Rotor shaft, in particular for a gas turbine

1. A rotor shaft comprising:

a cooling air supply disposed inside the rotor shaft; and

a plurality of cooling air ducts connected to the cooling air supply and extending essentially radially outward to an outside of the shaft, wherein each of the cooling air ducts has an elliptic cross section;

wherein the rotor shaft has a compressor part and a turbine part, and wherein the plurality of cooling air ducts are arranged in the turbine part; and

wherein the turbine part includes a plurality of rotor disks arranged adjacent to one other in an axial direction of the shaft, the rotor disks configured to fasten moving blades, and wherein the cooling air ducts are arranged between adjacent ones of the rotor disks.

2. The rotor shaft as recited in claim 1 , wherein the plurality of cooling air ducts are arranged so as to be distributed over a circumference of the rotor shaft, and wherein the elliptic cross section of each cooling air duct includes a major axis and a minor axis and is oriented such that the major axis is oriented in a circumferential direction and the minor axis is oriented in an axial direction of the rotor shaft.

3. The rotor shaft as recited in claims 1 , further comprising at least one cavity formed inside the rotor shaft concentrically with respect to the rotor axis, wherein the cooling air ducts emanate from the at least one cavity and wherein the at least one cavity connects the cooling ducts to the cooling air supply.

4. The rotor shaft as recited in claim 3 , wherein the cavities have an at least partially elliptic cross-sectional contour at an outer circumference.

5. The rotor shaft as recited in claim 4 , wherein the cross-sectional contour on the outer circumference is composed of segments of two ellipses that are tilted with respect to one another and having major axes oriented approximately in the radial direction.

6. The rotor shaft as recited in claim 1 , wherein the rotor shaft is gas turbine rotor shaft.

7. A rotor shaft comprising:

a cooling air supply disposed inside the rotor shaft; and

a plurality of cooling air ducts connected to the cooling air supply and extending essentially radially outward toward an outside of the shaft, wherein each of the cooling air ducts has an elliptic cross section;

at least one cavity formed inside the rotor shaft concentrically relative to the rotor axis, the cooling ducts emanating from the at least one cavity, wherein the at least one cavity connects the cooling ducts to the cooling air supply and wherein the cavity has an at least partially elliptic cross-sectional contour at an outer circumference of the cavity.

8. The rotor shaft as recited in claim 7 , wherein the cross-sectional contour includes segments of two ellipses tilted relative to one another and having major axes oriented in a substantially radial direction.

9. The rotor shaft as recited in claim 7 , wherein the rotor shaft is a gas turbine rotor shaft.

10. The rotor shaft as recited in claim 7 , wherein the plurality of cooling ducts are arranged so as to be distributed over a circumference of the rotor shaft and wherein the elliptic cross section of each cooling air duct includes a major axis oriented in a circumferential direction and a minor axis oriented in an axial direction of the rotor shaft.

11. The rotor shaft as recited in claim 7 , wherein the rotor shaft includes a compressor part and a turbine part and wherein the plurality of cooling air ducts is arranged in the turbine part of the rotor shaft.

12. The rotor shaft as recited in claim 11 , wherein the turbine part includes a plurality of rotor disks arranged adjacent to one another in an axial direction of the shaft, the rotor disks configured to fasten moving blades and wherein the cooling air ducts are arranged between adjacent ones of the rotor disks.