Segmented Aircraft Engine Seal for Heat and Misalignment
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Solution Overview
Problem
Existing seals for aircraft engines in hot air systems face challenges in balancing sealing effectiveness and service life, particularly in high-temperature environments where O-rings are inadequate.
Innovation Solution
A seal design featuring an annular body with an inner and outer portion, where one portion defines cuts extending towards the other portion, allowing for interference fit and sliding engagement with cylindrical components, and optionally coated with an anti-friction coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal is made with a continuous annular body for strong sealing, then sealing effectiveness is improved, but service life deteriorates due to excessive friction and hoop stress
Solution Approach 1:
The annular body is divided into multiple circumferential segments by introducing cuts, creating a segmented structure. This segmentation reduces continuous hoop stress and friction while maintaining sealing effectiveness through controlled contact between segments and the cylindrical components.
Solution Approach 2:
The cut depth parameter is optimized to extend into the intermediate portion but not beyond the radial mid-point, changing the structural parameters to balance flexibility and strength. This parameter optimization allows the seal to accommodate misalignment and thermal expansion while maintaining adequate service life.
2Duration of action of moving object
If the cut extends deeply into the intermediate portion to reduce hoop stress, then service life is improved, but sealing effectiveness deteriorates due to reduced structural integrity
Solution Approach 1:
The cut depth is precisely controlled to extend into the intermediate portion but not beyond the radial mid-point. This parameter optimization maintains sufficient structural integrity for sealing while reducing hoop stress and friction to extend service life.
Solution Approach 2:
The cut configuration is optimized locally in the intermediate portion, creating a specific geometric structure that provides both stress relief and sealing capability. The local quality of the cut geometry balances the competing requirements of reduced friction and maintained sealing effectiveness.
3Reliability
If the seal is designed with interference fit for strong sealing, then sealing effectiveness is improved, but service life deteriorates due to increased friction and wear
Solution Approach 1:
The segmented structure created by cuts in the annular body reduces continuous contact pressure and friction during sliding engagement. This segmentation allows interference fit for sealing while reducing wear through distributed contact stresses.
Solution Approach 2:
The interference fit parameters are optimized in conjunction with cut depth and configuration to achieve the balance between sealing force and friction reduction. The parameter changes in cut geometry modify the stress distribution to extend service life.
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 effectively balances sealing performance and service life by accommodating misalignment and thermal expansion, reducing friction and hoop stress, and maintaining contact with cylindrical components, thereby enhancing durability and reducing leakage.
Implementation Method 1
an annular body receivable in interference fit in a radial spacing defined between inner and outer cylindrical components
Implementation Method 2
accommodating misalignment and thermal expansion
Data Source
AI summary
A seal for an aircraft engine includes an annular body receivable in interference fit in a radial spacing defined between inner and outer cylindrical components of the aircraft engine, the annular body defining a central axis coaxial with the inner and outer cylindrical components, the annular body including an inner portion defining an inner diameter, an outer portion defining an outer diameter, and an intermediate portion extending between the inner and outer portions. The outer portion is slidably engageable to the outer cylindrical component at an outer contact sealing portion of the annular body. One of the inner portion and the outer portion defines at least one cut extending from the one of the inner portion and the outer portion toward another one of the inner portion and the outer portion. A method for sealing a radial spacing between coaxial cylindrical components in an aircraft engine is also described.