分子过滤瑞利散射技术测量火焰温度和密度

 为了解决瑞利散射光易受米散射和背景杂散光干扰的问题，发展了结合窄线宽激光器、分子过滤器以及像增强器等技术的分子过滤瑞利散射技术。在图像诊断的基础上，依据测量的碘蒸气吸收光谱曲线，对CH₄/air预混火焰进行了诊断，获得了密度场和温度场分布。距炉面15 mm火焰中心区域处，分子过滤瑞利散射(FRS)技术测量的温度为1 827 K±84 K，密度为0.19 kg/m³，其测温结果与CARS法的测温结果基本吻合。最后分析了FRS技术测温不确定度。实验表明FRS技术具有较高的信噪比，可以定量测量温度和密度信息，有望应用于超音速燃烧流场、紊流场等复杂流场的诊断。

Molecular filtered Rayleigh scattering diagnostic for measurement of temperature and density in flame

Molecular filtered Rayleigh scattering(FRS) is an optical technique that utilizes the light scattering by atoms/molecules to allow the computation of thermodynamic properties and velocity in flow fields.The main components of diagnostics system are a narrow line-width laser,a molecular/atomic absorption filter and a collecting device such as ICCD,which can be used to suppress background surface/particle scattering and enhance flow visualization.In this paper,FRS working principle,the FRS diagnostic system and the iodine filter cell are described.On the basis of diagnosing FRS image and measuring iodine vapor absorption spectrum,methane/air premixed flame is diagnosed and the 2-dimension temperature and density fields are obtained.The temperature measured is compared with the result by CARS method,and the uncertainty of temperature measurement is analyzed.