Turbine vane with cooled fillet

1. A vane comprising:

a platform; and

an airfoil extending from said platform and connected to the platform by a fillet, wherein the airfoil which extends in longitudinal direction away from the platform has a pressure side and a suction side with a pressure side wall and a suction side wall, which join at a leading edge and at a trailing edge;

an impingement tube inserted into said airfoil delimiting a cooling channel between the impingement tube and the side walls;

a baffle structure positioned adjacent said fillet which follows an inside contour of the fillet and delimits a first cooling passage between the fillet and the baffle structure, a first obstruction arranged on an inside of the airfoil at the connection of the fillet to the side walls, the first obstruction separating the first cooling passage from the cooling channel;

a second impingement structure adjacent the platform delimits a second cooling passage between the platform and the second impingement structure; and

a second obstruction arranged on an inside of the platform and separates the first cooling passage from the second cooling passage.

2. The vane according to claim 1 , wherein the baffle structure comprises impingement holes for impingement cooling of the fillet.

3. The vane according to claim 1 , wherein the second impingement structure follows a contour of the platform.

4. The vane according to claim 3 , wherein the second obstruction is arranged on the inside of the platform at the connection between the second cooling passage and the first cooling passage for separating the first cooling passage.

5. The vane according to claim 4 , wherein the second obstruction spans around a circumference of the fillet.

6. The vane according to claim 4 , wherein the second obstruction extends around the leading edge and or the trailing edge for shielding the impingement cooling of the fillet from a cross flow of cooling gas coming from the second cooing passage towards the first cooing passage in a leading edge region and/or a trailing edge region of the fillet.

7. The vane according to claim 3 , wherein the second cooling passage is connected to the first cooling passage such that cooling gas flows from the second cooling passage to first cooling passage for subsequent convective cooling of the fillet during operation.

8. The vane according to claim 1 , wherein the first cooling passage has an opening to the impingement tube such that cooling gas flows from first cooling passage into the impingement tube for subsequent impingement cooling of the airfoil during operation.

9. The vane according to claim 1 , wherein the fillet comprises a row of film cooling holes arranged in the fillet wall such that during operation cooling gas is used for film cooling of the fillet after impingement cooling and/or in that the platform comprises a convective cooling hole arranged in the platform such that during operation cooling gas is used for convective cooling of the platform after impingement cooling.

10. The vane according to claim 1 , wherein the fillet has a curved shape with an outer surface facing hot gases during operation wherein a curvature of the fillet is tangential to an outer surface of the platform at the connection of the fillet to the platform and tangential to an outer surface of the airfoil at the connection of the fillet to the airfoil.

11. The vane according to claim 1 , wherein a wall thickness of fillet is equal to a wall thickness of the platform at the connection to the platform and in that the wall thickness of the fillet is equal to a wall thickness of airfoil side walls at the connection to the airfoil side walls wherein the wall thickness of the fillet continuously decreases or continuously increases along an extension of the fillet from the platform to the airfoil side walls.

12. The vane according to claim 1 , wherein the impingement tube is arranged in a leading edge section of the airfoil and a convective cooling section is arranged in a trailing edge section of the airfoil wherein the convective cooling section is divided into a first convective cooling section adjacent to the platform and into a second convective cooling section extending towards an opposite end of the airfoil by a wall.

13. The vane according to claim 12 , wherein a cooling gas feed connects the first cooling passage to the first convective cooling section for directly feeding cooling gas from the first cooling passage to first convective cooling section.

14. A method for cooling a vane, wherein the vane includes a platform, an airfoil extending form said platform and connected to the platform by a fillet, wherein the airfoil which extends in longitudinal direction away from the platform has a pressure side and a suction side with a pressure side wall and a suction side wall, respectively, which join at a leading edge and at a trailing edge, and an impingement tube inserted into said airfoil delimiting a cooling channel between the impingement tube and the pressure and suction side walls; the method of cooling the vane comprising:

supplying cooling gas to a baffle structure positioned adjacent the fillet which follows an inside contour of the fillet;

delimiting a first cooling passage between the fillet and the baffle structure;

impinging the cooling gas onto the fillet for impingement cooling;

guiding the cooling gas via an obstruction arranged on an inside of the airfoil at the connection of the fillet to the pressure and suction side walls into the impingement tube; and

impinging the cooling gas on the pressure and suction side walls.