SEALING FOR VANE SEGMENTS

• US 20110081237A1
• Filed: 10/01/2009
• Published: 04/07/2011
• Est. Priority Date: 10/01/2009
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: PIETROBON, John, DUROCHER, Eric
• Granted Patent: US 8,500,392 B2
• Time in Patent Office: Days
• US Class Current: 415/173.1
• CPC Class Codes: F01D 11/00 Preventing or minimising internal leakage of working-fluid, e.g. between stages sealings in general F16J ; sealing arrangements for transition ducts of combustor cans F01D9/023
• CPC Class Codes: F01D 25/12 Cooling
• CPC Class Codes: F01D 9/06 Fluid supply conduits to nozzles or the like

Abstract

A seal housing is provided to substantially cover at least one duct wall of vane array duct of a gas turbine engine, and one example arrangement is employed in a mid-turbine frame. The arrangement provides improved sealing of the vane array duct through the provision of a plurality of cavities extending along the duct wall. The arrangement may also include insulation tubes to assist in sealing around load transfer spokes passing through the vane array.

Claims

1. A gas turbine engine comprising:

a segmented vane array disposed radially between annular outer and inner engine cases and including a segmented annular outer duct wall;

a segmented annular inner duct wall, and a plurality of hollow airfoils radially extending between the outer and inner duct walls, a plurality of seals extending between adjacent segments on the inner and outer duct walls to thereby provide a gas path between the inner and outer duct walls, the gas path extending in an axial direction; and

an annular seal housing extending axially substantially along an entire axial length of one of the duct walls, the seal housing spaced apart from said duct wall and from an adjacent one of the inner and outer engine cases to thereby provide an annular case cavity between said case and the seal housing and an annular duct cavity between the seal housing and said duct wall, the case cavity in fluid communication with an engine source of pressurized cooling air, the seal housing sealingly mounted within the engine to in use permit said cooling air to provide a pressure differential in the case cavity relative to the duct cavity.

2. The gas turbine engine as defined in claim 1, wherein the inner and outer engine cases have a plurality of load spokes extending radially therebetween through the airfoils, and wherein the seal housing has openings to allow the respective load spokes to radially extend through the seal housing, and wherein the seal housing has a sealing apparatus at each opening to seal between the case cavity and the duct cavity.

3. The gas turbine engine as defined in claim 2, wherein the sealing apparatus comprises a plurality of insulation tubes disposed around respective load spokes and extending through the airfoils, the tubes aligning with the openings in the seal housing and attached to the seal housing.

4. The gas turbine engine as defined in claim 1, wherein two said seal housings are provided, a first one between the outer engine case and the outer duct wall, and a second one between the inner engine case and the inner duct wall.

5. The gas turbine engine as defined in claim 4, wherein the seal housings are monolithically ring-shaped.

6. The gas turbine engine as defined in claim 2 wherein the case cavity communicates with a source of pressurized cooling air through a load spoke control radial passage.

7. The gas turbine engine as defined in claim 1 further comprising a plurality of holes in the seal housing for directing cooling air from the case cavity into the duct cavity.

8. The gas turbine engine as defined in claim 7 wherein at least some of the holes are disposed to align with the plurality of seals between the duct wall segments.

9. The gas turbine engine as defined in claim 7 wherein at least some of the holes are disposed to align with and cool the duct wall segments.

10. A gas turbine engine comprising:

a mid turbine frame (MTF) disposed axially between first and second turbine rotors, the MTF including an annular outer engine case, an annular inner engine case and a plurality of load spokes radially extending between and interconnecting the outer and inner engine cases to transfer loads from the inner engine case to the outer engine case;

an annular inter-turbine duct (ITD) disposed radially between the outer and inner engine case of the MTF, the ITD including an annular outer duct wall and annular inner duct wall, thereby defining an annular hot gas path between the outer and inner duct walls for directing hot gases from the first turbine rotor to the second turbine rotor, a plurality of hollow struts radially extending between and interconnecting the outer and inner duct walls, the load spokes radially extending through at least a number of the hollow struts, the ITD being assembled from a plurality of circumferential duct wall segments, each having at least one strut interconnecting a circumferential section of the outer duct wall and a circumferential section of the inner duct wall;

a first annular case cavity defined between the annular outer engine case and outer duct wall and a second annular case cavity defined between the annular inner duct wall and inner engine case, the first and second case cavities being in fluid communication with an inner space within the respective hollow struts; and

an air sealing system for the first and second case cavities and the hollow struts against cooling air leakage through gaps between the circumferential segments of the ITD, the system including;

an annular first seal housing disposed in the first annular case cavity and extending axially along a substantial length of the outer duet wall;

an annular second seal housing disposed in the second annular case cavity and extending axially along a substantial length of the inner duct wall, the first and second seal housings having a plurality of openings to allow the respective load spokes to radially extend therethrough; and

a plurality of insulation tubes aligning with the openings in the respective first and second seal housings, to surround the respective load spokes and to be attached to the first and second seal housings.

11. The gas turbine engine as defined in claim 10 wherein a source of pressurized cooling air communicates with the case cavity through a load spoke central radial passage.

12. The gas turbine engine as defined in claim 10 further comprising a plurality of holes in the seal housings for directing cooling air from the case cavities to the respective outer and inner duct walls.

13. The gas turbine engine as defined in claim 12 wherein at least some of the holes are disposed to align with a plurality of seals between the duct wall segments.

14. The gas turbine engine as defined in claim 12 wherein at least some of the holes are disposed to align with and cool the duct wall segments.

15. The gas turbine engine as defined in claim 10 wherein each of the insulation tubes further comprises a flange extending laterally from an end of the tube generally in a plane defined by one of the seal housings, and is sized to overlap said opening in the seal housing.

16. The gas turbine engine as defined in claim 10 wherein the inner seal housing is sealingly mounted to the inner duct wall, and wherein the outer seal housing is sealingly mounted to the outer engine case.

17. The gas turbine engine as defined in claim 16 wherein the annular outer duct wall comprises front and rear hooks at opposed axial ends for connection with the annular outer engine case, the outer duct wall and annular outer engine case thereby defining the first case cavity axially positioned between the front and rear hooks.