Optical Fluorescence Sensor for Fuel Oxygen Monitoring
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Solution Overview
Problem
Current technologies for measuring oxygen concentration in fuel systems, particularly in aerospace applications, face challenges such as limited temperature range, reliability, and safety concerns due to the presence of metal parts, which can lead to ignition risks and are not suitable for long-term use.
Innovation Solution
An optical method and device utilizing intrinsic fluorescence to measure oxygen concentration in fuel systems, which operates across a wide temperature range (-50°C to 50°C) without metal parts, using excitation light and fluorescence detection to determine oxygen levels in both liquid fuel and the gas phase, with a calibration process to convert fluorescence signals into concentration values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrochemical sensors with metal parts are used to measure oxygen concentration, then measurement capability is provided, but ignition risk increases and reliability decreases in fuel systems
Solution Approach 1:
The patent replaces electrochemical sensors with metal parts with an optical sensing system that uses fluorescence quenching by oxygen. The system employs a light source, optical fibers, and a detector to measure oxygen concentration without any metal components that could generate sparks, thereby eliminating the ignition risk while maintaining measurement capability
Solution Approach 2:
The patent creates an inherently safe measurement environment by using optical fields instead of electrical fields or chemical reactions that could produce sparks. The optical sensing method operates passively in the fuel atmosphere without introducing any ignition sources, effectively creating a safe inert measurement environment
2Reliability
If conventional sensors are used in fuel systems, then oxygen concentration can be measured, but device lifespan is limited due to wear and corrosion
Solution Approach 1:
The patent replaces mechanical and electrochemical sensing mechanisms with an optical sensing system that has no moving parts and is not susceptible to corrosion or wear. The optical fibers and fluorescent materials used in the system are chemically inert and can operate indefinitely in fuel environments, dramatically extending service life
Solution Approach 2:
The optical sensing system requires no maintenance, calibration adjustments, or replacement of consumable parts. The fluorescent material maintains its properties over time, and the optical components are sealed and protected, allowing the system to serve itself without external intervention for extended periods
3Adaptability or versatility
If electrochemical sensors are used to monitor oxygen concentration, then real-time data is provided, but operating range is limited by temperature constraints
Solution Approach 1:
The patent employs a fluorescent material whose emission properties change with oxygen concentration and temperature. By selecting appropriate fluorescent materials and compensation algorithms, the system can operate across a wide temperature range from -50°C to 150°C, adapting to various environmental conditions without losing measurement accuracy
Solution Approach 2:
The patent utilizes the temperature-dependent phase behavior and emission characteristics of fluorescent materials to maintain measurement capability across different temperatures. The system can compensate for temperature effects by monitoring the fluorescence lifetime and intensity ratios at different wavelengths, enabling operation throughout a broad temperature spectrum
4Loss of energy
If oxygen concentration monitoring is implemented to optimize inerting systems, then fuel consumption is reduced, but measurement accuracy must be sufficient to detect spatial distribution variations
Solution Approach 1:
The patent divides the fuel tank into multiple measurement zones by positioning several optical sensors at different locations. Each sensor independently measures oxygen concentration in its local zone, providing spatial distribution data that enables precise control of the inerting system to target specific areas with high oxygen levels, thereby optimizing nitrogen injection and reducing fuel consumption
Solution Approach 2:
The optical sensing system provides high-precision measurements of oxygen concentration and spatial distribution without the mechanical complexity of traditional sensor arrays. The optical fibers can be positioned flexibly to map three-dimensional oxygen distribution, enabling accurate detection and control with minimal fuel consumption for inerting operations
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
This solution provides a reliable, long-lasting, and safe method for monitoring oxygen concentration, optimizing the functioning of fuel tank inerting systems, reducing wear and fuel consumption, while avoiding ignition risks and meeting regulatory safety standards.
Implementation Method 1
a first wavelength component corresponding to a fluorescence wavelength of the fluid and attenuated by a concentration of oxygen in the fluid
Data Source
AI summary
The invention concerns a method for measuring the concentration of a substance or mixture of substances and/or determining the level in a fluid with intrinsic fluorescence, preferably fuel systems. The invention also refers to the optical device suitable for implementing the method, which comprises a unit which generates light for excitation of the sample; a unit of detection of the signal emitted by the sample and a unit of signal processing.The device and method by which it is implemented also allow the determination of the spatial distribution of the substance or mixture of liquid substances and/or the fluid level in a container. One of the main applications is the measurement of the concentration of oxygen in the fuel tank of aircrafts, based on the measurement of the intrinsic fluorescence of the fuel.