 314 a , 314 b ) is in the range 30-100 mm, a thickness of all of the superficial metal strips ( 314 a , 314 b ) is in the range 2-30 mm, and a length, Ltip, of the tip part ( 312 ) is in the range 30-200 mm.
16. A wind turbine blade having a root end and a tip end, wherein the wind turbine blade comprises the replaceable wind turbine blade tip section ( 301 , 302 , 303 , 1301 ) in accordance with claim 1 .
17. The wind turbine blade in accordance with claim 16 , wherein the wind turbine blade comprises a first blade part ( 330 ) having an airfoil region ( 34 ), a root end ( 31 ) connectable to a wind turbine hub, and a first end ( 323 , 1305 ) opposite the root end ( 31 ), the first end ( 323 , 1305 ) of the first blade part ( 330 ) being rigidly joined to the tip section at the intermediary blade section second end ( 322 ).
18. The wind turbine blade in accordance with claim 17 , wherein a thickness of a wall of the first blade part ( 330 ) at the first end ( 323 ) comprises a step ( 1331 , 1332 ) that overlaps with a wall of the intermediary blade section ( 310 ) to form a flush blade surface.
19. The wind turbine blade in accordance with claim 16 , wherein the one or more superficial metal strips ( 314 a , 314 b ) are substantially parallel to a longitudinal axis of the first blade part ( 330 ).