Hot gas overheat protection device for gas turbine engines

• US 5,027,604 A
• Filed: 01/03/1989
• Issued: 07/02/1991
• Est. Priority Date: 05/06/1986
• Status: Expired due to Fees

• Current Assignee: MTU Motoren- und Turbinen-Union Muenchen GmbH (MTU)
• Original Assignee: MTU Motoren- und Turbinen-Union Muenchen GmbH (MTU)
• Inventors: Krueger, Wolfgang
• Primary Examiner(s): Casaregola, Louis J.
• Assistant Examiner(s): Thorpe, T.
• Application Number:
  US07/293,574
• Time in Patent Office: 910 Days
• Field of Search: 60/752, 60/753, 60/754, 60/755, 60/757, 415/9, 415/197, 416/96 A
• US Class Current: 60/752
• CPC Class Codes: F01D 11/24 by selectively cooling-heating stator or rotor components
• CPC Class Codes: F01D 21/045 special arrangements in stators or in rotors dealing with breaking-off of part of rotor
• CPC Class Codes: F01D 5/187 Convection cooling
• CPC Class Codes: F01D 5/28 Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
• CPC Class Codes: F05B 2260/3011 of the frangible or shear type
• CPC Class Codes: F05D 2260/201 by impingement of a fluid
• CPC Class Codes: F23R 2900/03044 Impingement cooled combustion chamber walls or subassemblies
• CPC Class Codes: F23R 3/002 Wall structures F23R3/02 and F23R3/007 take precedence
• CPC Class Codes: F23R 3/007 constructed mainly of ceramic components
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A hot gas overheat protection device is provided for gas turbine engines and the like. An outer metal wall having cooling air supplied through cooling holes therethrough from the outside is shielded from hot gas flow by the provision of highly temperature resistant lining wall elements spaced from the metal wall. A thin metal skin is provided between the metal wall and the wall elements defining intermediate spaces communicating with cooling air ports in the metal wall. The thin metal skin has a melting point equal to or lower than that of the metal wall so as to provide for fusion or rupture of the thin metal skin in the event the insulating wall elements are locally ruptured, whereby the cooling air is provided through the cooling air ports in a direction against the flow of hot gases to thereby mitigate the effects of the rupture and protect the metal wall.

Claims

1. Device for preventing the scorching of a hot-gas-wetted metal wall of a gas turbine engine or the like, comprising:

highly temperature resistant wall element means disposed between a metal wall and a space subjected to hot gas flow,

thin metal skin means disposed between the temperature resistant wall element means and the metal wall, said thin metal skin means lining the metal wall and forming intermediate cooling air space means bounded by the metal wall and the thin metal skin means,

and cooling air hole means extending through the metal wall and opening into the intermediate cooling air space means,

wherein said thin metal skin means is formed of material having a relatively low melting point such that, upon rupture of said temperature resistant wall element means and consequent communication of hot gas flow to the thin metal skin means, said thin metal skin means is melted to open said cooling air intermediate space means and permit cooling air from said cooling air holes to flow against the flow of hot gases resulting from said rupture and thereby protect the metal wall from scorching.

2. Device according to claim 1, wherein said thin metal skin means is spaced from said wall element means along at least a substantial portion of its surface area which faces said wall element means.

3. Device according to claim 1, wherein said thin metal skin means is locally positively connected to the metal wall at portions of said thin metal skin means determining boundaries of said intermediate cooling air space means.

4. Device according to claim 3, wherein said intermediate cooling air space means includes a plurality of separate cooling air spaces, said cooling air hole means including a plurality of cooling air holes opening into each of said cooling air spaces.

5. Device according to claim 4, wherein said cooling air space means are closed with respect to the wall element means until melted upon rupture of an adjacent portion of the wall element means due to said consequent communication of hot gas flow to the thin metal skin means.

6. Device according to claim 1, wherein said cooling air space means are closed with respect to the wall element means until melted upon rupture of an adjacent portion of the wall element means due to said consequent communication of hot gas flow to the thin metal skin means.

7. Device according to claim 1, wherein said intermediate cooling air space means includes a plurality of separate cooling air spaces, said cooling air hole means including a plurality of cooling air holes opening into each of said cooling air spaces.

8. Device according to claim 7, wherein the cooling spaces are rectangular in shape from one another and are equally spaced over the area of the metal wall.

9. Device according to claim 8, wherein the thin metal skin means is positively connected to the metal wall along boundaries of said cooling spaces.

10. Device according to claim 9, wherein the thin metal skin means is positively connected to the metal wall along outwardly bent portions of the thin metal skin means.

11. Device according to claim 9, wherein the thin metal skin means is positively connected to the metal wall along internally projecting webs of the metal wall.

12. Device according to claim 9, wherein the thin metal skin means is positively connected to the metal wall by way of intermediate space means.

13. Device according to claim 12, wherein said intermediate space means are spacer plates or strips.

14. Device according to claim 1, wherein said thin metal skin means is attached to the metal wall by welding means.

15. Device according to claim 1, wherein said thin metal skin means is attached to the metal wall by brazing means.

16. Device according to claim 1, wherein said thin metal skin means is attached to the metal wall by rivet means.

17. Device according to claim 1, wherein said wall element means includes at least one wall element in the form of a shingle or scale-like hot gas shield element made of a highly temperature resistant metallic or ceramic material.

18. Device according to claim 17, wherein said thin metal skin means is secured in place without contacting said at least one wall element.

19. Device according to claim 1, wherein the metal wall is a load-bearing outer or inner wall of a flame tube of an annular combustion chamber of a gas turbine engine, and is supplied with cooling air taken from a high-pressure compressor exit through an outer or inner annular secondary air duct formed between outer casing structure components and the flame tube.

20. Device according to claim 19, wherein the wall element means for the inner hot gas shield is broken down into several individual wall elements that are spread in axial and/or circumferential direction and have spaces allowed between their respective abutting ends.

21. Device according to claim 1, wherein the metal wall is a radially spaced-apart inner circumferential wall of a tail pipe for an afterburner of a gas turbine engine, and wherein said wall element means take the form of a shingle- or scale-like heat shield.

22. Device according to claim 1, wherein the metal wall is an outer high-pressure turbine rotor blade shell and is energized with air taken from a compressor exit through an annulus enclosed between the metal wall and an outer casing wall, and wherein the wall element means are divided into circumferential segments and face rotor blade tips of a high-pressure turbine in a turbine hot gas duct.

23. Device according to claim 1, wherein the metal wall forms part of load-bearing metallic core of a blade for a gas turbine engine turbine nozzle vane or rotor blade cooled with air taken from a compressor, wherein the directly hot gas wetted wall element forms an outer blade shell, and wherein the cooling air is ducted from an interior of the blade core to the intermediate spaces through perforated sections in the metal wall, said intermediate spaces being formed in at least one cavity between the metal wall of the core and the outer wall element on account of the arrangement of the metal skin on the metal wall on the core side.

24. Device according to claim 1, wherein the melting point of the material forming the thin skin means is equal to or lower than the melting point of the material forming the metal wall.

25. Device according to claim 1, wherein the melting point of the material forming the thin metal skin means is lower than the melting point of the material forming the metal wall.

26. A device according to claim 1, further comprising air chamber means surrounding said metal wall and being supplied by compressed air from a turbine engine, said compressed air serving as said cooling air which is permitted to flow through said cooling air holes against the flow of hot gases resulting from said rupture.

27. Device for preventing the scorching of a hot-gas-wetted metal wall of a gas turbine engine or gas turbine jet engine respectively comprising:

highly temperature resistant wall element means disposed between a metal wall and a space subjected to hot gas flow,

thin metal skin means disposed between the temperature resistant wall element means and the metal wall, said thin metal skin means lining the metal wall and forming intermediate air space means bounded by the metal wall and the thin metal skin means,

a plurality of air holes extending in axial and circumferential direction through the metal wall and opening into the intermediate air space means,

and air chamber means surrounding said metal wall and being supplied by compressed air from said turbine engine,

wherein said thin metal skin means is formed of material having a relatively low melting point such that, upon rupture of said temperature resistant wall element means and consequent communication of hot gas flow to the thin metal skin means, said thin metal skin means is melted to open said intermediate air space means and permit compressed air from said air chamber means to flow through said air holes and thus serving for highly energized flow of cooling air against the flow of hot gases resulting from said rupture and thereby shielding and protecting the metal wall from scorching.