Turbine shaft and method for cooling a turbine shaft

A steam turbine, comprising:

• a casing;
• turbine blades;
• a turbine shaft extending along a principal axis in said casing, said turbine shaft having a shaft surface, an end region and an inflow region for a working fluid, said turbine shaft having at least two recesses formed therein and spaced apart axially from one another and from said inflow region, for receiving at least one of said turbine blades in each of said at least two recesses, said at least two recesses including a first recess and another recess downstream of said first recess, and said turbine shaft having a cavity formed therein associated with said inflow region;
• and
• a feed line and a discharge line connected to said cavity for conducting a partial stream of the working fluid as cooling fluid, said feed line opening at said shaft surface downstream of said first recess, and said discharge line guided into said casing through said end region and in said casing as far as a region downstream of said other recess.

A method for cooling an inflow region of a turbine shaft disposed in a turbine, which comprises:

• providing a turbine shaft with a shaft surface, an inflow region and a cavity formed within the turbine shaft and associated with the inflow region;
• providing rotating blade rows including a first rotating blade row;
• feeding a partial stream of a working fluid as cooling fluid from the shaft surface downstream of the first rotating blade row at a first pressure level into the cavity;
• and
• guiding the partial stream of the working fluid from the cavity out of the turbine shaft through a discharge line discharging at the shaft surface at a second pressure level lower than the first pressure level.