Blade clearance control using high-CTE and low-CTE ring members

• US 8,790,067 B2
• Filed: 04/27/2011
• Issued: 07/29/2014
• Est. Priority Date: 04/27/2011
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: McCaffrey, Michael G., Hudson, Eric A.
• Primary Examiner(s): Landrum, Ned
• Assistant Examiner(s): MCDOWELL, LIAM J
• Application Number:
  US13/095,326
• Publication Number:
  US 20120275898A1
• Time in Patent Office: 1,189 Days
• Field of Search: 415/1, 415/173.1, 415/213.1, 415/214.1, 415/173.2, 415/173.3
• US Class Current: 415/1
• CPC Class Codes: F01D 11/18 using stator or rotor components with predetermined thermal response, e.g. selective insulation, thermal inertia, differential expansion
• CPC Class Codes: F05D 2240/11 Shroud seal segments
• CPC Class Codes: F05D 2300/50212 dissimilar
• CPC Class Codes: F05D 2300/6033 Ceramic matrix composites [CMC]
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

An engine has a blade stage and a circumferential array of blade outer air seal segments. A support ring carries the blade outer air seal segments. The support ring has a low-CTE member and a high-CTE member intervening between the blade outer air seal segments and the low-CTE member.

Claims

1. An engine comprising:

a blade stage;

a circumferential array of blade outer air seal segments; and

a support ring carrying the blade outer air seal segments and comprising;

a full hoop non-metallic member; and

a metallic member intervening between the blade outer air seal segments and the non-metallic member.

2. The engine of claim 1 wherein the metallic member and non-metallic member have dimensions and physical properties so that:

over an operational temperature range there are distinct stages in which the circumferential thermal expansion of one member versus the other dictate radial expansion of the circumferential array of blade outer air seal segments.

3. The engine of claim 2 wherein the distinct stages include:

a stage in which the circumferential thermal expansion of the non-metallic member alone essentially dictates said radial expansion; and

a stage in which the circumferential thermal expansion of the metallic member as resisted by the non-metallic member essentially dictates said radial expansion.

4. The engine of claim 3 wherein the distinct stages include:

a stage in which the circumferential thermal expansion of the metallic member alone essentially dictates said radial expansion.

5. The engine of claim 1 wherein:

the blade stage is a turbine stage.

6. The engine of claim 1 wherein:

the metallic member comprises a nickel-based superalloy; and

the non-metallic member comprises a ceramic matrix composite.

7. The engine of claim 1 wherein:

the metallic member comprises an integral full hoop; and

the non-metallic member comprises an integral full hoop.

8. The engine of claim 1 wherein:

the metallic member has a CTE of 3.0-4.0 ppm/C; and

the non-metallic member has a CTE of 0.5-2.0 ppm/C.

9. The engine of claim 1 wherein:

the metallic member comprises a circumferential array of edge-to-edge segments.

10. The engine of claim 9 wherein each of the edge-to-edge segments comprises:

a forward half; and

an aft half secured to the forward half to capture the non-metallic member and capture an associated one of the blade outer air seal segments.

11. The engine of claim 1 wherein the metallic member and non-metallic member have dimensions and physical properties so that:

as a temperature increases from a first temperature of less than 200 C to a second temperature of at least 550 C there are distinct stages in which the physical properties of one member versus the other dictate radial expansion of the circumferential array of blade outer air seal segments.

12. A method for operating the engine of claim 1 comprising:

running the engine in a range from a first condition to a second condition, a characteristic inner diameter of the blade outer air seal array increasing from a first diameter to a second diameter due to thermal expansion of the support ring wherein;

in a first portion of the range, the expansion is dictated essentially by one of the metallic member and non-metallic member but not the other; and

in a second portion of the range, the thermal expansion is dictated substantially by the other.

13. The method of claim 12 wherein:

the first portion of the range is at lower temperature than the second portion of the range;

in the second portion of the range, the metallic member essentially dictates the thermal expansion and a radial gap between the metallic member and non-metallic member decreases with increasing temperature; and

in the first portion of the range, the thermal expansion is substantially dictated by the non-metallic member.

14. The method of claim 12 wherein:

in the first portion of the range, an edge-to-edge clearance between segments of the metallic member decreases with temperature and the non-metallic member essentially dictates the thermal expansion; and

in the second portion of the range, the edge-to-edge clearance is closed.

15. A method for operating the engine of claim 1 comprising:

an acceleration of the engine from a first speed to a second speed during which segments of the metallic member engage each other; and

a deceleration of the engine from the second speed to the first speed during which the segments of the metallic member decouple from each other at a larger radius than a radius at which they originally engaged each other; and

a reacceleration wherein the segments of the metallic member reengage each other while still at a larger radius that the radius at which they originally engaged each other.

16. An engine comprising:

a blade stage;

a circumferential array of blade outer air seal segments; and

a support ring carrying the blade outer air seal segments and comprising;

a non-metallic member;

a metallic member intervening between the blade outer air seal segments and the non-metallic member; and

a radially compliant member between the metallic member and the non-metallic member.

17. The engine of claim 16, wherein:

the radially compliant member comprises a plurality of springs.

18. An engine comprising:

an engine case;

a blade stage;

a circumferential array of blade outer air seal segments; and

a support ring carried by the engine case and carrying the blade outer air seal segments and comprising;

a full annulus member; and

a segmented member intervening between the blade outer air seal segments and the full annulus member,

wherein the segmented member and full annulus member have dimensions and physical properties so that;

in a first portion of an operational temperature range, an edge-to-edge clearance between segments of the segmented member decreases with temperature and the full annulus member essentially dictates the thermal expansion; and

in the second portion of the operational temperature range, the edge-to-edge clearance is closed and a radial gap between the segmented member and full annulus member decreases with increasing temperature.

19. The engine of claim 18 wherein:

the segmented member comprises a nickel-based superalloy; and

the full annulus member comprises a CMC or a gamma titanium.

20. The engine of claim 18 wherein the segmented member is metallic and the full annulus member is nonmetallic.

21. An engine comprising:

an engine case;

a blade stage;

a circumferential array of blade outer air seal segments; and

a support ring carried by the engine case and carrying the blade outer air seal segments and comprising;

a full annulus member; and

a segmented member intervening between the blade outer air seal segments and the full annulus wherein the segmented member and full annulus member have dimensions and physical properties so that;

over an operational temperature range there are distinct stages in which the circumferential thermal expansion of one member versus the other dictate radial expansion of the circumferential array of blade outer air seal segments; and

over a portion of the operational temperature range, a radial gap between the segmented member and full annulus member decreases with increasing temperature.

22. An engine comprising:

an engine case;

a blade stage;

a circumferential array of blade outer air seal segments; and

a support ring carried by the engine case and carrying the blade outer air seal segments and comprising;

a full annulus member;

a segmented member intervening between the blade outer air seal segments and the full annulus member; and

a radially compliant member between the segmented member and the full annulus and biasing open a radial gap between the segmented member and the full annulus member.

23. An engine comprising:

an engine case;

a blade stage;

a circumferential array of blade outer air seal segments; and

a support ring carried by the engine case and carrying the blade outer air seal segments and comprising;

a full annulus member; and

a segmented member intervening between the blade outer air seal segments and the full annulus member and supported by the engine case to, in turn, support the full annulus member.

24. The engine of claim 23 wherein:

the support ring is carried by the engine case by lugs received in channels and for each lug and associated channel there being a radial gap between the lug and a base of the channel.

25. An engine comprising:

an engine case;

a blade stage;

a circumferential array of blade outer air seal segments; and

a support ring carried by the engine case and carrying the blade outer air seal segments and comprising;

a full annulus member expandably and contractably supported relative to the engine case; and

a segmented member intervening between the blade outer air seal segments and the full annulus member, wherein there is a radial gap between the segmented member and the full annulus member.

26. The engine of claim 25 wherein:

the support ring is carried by the engine case by lugs received in channels and for each lug and associated channel and wherein the radial gap is between the lug and a base of the channel.