Foldable Hanger for Gas Turbine Cooling Liner
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Solution Overview
Problem
Current gas turbine engine exhaust ducts require a significant amount of cooling air, leading to performance penalties, and the use of multiple individual cooling liner segments results in weight, manufacturing, and sealing inefficiencies due to redundant parts and non-desirable joints, especially in swivelable exhaust ducts with complex configurations.
Innovation Solution
A foldable attachment hanger system is used to attach a cooling liner to the exhaust duct case, allowing for reduced joints and improved sealing efficiency, weight reduction, and simplified assembly by enabling axial growth and minimizing the number of joints between cooling liner segments, which are designed to rotate through bearing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple individual cooling liner segments are assembled within the duct, then the cooling liner can be installed in swivelable exhaust ducts with complex configurations, but the number of joints increases leading to weight penalty, manufacturing complexity, and sealing inefficiency
Solution Approach 1:
The exhaust duct is divided into multiple swivelable segments connected by bearing joints, allowing the duct to articulate between cruise and hover configurations. The cooling liner is correspondingly segmented to fit within each duct section, with the foldable hanger system enabling each segment to be independently installed and positioned.
Solution Approach 2:
The foldable attachment hanger system transitions from a folded configuration during assembly (to pass through bearing joints) to an unfolded configuration during operation (to provide structural support). This dynamic transformation reduces the number of permanent joints needed while maintaining adaptability to the swivelable duct structure.
2Adaptability or versatility
If multiple individual cooling liner segments are assembled within the duct, then the cooling liner can accommodate bearing systems, but weight and manufacturing penalty increase due to redundant parts
Solution Approach 1:
Multiple cooling liner segments are merged into a single continuous structure where possible, eliminating redundant joints and associated hardware. The foldable hanger system serves multiple functions: it provides structural support, enables thermal expansion, and facilitates assembly, replacing what would otherwise require multiple separate fastening mechanisms.
Solution Approach 2:
The foldable attachment hanger system performs multiple functions simultaneously: it structurally supports the cooling liner, accommodates thermal expansion, and enables the liner to pass through bearing joints during assembly. This multi-functionality eliminates the need for separate components for each function, reducing overall weight.
3Adaptability or versatility
If multiple individual cooling liner segments are assembled within the duct, then the cooling liner can be installed in articulated ducts, but sealing efficiency decreases due to numerous joints
Solution Approach 1:
The foldable hanger system is deployed dynamically during assembly to provide support, then folded back to create a smoother, more continuous surface. This reduces the number of permanent discontinuities in the cooling liner structure, improving sealing efficiency while maintaining compatibility with the articulated duct.
Solution Approach 2:
The cooling liner segments are designed with flexible sealing surfaces that can accommodate minor misalignments between segments. The foldable hanger system provides support while allowing the liner material to conform and seal effectively across joint regions, maintaining sealing integrity despite the articulated duct structure.
4Strength
If a rigid attachment system is used to fasten cooling liner segments to the duct case, then structural support is provided, but thermal growth is constrained and assembly access is limited
Solution Approach 1:
The attachment hanger system transitions from a folded state during assembly (providing access through bearing joints) to an unfolded state during operation (providing structural support). This dynamic configuration allows the system to satisfy both requirements at different stages without compromise.
Solution Approach 2:
The hanger system changes its geometric parameters (folded vs. unfolded configuration) to adapt to different operational requirements. During assembly, the folded configuration provides access; during operation, the unfolded configuration provides the necessary structural support while allowing thermal expansion.
5Reliability
If cooling air flow is increased to maintain positive pressure in the cooling liner, then cooling effectiveness improves, but engine performance penalty increases
Solution Approach 1:
The cooling liner is segmented to fit within the swivelable duct sections, allowing cooling air to be contained more effectively within the liner structure. This segmentation, combined with the foldable hanger support system, improves pressure maintenance efficiency, reducing the total cooling air flow required to maintain positive pressure.
Data Source
AI summary
An exhaust duct assembly includes a cooling liner spaced apart from an exhaust duct case that articulate for use in a short take off vertical landing (STOVL) type of aircraft. The cooling liner assembly is attached to the exhaust duct case through a foldable attachment hanger system. The foldable attachment hanger system provides a low profile (foldable up/down) for a limited access installation envelope typical of a three bearing swivel duct (3BSD) which rotates about three bearing planes to permit transition between a cruise configuration and a hover configuration. In this way, each cooling liner segment may be formed as a complete cylindrical member requiring joints only between the swivelable duct sections.