Alstom Technology Limited

Rabiye Bekyigit

Martin Reigl

Maurus Herzog

Thomas Mokulys

Davor Kriz

Luca Marie Ripamonti

Giorgio Zanazzi

Jian Chen

Jozo Drmic

Andreas Ehrsam

Thomas Schreier

Philipp Brunner

Vishal Borikar

Hans-Ludwig Boxheimer

Rolf Doebler

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

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Wald-Michelbach, Germany

Rabiye Bekyigit