Alternative partial steam admission arc for reduced noise generation

A steam turbine, comprising:

• a steam chest fluidly coupled to a plurality of supply pipes regulated by a corresponding plurality of valves, the steam chest being configured to supply a working fluid to the plurality of supply pipes when the corresponding plurality of valves are in an open position;
• and
• a diaphragm fluidly coupled to each supply pipe and having an outer arcuate wall radially-offset from an inner arcuate wall, the diaphragm defining a first arc of admission having a plurality of nozzle vanes arranged between the inner and outer arcuate walls and circumferentially-spaced between a first end and a second end, wherein a first set of nozzle passages adjacent the first end and a second set of nozzle passages adjacent the second end have a height that is reduced.

A method of reducing sudden load impulses on rotor blades, comprising:

• injecting a working fluid into an arc of admission having a plurality of nozzle vanes circumferentially-spaced between a first end and a second end, the plurality of nozzle vanes including a first set of nozzle passages disposed at the first end and a second set of nozzle passages disposed at the second end, wherein the first and second sets of nozzle passages have a reduced flow area;
• and
• ejecting the working fluid from the arc of admission and downstream toward rotor blades rotating about a central axis, wherein a load impulse imparted by the working fluid on each rotor blade progressively increases across the first set of nozzle passages and then progressively decreases across the second set of nozzle passages.