Segmented Double-Walled Tube Assembly for Gas Turbine Engines
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Solution Overview
Problem
Conventional gas turbine engine fluid circulation systems with double-walled tubes are complex and heavy, with hardware support structures that can weaken the tubes and increase the risk of fluid leaks, affecting engine reliability and performance.
Innovation Solution
A tube assembly with a unitary inner tube surrounded by segmented outer tubes, using spacers and ferrules to maintain separation and prevent fluid buildup, and employing welding or brazing for attachment, reducing complexity and weight while enhancing leak resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hardware support structures are used to support double-walled tube assemblies, then the tubes are mechanically supported and mounted, but the weight and complexity of the system increase and the tubes are weakened at interface points
Solution Approach 1:
The support structure is merged with the outer tube by forming protrusions directly on the outer tube surface. This integration eliminates separate support hardware, reducing assembly complexity while maintaining mechanical strength. The protrusions become both structural supports and mounting features without requiring additional components.
Solution Approach 2:
The outer tube is segmented into multiple sections with protrusions at specific locations. This segmentation allows the support structure to be distributed along the tube length, providing mechanical support at multiple points without concentrating stress at single interface locations, thereby maintaining tube strength while reducing overall complexity.
2Ease of operation
If hardware support structures are used to mount tube assemblies, then mounting capability is provided, but weight penalty is incurred
Solution Approach 1:
Mounting features are merged directly into the outer tube structure through formed protrusions. This eliminates the need for separate mounting hardware, brackets, or fasteners, thereby reducing the overall weight of the assembly while maintaining full mounting capability. The tube itself becomes the mounting structure.
3Reliability
If double-walled tube arrangement is used, then leak containment is provided, but system weight and complexity increase
Solution Approach 1:
The double-walled tube system is segmented into discrete sections with defined inner and outer tubes. This segmentation allows for simplified assembly and maintenance while maintaining the leak containment function. The segmented structure reduces complexity compared to a continuous, monolithic double-walled system.
4Strength
If hardware interfaces are added to support tube assemblies, then structural support is provided, but the tubes are weakened at interface points
Solution Approach 1:
The support structure is merged with the tube body through formed protrusions that are integral to the tube structure. This eliminates separate interface points where hardware would attach to the tube, thereby maintaining tube integrity and leak resistance while providing the necessary structural support. The tube wall continues uninterrupted through the support features.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Aspects of the disclosure are directed to a tube assembly comprising a first tube (314) having a radial exterior surface, a second tube composed of a plurality of segments (308, 308-1, 308-2), the first tube (314) co-axially nested within the second tube, at least a first spacer (320-1, 320-2) coupled to the first tube (314), and a second spacer (326) coupled to the at least a first spacer (320-1, 320-2), where a first segment (308-1) of the plurality of segments (308, 308-1, 308-2) is coupled to a first axial end of the second spacer (326), and a second segment (308) of the plurality of segments (308, 308-1, 308-2) is coupled to a second axial end of the second spacer (326).