What is described as a single-piece construction bolted between the rear flange of the inlet casing and the forward flange of the rear bearing support that encases the turbine rotor?

What is described as a single-piece construction bolted between the rear flange of the inlet casing and the forward flange of the rear bearing support that encases the turbine rotor?

• A. Inlet diaphragm
• B. Turbine vane casing
• C. Rear bearing housing
• D. Front frame

Answer: (B)

The turbine vane casing. This is the one-piece shell that forms the outer enclosure around the turbine rotor and houses the nozzle and rotor vanes, guiding the hot gas flow over the blades. It is bolted between the rear flange of the inlet casing and the forward flange of the rear bearing support, creating a continuous housing for the turbine section and helping maintain precise rotor alignment and seal integrity as the hot gases pass through the vane passages. The other components aren’t describing this enclosing shell. The inlet diaphragm is a flow-directing ring inside the compressor inlet, not the turbine enclosure. The rear bearing housing holds the back end bearings, not the entire turbine rotor enclosure. The front frame is the front-support structure, not the casing that encloses the turbine rotor and vanes.

The turbine vane casing. This is the one-piece shell that forms the outer enclosure around the turbine rotor and houses the nozzle and rotor vanes, guiding the hot gas flow over the blades. It is bolted between the rear flange of the inlet casing and the forward flange of the rear bearing support, creating a continuous housing for the turbine section and helping maintain precise rotor alignment and seal integrity as the hot gases pass through the vane passages.

The other components aren’t describing this enclosing shell. The inlet diaphragm is a flow-directing ring inside the compressor inlet, not the turbine enclosure. The rear bearing housing holds the back end bearings, not the entire turbine rotor enclosure. The front frame is the front-support structure, not the casing that encloses the turbine rotor and vanes.