Cellular Conduit Bushing for Thermal Shift and Rubbing Prevention
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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, as existing arrangements do not effectively manage vibrations and thermal movements.
Innovation Solution
Incorporating a bushing made of cellular material that circumscribes the conduit and is engaged with a boss, allowing for lateral and longitudinal movement while damping vibrations, and is fixed through a threaded connection or fastener for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conduit is rigidly supported within the port, then the conduit is stable and supported, but thermal shifting between the exhaust case and the conduit is restricted causing stress and rubbing
Solution Approach 1:
The bushing is constructed from cellular material with a porous structure that provides both mechanical support and compliance. The cellular structure allows the bushing to deform elastically under thermal loads, accommodating conduit shifting while maintaining positional stability and support.
Solution Approach 2:
The bushing material properties are selected to provide viscoelastic behavior that changes with temperature and frequency. This allows the bushing to be stiff enough to support the conduit statically while being compliant enough to accommodate dynamic thermal movements and vibrations.
2Adaptability or versatility
If the conduit is allowed to float freely in the port, then thermal shifting is accommodated, but the conduit lacks support and stability
Solution Approach 1:
The bushing acts as an intermediary element between the conduit and the exhaust case. It provides a compliant interface that simultaneously offers mechanical support and allows thermal movement, resolving the contradiction between support and freedom of movement.
3Ease of manufacture
If conventional solid material is used for the bushing, then manufacturing is simple, but vibration damping and thermal movement accommodation are insufficient
Solution Approach 1:
The cellular material structure provides superior vibration damping compared to solid materials. The porous structure dissipates vibrational energy through friction and hysteresis within the cell walls, while the material can still be manufactured using conventional casting or molding processes.
Solution Approach 2:
The bushing may be constructed from composite cellular materials that combine different phases or materials to achieve optimized damping properties, thermal stability, and mechanical strength while maintaining manufacturability.
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 solution effectively supports the conduit, reduces internal stresses, and prevents rubbing between the stationary structure and the conduit, while accommodating thermal movements and damping vibrations, thereby enhancing the operational reliability of the gas turbine engine.
Implementation Method 1
The bushing may be 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. There is a need in the art, in particular, to support the fluid conduit proximate the exhaust case while still permitting thermally induced shifting between the exhaust case and the fluid conduit.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An assembly (20) is provided for a gas turbine engine (136). This engine assembly (20) includes a gas turbine engine case (30), a conduit (24) and a bushing (26). The gas turbine engine case (30) includes a case wall (36) and a boss (38) at a port (66) through the case wall (36). The conduit (24) extends longitudinally along a centerline (60) through the port (66) and into an interior of the gas turbine engine case (30). The bushing (26) circumscribes the conduit (24) and is arranged within the port (66). The bushing (26) is engaged with and laterally between the conduit (24) and the boss (38). The bushing (26) is configured from or otherwise includes a cellular material (120). The cellular material (120) may be or otherwise include a cellular metal material and/or a cellular composite material.