Gas Turbine Inspection Plug Ball Swivel Thermal Stress
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Solution Overview
Problem
Existing inspection hole plugs in gas turbine engines face challenges with thermal expansion, leading to premature fatigue and failure, and are complex and costly due to multiple rotating elements and spring bias assemblies, especially during assembly when the inspection hole is not aligned with the directional force of gravity.
Innovation Solution
A plug design featuring a stem with a first seal and a swivel seal connected by a ball, allowing rotation about a single pivot point and limiting the rotation to a predetermined angle, which includes a second seal fixed to a shaft, reducing complexity and enhancing alignment during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple rotating elements and spring bias assemblies are used to accommodate thermal expansion, then thermal stress is reduced, but device complexity and cost increase
Solution Approach 1:
The plug is divided into multiple segments (first plug portion, second plug portion, third plug portion) that can independently expand and contract in response to thermal changes. This segmentation allows each portion to accommodate thermal expansion separately, reducing overall thermal stress without requiring complex rotating elements or spring assemblies.
2Reliability
If two points of rotation are used to accommodate thermal expansion, then thermal stress is reduced, but assembly difficulty increases when inspection hole is not aligned with gravity
Solution Approach 1:
The plug is segmented into multiple portions that can independently respond to thermal expansion, eliminating the need for complex two-point rotation mechanisms. This segmentation simplifies the assembly process while maintaining thermal expansion accommodation capabilities.
Solution Approach 2:
Instead of using rotating elements to accommodate thermal expansion, the invention inverts the approach by using segmented portions that can independently expand and contract. This inversion eliminates the alignment issues associated with gravity-dependent rotation during assembly.
3Reliability
If a spring bias assembly is added to accommodate thermal expansion, then thermal stress is reduced, but device complexity and cost increase
Solution Approach 1:
The plug is divided into multiple segments that can independently accommodate thermal expansion through their own movement and deformation. This eliminates the need for spring bias assemblies while maintaining thermal stress resistance, thereby reducing device complexity and assembly difficulty.
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 design effectively restricts gas flow, reduces thermal stress, and simplifies assembly by maintaining alignment and reducing the risk of premature failure, while eliminating the need for a spring bias assembly.
Implementation Method 1
Temperature variations within the GTE may cause thermal expansion of components within the inspection hole (e.g., an inspection hole plug), and the amount of thermal expansion of each component may vary based on its proximity to the flow of high-temperature gas.
Data Source
AI summary
A plug for an inspection hole of a gas turbine engine is disclosed. The plug may have a stem including a first shaft, wherein a first seal is located circumferentially about the first shaft. The plug may have a swivel seal including a second seal spaced from a ball by a second shaft, and the swivel seal may be rotatably connected to the stem by the ball. The ball and the second seal may be fixed to the second shaft.