Gas turbine guide vane segment and method of manufacturing

1. A gas turbine guide vane segment, comprising:

a first guide vane part comprising an aerofoil and a first platform section, the first platform section being a segment of a boundary wall for a working fluid during operation, and

a second guide vane part comprising a second platform section and a seal section, the second platform section being a segment of the boundary wall for a working fluid during operation and the seal section being an element of a seal arrangement at an, in respect of a flow direction of the working fluid, upstream end of the gas turbine guide vane segment,

wherein the first guide vane part and the second guide vane part are separately manufactured parts joined together such that the second platform section defines a leading edge of the gas turbine guide vane segment and such that the first platform section and the second platform section form an aligned common platform surface of the gas turbine guide vane segment,

wherein the first platform section comprises slots in a surface facing the working fluid of the first platform section for guiding cooling fluid along the surface facing the working fluid of the first platform section for film cooling of the surface facing the working fluid, the slots located at an upstream bend of the first platform section, and

wherein the second platform section comprises grooves in the second platform section for guiding a film cooling fluid directly onto the surface facing the working fluid, the grooves located at a down-stream end of the second platform section and the grooves located on a surface of the second platform section facing away from the working fluid.

2. The gas turbine guide vane segment according to claim 1 , wherein the slots are distributed along the upstream bend.

3. The gas turbine guide vane segment according to claim 1 , wherein the slots have a continuous reducing depth in downstream direction.

4. The gas turbine guide vane segment according to claim 3 , wherein the grooves have a continuous increasing depth in downstream direction.

5. The gas turbine guide vane segment according to claim 3 , wherein the grooves and the slots are aligned in pairs to allow cooling fluid from the grooves into the slots during operation.

6. The gas turbine guide vane segment according to claim 1 , wherein the grooves are distributed along a downstream rim of the second platform section.

7. The gas turbine guide vane segment according to claim 1 ,

wherein the second guide vane part comprises a connecting wall lateral to the second platform section which is connected to the second platform section,

wherein the second platform section comprises a front-section,

wherein the connecting wall provides a plurality of cooling fluid holes, the plurality of cooling fluid holes being angled onto a back face of the front-section.

8. The gas turbine guide vane segment according to claim 7 , wherein the plurality of cooling fluid holes through the connecting wall are each aligned with cooling fluid passages in a front wall of the first guide vane part.

9. The gas turbine guide vane segment according to claim 1 , wherein the second guide vane part comprises a flange substantially parallel to the second platform section, the flange being a component of the seal section as a barrier for the working fluid during operation.

10. The gas turbine guide vane segment according to claim 1 , wherein the seal section forms a non-contact seal with a further element of the seal arrangement.

11. The gas turbine guide vane segment according to claim 1 , wherein the first guide vane part and the second guide vane part are joined together such that the first guide vane part and the second guide vane part are joined inseparably.

12. The gas turbine guide vane segment according to claim 1 , wherein the grooves abut the slots so that the cooling fluid exits the grooves and directly enters the slots.

13. A gas turbine guide vane segment, comprising:

a first guide vane part comprising an aerofoil and a first platform section, the first platform section being a segment of a boundary wall for a working fluid during operation, and

a second guide vane part comprising a second platform section and a seal section, the second platform section being a segment of the boundary wall for a working fluid during operation and the seal section being an element of a seal arrangement at an, in respect of a flow direction of the working fluid, upstream end of the gas turbine guide vane segment,

wherein the first guide vane part and the second guide vane part are separately manufactured parts joined together such that the second platform section defines a leading edge of the gas turbine guide vane segment and such that the first platform section and the second platform section form an aligned common platform surface of the gas turbine guide vane segment,

wherein the first guide vane part and the second guide vane part are joined inseparably via brazing,

wherein the first platform section comprises slots in a surface facing the working fluid of the first platform section for guiding cooling fluid along the surface facing the working fluid of the first platform section for film cooling of the surface facing the working fluid, the slots located at an upstream bend of the first platform section, and

wherein the second platform section comprises grooves in the second platform section for guiding a film cooling fluid directly onto the surface facing the working fluid, the grooves located at a down-stream end of the second platform section and the grooves located on a surface of the second platform section facing away from the working fluid.