Cellular Conduit Bushing for Thermal Shift and Vibration Damping
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Solution Overview
Problem
Gas turbine engines face challenges in supporting fluid conduits while allowing for thermally induced shifting between the exhaust case and the conduit, which can lead to vibrations and potential rubbing, necessitating a solution that addresses both support and vibration damping.
Innovation Solution
Incorporating a bushing made of cellular material, such as cellular metal or composite, that circumscribes the conduit and is engaged with the conduit boss, providing support and damping for both longitudinal and lateral vibrations, while allowing for relative movement between the conduit and the gas turbine engine case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conduit is supported rigidly within the port, then the conduit is stable and supported, but the exhaust case cannot thermally shift relative to the conduit and vibrations are not damped
Solution Approach 1:
The bushing is made from cellular material with a porous structure that provides both mechanical support and vibration damping. The cellular structure allows the bushing to be compliant under dynamic loads while maintaining structural integrity, enabling thermal shifting while preventing excessive conduit movement and rubbing.
Solution Approach 2:
The cellular material properties are optimized to provide appropriate stiffness and damping characteristics. The material structure allows it to be rigid enough to support the conduit but compliant enough to allow thermal expansion and damp vibrations, changing the mechanical parameters between rigid support and flexible accommodation.
2Adaptability or versatility
If the conduit is allowed to float freely, then thermal shifting is permitted, but the conduit lacks support and experiences excessive vibrations and rubbing
Solution Approach 1:
The bushing acts as an intermediary element between the conduit and the exhaust case. It provides a controlled interface that allows thermal shifting while preventing excessive movement through its damping properties. The bushing mediates between the need for freedom of movement and the need for stability.
Solution Approach 2:
The bushing provides beforehand cushioning by being pre-installed in the port to accommodate thermal expansion and vibration before they occur during engine operation. The cellular material is designed to compress and deform under expected thermal and vibrational loads, protecting the conduit from excessive movement and rubbing.
3Strength
If a solid non-porous bushing material is used, then the bushing provides strong support, but vibration damping is reduced
Solution Approach 1:
The cellular material structure provides inherent vibration damping through its porous architecture. The cells within the material absorb vibrational energy through compression and deformation, reducing the transmission of vibrations to the conduit and preventing rubbing while maintaining adequate structural strength.
Solution Approach 2:
The cellular material may be a composite structure combining different materials to achieve both strength and damping properties. The composite structure allows optimization of mechanical strength for support while the cellular architecture provides vibration damping characteristics that solid materials cannot achieve.
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 cellular material bushing effectively supports the conduit, reduces internal stresses, and dampens vibrations, preventing rubbing and accommodating thermal shifts, thereby enhancing the operational stability and longevity of the gas turbine engine.
Implementation Method 1
The bushing is configured to damp longitudinal vibrations of the conduit. The bushing may be configured to damp lateral vibrations of the conduit.
Implementation Method 2
The exhaust case may thermally shift relative to the fluid conduit
Data Source
AI summary
An assembly is provided for a gas turbine engine. This engine assembly includes a gas turbine engine case, a conduit and a bushing. The gas turbine engine case includes a case wall and a boss at a port through the case wall. The conduit extends longitudinally along a centerline through the port and into an interior of the gas turbine engine case. The bushing circumscribes the conduit and is arranged within the port. The bushing is engaged with and laterally between the conduit and the boss. The bushing is configured from or otherwise includes a cellular material. The cellular material may be or otherwise include a cellular metal material and/or a cellular composite material.