Stator vane for 3D composite blower

1. A method of fabricating a guide vane, the method comprising:

a) producing a fiber preform by 3D weaving a single piece, the preform comprising a first portion extending along the longitudinal axis and constituting the preform for the airfoil of the vane, and at a longitudinal end of the first portion, a second portion constituting the preform for the platform of the vane, the second portion being produced as a first layer and a second layer facing the first layer and separated from the first layer by unlinking without cutting while producing the preform;

b) folding the first and second layers such that each of them lies in a plane perpendicular to the longitudinal axis, substantially symmetrically to each other relative to the first portion, and such that a first region of the first layer covers a second region of the second layer in front of a front edge of the first portion;

c) conforming the preform in a mold; and

d) densifying the preform with a polymer matrix.

2. A method according to claim 1 , wherein the first layer and the second layer are substantially identical in volume and shape.

3. A method according to claim 1 , wherein the fiber preform of the first layer is cambered in a zone adjacent to the first portion, and the fiber preform of the second layer is cambered in a zone adjacent to the first portion such that the zone of the first layer and the zone of the second layer that are adjacent to the first portion tend to take up symmetrical positions on respective sides relative to the first portion under influence of the cambering.

4. A method according to claim 1 , wherein prior to conforming the preform in the mold, a third portion situated at the other longitudinal end of the first portion is made in a manner similar to the second portion for purpose of forming another platform.

5. A method according to claim 1 , wherein the first portion includes a metal leading edge fitted on the front edge.

6. A guide vane made of composite material comprising a polymer matrix reinforced by a fiber structure, the vane comprising:

an airfoil-forming first portion and a second portion situated at a longitudinal end of the first portion and forming a platform extending in a plane substantially perpendicular to the airfoil,

wherein all of the fiber elements forming the fiber structure are continuous, and the region of the fiber structure forming the second portion includes a first layer extending in the plane on one side of the airfoil and in front of a front edge of the airfoil, and a second layer extending in the plane on one side of the airfoil and in front of the front edge of the substantially symmetrically to the first layer relative to the airfoil, such that a first region of the first layer covers a second region of the second layer in front of the front edge.

7. A guide vane according to claim 6 , wherein the first layer and the second layer are substantially identical in volume and shape.

8. A guide vane according to claim 6 , wherein the first region of the first layer covers the second region of the second layer over a zone that is substantially rectangular, constituting all of the portion of the platform that is situated in front of the front edge of the airfoil.

9. A guide vane according to claim 6 , wherein the first region of the first layer covers the second region of the second layer over a zone that is substantially triangular, flaring forwards from the front edge of the airfoil.

10. A guide vane according to claim 6 , wherein the surface where the first layer covers the second layer is substantially plane.

11. A guide vane according to claim 6 , further comprising a third portion similar to the second portion and situated at the other longitudinal end of the first portion, the third portion serving to form another platform.

12. A guide vane according to claim 6 , wherein the airfoil includes a metal leading edge fitted on the front edge.

13. A turbomachine including at least one guide vane according to claim 6 .