基于时域激光诱导辐射确定湍流火焰烟黑粒径

The size determination of soot particle in turbulent flame based on time-resolved laser-induced emission

对非稳态丙烷湍流火焰中的烟黑粒径进行在线测量.高能脉冲激光直接照射火焰中的烟黑微粒,其受热辐射光谱信号由光电倍增管检测.为降低信号噪音,采用分段平均方法拟合获得烟黑等亚微米量级固体颗粒粒径.所得结果与透射电镜测量结果吻合.通过统计多个激光脉冲下颗粒各粒径值,获得了不同空燃比下丙烷湍流火焰中烟黑粒径分布的变化规律.本方法为非稳态燃烧过程中可吸入颗粒物尺寸分布提供了一种有效的在线监测手段.

An on-line size measurement of soot particles in unsteady-state propane turbulent flame was investigated.By applying high-power pulse laser beam,the soot particles in flame were heated and their thermal radiation was detected by a photomultiplier.In order to reduce the signal noise,a time-division average fitting method was developed to determine the size of such submicron scale solid particulates as soot particles,and the results coincide with those obtained by Transmission Electron Microscope.By counting the particle size under a series of laser pulses,the size distribution of soot particles in turbulent flame with various ratio of air to fuel was obtained.The above method can be used as an effective tool for on-line monitoring size distribution of inhalable particulates in unsteady-state combustion processes.