Research on Pressure Compensation of TDLAS Methane Detection System
Based on tunable semiconductor laser absorption spectroscopy technology,com-bined with wavelength modulated spectral absorption technology(WMS)in the 1653 nm wavelength band,a gas detection system was composed of a Herriott type multi path cell with an optical path length of 14 m.Through this system,CH4 was measured under normal temperature and pressure condi-tions,with a fitting determination coefficient of 0.998.In order to analyze the influence of pressure on the second harmonic signal,this system was used to measure the second harmonic signals correspond-ing to different pressures.The amplitude of the second harmonic signal was linearly fitted with the pres-sure,and the linear relationship was good.The pressure of the measured gas is calculated using an ana-lytical formula for the zero crossing distance of the second harmonic,and the pressure compensation function without the need for a pressure sensing device is achieved through a fitting formula.This has a wide range of application prospects in industrial measurement under negative pressure scenarios.
gas detection systemabsorption spectroscopy technologysecond harmonic sig-nalpressure compensation
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