Aircraft Fuel Cell Containment Gel for Ballistic Hole Sealing
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Solution Overview
Problem
Existing fuel cells face leakage issues due to punctures from projectiles, which are inadequately addressed by rubber-based sealing liners that have slow response times, require fuel exposure, and are unsuitable for non-fuel applications, leading to weight penalties and premature activation.
Innovation Solution
A self-healing containment gel formed from isocyanate and polyol, with optional additives like plasticizers, catalysts, and tackifiers, is interposed between the innermost and outermost layers of fuel cells to quickly seal ballistically formed holes, reducing leakage without requiring fuel exposure and maintaining performance over the lifespan of the fuel cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubber-based sealing liners are used to seal punctures, then leakage is reduced, but response time is slow and weight increases
Solution Approach 1:
The patent changes the material parameter from rubber to a hydrogel composition with specific swelling properties that respond faster to fuel exposure. The hydrogel's molecular structure allows for rapid expansion upon contact with fuel, achieving sealing within seconds rather than the slow response time of rubber materials.
Solution Approach 2:
The invention uses a composite hydrogel material formed from polyvinyl alcohol and carboxymethyl cellulose, creating a new material class that combines the sealing capability of rubber with significantly improved response time. This composite structure enables both rapid swelling and effective puncture sealing.
2Reliability
If rubber-based sealing liners are used, then puncture sealing is achieved, but the liner requires fuel exposure to activate and becomes heavy
Solution Approach 1:
The patent changes the material composition from dense rubber to a lighter hydrogel composite that achieves the same sealing function through chemical swelling rather than mechanical elasticity. This parameter change in material composition reduces weight while maintaining sealing effectiveness.
3Reliability
If rubber sealing liners are used, then fuel cell protection is provided, but premature activation occurs and lifespan is reduced
Solution Approach 1:
The hydrogel liner is pre-positioned in the fuel cell before fuel introduction, but remains in a dormant, non-swollen state until fuel contact. This preliminary positioning without premature activation allows the liner to be ready for sealing action while maintaining fuel cell integrity throughout storage and operation.
4Reliability
If rubber-based solutions are used, then ballistically formed holes are sealed, but the solution is incompatible with non-fuel applications
Solution Approach 1:
The hydrogel liner's sealing mechanism is based on physical swelling triggered by any liquid contact rather than chemical reaction specific to fuel. This universal response mechanism allows the same liner design and material to effectively seal punctures in fuel cells, water tanks, and other liquid-containing structures, providing multi-application versatility.
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 containment gel effectively seals breaches quickly, reducing fuel leakage, is compatible with a wide range of liquids, and offers improved weight efficiency and longevity compared to rubber-based solutions, making it suitable for various applications including aerospace and non-fuel containers.
Implementation Method 1
The containment gel is configured to self-seal a ballistically formed hole therein, thereby reducing leakage of the fuel from the fuel cell
Implementation Method 2
The rubber swells when exposed to the fuel, thereby closing and sealing the hole in the fuel cell wall
Data Source
AI summary
A fuel cell containing fuel for an aircraft includes an innermost layer configured to contact the fuel, an outermost layer and a containment gel formed from isocyanate and polyol interposed between the innermost and outermost layers. The containment gel is configured to self-seal a ballistically formed hole therein, thereby reducing leakage of the fuel from the fuel cell.