Optical Sensor for Harsh Environment Pressure Measurement
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Solution Overview
Problem
Current aircraft engines rely on electrical sensors for pressure measurement, which are unreliable at high temperatures, require complex cable harnesses, and lead to measurement instability, especially when measuring absolute pressure above 300°C in the engine core.
Innovation Solution
An optoelectronic system using Fabry-Pérot interferometers and Fizeau interferometers with narrow band light sources and optical detectors, capable of measuring pressure and temperature directly in harsh environments, eliminating the need for pressure pipes and simplifying engine architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical sensors are used for pressure measurement in high-temperature environments, then the measurement can be performed, but the reliability deteriorates at temperatures above 300°C
Solution Approach 1:
The patent replaces electrical sensing systems with optical sensing systems. Specifically, it uses Fabry-Pérot interferometers and Fizeau interferometers with optical fibers to measure pressure and temperature, eliminating the reliance on electrical sensors that fail at high temperatures. The optical system uses light interference patterns to detect physical parameters, providing reliable measurements in harsh environments where electrical sensors cannot operate.
Solution Approach 2:
The patent changes the measurement principle from electrical to optical domain. By using optical interferometry instead of electrical resistance or capacitance changes, the system can withstand high temperatures. The optical fibers and interferometric sensors maintain their measurement capabilities at temperatures above 300°C where electrical sensors deteriorate, fundamentally changing the operational parameter range.
2Measurement precision
If electrical sensors with cable harnesses are used, then pressure measurement is achieved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex cable harness infrastructure from the engine architecture. By using optical fibers that can be multiplexed and centralized readout systems, the distributed electrical wiring is removed. The optical system allows multiple sensors to share common optical paths and processing units, dramatically simplifying the physical architecture while maintaining measurement precision.
Solution Approach 2:
The optical sensing system provides multi-functionality by using the same optical infrastructure for both pressure and temperature measurements. The Fabry-Pérot interferometers can detect multiple physical parameters using the same optical fiber and interrogator system, eliminating the need for separate electrical cable harnesses for different sensor types and reducing overall system complexity.
3Measurement precision
If pressure pipes are routed from combustion chamber to sensor, then pressure measurement is possible, but the weight increases
Solution Approach 1:
The patent replaces mechanical pressure transmission through pipes with optical sensing that can directly measure pressure at the measurement location. The optical fibers can be positioned close to the combustion chamber, and the interferometric sensors detect pressure changes through optical path length changes, eliminating the need for long pressure pipes and their associated weight while maintaining accurate absolute pressure measurement.
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 accurate and reliable pressure and temperature measurements in high-temperature environments, reducing weight and complexity, and improving measurement stability by centralizing data readout and processing.
Implementation Method 1
a first Fabry-Pérot interferometer arranged to receive a first portion of a combined light wherein the first Fabry-Pérot interferometer is exposed to a physical parameter of interest and temperature
Implementation Method 2
a first Fizeau interferometer arranged to receive light reflected from a first cavity of the first Fabry-Pérot interferometer through an optical path comprising a combination of lenses and/or mirrors
Implementation Method 3
a first narrow band light source with a first peak frequency; a second narrow band light source with a second peak frequency different from the first peak frequency
Data Source
AI summary
An optoelectronic system for measuring physical parameters comprising: two narrow band light sources with different peak frequencies coupled together into a combined light using a coupler. The combined light is split into a first Fabry-Pérot interferometer arranged to be exposed to both temperature and physical parameter of interest and a second Fabry-Pérot interferometer arranged to be exposed only to temperature. The system further comprises first and second optical detectors arranged to receive light reflected from the cavities of the first and second Fabry-Pérot interferometers respectively through an optical path comprising a combination of lenses and/or mirrors and a Fizeau interferometer. A processor is arranged to analyze the data received by the first optical detector and second optical detector and calculate a value for temperature and the physical parameter of interest.