Yang Chaobo, Tang Hao, Magnotti Gaetano
Opt Lett. 2020 May 15;45(10):2817-2820. doi: 10.1364/OL.390299.
In this Letter, we demonstrate a 5 kHz 1D Raman instrument for temporally and spatially resolved quantitative measurements of temperature and all the major species (, , , and ) concentration in -air flames. The major constituents of the system are a pulse-burst laser operated at 5 kHz and four back-illuminated CCD cameras operated in subframe burst-gating mode. The use of CCD cameras allows achieving a high sampling rate with no compromise on instrument precision, but it requires one camera for each species of interest. A cascade of dichroic mirrors and bandpass filters spectrally separates the Raman signal associated with each of the four species and directs it to a separate camera. Measurements in a well-characterized -air premixed flat flame show that the system has precision comparable with the low-speed Raman system. The measuring uncertainty of the species mole fraction ranges between 1% () and 3∼4 ( in lean flames). Measurements in laminar and turbulent / jet flames show good agreement with the theoretical prediction. By measuring all species simultaneously, important combustion quantities such as the mixture fraction are also derived.
在本信函中，我们展示了一种5千赫兹的一维拉曼仪器，用于对碳氢化合物 - 空气火焰中的温度以及所有主要物种（ 、 、 和 ）浓度进行时间和空间分辨的定量测量。该系统的主要组成部分是一台以5千赫兹运行的脉冲串激光器和四个以子帧脉冲门控模式运行的背照式电荷耦合器件（CCD）相机。使用CCD相机能够在不影响仪器精度的情况下实现高采样率，但对于每种感兴趣的物种都需要一台相机。一系列二向色镜和带通滤波器在光谱上分离与四种物种中的每一种相关的拉曼信号，并将其导向单独的相机。在一个特性良好的碳氢化合物 - 空气预混平面火焰中的测量表明，该系统的精度与低速拉曼系统相当。物种摩尔分数的测量不确定度在1%（ ）到3 - 4%（贫燃火焰中 ）之间。在层流和湍流碳氢化合物 / 射流火焰中的测量结果与理论预测吻合良好。通过同时测量所有物种，还能得出诸如混合分数等重要的燃烧量。
