Clam Shell Axial Support for Air Separation Module
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Solution Overview
Problem
Current air separation modules (ASMs) for on-board inert gas generating systems (OBIGGS) face challenges in increasing nitrogen-enriched air (NEA) flow, reducing size and weight, and extending maintenance intervals to effectively inert fuel tanks and minimize leakage and performance degradation.
Innovation Solution
The design incorporates an axial support assembly positioned outside the fiber bundle, which allows for a more compact configuration, increased hollow fiber membrane packing, and the use of o-rings and tubesheets to form fluid-tight seals, enhancing the separation efficiency and structural integrity while minimizing weight and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an inner tube is included within the fiber bundle to provide axial support, then the structural integrity is improved, but the device complexity and weight increase
Solution Approach 1:
The axial support function is extracted from the interior of the fiber bundle and relocated to the exterior. The clam shell axial support structure surrounds the fiber bundle externally, eliminating the need for an inner tube within the bundle while maintaining the required axial support and structural integrity.
Solution Approach 2:
The clam shell axial support structure is designed to surround and nest with the fiber bundle, creating a compact integrated assembly where the support structure encapsulates the membrane elements without adding significant volume or weight.
2Reliability
If both ends of the fiber bundle are encapsulated with tubesheets, then the fluid-tight relationship is improved, but the manufacturing complexity and potential for cracking increase
Solution Approach 1:
The tubesheet structure is segmented into multiple sections or layers, allowing for distributed sealing surfaces and reduced stress concentration. This segmentation enables better manufacturing control and reduces the likelihood of cracking while maintaining fluid-tight integrity.
Solution Approach 2:
The tubesheets utilize composite material construction, combining materials with complementary properties to achieve both fluid-tight sealing and crack resistance. The composite structure allows for stress distribution and defect tolerance while maintaining reliability.
3Weight of stationary object
If the ASM size and weight are reduced, then the OBIGGS size and weight decrease, but the maintenance interval may be reduced
Solution Approach 1:
The hollow fiber membranes utilize thin-film technology to achieve high separation performance in a compact, lightweight package. The thin-film construction reduces overall ASM weight and size while maintaining durability through careful material selection and protective structural design.
Solution Approach 2:
The design incorporates protective features and stress-distribution structures that prevent damage accumulation before failure occurs. The clam shell support and optimized tubesheet design provide cushioning against thermal and mechanical stresses, extending the maintenance interval despite reduced size.
4Productivity
If hollow fiber membrane packing is increased, then the NEA flow increases, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The hollow fiber membranes are arranged in a three-dimensional packed configuration that maximizes surface area density. This spatial optimization allows high NEA flow capacity within a compact volume, achieving increased productivity without proportionally increasing manufacturing complexity.
Solution Approach 2:
The axial support structure serves multiple functions simultaneously: it provides mechanical support, facilitates membrane replacement, and aids in assembly/disassembly. This multi-functionality simplifies the overall manufacturing process while enabling high membrane packing density.
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
This configuration increases NEA flow, reduces the size and weight of the ASM, and extends maintenance intervals by preventing tubesheet cracking and leakage, thereby improving the overall performance and reliability of the fuel tank inerting system.
Implementation Method 1
Oxygen may be separated from the air flow due to diffusion through the fiber walls because the fiber walls may be more permeable to oxygen than to nitrogen
Implementation Method 2
the fiber walls may be more permeable to oxygen than to nitrogen
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An air separation module (40) includes a housing (42), a bundle of hollow fiber membranes (44), and a clam shell axial support assembly (48). The axial support assembly includes two supportive elements, each supportive element including a flowthrough component (80a). The flow-through component includes a plurality of openings through which a supply of fluid (e.g. oxygen enriched air) may pass. The axial support assembly is secured around the bundle of hollow fiber membranes at a position radially inward from the housing and radially outward from the fiber bundle.