Device and method for measuring gas pressure intensity and component concentration by using wavelength modulation spectrum

Abstract

The invention discloses a device for measuring the gas pressure intensity and component concentration by using a wavelength modulation spectrum, and further discloses a method for measuring the gas pressure intensity and component concentration by using the wavelength modulation spectrum. According to the method disclosed by the invention, transmission light intensity signals are processed by using digital phase locking and low-pass filtering based on a wavelength modulation absorption spectrum technology so as to acquire a background deducted secondary harmonic signal and a primary harmonic normalized secondary harmonic signal, a relation between a simulation signal secondary harmonic peak feature and the pressure intensity is established, a relation between a simulation signal primary harmonic normalized secondary harmonic peak value and the concentration is established at the same time, and pressure intensity and component concentration information of a gas to be measured is calculated by adopting an interpolation method. The measuring method disclosed by the invention has the characteristics of non-invasion, high response speed, high sensitivity and the like, and is applicable to measuring the gas pressure intensity and component concentration simultaneously at the industrial field.

Description

technical field [0001] The invention relates to a device for measuring gas pressure and component concentration by using wavelength modulation spectrum, and also relates to a method for measuring gas pressure and component concentration by using wavelength modulation spectrum, belonging to the technical field of laser absorption spectroscopy. Background technique [0002] Tunable laser absorption spectroscopy technology utilizes the laser absorption characteristics of the components in the measured gas to achieve online measurement of component concentration, temperature, pressure, velocity and other parameters. As an optical measurement technology, tunable laser absorption spectroscopy has the characteristics of non-contact, high sensitivity, and high time resolution, and has broad application prospects in the fields of atmospheric environment detection and combustion diagnosis. Tunable laser absorption spectroscopy is mainly divided into two methods: direct absorption spec...

AI Technical Summary

Problems solved by technology

At present, wavelength modulation spectroscopy technology generally uses the ratio of the fourth harmonic peak value to the second harmonic peak value to measure pressure, but the fourth harmonic has a high demand for detector bandwidth, and at the same time, the phase-locking filter has a large amount of calculation, which is not easy to implement in hardware.

And as the harmonic order increases, the strength of the harmonic signal gradually attenuates, so the signal-to-noise ratio of the fourth harmonic signal in industrial occasions is low, and the peak value of the signal cannot be accurately extracted, thereby reducing the accuracy of pressure measurement

Pressure uncertainty further affects the accuracy of second harmonic detection to measure gas concentration

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