Gas absorption rate online measuring method based on sinusoidal modulation time domain fitting

A technology of sinusoidal modulation and measurement method, applied in the field of laser spectroscopy and gas measurement, can solve the problems of low time resolution and large uncertainty in baseline fitting, achieve high repeatability, facilitate frequency modulation, and realize automatic software processing. Effect

Inactive Publication Date: 2019-01-25
TSINGHUA UNIV
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Problems solved by technology

[0006] In order to solve the problems of large baseline fitting uncertainty and low time resolution of the direct absorption method, the present invention provides an online measurement method of gas absorption rate based on sinusoidal modulation time domain fitting, so as to further improve the measurement accuracy of gas absorption rate and simplify the measurement process

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  • Gas absorption rate online measuring method based on sinusoidal modulation time domain fitting
  • Gas absorption rate online measuring method based on sinusoidal modulation time domain fitting
  • Gas absorption rate online measuring method based on sinusoidal modulation time domain fitting

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Embodiment

[0048] 1) Embodiment Taking the R (11) spectral line of CO as an example, measure its absorptivity, select its central wavelength v from the spectral database 0 =4300.699cm -1 ;

[0049] 2) Control the output laser wavelength of the tunable semiconductor laser 3 at the wavelength v by adjusting the center current of the laser controller 2 to 100 mA and the temperature to 32.07° 0 =4300.699cm -1 Nearby, a sinusoidal signal with a frequency ω=2×π×100 is generated by a signal generator, which is input to the laser controller 2 to modulate the output current of the laser controller 2, and then modulate the wavelength of the output laser of the tunable semiconductor laser 3;

[0050] 3) The laser light generated by the tunable semiconductor laser 3 is divided into two paths through the optical fiber beam splitter 4, one path passes through the gas chamber 5 to be measured after being collimated, and the transmitted laser intensity is received by the first photodetector 6; Inject...

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Abstract

The invention provides a gas absorption rate online measuring method based on sinusoidal modulation time domain fitting, and belongs to the technical field of tunable diode laser absorption spectrum (TDLAS). The method is characterized in that a sinusoidal signal is used for modulating tunable diode laser current; the laser wavelength sinusoidal modulation is realized; meanwhile, the incident light intensity laser intensity (base line) is enabled to has the clear expression formula; the absorption rate is converted between the frequency domain and the time domain, the clear base line expression formula is combined; the transmission laser intensity is subjected to fitting on the time domain; the synchronous online measurement of the base line and the gas absorption rate is realized. The method has the advantages that the operation is simple and convenient; the problems that the conventional direct absorption method (triangular or sawtooth signal scanning) base line fitting is greatly influenced by artificial factors; the absorption rate measurement precision is low; the time resolution ratio is low; the data processing is completed, and the like. The measurement measure can be provided for spectral line parameter high-precision calibration and gas parameter online monitoring in a complicated industrial field.

Description

technical field [0001] The invention relates to an online measurement method of gas absorption rate, in particular to an absorption rate measurement method based on tunable diode laser absorption spectrum direct absorption method technology, and belongs to the technical field of laser spectrum and gas measurement. Background technique [0002] Tunable diode laser absorption spectroscopy (TDLAS) has developed into one of the main means of high-precision gas parameter diagnosis due to its advantages of non-contact, high measurement sensitivity, and strong anti-interference ability. In this method, a narrow-band tunable semiconductor laser is used to scan the molecular absorption spectrum, combined with the Beer-Lambert (Beer-Lambert) law, to calculate the molecular absorption rate, and then determine the gas temperature, concentration, pressure, physical parameters of the spectral line and other information. [0003] After years of development, TDLAS has formed two main measur...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/39
CPCG01N21/39G01N2021/399
Inventor 杜艳君彭志敏丁艳军
Owner TSINGHUA UNIV
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