Aircraft Hydrogen Inerting Recirculation for Low-Weight Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inerting systems for aircraft hydrogen systems are space and weight inefficient due to the use of nitrogen bottles or generation systems, and halon is being phased out for environmental reasons, necessitating a more effective and space-efficient solution for inerting fuel tanks and fuel cell casings.
Innovation Solution
An inerting system that recirculates inert gas within the casing, using sensing and control means to regulate the flow based on oxygen and hydrogen concentrations, reducing the need for additional inert gas supply and incorporating a fluid recirculation system to maintain a safe atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitrogen bottles or nitrogen generation system are used to supply inert gas to the casing, then the hydrogen system can be effectively inerted to prevent explosion risks, but the installation space and weight on the aircraft increase
Solution Approach 1:
The system recirculates the inerted atmosphere from the casing back through the nitrogen generator, recovering and reusing the inert gas instead of continuously consuming new nitrogen from bottles or generation systems. This reduces the overall quantity of inert gas storage and supply equipment needed on the aircraft.
Solution Approach 2:
The nitrogen generator operates continuously to maintain the inert atmosphere in the casing, rather than relying on finite nitrogen bottles. The continuous generation and recirculation ensures sustained explosion prevention without requiring large initial gas storage capacity.
2Reliability
If nitrogen bottles or nitrogen generation system are used to supply inert gas to the casing, then the hydrogen system can be effectively inerted to prevent explosion risks, but the installation space on the aircraft increases
Solution Approach 1:
The recirculation system recovers inert gas from the casing atmosphere and feeds it back to the nitrogen generator, reducing the need for large nitrogen storage bottles or oversized generation systems. This significantly reduces the installation space required for the inert gas supply system.
Solution Approach 2:
The nitrogen generator serves dual functions: generating fresh inert gas for the casing and processing/recycling the atmosphere from the casing. This multi-functionality reduces the overall system size and space requirements compared to systems that only generate or store gas.
3Reliability
If halon is used as extinguishing agent in the casing, then fire can be suppressed in case of emergency, but environmental damage occurs and halon is being phased out
Solution Approach 1:
The system converts the potentially harmful recirculated atmosphere into a beneficial fire suppression mechanism. By maintaining low oxygen levels through continuous inerting and recirculation, the system creates an atmosphere that naturally suppresses fire without requiring halon or other harmful chemical agents.
Solution Approach 2:
The system maintains a permanently inert atmosphere in the casing through continuous nitrogen supply and recirculation, eliminating the need for halon fire suppression. The inert environment itself prevents fire propagation, providing environmental-friendly fire safety.
4Reliability
If the nitrogen circulation rate is sized for worst case scenario with maximum anticipated leakages, then safety limits are ensured, but the system uses more inert gas than necessary under normal conditions
Solution Approach 1:
The recirculation system dynamically adjusts to maintain safety: during normal operation with low leakages, the recirculated atmosphere maintains the inert condition with minimal additional nitrogen; during worst-case scenarios with maximum leakages, the system can increase nitrogen supply while the recirculation continues to optimize gas utilization. This dynamic operation reduces overall inert gas consumption while maintaining safety compliance.
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 reduces installation space and weight by optimizing inert gas usage, provides rapid detection and response to hazardous concentrations, and eliminates the need for halon, ensuring efficient and rapid inerting of hydrogen systems.
Implementation Method 1
a fluid recirculation system configured to recirculate part of the fluid located inside the casing to the inlet conduct for supplying the recirculated fluid mixed with the pure inert gas to the inside of the casing
Implementation Method 2
sensing means configured to measure the concentration of oxygen and the concentration of hydrogen of a fluid located inside the casing
Implementation Method 3
control means in data communication with the sensing means and configured to independently control at least the outlet valve and the fluid recirculation system based on the concentration of oxygen and the concentration of hydrogen inside the casing
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to an inerting system for an aircraft and a method of inerting a hydrogen system, and in particular to an improved inerting system that reuses the inert gas already supplied to the hydrogen system through a fluid recirculation system.