Insert assembly, airfoil, gas turbine, and airfoil manufacturing method

1. An insert assembly that is disposed inside a turbine airfoil composed of an airfoil body and an outer shroud and an inner shroud formed respectively at both ends of the airfoil body in a radial direction, and that is provided inside an airfoil air passage through which cooling air is supplied into the airfoil body, the insert assembly comprising:

an insert that is formed as a cylindrical body having a plurality of cooling holes and is fixed to an end of the airfoil body on one side in the radial direction;

a plate-shaped reinforcing member that is provided inside the insert, extends in a direction orthogonal to the radial direction, is fixed at both ends to an inner circumferential surface of the cylindrical body, and is disposed adjacent to an end of the cylindrical body on the other side in the radial direction; and

an annular retaining member that is fixed to an end of the airfoil body on the other side in the radial direction, comes in contact with an end of the insert so as to form a sealing interface on which the insert is slidable in the radial direction, and allows the insert to be positioned relative to the airfoil body in a direction orthogonal to the radial direction.

2. The insert assembly according to claim 1 , wherein the sealing interface is formed on an inner circumferential surface of the end of the insert.

3. The insert assembly according to claim 1 , wherein the sealing interface is formed on an outer circumferential surface of the end of the insert.

4. The insert assembly according to claim 1 , wherein

the retaining member has an L-sectional shape that is tapered toward the one end in the radial direction, and

the retaining member includes:

an annular positioning part that is formed at a leading end on a side of the one end in the radial direction;

a positioning protrusion that is provided adjacent to the positioning part, on a side of the other end in the radial direction, and has a larger diameter than the positioning part; and

a flange that is provided adjacent to the positioning protrusion, on the side of the other end in the radial direction, has a larger diameter than the positioning protrusion, and is fixed to the airfoil body.

5. The insert assembly according to claim 4 , wherein the positioning part is fitted in the radial direction on the end of the insert.

6. The insert assembly according to claim 4 , wherein the positioning protrusion has a side surface thereof fitted in an opening of the airfoil air passage on the side of the one end.

7. The insert assembly according to claim 1 , wherein the reinforcing member is formed so as to cover the entire area of a passage cross-section of an inner cavity surrounded by the insert.

8. The insert assembly according to claim 1 , wherein the reinforcing member has at least one through-hole.

9. The insert assembly according to claim 8 , further comprising a cover plate that closes an opening provided at the other end of the airfoil body.

10. The insert assembly according to claim 9 , wherein

the through-hole formed in the reinforcing member is a vent hole through which dust accumulating in a space inside the insert is removed,

the insert has a dust housing space surrounded by the reinforcing member and the cover plate, and

the retaining member is formed so as to be fittable in the insert with the sealing interface therebetween.

11. The insert assembly according to claim 9 , wherein the cover plate is fixed to the retaining member and the retaining member is integrated with the cover plate.

12. An airfoil comprising the insert assembly according to claim 1 .

13. A gas turbine comprising the airfoil according to claim 12 .

14. An airfoil manufacturing method comprising the steps of:

forming an insert that is insertable into an airfoil air passage that is formed so as to extend from an outer shroud to an inner shroud of an airfoil;

fixing a reinforcing member to an inner circumferential surface of the insert so as to integrate the reinforcing member with the insert;

forming a retaining member that allows a first end of the insert to be positioned relative to the vane air passage;

fixing a flange of the retaining member to a rim of a first opening of the vane air passage;

inserting the insert into the vane air passage through a second opening located on the opposite side from the first opening in which the retaining member is mounted, and positioning the first end of the insert by the retaining member; and

fixing a second end of the insert to a rim of the second opening of the vane air passage.