论文标题
基于短门控自发拉曼散射的原位温度和主要物种测量
In-situ temperature and major species measurements of sooting flames based on short-gated spontaneous Raman scattering
论文作者
论文摘要
自发拉曼光谱法（SRS）是一种常见的原位激光诊断方法，已被广泛用于测量温度和主要物种。然而，烟雾中的SRS受到强大干扰，包括激光诱导的荧光，激光诱导的白炽灯和火焰光度，这是一个持久的挑战。这项工作基于355 nm的纳秒激光束引入了低成本，易于实现的烟雾中的无校准SRS温度计。利用几种策略来增加信噪比并抑制干扰：（1）纳秒ICCD门宽； （2）优化的ICCD门延迟； （3）专门设计的激光束的聚焦形状； （4）紫外线偏振滤光片。通过拟合N2分子的Stokes-Raman光谱轮廓来获得温度，该轮廓不需要额外的校准。基于测得的温度，可以通过校准获得主要物种的摩尔分数。该方法用于基于乙烯的逆流扩散火焰的温度和主要物种测量。实验结果表明，与仿真结果非常一致，证明了对烟灰和其他含有颗粒的火焰进行非侵入性激光诊断的可行性。
Spontaneous Raman spectroscopy (SRS) is a conventional in-situ laser diagnostic method that has been widely used for measurements of temperature and major species. However, SRS in sooting flames suffers from strong interference including laser-induced fluorescence, laser-induced incandescence, and flame luminosity, which is a long-lasting challenge. This work introduces a low-cost, easy-to-implement, and calibration-free SRS thermometry in sooting flames based on a 355-nm nanosecond laser beam. Several strategies were utilized to increase the signal-to-noise ratio and suppress the interference: (1) nanosecond ICCD gate width; (2) optimized ICCD gate delay; (3) specially designed focusing shape of the laser beam; (4) ultraviolet polarizer filter. The temperature was obtained by fitting the contour of Stokes-Raman spectra of N2 molecules, which does not require additional calibration. Based on the measured temperature, the mole fraction of major species can be obtained with calibration. This method was used in the temperature and major species measurements of an ethylene-based counterflow diffusion flame. The experimental results show an excellent agreement with the simulation results, demonstrating the feasibility of performing non-intrusive laser diagnostics of sooting and other particle-laden flames accurately.
