Quantitative Planar Laser-Induced Fluorescence Technology

Planar laser-induced fluorescence (PLIF) is a highly sensitive and space-time-resolved laser diagnostic technique. It is widely used in the diagnosis of combustion and flow fields to obtain the thermodynamic information of active components and interested molecules in flames. Nowadays, the PLIF technology is developing in two directions: high speed and quantification. In view of the high spatial and temporal resolution characteristics of PLIF technology that other laser diagnostics do not possess, this chapter will focus on the basic principle of laser-induced fluorescence and the current research status of quantitative PLIF technology. In addition, the advantages and disadvantages of various quantitative technologies of component concentration in flames based on laser-induced fluorescence technology are analyzed. At last, the latest works on the quantification of species concentration using planar laser-induced fluorescence in combustion are introduced. confirm the validity of the modified measurement equation, the effective peak absorption cross section of the band (0,0) and band (1,0) within the Q 1 (8) line for the OH radical is measured, respectively. The experimental results show that the OH effective peak absorption cross section of the Q 1 (8) line for band (0,0) turns out to be about 5.5 times higher than that of band (1,0), while the theoretical calculation given by the LIFBASE simulation is about 6 times. The experimental result has been proven to be in good agreement with the simulation results. and disadvantages of current quantitative PLIF technologies for species concentration measurements in flames are reviewed. the latest works on the quantification of species concentration using PLIF in combustion are introduced. a non-calibration quantitative PLIF technology, named bidirectional PLIF, which is independent of collisional quenching effect, has been introduced in detail. As the current measurement equation of effective peak absorption cross section provided by Versluis et al. is found to be not applicable to the case of weak absorption, experimental equation the two-dimensional spatial distributions of OH concentration its variations with the equivalence ratios investigated in the methane/air partially premixed flame. comparison between the experimental OH concentrations and the numerical simulation results under the equivalence ratios of 0.7 – indicates the OH concentration profiles measured by bidirectional in good agreement with the predictive values performed by