Guided-Wave Monitoring for Cryogenic Hydrogen Tank Integrity
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Solution Overview
Problem
Conventional structural health monitoring systems are inadequate for hydrogen fuel tanks in cryogenic environments due to challenges posed by cryogenic temperatures, hydrogen embrittlement, and the potential for gaseous leaks, which can lead to premature ignition and structural integrity issues.
Innovation Solution
A dual guided wave sensor array system is employed for the inner and outer tanks, with a controller to monitor guided waves for structural health, outputting alerts for any deviations from baseline conditions, and integrated with an IVHM system for real-time monitoring and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional structural health monitoring systems are used for hydrogen fuel tanks, then the system design is simple and cost-effective, but the system fails to detect structural damage and hydrogen embrittlement in cryogenic environments
Solution Approach 1:
The patent replaces conventional mechanical/physical monitoring systems with acoustic wave-based guided wave sensors. These sensors detect structural changes through acoustic wave propagation characteristics, enabling detection of hydrogen embrittlement and structural damage in cryogenic environments without complex mechanical contact or visual inspection systems
Solution Approach 2:
The guided wave sensor system serves multiple functions simultaneously: it monitors structural integrity, detects hydrogen embrittlement, identifies cracks and damage, and operates across the entire service lifespan of the fuel tank. This multi-functionality consolidates what would otherwise require multiple separate monitoring systems
2Duration of action of stationary object
If traditional safe-life implementation is used for fuel tanks, then the design and manufacturing process is straightforward, but the tanks cannot withstand cryogenic temperatures and hydrogen embrittlement throughout service lifespan
Solution Approach 1:
The system performs preliminary detection of structural changes and hydrogen embrittlement before critical failure occurs. By continuously monitoring acoustic wave propagation from the beginning of service, the system identifies early signs of degradation and enables proactive maintenance, extending the effective service lifespan beyond traditional safe-life limitations
Solution Approach 2:
The monitoring system provides continuous feedback on the structural health status of the fuel tank throughout its service lifespan. This feedback mechanism allows for real-time assessment of structural integrity under cryogenic conditions and hydrogen exposure, enabling adaptive maintenance strategies that extend reliable operation
3Object-affected harmful factors
If no continuous monitoring system is implemented, then the system is simple and maintenance-free, but structural damage and hydrogen leaks go undetected leading to premature ignition and safety incidents
Solution Approach 1:
The guided wave sensors act as intermediaries between the structural health status and the monitoring system. Rather than directly detecting hydrogen leaks or structural failures, the sensors detect changes in acoustic wave propagation caused by these conditions, providing indirect but reliable detection of harmful factors without requiring direct contact with hydrogen or complex detection mechanisms
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
Ensures structural integrity and safety of hydrogen fuel tanks by detecting changes and potential damage at cryogenic temperatures, enabling proactive maintenance and ensuring safe operation of aircraft fuel systems.
Implementation Method 1
monitor guided waves emitted by the at least one guided wave emitter using the at least one guided wave detector
Implementation Method 2
The insulation gap can be an insulative vacuum with respect to heat transfer between the inner tank and an ambient environment external to the outer tank
Data Source
AI summary
A method of health monitoring aircraft fuel system structures can include monitoring guided waves emitted by at least one guided wave emitter mounted to an inner hydrogen tank using at least one guided wave detector mounted to the inner hydrogen tank to monitor for a change versus a first baseline. The method can include monitoring guided waves emitted by at least one guided wave emitter mounted to an outer hydrogen tank surrounding the inner hydrogen tank using at least one guided wave detector mounted to the outer tank to monitor for a change versus a second baseline. The method includes outputting an alert to at least one of aircraft avionics and/or an onboard integrated Vehicle Health Management system (IVHM) if a change versus either or both of the first or second baselines is detected.