TDLAS-WMS second harmonic detection based on spectral analysis

Jiang, Chunlei; Liu, Yunfei; Yu, Bo; Yin, Shi; Chen, Peng

doi:10.1063/1.5031683

Cited by 10 publications

(6 citation statements)

References 18 publications

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“…Calibration-free WMS is essentially a signal processing technique to extract information about molecular absorption from a noisy environment with higher signal fidelity. In view of the unsolved issues arising from potential uncertainties in laser characteristic parameters, spectroscopic constants, as well as requirements for digital filter design in the digital lock-in amplification process [107][108][109], new signal analysis methodologies have been proposed to better analyze the time-dependent signal harmonics.…”

Section: Harmonic Wavelet Analysis Of Modulated Tdlas Signalsmentioning

confidence: 99%

Laser Absorption Sensing Systems: Challenges, Modeling, and Design Optimization

Wang

Chao

2019

Applied Sciences

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Laser absorption spectroscopy (LAS) is a promising diagnostic method capable of providing high-bandwidth, species-specific sensing, and highly quantitative measurements. This review aims at providing general guidelines from the perspective of LAS sensor system design for realizing quantitative species diagnostics in combustion-related environments. A brief overview of representative detection limits and bandwidths achieved in different measurement scenarios is first provided to understand measurement needs and identify design targets. Different measurement schemes including direct absorption spectroscopy (DAS), wavelength modulation spectroscopy (WMS), and their variations are discussed and compared in terms of advantages and limitations. Based on the analysis of the major sources of noise including electronic, optical, and environmental noises, strategies of noise reduction and design optimization are categorized and compared. This addresses various means of laser control parameter optimization and data processing algorithms such as baseline extraction, in situ laser characterization, and wavelet analysis. There is still a large gap between the current sensor capabilities and the demands of combustion and engine diagnostic research. This calls for a profound understanding of the underlying fundamentals of a LAS sensing system in terms of optics, spectroscopy, and signal processing.

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Section: Harmonic Wavelet Analysis Of Modulated Tdlas Signalsmentioning

confidence: 99%

Laser Absorption Sensing Systems: Challenges, Modeling, and Design Optimization

Wang

Chao

2019

Applied Sciences

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“…In the WMS scheme, a hybrid signal is applied to the DFB laser driver, which is composed of a low frequency sawtooth wave scanning signal and a high frequency sinusoidal modulation signal. In order to obtain the optimized WMS signals, we performed a theoretical simulation according to principle of WMS and carried out the experimental test in the laboratory to obtain the optimized parameters of frequency, amplification factor, phase, and baseline of the modulated signal [13][14][15]. A scanning frequency (5 Hz) of the sawtooth wave tuning signal was used in this system and the modulation frequency of sinusoidal modulation signal was 7.8 kHz.…”

Section: Cascaded Integrator Comb (Cic) Filter-assisted Wavelength-momentioning

confidence: 99%

A Near-Infrared Trace CO2 Detection System Based on an 1,580 nm Tunable Diode Laser Using a Cascaded Integrator Comb (CIC) Filter-Assisted Wavelength Modulation Technique and a Digital Lock-in Amplifier

Dong

2019

Front. Phys.

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A near-infrared trace CO 2 detection system was experimentally demonstrated based on an 1,580 nm distributed feedback (DFB) laser using a cascaded integrator comb (CIC) filter-assisted wavelength modulation spectroscopy (WMS) technique and a digital lock-in amplifier (DLIA). An 1,580 nm DFB laser emitting at 1,579.1 nm was selected as the light source. A multi-pass cell (MPGC with a 30 m-long path) was adopted as the absorption cell. A DLIA was developed to extract the second harmonic WMS (WMS-2f) signal. The cascade-integrated comb filter (CICF) and the finite impulse response (FIR) low-pass filter (LPF) were combined in the DLIA to improve the performance of DLIA. Three methods of PD (Peak detection), LIA, CICF-assisted WMS, and DLIA were adopted to detect the CO 2 concentration levels and the anti-interference performance of each detection method was analyzed. The experimental results indicated that compared with the peak detection and the lock-in amplifier method of the CICF-assisted WMS and DLIA developed in this manuscript had the highest linearity and precision. When the integration time is 3s, the LOD of the system was predicted to be 0.0812 ppm. Due to the advantages of high sensitivity, a low detection limit and a rapid response, the CO 2 detection system reported in this manuscript has a good application prospect in the area of oilfield associated gases detection.

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“…This measurement method was proposed by Hinkley and Reid 4,5 and has now developed into a very sensitive and commonly used technique for monitoring atmospheric trace gases. It has the advantages of high sensitivity, real-time, dynamic, and simultaneous multi-component measurements, especially in the measurement of gas temperature and concentration 6,7,8 . At the same time, the TDLAS measurement method is non-contact and very well adapted to the detection of gas parameters in combustion flow fields.…”

Section: Introductionmentioning

confidence: 99%

Simulated methane combustion temperature detection based on TDLAS technology

Shi

Hao

Huang

et al. 2023

AOPC 2022: Optical Sensing, Imaging, and Display Technology

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To study the temperature distribution of the methane combustion process, the methane and air premixing model was simulated using fluent fluid simulation software, and the distribution clouds of temperature and H2O molecules were given. And the combustion region at 5 cm high was selected to study the relationship between the temperature and the mass fraction of H2O. Meanwhile, according to the principle of temperature measurement by TDLAS technology, the gas temperature was simulated in SIMULINK, the absorption line of H2O molecules was selected as the temperature measurement spectral line, and the spectral absorption model was established using the HITRAN database, and the flow chart of the simulation platform construction was given, including the light source module, gas chamber module, and data detection module. Under certain conditions, the temperature simulation data were obtained by giving 15 groups of H2O mass fractions. The results showed that the temperature measured by the TDLAS system was consistent with the temperature simulated by Fluent software, and the error range was within 5%.

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TDLAS-WMS second harmonic detection based on spectral analysis

Cited by 10 publications

References 18 publications

Laser Absorption Sensing Systems: Challenges, Modeling, and Design Optimization

Laser Absorption Sensing Systems: Challenges, Modeling, and Design Optimization

A Near-Infrared Trace CO2 Detection System Based on an 1,580 nm Tunable Diode Laser Using a Cascaded Integrator Comb (CIC) Filter-Assisted Wavelength Modulation Technique and a Digital Lock-in Amplifier

Simulated methane combustion temperature detection based on TDLAS technology

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