CMC Turbine Shroud Pin Mounting With Local Impingement Cooling
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Solution Overview
Problem
Coupling ceramic matrix composite (CMC) components with traditional arrangements and using conventional cooling methods presents challenges due to thermal expansion and material properties, leading to potential deformation and reduced life of pins in gas turbine engine shrouds.
Innovation Solution
A turbine shroud assembly with a blade track segment made of CMC materials, featuring a cooling passageway in a metallic support structure that directs cooling air onto preselected areas between the shroud wall and pins to dissipate heat, mitigating thermal gradients and extending pin life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cooling methods are used with CMC components, then the structure is simple, but thermal gradients cause pin deformation and reduced pin life
Solution Approach 1:
The cooling passageway is configured to direct cooling air onto preselected cooling areas of the attachment flange, specifically targeting regions between the shroud wall and pins. This localized cooling approach addresses thermal gradients at critical locations without requiring complex cooling systems throughout the entire structure, thereby extending pin life while maintaining reasonable structural complexity
Solution Approach 2:
Cooling air is introduced as an intermediary substance to dissipate heat from the attachment flange before it reaches the pins. The cooling passageway delivers this intermediary cooling medium to preselected areas, creating a thermal barrier that protects the pins from excessive heat and deformation, thus improving pin reliability
2Temperature
If CMC materials are used in blade track segments, then high temperature resistance is improved, but thermal expansion and material properties cause deformation issues
Solution Approach 1:
The cooling system applies targeted cooling to preselected areas of the attachment flange where thermal gradients are most severe. By localizing the cooling effect to specific regions between the shroud wall and pins, the system maintains dimensional stability at critical interfaces while allowing the CMC blade track segment to retain its high-temperature resistance properties
Solution Approach 2:
The cooling passageway design accounts for thermal expansion characteristics of CMC materials by directing cooling air to areas that experience the most significant thermal gradients. This controlled thermal management compensates for differential expansion and contraction, reducing deformation in the CMC blade track segment while maintaining its heat resistance
3Loss of energy
If cooling air is directed to preselected areas, then heat dissipation is improved, but the cooling system complexity increases
Solution Approach 1:
The cooling passageway is designed to direct cooling air onto specific preselected cooling areas of the attachment flange rather than providing uniform cooling throughout. This localized approach maximizes heat dissipation efficiency at critical thermal gradient locations while avoiding the complexity of a comprehensive cooling system, thereby improving energy loss management with minimal added complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The cooling design effectively manages thermal gradients, reducing deformation and extending the life of pins by dissipating heat before it reaches the pins, thus enhancing the durability of the shroud assembly.
Implementation Method 1
a cooling passageway formed in the metallic support structure to direct cooling air onto a preselected cooling area of the attachment flange included in the blade track segment
Implementation Method 2
heat absorbed by the shroud wall during use of the turbine shroud assembly is dissipated by the cooling air directed onto the preselected cooling area before being conducted to the pin
Data Source
AI summary
An assembly adapted for use in a gas turbine engine includes a blade track segment, a carrier segment, and a pin. The blade track segment defines a portion of a gas path of the gas turbine engine. The carrier segment supports the blade track segment to locate the blade track segment radially outward of the axis. The pin couples the blade track segment to the carrier segment. The carrier segment may include cooling passageways to conduct cooling air to preselected cooling areas located on the blade track segment.