Vacuum-Assisted Air Separation Module for Fuel Tank Inerting
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Solution Overview
Problem
Conventional fuel tank inerting systems relying on air separation modules are limited by the need for compressed bleed air from aircraft engines, restricting their operation to times when engines are running, and struggle to generate sufficient nitrogen-enriched inert gas during aircraft descent due to pressure differential limitations.
Innovation Solution
A fuel tank inerting system utilizing a variable vacuum source to create a pressure differential across the air separation module membrane, allowing for the production of high-purity nitrogen-enriched air even when bleed air is not available, by using a vacuum pump or ejector array to manipulate the permeate side pressure and enhance inert gas production during descent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional air separation modules use compressed bleed air to generate nitrogen-enriched inert gas, then the system can effectively inert fuel tanks during normal flight operations, but the system fails to operate sufficiently during aircraft descent when bleed air pressure is insufficient
Solution Approach 1:
The patent changes the pressure parameter by introducing a vacuum source on the permeate side of the membrane, creating a pressure differential that drives oxygen permeation during descent when bleed air pressure is low. This allows the air separation module to maintain high productivity and reliability across all flight phases including descent
Solution Approach 2:
The system is designed to function universally across all flight phases by combining bleed air compression with vacuum assistance. The vacuum source enables the system to operate effectively whether bleed air is abundant (cruise) or scarce (descent), making the inerting system reliable throughout the entire flight cycle
2Ease of operation
If air separation modules rely on engine bleed air availability, then the system structure can be simplified, but the operation is restricted to times when engines are running
Solution Approach 1:
The vacuum source acts as an intermediary that enables air separation to occur without relying solely on engine bleed air. By creating a pressure differential through vacuum, the system can separate oxygen from air during ground operations and descent when engines may not be providing sufficient bleed air, thus improving operational availability
Solution Approach 2:
The system dynamically adapts to different operational conditions by using vacuum assistance selectively. The vacuum source is particularly valuable during phases when bleed air pressure is low, allowing the system to maintain effectiveness across varying flight conditions without requiring engine operation
3Volume of moving object
If the air separation module is designed for high oxygen permeation, then the membrane area can be reduced, but the pressure differential requirements become more stringent
Solution Approach 1:
The patent changes the pressure parameter by actively creating a pressure differential through vacuum assistance on the permeate side. This allows high oxygen permeation rates to be achieved with smaller membrane areas, as the vacuum-driven pressure differential compensates for the reduced membrane surface area available for gas separation
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
Enables the production of high-purity nitrogen-enriched air deeply depleted of oxygen, effectively inerting fuel tanks during descent and allowing for a physically smaller air separation module, while also enabling operation independent of engine bleed air, thus improving fuel tank inerting efficiency and flexibility.
Implementation Method 1
air separation module membrane, allowing for the production of high-purity nitrogen-enriched air deeply depleted of oxygen
Implementation Method 2
create a pressure differential across the air separation module membrane
Implementation Method 3
using a vacuum pump or ejector array to manipulate the permeate side pressure and enhance inert gas production during descent
Data Source
Figure 1
Figure 2A~2B
Figure 3~4B
AI summary
A fuel tank inerting system includes an air separation module (24) with an oxygen permeable membrane (25) and a variable vacuum source (26) in fluid communication with the air separation module. The variable vacuum source provides an adjustable vacuum to the permeate side of the oxygen permeable membrane in the air separation module, driving production of inert gas for fuel tank inerting or fire suppression.