Alstom Technology Limited

Giorgio Zanazzi

Thomas Mokulys

Davor Kriz

Vishal Borikar

Luca Marie Ripamonti

Martin Reigl

Maurus Herzog

Jian Chen

Jozo Drmic

Rabiye Bekyigit

Pierre-Alain Masserey

Andreas Ehrsam

Philipp Brunner

Thomas Schreier

Ludwig Boxheimer

Hans-Ludwig Boxheimer

Rolf Doebler

Michael Sell

The disclosure relates to a radially fed axial steam turbine with a cold inlet duct, axially displaced from a hot inlet duct such that is it further away from a first blade row than the hot inlet duct. The cold inlet duct receives a cold steam from a cold inlet spiral and directs it into the hot inlet duct in such a way that a boundary layer of cold steam is formed over the rotor circumferential surface between the outlet end of the cold inlet duct and the blade and vane rows. The rotor circumferential surface is also adapted to promote and maintain the boundary layer. In this way, a maximum temperature to which the rotor is exposed can be reduced.

High temperature radially fed axial steam turbine

A steam turbine is provided having a relief groove which is arranged in the region of the equalizing piston and extends in the circumferential direction of the rotor. The relief groove, with regard to an inlet passage, is arranged in the axial upstream direction so that it is arranged on the rotor outside a region in which the steam flow enters the bladed flow path via the inlet passage. The relief groove, with regard to the first blade row, is arranged in a region in which the greatest thermal stresses can arise in the rotor. As an option, the relief groove has a cover for reducing vortex flows, and also devices for reducing heating of the groove or devices for active cooling. The steam turbine allows an increased number of risk-free running up and running down operations of the steam turbine with minimum detriment to the turbine performance.

Steam turbine with relief groove on the rotor

A steam turbine (), especially for the high-pressure range or intermediate-pressure range, includes a rotor () which is rotatably mounted around an axis and concentrically enclosed at a distance by an inner casing (), wherein between the rotor () and the inner casing () a flow passage () is formed, which on the inlet side is axially delimited by a balance piston () which is arranged on the rotor (), and into which flow passage rotor blades () and stator blades (), alternating in the direction of flow, radially project, and wherein, at the entry of the flow passage (), an inlet scroll (), through which steam is guided from the outside radially inwards and deflected in a deflection region () in the axial direction to the inlet of the flow passage (), is formed on the inner casing (). A reduction of the thermal loads and stresses is achieved by a stress-relief slot () in the deflection region () upstream of the first rotor blade row () for reducing stresses in the fastening slot () of the first rotor blade row () in the rotor (), and by a heat shield () arranged in the region of the stress-relief slot () for protecting the rotor () against high temperatures.

Steam turbine

An exemplary control stage of a steam turbine is disclosed, which includes plural staging valves circumferentially distributed around the turbine for regulating steam admission flow so as to control the loading of the turbine. Nozzle chambers are connected to a downstream end of each staging valve. An arc of admission forms the downstream portion of each nozzle chamber, and control stage nozzles in the arcs of admission define the downstream end of the nozzle chamber. Each nozzle chamber has at least two arcs of admission, each with a different circumferential dimension.

Multifrequency control stage for improved dampening of excitation factors

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Baden, Switzerland

Giorgio Zanazzi