Hinged Seal Assembly for Exhaust Nozzle Flap Gap Sealing
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Solution Overview
Problem
Gas turbine engine exhaust nozzles face inefficiencies due to leakage of core air through gaps between moveable flaps and stationary sidewalls, which reduces thrust and efficiency, and existing dynamic seals like leaf seals require additional purge air and complex secondary seals to manage pressure and thermal variations.
Innovation Solution
A hinged seal assembly with a spring body, clip, and wear shoe that accommodates sliding motion and thermal growth, using pivot joints and multi-component design to seal gaps between flaps and sidewalls, reducing the need for external hardware and secondary seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gaps are left between the flap and sidewalls to accommodate thermal growth and sliding motion, then the seal assembly can adapt to thermal and mechanical variations, but core air leakage increases reducing thrust and efficiency
Solution Approach 1:
The seal assembly uses a flexible lip seal that can deform and conform to the gap variations caused by thermal growth and sliding motion. The flexible lip material allows the seal to maintain contact with both the flap and sidewall surfaces while accommodating relative movement between them, preventing core air leakage without rigid constraints.
Solution Approach 2:
The seal assembly is designed to be dynamic rather than static, allowing it to adapt its position and shape in response to thermal expansion and mechanical movement. The seal can move with the flap and sidewall while maintaining sealing contact, converting the static sealing problem into a dynamic adaptation solution.
2Reliability
If conventional dynamic seals like leaf seals are used to seal the gap, then sealing effectiveness improves, but the system requires additional purge air and complex secondary seals increasing device complexity
Solution Approach 1:
The invention extracts and eliminates the need for complex secondary seals and purge air systems that are typically required with conventional dynamic seals. By using a simplified seal assembly design with a flexible lip seal, the patent removes the disturbing elements (secondary seals, purge air requirements) while maintaining sealing effectiveness.
Solution Approach 2:
The seal assembly is designed to be self-contained and self-regulating, using the pressure differential and thermal conditions inherent in the exhaust nozzle environment to maintain sealing without requiring external purge air systems or additional secondary seals. The seal serves itself by adapting to the operating conditions.
3Device complexity
If a simple seal design is used to minimize weight and hardware complexity, then ease of manufacture and weight reduction are achieved, but the seal cannot accommodate sliding motion and thermal growth
Solution Approach 1:
The flexible lip seal uses a thin, flexible membrane structure that provides adaptability to sliding motion and thermal growth without requiring complex mechanical components. The flexibility of the lip material allows it to deform and follow the relative movement between the flap and sidewall while maintaining sealing contact.
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 seal assembly effectively prevents core air leakage to the ambient environment while minimizing weight and hardware complexity, maintaining performance under varying thermal and pressure conditions.
Implementation Method 1
a spring body, comprising: a first arm opposite a second arm... wherein at least a portion of the spring body exerts a force to urge at least one of the first arm and the second arm away from the other
Data Source
AI summary
Apparatuses and methods are provided herein useful to sealing a dynamic gap between a moveable flap and a sidewall. The apparatus may be a seal assembly that includes a spring body, a clip coupled to a distal end of the spring body, and a wear shoe coupled to the clip. The spring body includes a flap arm adjacent the flap and a wall arm adjacent the sidewall. The flap arm and the wall arm bias away from one another when under compression in the gap. A distal end of the wall arm includes a first knuckle and a second knuckle that are pivotally coupled to the clip to create a hinge feature. The wear shoe is pivotally coupled to the clip to create another hinge feature. A distal end of the flap arm includes a skirt that is received by the clip seal an interior space of the spring body.