Aircraft Engine Fire Seal Assembly for CSD Firewall Deflection
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Solution Overview
Problem
Existing fire seal assemblies for aircraft engines struggle to maintain a sufficient seal during engine movements and higher operating temperatures, particularly with larger, more powerful engines, which can lead to fire spread and safety concerns.
Innovation Solution
The fire seal assembly incorporates first and second L-caps forming a u-shaped channel, coupled to a core service disconnect (CSD) and engaging the engine firewall, with P-seals and end plugs to ensure a tight seal, allowing for flexible movement and contact with the firewall, even during engine deflections and temperature increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing fire seal assemblies are used, then the structure is simpler, but the seal becomes insufficient during engine movements and high temperatures
Solution Approach 1:
The fire seal assembly is divided into multiple L-cap units (first L-cap and second L-cap) that can independently deflect and seal against different surfaces. Each L-cap functions as a separate sealing element that can move autonomously to maintain contact with the firewall and thrust reverser seals, ensuring reliable sealing without requiring a complex monolithic structure.
Solution Approach 2:
The L-caps are designed with flexible legs that can deflect dynamically in response to engine movements and thermal expansion. The legs can bend and adjust their position to maintain continuous contact with the firewall and thrust reverser seals, allowing the fire seal assembly to adapt to changing conditions while maintaining sealing effectiveness.
2Adaptability or versatility
If the fire seal assembly accommodates larger engine movements, then it supports larger engines, but the seal may break during high temperature operation
Solution Approach 1:
The material properties of the L-cap legs are selected to change with temperature, allowing the legs to become more flexible at higher temperatures. This enables the legs to accommodate larger engine movements and thermal expansion without breaking the seal, as the material can deform elastically to maintain contact with the sealing surfaces.
Solution Approach 2:
The L-cap legs are constructed as flexible elements that can bend and deform to accommodate engine movements. This flexibility allows the fire seal assembly to adapt to larger engine sizes and movements while maintaining continuous contact with the firewall and thrust reverser seals, preventing fire spread even under extreme conditions.
3Adaptability or versatility
If the L-caps are made more flexible to accommodate engine movements, then the seal remains effective, but the structural strength may be reduced
Solution Approach 1:
The L-caps are constructed from composite materials that combine flexibility with structural strength. The composite structure allows the legs to bend and deflect to accommodate engine movements while maintaining sufficient strength to resist fire temperatures and mechanical loads. This resolves the contradiction by providing both flexibility for movement accommodation and strength for fire containment.
Data Source
AI summary
Fire seal assemblies for aircraft engines are described herein. An example fire seal assembly includes a first L-cap having a first leg and a second leg extending outward from the first leg, and a second L-cap having a third leg and a fourth leg extending outward from the third leg. The first and third legs are to be coupled to a core service disconnect (CSD) on a pylon of an aircraft, and the second and fourth legs are to extend outward and engage sides of a firewall of an engine of the aircraft. The first seal assembly further includes a seal coupled to the first and third legs and disposed between the second and fourth legs, a first end plug disposed between a first end of the seal and the second leg, and a second end plug disposed between a second end of the seal and the fourth leg.