Adjustable Brush Seal for Jet Engine Clearance Control
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Solution Overview
Problem
Existing seal technologies in aircraft jet engines, such as labyrinth seals and brush seals, face challenges in maintaining efficiency and longevity due to high gas flow rates and wear from imbalance, which reduces engine performance and contaminates air with oil.
Innovation Solution
A brush seal system with adjustable fiber inclination allows for precise adjustment of clearance between the rotary part and the seal, using inclination members and pressure members to modify the angle of fibers, thereby maintaining optimal gas flow and extending the seal's service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If labyrinth seals are used to seal between fixed and rotary elements, then oil retention is improved, but gas flow rate becomes excessively high which reduces engine efficiency
Solution Approach 1:
The patent changes the geometric parameters of the seal structure by transitioning from labyrinth geometry to brush seal geometry, where fibers are positioned at a specific angle (5-15 degrees) relative to the radial direction. This parameter change allows the seal to maintain oil retention while reducing gas flow rate and improving engine efficiency.
2Loss of energy
If brush seals are used to reduce gas flow rate, then engine efficiency is improved, but fiber wear from rubbing on the rotary part reduces seal efficacy over time
Solution Approach 1:
The patent introduces a dynamic adjustment mechanism where the brush body can pivot relative to the stator, and fibers can change their inclination angle in response to clearance variations. This dynamic capability allows the seal to adapt to wear and imbalance conditions, extending service life while maintaining efficiency.
Solution Approach 2:
The patent enables parameter changes in the fiber inclination angle and brush body position to compensate for wear over time. By adjusting these parameters, the seal maintains optimal clearance and performance throughout its service life, extending its duration of action.
3Reliability
If fiber inclination is increased to reduce gas flow rate, then sealing efficiency is improved, but clearance control precision deteriorates due to wear and imbalance
Solution Approach 1:
The patent implements a feedback mechanism where the brush body pivots in response to clearance changes caused by wear or imbalance. This automatic adjustment provides feedback control that maintains optimal fiber-to-part clearance and sealing efficiency despite changing conditions.
Solution Approach 2:
The seal structure is designed to self-adjust through brush body pivoting and fiber repositioning in response to clearance variations. This self-service capability compensates for wear and imbalance without external intervention, maintaining precision clearance control throughout operation.
Data Source
AI summary
The invention concerns a system for providing a seal between two volumes (V1, V2) delimited by a part (2A) mounted to rotate about an axis (A) and a stator (6), said system (S) including an annular brush seal (7) that comprises:a brush body (8) pivotally mounted in the stator; andfibers (10) fixed to the brush body and inclined at an angle α relative to a plane (P) orthogonal to the rotation axis (A),wherein it includes means (11, 12) for adjusting the angle α of the fibers (10) so as to be able to adjust precisely the clearance between the free end (10A) of the fibers and the rotary part (2A).