Chevron Ring Fire Seal Mounting for Exhaust Nozzle Integrity
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Solution Overview
Problem
Existing exhaust nozzle assemblies for aircraft propulsion systems do not adequately address noise reduction and structural integrity, particularly at the exhaust outlet where chevron rings are used.
Innovation Solution
The exhaust nozzle assembly incorporates a chevron ring with blind apertures and a fire seal mounted using fasteners, which provides enhanced noise reduction and structural stability by axially and circumferentially overlapping the ring base and nozzle ring, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a chevron ring is used at the exhaust outlet for noise reduction, then noise levels are reduced, but structural integrity and stability at the exhaust outlet are compromised
Solution Approach 1:
A fire seal acts as an intermediary component between the chevron ring and the exhaust nozzle assembly. The fire seal is mounted to the chevron ring using fasteners with blind apertures, creating a mediator structure that connects the noise-reducing chevron ring to the main exhaust nozzle while maintaining structural integrity and stability at the exhaust outlet.
2Reliability
If the fire seal is mounted to the chevron ring using fasteners with blind apertures, then structural stability is enhanced, but device complexity increases
Solution Approach 1:
The fastener structure employs a nested design where the blind aperture is formed within the fastener body itself, allowing the fastener to be inserted through the fire seal and threaded into the chevron ring without requiring separate blind hole drilling operations. This nesting of functions within the fastener component reduces overall assembly complexity while maintaining structural stability.
Data Source
AI summary
An apparatus includes a chevron ring, a first seal and a plurality of fasteners. The chevron ring extends axially along an axis to and forms a downstream trailing edge of an exhaust nozzle. The chevron ring includes a ring base and a plurality of chevrons. The ring base includes a plurality of blind apertures. Each blind aperture projects radially inward towards the axis partially into the ring base. The fire seal is disposed radially outboard of the chevron ring. The fire seal axially and circumferentially overlaps the ring base. The fasteners mount the fire seal to the chevron ring. Each fastener includes a shank and a head. The shank projects longitudinally out from the head, through the fire seal, and is threaded into a respective one of the blind apertures. The fire seal is radially clamped between the head of each of the fasteners and the ring base.