燃烧煤粉颗粒的粒度速度测量方法

摘要

Based on the radiation property of pulverized coal flame,an imaging method using blue light back-illumination was proposed,which could avoid or mitigate the effect of self-illumination of flame and obtain static or moving coal particle images.Single Frame Long Exposure (SFLE) measurement method was employed to simultaneously obtain the size and velocity of the burning coal particle from its moving trajectory in the image.In the flat flame entrained flow combustor system based on McKenna burner,an industrial camera was used to carry out experimental investigation on pulverized coal combustion and obtain the information of size and velocity of burning coal at different distances from the burner outlet.The measuring result of the particle size near the exit of burner nozzle agrees with the sieving result of the coal sample before adding to the feeder.The variation of size and velocity with the height above the nozzle outlet proves the feasibility of this method which lay a foundation for the visualization measurement study of the process of pulverized coal combustion.%基于煤粉火焰辐射特性,提出了蓝色背光照明成像的方法,可以避免或减少火焰自发光的影响,直接获得单个固体煤颗粒的静态或动态影像.采用单帧长曝光的测量方法,从煤粉颗粒的运动轨迹中同时获得燃烧中煤颗粒的粒度和速度.在基于McKenna燃烧器的平面火焰携带流燃烧器系统中,用工业相机对煤粉燃烧进行实验研究,并获得了燃烧器出口不同距离处燃煤颗粒的粒度和速度信息.紧邻出口的粒径测量结果与送入给料器前的煤样筛分粒度范围相符,粒度和速度随高度变化的趋势也证明了该方法的可行性.该方法的提出为煤粉燃烧过程的可视化测量研究奠定了基础.