Abstract: The invention relates to a rotor for thermal turbomachines in a steam power process with a centrally arranged hollow space, several axis-symmetrical hollow spaces, at least two pipes with different diameters and lengths, and at least two through-openings in the mantle, whereby at least one opening is arranged in the turbine part and at least one opening in the compressor part or the middle part, and the openings of the various pipes overlap in the warm operating state in the turbine part, while they overlap in the compressor part and middle part in the cold operating state. At the waste gas side end of the rotor, the hollow space is in the cylindrical part limited by the inside wall of the through-pipe and is provided for supplying steam. The pipe is surrounded in the cylindrical part by another hollow space that is arranged concentrically around the pipe and is provided for removing steam.