Annular Gap Seal Assembly With Thermal Isolation for Aircraft Nacelles
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Solution Overview
Problem
Existing seal assemblies for aircraft propulsion systems' thermal anti-icing systems face challenges in sealing high-temperature conduits effectively, leading to potential degradation and failure, particularly with polymer seal materials.
Innovation Solution
A seal assembly featuring a tubular outer and inner structure with a seal land and seal elements, including a polymer and potentially metal components, configured to provide a restrictive heat conduction path and extended seal land mounts, utilizing v-shaped geometry and cooling elements to manage heat and ensure effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expensive and complicated seal assemblies are used to seal high-temperature conduits, then sealing reliability is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The seal assembly is divided into distinct functional segments: a polymer seal element for primary sealing, a metal backup ring for structural support and heat resistance, and a cooling element for thermal management. This segmentation allows each component to be optimized for its specific function while simplifying the overall design and manufacturing process.
Solution Approach 2:
The seal assembly employs composite material construction by combining polymer material for the seal element with metal material for the backup ring and cooling element. This composite approach leverages the advantages of both materials: polymer provides excellent sealing characteristics and cost-effectiveness, while metal provides high-temperature resistance and structural integrity, thereby improving sealing reliability without requiring a completely complex single-material solution.
2Ease of manufacture
If polymer seal materials are used for sealing high-temperature conduits, then manufacturing cost and ease of manufacture are improved, but heat resistance and sealing durability worsen
Solution Approach 1:
The metal backup ring acts as an intermediary between the polymer seal element and the high-temperature conduit. It provides a thermally stable interface that protects the polymer from direct exposure to extreme temperatures while maintaining effective sealing. The cooling element further mediates thermal management by actively removing heat from the seal assembly, thereby preserving polymer material integrity in high-temperature environments.
Solution Approach 2:
By combining polymer and metal materials in a composite seal assembly, the design achieves both ease of manufacture (through polymer molding) and high heat resistance (through metal components). The polymer seal element can be manufactured using cost-effective molding processes, while the metal backup ring and cooling element provide the necessary thermal stability and durability.
3Device complexity
If conventional seal assemblies are used without cooling elements, then device complexity is reduced, but heat management and seal performance under thermal load worsen
Solution Approach 1:
The cooling element utilizes phase transition of coolant (typically from liquid to vapor) to efficiently remove heat from the seal assembly. As the coolant passes through channels in the cooling element, it absorbs thermal energy from the polymer seal element and surrounding structures, maintaining operational temperatures even under high thermal load. This phase-change cooling mechanism provides superior thermal management compared to conventional passive cooling methods.
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 seals high-temperature conduits, reducing heat conduction and preventing seal material degradation, while allowing the use of polymer materials for improved sealing characteristics and cost-effectiveness.
Implementation Method 1
The seal land is configured to provide a restrictive heat conduction path from the inner structure to an outer surface of the seal land
Implementation Method 2
The seal element may be configured from or otherwise includes a polymer material
Data Source
AI summary
A system is provided for a nacelle of an aircraft propulsion system. This system includes a tubular outer structure, a tubular inner structure and a seal assembly. The tubular inner structure projects through a bore of the tubular outer structure. The seal assembly is configured to close an end of an annulus between the tubular outer structure and the tubular inner structure. The seal assembly includes a seal land and a seal element. The seal land includes a seal land mount that circumscribes and is attached to the tubular inner structure. The seal land mount is configured with a v-shaped sectional geometry. The seal element is attached to the tubular outer structure. The seal element circumscribes and is sealingly engaged with the seal land. The seal element may be configured from or otherwise includes a polymer material.