Gas Volume Determination in Rocket Tank Devices
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Solution Overview
Problem
Existing methods for determining the volume of tank liquids in space rockets are inaccurate due to changes in position, speed, and vibrations, and require complex optical instrumentation, which is not suitable for weightlessness and extreme pressure changes.
Innovation Solution
A tank device with a pressure vessel containing a first and second chamber separated by an oscillatable membrane, where a pressure surge is used to induce pressure oscillations, allowing for the determination of gas volume through pressure and temperature measurements, independent of external conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical absorption measurement is used to determine liquid volume, then measurement can be performed in microgravity, but the device complexity increases due to required complex optical instrumentation
Solution Approach 1:
The patent replaces complex optical measurement systems with a mechanical oscillation-based measurement system. A diaphragm is excited to oscillate, and the oscillation characteristics are used to determine liquid volume, substituting optical fields with mechanical vibrations for a more robust and simpler measurement approach suitable for space applications
Solution Approach 2:
The invention utilizes mechanical vibration of a diaphragm as the core measurement mechanism. The diaphragm is excited to oscillate at its natural frequency, and the oscillation characteristics (frequency, amplitude, damping) are measured to determine the liquid volume in the tank, providing a reliable method that works in microgravity without complex instrumentation
2Device complexity
If capacitive level measurement is used, then the measurement method is simple, but measurement accuracy deteriorates when the vehicle is tilted, changes speed, or vibrates
Solution Approach 1:
The patent uses mechanical vibration of a diaphragm to create a measurement signal that is inherently insensitive to vehicle motion. The oscillation frequency and characteristics are determined by the system's physical properties (mass, stiffness, damping) rather than gravitational orientation, allowing accurate measurements during tilting, acceleration, and vibration
Solution Approach 2:
The invention changes the measurement parameter from static liquid level (which is affected by gravity and orientation) to dynamic oscillation characteristics (frequency, amplitude, damping ratio). These dynamic parameters remain consistent regardless of vehicle attitude or motion, providing measurement accuracy under dynamic conditions
3Reliability
If interferometric optical method is used, then liquid level can be measured in reduced gravity, but the measurement becomes considerably more complex and sensitive
Solution Approach 1:
The patent replaces the interferometric optical system with a mechanical oscillation system. Instead of using light interference patterns to measure liquid level, the invention uses the natural oscillation characteristics of a diaphragm, which are mechanically determined and less sensitive to environmental disturbances, reducing both complexity and sensitivity while maintaining microgravity measurement capability
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 precise and reliable determination of tank content, reducing errors from external conditions and simplifying the measurement process, allowing for more accurate fuel management and mass savings.
Implementation Method 1
a first chamber (11) for a tank liquid (200) and a second chamber (12)... interconnected by at least one oscillating membrane (13) separating them; a change in pressure in the first chamber (11) thus causes a change in volume in the second chamber (12) and vice versa
Implementation Method 2
The tank device also has at least one controllable element for generating a pressure pulse in the pressure vessel
Implementation Method 3
The controllable element can include the pressure sensor. The pressure sensor can be designed as a piezoelectric element or piezoelectric sensor
Data Source
Figure 1
AI summary
A tank device (100) for a tank liquid (200) is disclosed. The tank device comprises a pressure vessel (10) in the interior of which a first chamber (11) for the tank liquid and a second chamber (12) are arranged. The first and second chambers are sealed off from each other and are operatively connected by at least one oscillating membrane (13) separating them. The tank device further comprises a controllable element (14) for generating a pressure pulse in the pressure vessel (10), a pressure sensor (15) for detecting a pressure oscillation resulting from the pressure pulse, and a temperature sensor (18) for measuring the temperature prevailing in the pressure vessel. An evaluation device (20) of the tank device (100) is configured to determine a current gas volume in the pressure vessel (10) from each detected pressure oscillation and a temperature measured by the temperature sensor.From this, the mass of the available tank liquid (200) can be calculated. Also disclosed are a rocket for use in space and a method for determining a (variable) gas volume in a pressure vessel (10) of a tank device (100).