Wind turbine blade with a fairing

1 . A method of assembling a wind turbine blade extending along a longitudinal axis from a root to a tip, the wind turbine blade comprising a root region and an airfoil region with the tip, the wind turbine blade comprising a chord line extending between a leading edge and a trailing edge, the wind turbine blade comprising an aerodynamic exterior blade surface including a pressure side and a suction side, the method comprising:

providing a prefabricated structural blade body comprising:

a first exterior body surface defining part of the pressure side,

a second exterior body surface defining part of the suction side,

a first attachment surface located adjacent to the first exterior body surface, and

a second attachment surface located adjacent to the second exterior body surface;

separately providing a prefabricated fairing extending along the longitudinal axis, the fairing extends along a fairing profile terminating at a first fairing lip of the fairing and at a second fairing lip of the fairing, the fairing comprising:

an exterior fairing surface positioned exteriorly relative to the fairing profile,

an interior fairing surface positioned interiorly relative to the fairing profile, and

one or more fibre-reinforced layers extending from the first fairing lip to the second fairing lip and along the longitudinal axis,

wherein the fairing has a first fairing state and a second fairing state, wherein the fairing lips are forced toward each other in the second fairing state relative to the first fairing state;

while the fairing is in the first fairing state, arranging the fairing so that the interior fairing surface faces the attachment surfaces of the blade body and gaps are present respectively between the first attachment surface of the blade body and the first fairing lip of the fairing and between the second attachment surface of the blade body and the second fairing lip of the fairing;

applying a compression force onto the fairing lips to deform the one or more fibre-reinforced layers of the fairing from the first fairing state to the second fairing state so that the first fairing lip and the first attachment surface are brought into contact with a first adhesive and so that the second fairing lip and the second attachment surface are brought into contact with a second adhesive; and

while maintaining the compression force, curing the first and second adhesives to fix the fairing in its second fairing state to the blade body so that the exterior fairing surface defines a part of the exterior blade surface arranged flush with the first exterior body surface and the second exterior body surface and so that the exterior fairing surface defines either the leading edge of the wind turbine blade or the trailing edge of the wind turbine blade,

wherein the fairing further has a relaxed fairing state in which the fairing is relaxed and wherein the fairing lips are expanded away from each other in the first and second fairing states relative to the relaxed fairing state.

2 . The method according to claim 1 , further comprising:

providing a jig extending along the longitudinal axis and along a jig profile terminating at a first jig lip of the jig and at a second jig lip of the jig and corresponding in shape to the fairing profile, the jig further comprising an interior jig surface positioned interiorly relative to the jig profile and matching the exterior fairing surface of the fairing, wherein the jig has a first jig state and a second jig state, wherein the jig profile in the first jig state matches the fairing profile in the first fairing state and the jig profile in the second jig state matches the fairing profile in the second fairing state.

3 . The method according to claim 2 , wherein the method comprises, prior to the arranging the fairing:

applying an expansion force on the jig lips to expand jig lips of the jig;

positioning the fairing in the relaxed fairing state in the jig so that the exterior fairing surface contacts the interior jig surface; and

releasing the expansion force until the jig and the fairing are deformed to the first jig state and the first fairing state, respectively;

wherein the compression force is applied onto the exterior fairing surface at the fairing lips so that the jig and the fairing are deformed to the second jig state and the second fairing state, respectively.

4 . The method according to claim 2 , wherein the jig has a relaxed jig state and wherein the jig lips are expanded in the first jig state and second jig state relative to the relaxed jig state, wherein the step of applying the compression force is at least partly achieved by a spring back force of the jig upon releasing the expansion force on the jig lips.

5 . The method according to claim 1 , further comprising:

providing one or more clamping tool sets, wherein each clamping tool set comprises:

a first clamping tool having a first clamping head and being secured to the blade body adjacent to one of the attachment surfaces, and

a second clamping tool having a second clamping head and being secured to the blade body adjacent to the other one of the attachment surfaces,

wherein the applying the compression force is at least partly achieved by actuating the clamping tools of each clamping tool set to urge the clamping heads to apply the compression force onto the fairing.

6 . The method according to claim 1 , wherein the compression force is at least partly applied by inflating one or more bladders.

7 . The method according to claim 1 , further comprising:

providing one or more alignment tool sets, wherein each alignment tool sets comprises:

a first tool pair including a first jig tool part secured to one of the fairing lips or jig lips, and a first blade tool part secured to the blade body or a fixture lip adjacent to the corresponding attachment surface; and

a second tool pair including a second jig tool part secured to the other fairing lip or jig lip, and a second blade tool part secured to the blade body or another fixture lip adjacent to the corresponding other attachment surface, respectively;

wherein one of the first jig tool part and the first blade tool part of each tool pair comprises a pin and the other one of the first jig tool part and the first blade tool part of each tool pair comprises a guide, the guide being configured for retaining the respective pin while allowing the pin to move along a predefined guide course from a pin entry position to a pin terminal position,

wherein the arranging the fairing comprises inserting each pin in the respective guide to the pin entry position to bring the fairing to the first fairing state, each pin being retained in the respective guide, and

wherein the applying the compression force causes each pin to move from the pin entry position to the pin terminal position of the respective guide.

8 . The method according to claim 7 , wherein the guide of each tool pair comprises a sloping section between a pin entry position and a first pin position, wherein the inserting each pin in the respective guide comprises sliding each pin along the sloping section of the respective guide from the pin entry position to the first pin position to gradually increase the expansion force on the jig lips.

9 . The method according to claim 7 , further comprising:

providing a fixture comprising a fixture profile terminating at a first fixture lip of the fixture and at a second fixture lip of the fixture; and

securing the fixture on the exterior blade surface of the blade body so that the first fixture lip and the second fixture lip are positioned adjacent to the first attachment surface and the second attachment surface, respectively;

wherein the blade tool parts of the one or more alignment tool sets are fixed to the fixture thereby securing the blade tool parts to the blade body, and/or

wherein the first clamping tool and/or the second clamping tool is/are fixed to the fixture thereby securing the clamping tool(s) to the blade body.

10 . The method according to claim 1 , wherein a difference between a first fairing lip distance and a second fairing lip distance is equal to or greater than 5 mm, the first fairing lip distance corresponding to a distance between the fairing lips when the fairing is in the first fairing state, and the second fairing lip distance corresponding to a distance between the fairing lips when the fairing is in the second fairing state, the first fairing lip distance being greater than the second fairing lip distance.

11 . A kit of parts for assembly into a wind turbine blade extending along a longitudinal axis from a root to a tip, the wind turbine blade comprising a root region and an airfoil region with the tip, the wind turbine blade comprising a chord line extending between a leading edge and a trailing edge, the wind turbine blade comprising an aerodynamic exterior blade surface including a pressure side and a suction side, the kit of parts comprising:

a prefabricated structural blade body-comprising:

a first exterior body surface defining part of the pressure side,

a second exterior body surface defining part of the suction side,

a first attachment surface located adjacent to the first exterior body surface, and

a second attachment surface located adjacent to the second exterior body surface;

a prefabricated fairing extending along the longitudinal axis and along a fairing profile terminating at a first fairing lip of the fairing and at a second fairing lip of the prefabricated fairing, the fairing comprising:

an exterior fairing surface positioned exteriorly relative to the fairing profile;

an interior fairing surface positioned interiorly relative to the fairing profile; and

one or more fibre-reinforced layers extending from the first fairing lip to the second fairing lip and along the longitudinal axis;

wherein the prefabricated fairing is configured for being fixed to the blade body so that the exterior fairing surface defines a part of the exterior blade surface connecting the first exterior body surface and the second exterior body surface, and so that the exterior fairing surface defines either the leading edge of the wind turbine blade or the trailing edge of the wind turbine blade;

wherein the fairing has a first fairing state in which the fairing is adapted to be mounted to a blade body prior to being fixed and has a second fairing state in which the fairing is adapted to be fixed to the blade body, the fairing lips of the fairing being compressed towards each other in the second fairing state relative to the first fairing state,

wherein the one or more fibre-reinforced layers of the fairing are configured for being deformed so that, upon application of a compression force onto the exterior fairing surface at fairing lips, the fairing is brought from the first fairing state to the second fairing state; and

a jig extending along the longitudinal axis and along a jig profile terminating at a first jig lip of the jig and at a second jig lip of the jig, the jig comprising:

an interior jig surface positioned interiorly relative to the jig profile and configured to match and receive the exterior fairing surface of the fairing,

wherein the jig has a first jig state and a second jig state, wherein the jig profile in the first jig state matches the fairing profile in the first fairing state and the jig profile in the second jig state matches the fairing profile in the second fairing state

wherein the kit of parts further comprising one or more alignment tool sets each including:

a first tool pair including a first jig tool part and a first blade tool part secured to one of the fairing lips and to the blade body adjacent to the corresponding attachment surface, respectively; and

a second tool pair including a second jig tool part and a second blade tool part secured to the other fairing lip and to the blade body adjacent to the corresponding other attachment surface, respectively;

wherein one of the tool parts of each tool pair comprises a pin and the other one of the tool parts of each tool pair comprises a guide configured for retaining the respective pin while allowing the pin to move along a predefined guide course from a pin entry position to a pin terminal position;

wherein each tool pair is configured so that, when the pin is positioned in the pin entry position in the respective guide, the fairing is in the first fairing state, and so that, when the pin has been moved from the pin entry position to the pin terminal position along the predefined guide course, the fairing is in the second fairing state.

12 . The kit of parts according to claim 11 , further comprising one or more clamping tool sets each comprising:

a first clamping tool having a first clamping head and configured for being secured to the blade body adjacent to one of the attachment surfaces; and

a second clamping tool having a second clamping head and being secured to the blade body adjacent to the other one of the attachment surfaces;

wherein each clamping tool set is configured for actuating the clamping tools of each clamping tool set to urge the clamping heads to apply a compression force (Fc) onto the exterior fairing surface.

13 . The kit of parts according to claim 11 , wherein the jig comprises one or more bladders configured for, when being inflated, forcing the jig lips ( 62 , 63 ) towards each other to bring the jig to the second jig state.

14 . A wind turbine blade extending along a longitudinal axis from a root to a tip, the wind turbine blade comprising a root region and an airfoil region with the tip, the wind turbine blade comprising a chord line extending between a leading edge and a trailing edge thereof, the wind turbine blade comprising an aerodynamic exterior blade surface including a pressure side and a suction side, the wind turbine blade comprising:

a structural blade body; and

a prefabricated fairing extending along the longitudinal axis and along a fairing profile terminating at a first fairing lip of the fairing and at a second fairing lip of the fairing, the fairing comprising:

an exterior fairing surface positioned exteriorly relative to the fairing profile;

an interior fairing surface positioned interiorly relative to the fairing profile; and

one or more fibre-reinforced layers extending from the first fairing lip to the second fairing lip and along the longitudinal axis;

wherein the fairing has a relaxed fairing state in which the fairing profile assumes an unloaded shape, a first fairing state, has a second fairing state,

wherein the fairing is mounted to the structural blade body in the first fairing state

wherein the fairing is attached to the structural blade body in the second fairing state; and

wherein the fairing lips of the fairing are expanded away from each other in the first and second fairing states relative to the relaxed fairing state.

15 . The wind turbine blade according to claim 14 , wherein the one or more fibre-reinforced layers forms part of a plurality of layers further including an exterior erosion-resistant elastomer layer forming at least a portion of the exterior fairing surface and being configured for defining the leading edge of the wind turbine blade, wherein the exterior erosion-resistant elastomer layer is made of polyurethane.

16 . The wind turbine blade according to claim 14 , further comprising a cured first resin binding an erosion-resistant elastomer layer and the one or more fibre-reinforced layers together.