Aircraft Enclosure Inerting With Hybrid Separators for Lower Weight
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Solution Overview
Problem
Current aircraft fuel tank inerting systems using membrane-based Air Separate Modules (ASMs) are bulky, costly, and require significant maintenance due to membrane degradation, while vortex tubes produce less pure nitrogen-enriched air, leading to inefficiencies and increased weight.
Innovation Solution
An aircraft enclosure inerting system with differently configured air separators, such as vortex tubes and membrane-based ASMs, connected in series or parallel, allowing tailored separation for various flow rates and purities, reducing the need for over-sizing and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple membrane-based ASMs are connected in parallel to ensure sufficient NEA availability at high flow rate, then the required NEA purity and flow rate are achieved, but the system becomes heavy and requires considerable space
Solution Approach 1:
The system divides the air separation function into multiple parallel ASMs, each handling a portion of the total flow. This segmentation allows the system to achieve high total flow rate while using smaller, lighter individual modules rather than one large heavy module, optimizing the weight-performance ratio.
Solution Approach 2:
The patent transitions from a single-module approach to a multi-dimensional parallel architecture, adding the dimension of parallelism to handle high flow rates. This dimensional change in system configuration enables achieving high productivity without proportionally increasing weight, as multiple lighter modules replace one heavy module.
2Manufacturing precision
If membrane-based ASMs are used to separate air into NEA and OEA, then the required NEA purity is achieved, but the membranes degrade over service life requiring frequent replacement
Solution Approach 1:
The system operates ASMs at optimized parameters including controlled temperature, pressure, and air quality conditions to extend membrane life. By carefully managing operational parameters and implementing pre-cooling and filtering, the system maintains high NEA purity while reducing membrane degradation rates.
Solution Approach 2:
The system performs preliminary cooling and filtering of bleed air before it enters the ASMs. This preliminary action prevents contaminants from reaching and damaging the membranes, extending their service life while maintaining the required separation precision and purity levels.
3Reliability
If cooling and filtering apparatus are added to protect ASMs from hot and contaminated air, then membrane degradation is reduced, but the system becomes more complex with increased weight and bulk
Solution Approach 1:
The cooling and filtering functions are merged with the ASM assembly rather than being separate standalone components. The cooling apparatus is integrated into the ASM housing, and filters are positioned within the air path leading to the membranes, combining multiple protective functions into a unified structure that reduces overall system complexity.
Solution Approach 2:
The cooling apparatus serves multiple functions: it cools the bleed air to protect membranes, condenses moisture to prevent contamination, and stabilizes temperature for optimal membrane performance. This multi-functionality reduces the need for separate dedicated components, simplifying the overall system.
4Productivity
If the number of ASMs is increased to provide sufficient NEA at required purity, then the NEA availability is improved, but the system requires more space within aircraft structure
Solution Approach 1:
By segmenting the total NEA requirement into multiple parallel ASMs, each module can be smaller and more compact. The distributed architecture allows for optimized packaging and reduces the total footprint compared to a single large ASM, as multiple small modules can be arranged efficiently within the aircraft structure.
Solution Approach 2:
The system employs a nested arrangement where cooling apparatus, filters, and ASM components are arranged concentrically or in nested configurations. This nesting maximizes space utilization by placing components within the boundaries of others, reducing the overall envelope volume required for the system.
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 system achieves higher flow rates and purities of nitrogen-enriched air with reduced weight and maintenance, improving energy efficiency and versatility, while minimizing the need for additional cooling and filtering apparatus.
Implementation Method 1
The membrane of the/each ASM is permeable to oxygen but not to nitrogen, so as the air passes over the membrane much of the oxygen it contains passes through the membrane while the nitrogen continues along it.
Implementation Method 2
A vortex tube has a chamber into which air is formed into vortex... As the air rotates inside the chamber it produces a hotter stream around the outside and a colder stream towards the middle. Vortex tubes are generally used to provide cooling rather than air separation. However, oxygen, being denser than nitrogen, tends to be thrown out into the outer stream, leaving the inner stream in a nitrogen enriched state.
Data Source
AI summary
An aircraft enclosure inerting system has an inerting apparatus which receives air from an inlet, separates that air into nitrogen enriched air to be delivered to one or more enclosures of the aircraft, and oxygen enriched air. The inerting apparatus comprises at least first and second air separators. The first and second air separators are configured differently to one another. In some embodiments one of the air separators is a vortex tube and the other is a membrane-based air separation module. In some embodiments the inerting apparatus has at least two vortex tubes which are configured differently to one another.