Patent ID: 8702376

Claim:
A high temperature radially fed axial steam turbine comprising: a rotatable rotor with a rotational axis and a circumferential surface; a casing enclosing the rotor so as to form an annular space between the rotor and the casing; axially distributed blade and vane rows mounted in the annular space on the rotor; a hot inlet duct for hot steam, that circumferentially extends around the rotor axis and including a radial inlet end circumscribing the rotor, and an axial outlet end circumscribing the rotor and axially joined to the annular space immediately upstream of the blade and vane rows; a cold inlet spiral for receiving a cold steam, circumferentially extending around the rotor axis that is configured to circumferentially distribute the cold steam; and a cold inlet duct for a cold steam, connected at an inlet end to a downstream end of the cold inlet spiral and axially displaced from the hot inlet duct such that the hot inlet duct is between the cold inlet duct and blade and vane rows, the cold inlet duct having an outlet end, in the hot inlet duct, that circumscribes the rotor and is configured to provide a boundary layer of cold steam over the circumferential surface between the outlet end of the cold inlet duct and the blade and vane rows, wherein the rotor circumferential surface between the cold inlet duct outlet end and the blade and vane rows is configured to promote and maintain the boundary layer.