초록 ▼

Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows in

Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. A skirt or flange structure is provided for shielding the steam cooling impingement holes adjacent the inner wall aerofoil fillet region of the nozzle from the steam flow exiting the aft nozzle cavities. Moreover, the gap between the flash rib boss and the cavity insert is controlled to minimize the flow of post impingement cooling media therebetween. This substantially confines outflow to that exiting via the return channels, thus furthermore minimizing flow in the vicinity of the aerofoil fillet region that may adversely affect impingement cooling thereof.

대표청구항 ▼

1. A turbine vane segment for forming part of a stage of a turbine, comprising:inner and outer walls spaced from one another; a turbine vane extending between said inner and outer walls and having leading and trailing edges, said vane including a plurality of discrete cavities between the leading an

1. A turbine vane segment for forming part of a stage of a turbine, comprising:inner and outer walls spaced from one another; a turbine vane extending between said inner and outer walls and having leading and trailing edges, said vane including a plurality of discrete cavities between the leading and trailing edges and extending lengthwise of said vane for flowing a cooling medium in a substantially closed circuit through said vane; an impingement plate mounted to said inner wall in spaced relation to an inner surface thereof, said impingement plate having openings enabling passage of the cooling medium for impingement cooling of said inner wall; an inner cover plate mounted to said inner wall and spaced from said inner surface with said impingement plate therebetween, thereby to define a plenum of said inner wall between said impingement plate and said cover plate and an impingement gap between said impingement plate and said inner surface, at least one of said cavities of said vane being in communication with said plenum of said inner wall via an opening in said vane, to enable passage of the cooling medium from said at least one cavity into said plenum, and an extension structure for channeling cooling media flow exiting said at least one cavity into said plenum and for substantially shielding at least a portion of said impingement plate adjacent a periphery of said opening from said exiting flow.