Optical Comb Gas Temperature and Concentration Measurement
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Solution Overview
Problem
Current laser-based combustion diagnosis techniques, such as TDLAS, have limited wavelength scanning ranges, restricting the simultaneous online measurement of gas temperature and component concentrations in combustion fields, which is essential for precise and rapid combustion analysis.
Innovation Solution
A system utilizing two pulse laser devices and two continuous laser devices, along with a beam splitting device, coupler, photodetector, and signal acquisition and analysis device, generates an optical beat signal and adaptive compensation signals to process interference signals, enabling the measurement of gas temperature and component concentrations through wide spectrum coverage and double or multiple line temperature measurement principles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If TDLAS system is used for combustion diagnosis, then measurement speed and environmental adaptability are improved, but wavelength scanning range is limited
Solution Approach 1:
The patent segments the wavelength measurement task by using multiple tunable diode lasers, each responsible for a specific wavelength range or absorption line. This allows the system to maintain fast response speeds of individual lasers while collectively covering a broader wavelength spectrum necessary for simultaneous temperature and concentration measurements
Solution Approach 2:
The patent makes the laser-based measurement system multi-functional by enabling it to perform both temperature measurement (via wavelength-dependent absorption) and concentration measurement (via absorption intensity) simultaneously. The system achieves universal applicability across different combustion conditions by selecting appropriate absorption lines for different gas components
2Device complexity
If traditional contact temperature measurement technology is used, then equipment structure is simple, but reaction speed is slow and equipment service life is short
Solution Approach 1:
The patent replaces mechanical contact-based temperature measurement devices (such as thermocouples) with a laser-based optical measurement system. This substitution eliminates the need for physical contact with the combustion field, thereby achieving real-time measurement response while avoiding equipment degradation from harsh thermal and chemical environments
3Reliability
If laser-based measurement method is used, then measurement is real-time and non-contact, but wavelength scanning range is insufficient for simultaneous measurement of temperature and concentrations
Solution Approach 1:
The patent employs dynamic wavelength tuning capability where the system can rapidly switch between different wavelength ranges by controlling multiple tunable diode lasers. This dynamic adaptability allows real-time selection of appropriate absorption lines for different measurement objectives (temperature vs. concentration) while maintaining continuous real-time 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
This approach allows for accurate and simultaneous measurement of gas temperature and component concentrations, improving measurement accuracy and adaptability in combustion environments by covering a broader wavelength range and eliminating carrier envelope phase offset jitter.
Implementation Method 1
The coupler is coupled to the third output port and an output of the combustion field, and is configured to generate an optical beat signal by processing the second pulse laser beam and the third pulse laser beam
Implementation Method 2
The photodetector is configured to convert the optical beat signal to an electric signal
Implementation Method 3
A waveband of each of the first pulse laser beam and the second pulse laser beam covers an absorption line range of components in gas to be measured
Data Source
AI summary
Provided is a system for measuring gas temperature and component concentrations in a combustion field based on optical comb. The system includes two pulse laser devices, two continuous laser devices, a beam splitting device, a measurement path, an interference signal detecting device, an optical processing and electrical processing device and a signal acquisition and analysis device. The measurement path refers to the combustion field to be measured. The interference signal detecting device outputs an interference signal. The optical processing and electrical processing device includes several optic elements and electrical elements, and outputs an adaptive compensation signal and an asynchronous sampling clock signal after a series of processing on output of the two pulse laser devices and two continuous laser devices. The signal acquisition and analysis device outputs the measurement result based on the adaptive compensation signal, the asynchronous sampling clock signal and a stable interference signal.