• Laser & Optoelectronics Progress
  • Vol. 60, Issue 17, 1730004 (2023)
Jiaqi Yu, Ning Li*, Xiaolong Huang, Yang Kang..., Can Li, Xudong Fan and Chunsheng Weng|Show fewer author(s)
Author Affiliations
  • National Key Laboratory of Transient Physics, Nanjing University of Technology, Nanjing 210094, Jiangsu , China
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    DOI: 10.3788/LOP222452 Cite this Article Set citation alerts
    Jiaqi Yu, Ning Li, Xiaolong Huang, Yang Kang, Can Li, Xudong Fan, Chunsheng Weng. Laser-Absorption-Spectroscopy-Based Reconstruction of Two-Dimensional Velocity Distributions in Circular Combustion Fields[J]. Laser & Optoelectronics Progress, 2023, 60(17): 1730004 Copy Citation Text show less

    Abstract

    Herein, a two-dimensional reconstruction method for circular combustion velocity fields based on tunable diode laser absorption spectroscopy is proposed to obtain the velocity distribution of a circular-cross-section nonuniform flow field. A physical model of laser spectral absorptivity and flow velocity distribution is established, and the region of interest is covered with multiple laser beams from different angular views. The spectral absorption coefficient distribution is reconstructed using an algebra reconstruction technique. The frequency shift in the absorption spectrum of water molecules is substituted to determine the velocity distribution of the flow field so that the velocity distribution in the circular and annular regions in polar coordinates can be reconstructed. For the velocity distribution reconstruction in the circular region, the average relative error is stable at 3.73% in the reconstruction verification with a signal-to-noise ratio of 15 dB. When the signal-to-noise ratio exceeds 35 dB, the average relative error of the reconstruction results is stable below 1.50%. The reconstruction results of the proposed method are thus stable for the velocity distribution reconstruction using different input models (bimodal and annular). The results reveal that the proposed reconstruction method can precisely reflect the velocity distribution of the flow field. Overall, the research results presented herein are significant for promoting the applications of laser absorption spectroscopy in the gas diagnosis of circular and annular exit engine flow fields.
    It(ν)=I0(ν)exp{-0LP(l)S[T(l)]X(l)φ(ν,l)dl}
    a(l)=P(l)S[T(l)]X(l)
    A=0La(l)dl
    Δνν0=ucosθc
    Δν=2ν0cosθcu
    Δν¯A=0La(l)Δν(l)dl
    A=r=1Rn=1Narnlrn
    Δν¯A=r=1Rn=1NarnΔνrnlrn
    Am=r=1Rn=1Narnlrnm
    Δν¯mAm=r=1Rn=1NarnΔνrnlrnm
    r=1Rn=1Narnlrn1=A1             r=1Rn=1Narnlrnm=Am             r=1Rn=1NarnlrnM=AM
    la=A
    r=1Rn=1NarnΔνrnlrn1=A1Δν¯1                r=1Rn=1NarnΔνrnlrnm=AmΔν¯m               r=1Rn=1NarnΔνrnlrnM=AMΔν¯M
    QΔν=H
    u=c2ν0cosθΔν
    erna=arnr-arnoarno
    ernu=urnr-urnourno
    Eu=1RNr=1Rn=1Nernu
    Es=r=1Rn=1Narn
    En=r=1Rn=1Ngrn
    RSNR=10lnEsEn
    Jiaqi Yu, Ning Li, Xiaolong Huang, Yang Kang, Can Li, Xudong Fan, Chunsheng Weng. Laser-Absorption-Spectroscopy-Based Reconstruction of Two-Dimensional Velocity Distributions in Circular Combustion Fields[J]. Laser & Optoelectronics Progress, 2023, 60(17): 1730004
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