Composite Polyimide Seal for High-Temperature Leak Prevention
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Solution Overview
Problem
Gas turbine engine seals face challenges in withstanding high temperatures while preventing fluid leaks, as existing materials like perfluoroelastomers and ceramic seals either degrade or release harmful compounds, and elastomeric seals are not suitable for temperatures above 550 degrees Fahrenheit.
Innovation Solution
The use of fiber-reinforced polyimide resin layers, which are compressed and heated to conform to sealing surfaces, providing a fluid-tight seal that can withstand temperatures up to 750 degrees Fahrenheit and is reusable, with the option of additional adhesion-reducing coatings to facilitate separation and reusability of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perfluoroelastomers are used for sealing, then fluid leak prevention is improved, but temperature resistance deteriorates above 550 degrees Fahrenheit
Solution Approach 1:
The invention uses a composite material consisting of polyimide resin combined with fibers (such as aramid, glass, or carbon fibers). This composite structure provides both the high-temperature resistance of polyimide (stable up to 750°F) and the mechanical strength needed to prevent fluid leaks, overcoming the limitations of perfluoroelastomers which degrade above 550°F.
Solution Approach 2:
The invention changes the material parameter from elastomeric compounds to cured polyimide resin, which has a higher glass transition temperature and maintains structural integrity at elevated temperatures. The curing process transforms the resin into a cross-linked network that resists thermal degradation while maintaining sealing capability.
2Temperature
If graphite or ceramic seals are used, then temperature resistance is improved, but fluid leak prevention deteriorates due to less conformability
Solution Approach 1:
The polyimide resin seal acts as a flexible thin film that can conform to irregular sealing surfaces. Unlike rigid graphite or ceramic seals, the resin-based seal can deform and adapt to surface imperfections, ensuring complete contact and preventing fluid leaks while maintaining high-temperature resistance.
Solution Approach 2:
The sealing surfaces are prepared in advance by applying the uncured polyimide resin to the sealing surface before assembly. This preliminary action allows the resin to flow and conform to the surface geometry, then cure in place to create a customized seal that perfectly matches the sealing interface.
3Reliability
If elastomeric seals are used to reduce fluid leaks, then fluid leak prevention is improved, but temperature resistance deteriorates and decomposition products are generated
Solution Approach 1:
The invention changes the chemical composition parameter from elastomeric materials to polyimide resin, which has superior thermal stability. Polyimide's aromatic structure and imide groups provide resistance to thermal decomposition up to 750°F, preventing the generation of harmful decomposition products that would occur with conventional elastomers at these temperatures.
4Reliability
If fluoroelastomers are used for sealing, then fluid leak prevention is improved, but compatibility with titanium deteriorates at temperatures around 550 degrees Fahrenheit or higher
Solution Approach 1:
The invention uses a composite material of polyimide resin with reinforcing fibers, replacing fluoroelastomers. This composite provides both the needed sealing performance and chemical compatibility with titanium at high temperatures, as polyimide does not release fluorinated compounds that could contaminate or damage titanium components.
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 fiber-reinforced polyimide resin layers create a reliable, high-temperature-resistant seal that prevents fluid leaks and allows for the separation and reusability of components, addressing the limitations of existing materials in gas turbine engines.
Implementation Method 1
At least one fiber reinforced polyimide resin layer is heated to promote flow and conformation to the first sealing surface and the second sealing surface
Implementation Method 2
At least one fiber reinforced polyimide resin layer is compressed against the first sealing surface and the second sealing surface prior to curing
Implementation Method 3
At least one fiber reinforced polyimide resin layer is cured to provide a fluid tight seal between the first component and the second component
Data Source
AI summary
A method of sealing a first component to a second component comprising the steps of locating at least one fiber reinforced polyimide resin layer against a first sealing surface on a first component and against a second sealing surface on a second component. At least one fiber reinforced polyimide resin layer is compressed against the first sealing surface and the second sealing surface prior to curing at least one fiber reinforced polyimide resin layer. At least one fiber reinforced polyimide resin layer is heated to promote flow and conformation to the first sealing surface and the second sealing surface. At least one fiber reinforced polyimide resin layer is cured to provide a fluid tight seal between the first component and the second component.