Turbine shroud segment sealing
AssigneePratt & Whitney Canada Corp.
InventorsJohn Pietrobon, Remy Synnott
Life of this patent
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Abstract
An integrated shroud structure surrounds a circumferential array of stator vanes and a circumferential array of rotor blades of a gas turbine engine. The shroud structure includes a plurality of vane shroud segments and a plurality of blade shroud segments. The blade shroud segments integrally extend downstream from the vane shroud segments and each pair of circumferentially adjacent blade shroud segments defines an inter-segment gap. At least one slot extends axially from a location downstream of the vane shroud segments to an aft end of the blade shroud segment. The inter-segment gaps and slots are sealed by a sealing band mounted around the full circumference of the integrated shroud structure.
Claims16
A shroud structure integrally cast with a circumferential array of stator vanes for surrounding a circumferential array of rotor blades of a gas turbine engine, the circumferential array of stator vanes positioned axially upstream of the circumferential array of rotor blades, the shroud structure comprising:
- a plurality of blade shroud segments disposed circumferentially one adjacent to another and configured to surround the circumferential array of rotor blades, the blade shroud segments extending integrally from the circumferential array of stator vanes, each pair of circumferentially adjacent blade shroud segments defining an inter-segment gap, at least one of the plurality of blade shroud segments having a radially inner gas path surface and an opposed radially outer surface and at least one slot extending axially from a location downstream of the circumferential array of stator vanes to a downstream end of the at least one of the plurality of the blade shroud segments between the radially inner gas path surface and the opposed radially outer surface thereof;
- and
- a sealing band mounted around the radially outer surface of the blade shroud segments and extending across the inter-segment gaps and the at least one slot around the full circumference of the integrated shroud structure;
- wherein the at least one slot is configured to extend axially upstream of the array of rotor blades, and wherein the at least one slot has a portion thereof that extends axially downstream of the sealing band.
A shroud assembly surrounding stator vanes and rotor blades of a gas turbine engine, the shroud assembly comprising:
- a plurality of shroud structures disposed circumferentially one adjacent to another to form a circumferentially segmented shroud ring, the segmented shroud ring comprising:
- a plurality of vane shroud segments;
- and
- a plurality of blade shroud segments, the blade shroud segments and the vane shroud segments being of unitary construction, each one of the blade shroud segments having a body axially defined from a forward end to an aft end in a direction from an upstream position to a downstream position of a gas flow passing through the integral shroud assembly, and being circumferentially defined between opposite first and second lateral sides, said body including a platform having a radially inner gas path surface and an opposed radially outer back surface, and forward and aft arms extending from the back surface of the platform, said forward and aft arms being axially spaced-apart from each other, at least one slot extending axially from the aft arm towards the forward arm and between the radially inner gas path surface and the opposed radially outer surface thereof;
- and
- a sealing band mounted between the forward and aft arms on the back surface of the blade shroud segments, the sealing band encircling the segmented blade shroud ring and circumferentially spanning all the inter-segment gaps and at least partially axially covering the at least one slot;
- wherein the at least one slot has a portion thereof that extends axially downstream of the sealing band.
A method for sealing and cooling a circumferentially segmented shroud structure, the shroud structure including a segmented blade shroud ring and a segmented vane shroud ring in a gas turbine engine, the segmented blade shroud ring comprising blade shroud segments, the segmented vane shroud ring comprising vane shroud segments, the blade shroud segments and the vane shroud ring segments being of unitary construction, the method comprising:
- surrounding the segmented blade shroud ring with a sealing band configured to fully encircle the segmented blade shroud ring;
- surrounding at least a portion of axially extending slots defined in the segmented blade shroud ring with the sealing band, the axially extending slots having a portion thereof extending axially downstream of the sealing band;
- forming a pressurized air plenum around the sealing band for urging the sealing band in sealing engagement against a radially outer surface of the segmented blade shroud ring;
- and
- providing impingement jet holes in the sealing band to allow some of the pressurized air in the plenum to impinge upon a radially outer surface of the segmented blade shroud ring.
Dependencies are inferred from the claim text.