Wind turbine blade, method of manufacturing wind turbine blade, and use of fabric in composite structure of wind turbine blade

1. A wind turbine blade for a wind turbine, comprising:

at least one composite structure having a length, a width and a thickness, the at least one composite structure comprising a plurality of pultruded elements arranged in at least one stacked structure, wherein at least one infusion-promoting layer is arranged between at least two adjacent pultruded elements within the at least one stacked structure, the at least one infusion-promoting layer has a first permeability parameter, K 1 , in a width direction and further has a permeability parameter, K 2 , in a length direction, wherein K 2 is less than K 1 ,

at least one surrounding layer arranged relative to the at least one composite structure, the at least one surrounding layer has a second permeability parameter, K 1a in the width direction,

K 1 is greater than K 1a , and

wherein a first infusion speed, V 1 , of a resin through the at least one infusion-promoting layer is greater than a second infusion speed, V 1a , of the resin through the at least one surrounding layer.

2. The wind turbine blade according to claim 1 , wherein the at least one infusion-promoting layer is a fabric with unidirectional fibres.

3. The wind turbine blade according to claim 2 , wherein the fibres are orientated between 85-95 degrees relative to the length direction.

4. The wind turbine blade according to claim 2 , wherein the fabric comprises untwisted yarns.

5. The wind turbine blade according to claim 1 , wherein the at least one infusion-promoting layer has an areal weight of 50-300 gram per square meter.

6. The wind turbine blade according to claim 1 , wherein the at least one infusion-promoting layer further has a third permeability parameter, K 3 , in a thickness direction, wherein K 1 is greater than K 3 .

7. The wind turbine blade according to claim 1 , wherein a local width of the at least one infusion-promoting layer corresponds to a local width of the at least one stacked structure or one pultruded element.

8. The wind turbine blade according to claim 1 , wherein the at least one surrounding layer forms part of the composite structure or an aerodynamic shell of the wind turbine blade.

9. The wind turbine blade according to claim 1 , wherein the composite structure forms a spar cap of the wind turbine blade.

10. A method of manufacturing a wind turbine blade, comprising:

providing a plurality of pultruded elements,

further providing at least one surrounding layer, wherein the at least one surrounding layer has a second permeability parameter, K 1a , in a width direction,

arranging the plurality of pultruded elements in at least one stacked structure, wherein at least the infusion-promoting layer is arranged between adjacent pultruded elements within the at least one stacked structure, the at least one infusion-promoting layer has a first permeability parameter, K 1 , in the width direction and further has a permeability parameter, K 2 , in a length direction, wherein K 2 is less than K 1 ,

introducing resin into the at least one stacked structure and the at least one surrounding layer using an infusion process, and

curing the at least one stacked structure with resin to form a composite structure, the composite structure having a length, a width and a thickness,

wherein K 1 is greater than K 1a , so that the resin flows through the at least one infusion-promoting layer at a first infusion speed, V 1 , and further through the at least one surrounding layer at a second infusion speed, V 1a , wherein V 1 is greater than V 1a .

11. The method according to claim 10 , wherein the resin is introduced in a chordwise direction.

12. The method according to claim 10 , wherein the plurality of pultruded elements and infusion-promoting layers are laid up in a blade mould or in a separate mould, and cured when placed the blade mould or separate mould.