Hydrogen Tank Fill Monitoring via Horizontal Vibration Modes
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Solution Overview
Problem
Existing methods for accurately monitoring the filling level of fluid tanks, particularly in aircraft applications, are inadequate due to the challenges posed by changing gravity vectors and safety concerns with electronic sensors, making it difficult to determine precise fuel levels in dynamic environments.
Innovation Solution
A filling level monitoring device utilizing a combination of exciting and sensing elements to measure the horizontal vibration mode of a fluid container, which is insensitive to external factors and highly correlated with the filling level, allowing for accurate determination through spectral analysis of resonance frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If weight-based measurement methods are used to determine filling level, then filling level can be measured, but accuracy deteriorates under changing gravity conditions (altitude changes, curved flight segments)
Solution Approach 1:
The patent applies mechanical vibration by exciting the fluid container with vibrational loads having multiple frequency components and measuring the resonance frequencies of the container. The resonance frequencies depend on the filling level and are independent of gravity vector changes, allowing accurate filling level determination during aircraft maneuvers and altitude changes.
Solution Approach 2:
The patent uses periodic excitation signals with multiple frequency components to continuously stimulate the container and obtain resonance frequency measurements. This periodic action enables real-time monitoring of filling level while the aircraft is in motion, capturing dynamic conditions without compromising measurement accuracy.
2Measurement precision
If electronic sensing solutions from kerosene tanks are used in hydrogen tanks, then filling level monitoring is enabled, but safety risks increase due to proximity of electronic instruments and hydrogen
Solution Approach 1:
The patent uses the container walls as an intermediary medium to transmit vibrational energy and measurement signals. By exciting the container and measuring its resonance frequencies, the system obtains filling level information without placing electronic sensors inside the hydrogen environment, thus maintaining safety while achieving measurement goals.
Solution Approach 2:
The patent replaces electronic sensing systems with a mechanical vibration-based measurement system. Instead of using electronic instruments that require direct contact with or proximity to hydrogen, the system uses mechanical excitation and resonance frequency measurement of the container, eliminating safety risks associated with electronic devices near hydrogen.
3Ease of operation
If vibration-based methods are used to monitor filling level, then non-intrusive sensing is achieved, but difficulty arises in determining and tracking stable vibrational modes
Solution Approach 1:
The patent applies mechanical vibration by exciting the fluid container with vibrational loads having multiple frequency components and measuring the resonance frequencies of the container. The resonance frequencies depend on the filling level and are independent of gravity vector changes, allowing accurate filling level determination during aircraft maneuvers and altitude changes.
Solution Approach 2:
The patent implements feedback by continuously measuring the resonance frequencies of the container and comparing them to reference data to determine the current filling level. This feedback mechanism allows the system to track changes in filling level over time and maintain accurate measurements despite dynamic operating conditions.
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 provides stable and precise monitoring of fluid levels in dynamic conditions, enhancing safety and accuracy by using the predictable shift in modal frequencies of the horizontal vibration mode, independent of external influences.
Implementation Method 1
a signal source and exciting elements to couple vibrational loads having a multitude of frequency components into a container
Implementation Method 2
Resonance frequencies of the container are depending on the filling level of the container. Sensing elements measure vibrations in the container
Data Source
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AI summary
A filling level monitoring device (100) for monitoring the filling level (210) of a fluid container (200) is disclosed. The filling level monitoring device comprises at least one exciting element (10), a first sensing element (21) and a second sensing element (22), a signal source (30), and a processing unit (40). The at least one exciting element is configured to be mounted to the fluid container. The first sensing element and the second sensing element are configured to be mounted to the fluid container at opposite sides (221, 222) of the fluid container. The signal source is connected to the at least one exciting element and is configured to generate an input signal (31) comprising a multitude of frequency components. The first sensing element and the second sensing element are each connected to the processing unit and are configured to sense vibrations within the fluid container and to generate and send corresponding vibration signals (23, 24) to the processing unit. The processing unit is configured to determine a horizontal vibration mode (25) from the vibration signals of the first sensing element and the second sensing element and the input signal, to determine a modal frequency (80) of the determined horizontal vibration mode, and to determine a current filling level of the fluid container based on the modal frequency of the determined horizontal vibration mode.