采用宽带相干反斯托克斯拉曼散射(CARS)技术测量了甲烷-空气预混火焰温度场分布,并分析了温度测量的不确定度。建立的宽带CARS实验系统采用非稳腔空间增强探测(USED)相位匹配构造,其横向空间分辨率约0.1 mm,纵向空间分辨率约3 mm,该系统能实现10 Hz重复频率测量火焰瞬时温度。采用宽带非稳腔空间增强探测CARS在甲烷-空气预混火焰中获得了单次激光脉冲的高信噪比氮气Q支CARS实验谱,用CARS理论计算软件拟合理论谱和实验谱确定了预混火焰的温度随高度的分布,采用单次激光脉冲的氮气Q支CARS实验谱测量火焰温度的不确定度小于5%。

The unstable-resonator spatially enhanced detection (USED) coherent antistokes Raman scattering (CARS) measurement of temperature in CH4/air flame is reported. The USED CARS measurement system which has a high spatial solution of ～0.1 mm in diameter and ～3 mm in length is constructed and permits instantaneous thermometry at a 10 Hz rate. The single-pulse N2 Q-branch CARS spectra have been obtained from CH4/air flame and the CARS data are analyzed by comparison with theoretical spectra generated at various temperature. The temperature distribution of CH4/air flame have been measured by broad-band USED CARS and the measurement results have been analyzed. The uncertainty of single-pulse temperature measurement is less than 5% for T=2038 K.