AXIAL-FLOW TURBINE AND POWER GENERATION PLANT WITH AXIAL-FLOW TURBINE

摘要

PROBLEM TO BE SOLVED: To provide an axial-flow turbine including a partial outlet/inlet structure, capable of suppressing energy loss resulting from the partial outlet/inlet structure, and capable of improving efficiency.SOLUTION: An axial-flow turbine according to an embodiment comprises: a nozzle structure 20 supported by a casing; and a rotor blade structure 40 provided downstream of the nozzle structure 20 and supported by a turbine rotor rotatable with respect to the casing. The nozzle structure 20 includes nozzles 25 provided in part of a circumferential region in an annular opening portion formed between a diaphragm outer ring and a diaphragm inner ring; and a closing portion 30 provided in the other circumferential region in the annular opening portion. The closing portion 30 closes the other region and prevents a working fluid from flowing into the other region. A penetrating opening portion 50 penetrating the closing portion 30 from an upstream side surface 31 to a downstream side surface 32 is provided in the closing portion 30.SELECTED DRAWING: Figure 5