Shingled laminated porous material

• US 4,312,186 A
• Filed: 10/17/1979
• Issued: 01/26/1982
• Est. Priority Date: 10/17/1979
• Status: Expired due to Term

• Current Assignee: Allison Engine Company, Inc. (Rolls-Royce Holdings Plc)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Reider, Samuel B.
• Primary Examiner(s): Garrett, Robert E.
• Application Number:
  US06/085,603
• Time in Patent Office: 832 Days
• Field of Search: 60/754, 416/231 R
• US Class Current: 60/754
• CPC Class Codes: F23R 3/002 Wall structures F23R3/02 and F23R3/007 take precedence

Abstract

A gas turbine engine combustor has a porous wall structure for directing coolant from a compressed air plenum into a combustion chamber to cool its inner surface; an outer lamina has a first hole pattern therein and an inner lamina diffusion bonded to the outer lamina has a second hole pattern offset from the first hole pattern to direct air from the air plenum in cross-flow relationship across internal walls to cool the outer and inner lamina and the outer lamina has a plurality of relief notches formed part way through its depth which are responsive to thermal gradients across the porous wall structure to break the outer lamina into a plurality of separated shingles thereby to prevent excessive stress formation in the porous wall structure; the inner lamina including flow control means to maintain a regulated flow of coolant from an inlet air plenum to the combustion chamber irrespective of the number of relief notches broken during operation of the gas turbine engine.

Claims

1. In a combustor assembly adapted for disposition in an air inlet plenum of a gas turbine engine and including a porous laminated wall structure having a first lamina and a second lamina with diffusion bond means therebetween for structural integrity, at least one of said first and said second lamina having coolant air distribution means therein in the form of relieved passage means of predetermined depth in said one lamina to permit coolant air flow between a plurality of pores in each of said first and said second lamina, said one lamina having minimum thickness at the deepest portion of said relieved passage means, the improvement comprising means on said one lamina defining a pattern of interconnecting stress relief grooves which cooperate with said relieved passage means in defining crack sections coextensive with said relief grooves and, having depth less than said minimum thickness so that thermal stress induced by a temperature gradient across said wall structure is concentrated at said crack sections to fracture said one lamina thereat into a plurality of separate shingles thereby preventing excessive stress formation in said wall structure.

2. The improvement recited in claim 1 further including flow control means on the other of said first and said second lamina operative to maintain regulated flow of coolant air across said wall structure regardless of the increase in porosity of said first lamina created by the fracture thereof into said plurality of shingles.

3. In a combustor assembly adapted for disposition in an air inlet plenum of a gas turbine engine and including a porous laminated wall structure having an inner lamina exposed to high temperatures in said combustor and an intermediate lamina and an outer lamina exposed to said inlet air plenum, said inner and said intermediate and said outer lamina being diffusion bonded together for structural integrity, first relieved passage means of predetermined depth in said outer lamina adjacent said intermediate lamina operative to permit coolant air flow from a plurality of pores in said outer lamina to a plurality of offset pores in said intermediate lamina with the minimum thickness of said outer lamina occurring at the deepest portion of said first relieved passage means, second relieved passage means of predetermined depth in said intermediate lamina adjacent said inner lamina operative to permit coolant air flow from said plurality of offset pores to a plurality of control pores in said inner lamina with the minimum thickness of said intermediate lamina occurring at the deepest portion of said second relieved passage means, in said combustor assembly the improvement comprising, means on said outer lamina defining a first pattern of interconnecting stress relief grooves which cooperate with said first relieved passage means in defining first crack sections coextensive with said first relief grooves and having depth less than said minimum thickness of said outer lamina, and means on said intermediate lamina defining a second pattern of interconnecting stress relief grooves corresponding in shape to said first pattern of stress relief grooves but offset therefrom, said second pattern of stress relief grooves cooperating with said second relieved passage means in defining second crack sections coextensive with said second relief grooves and having depth less than said minimum thickness of said intermediate lamina, each of said first and said second crack sections being operative to concentrate thermal stresses in corresponding ones of said outer and said intermediate lamina induced by a temperature gradient across said wall structure so that said outer and said intermediate lamina are fracturable at said crack sections into a plurality of separate shingles thereby preventing excessive stress formation in said wall structure, said control pores in said inner lamina being operative to regulate the flow of coolant air across said wall structure regardless of the increase in porosity of said outer and said intermediate lamina created by the fracture thereof into said plurality of shingles.