Triple Bend Finger Seal Deflection Accommodation
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Solution Overview
Problem
Conventional finger seals in gas turbine engines face challenges in providing adequate sealing due to irregular component profiles, tolerances, and large deflections, leading to installation difficulties and premature wear, especially when space is limited and deflections are maximum.
Innovation Solution
A triple bend finger seal design with specific bend angles and leg orientations is introduced, which includes a first bend segment radially outward of the first leg, a second bend segment radially inward of the second and third legs, and a third bend segment radially outward of the third leg, facilitating installation and accommodating differential deflections while reducing wear and the risk of crushing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional finger seal is used, then the structure is simple, but sealing performance deteriorates due to irregular component profiles, tolerances, and large deflections
Solution Approach 1:
The finger seal is divided into multiple segments including a first segment, second segment, third segment, and fourth segment connected by first, second, and third bends. This segmentation allows each segment to independently accommodate irregular component profiles, tolerances, and deflections while maintaining sealing contact, thereby improving sealing performance without excessive complexity
Solution Approach 2:
The seal design incorporates bends in multiple directions (first bend, second bend, third bend) that allow the seal to deflect in multiple dimensions. This multi-dimensional flexibility enables the seal to accommodate large deflections and irregular profiles by distributing deformation across multiple bend segments rather than requiring a single complex adjustment mechanism
2Adaptability or versatility
If the seal accommodates large deflections, then adaptability improves, but wear and crushing risk increase
Solution Approach 1:
By dividing the seal into multiple segments connected by bends, the total deflection is distributed across several smaller deformations rather than one large deformation. This reduces the stress and wear on any single segment while maintaining the ability to accommodate large overall deflections, thereby improving both adaptability and wear resistance
Solution Approach 2:
The seal design incorporates flexible bends that allow dynamic adjustment of the seal position and orientation in response to varying deflection conditions. This dynamic flexibility enables the seal to maintain optimal contact under different operating conditions without experiencing excessive localized wear or crushing
3Reliability
If the seal design is optimized for performance, then sealing improves, but installation difficulty increases
Solution Approach 1:
The segmented design with multiple bends allows the seal to be installed in a relatively simple configuration and then naturally conform to the mating surfaces through elastic deformation. This reduces installation complexity compared to rigid seals that require precise alignment, while still achieving high sealing performance through the flexible multi-segment structure
Data Source
AI summary
A finger seal for a gas turbine engine is disclosed. The finger seal includes a first leg, a second leg, a third leg, a fourth leg, a first bend segment disposed between the first leg and the second leg, a second bend segment disposed between the second leg and the third leg, and a third bend segment disposed between the third leg and the fourth leg. The third bend segment is radially outward of the first bend segment relative to an axial centerline of the gas turbine engine.