Two-dimensional temperature measurements using filtered Rayleigh scattering (FRS) were performed in confined CH₄/air swirl flames at atmospheric pressure. The investigated burner has a combustion chamber consisted of four quartz windows. The combustion chamber is 160 mm high with a square section of 50 × 50 mm². Measurements were challenging due to the strong interference from the incident laser impinging onto quartz windows, wall reflection and Mie scattering. Comparisons between the FRS and a conventional probe-based thermocouple were conducted through several investigated cases. Five operating conditions were studied with the equivalence ratios (Φ) of the premixed CH₄/air mixture covered a range of 0.67–0.83. Under each condition, five cross sections (C.S.) of the swirl flame were investigated and compared to analyze (1) the flame structures and temperature distributions of the instantaneous FRS images and (2) the uniform temperature radius as well as the joint probability density function (PDF) profiles of the averaged FRS signals. Results indicate that FRS can effectively suppress the background scattering and the average standard deviation of FRS measurements throughout the experiment is < 7.5%. The thermochemical state of the confined swirl flames is strongly influenced by Φ, leading to varieties of flame structures and temperature distributions.

在大气压力下，在受限的CH ₄ /空气涡流火焰中，使用过滤的瑞利散射（FRS）进行二维温度测量。被研究的燃烧器具有由四个石英窗组成的燃烧室。燃烧室的高度为160 mm，方形截面为50×50 mm ²。由于入射激光撞击石英窗，壁反射和Mie散射会产生强烈干扰，因此测量具有挑战性。FRS和传统的基于探头的热电偶之间的比较是通过几个调查的案例进行的。用预混合CH ₄的当量比（Φ）研究了五个工作条件。/空气混合物的覆盖范围是0.67–0.83。在每个条件下，5个的横截面（Ç。小号旋流火焰的。）研究并比较分析（1）的火焰结构和瞬时FRS图像的温度分布，（2）均匀的温度半径以及关节平均FRS信号的概率密度函数（PDF）曲线。结果表明，FRS可以有效抑制背景散射，并且整个实验期间FRS测量的平均标准偏差<7.5％。约束旋流火焰的热化学状态受Φ的强烈影响，导致火焰结构和温度分布的变化。