液-液雾化的射流特性与粒径分布  

Liquid-liquid Atomized Jet-flow Characteristics and Particle Diameter Distribution

作　　者：梁坤峰[1] 彭正标[1] 袁竹林[1] 凡凤仙[1] 

机构地区：[1]东南大学能源与环境学院,江苏南京210096

出　　处：《热能动力工程》2007年第3期326-331,共6页Journal of Engineering for Thermal Energy and Power

基　　金：教育部高等学校博士点专项科研基金资助项目(20060286034)

摘　　要：液滴的粒径分布是液-液循环流化床制取流体冰技术的关键因素之一。在流化床实验装置上,采用快速摄像与图像处理相结合的方法,研究低流速下液-液单孔雾化的射流及其对液滴粒径分布的影响,射流长度的变化和液滴的粒径分布运用数学统计的方法进行分析。研究结果发现,当射流速度大于1.14m/s时,开始出现射流;各个流速工况下射流长度的波动具有随机和非周期的特点,其均值与方差随射流速度增大的总体变化趋势是先增大后减小;转折点在射流速度为6.58m/s时,在射流长度波动的峰点处形成球形或锥形射流顶部是液滴的粒径具有大小差异及其运动路径发生摆动的主要原因;各流速工况下,液滴的粒径分布与Rosin-Rammler分布符合的很好;研究结果为液-液循环流化床实际运行时控制雾化形成液滴的粒径分布提供可靠依据。The particle diameter distribution of liquid droplets is one of the key factors involved in the technology for making fluid ice from a liquid-liquid circulating fluidized bed. On a fluidized bed test device, by using a method combining high speed photography with image processing, a study has been conducted of the liquid-liquid single-hole atomized jet-flow at a low flowing speed and its impact on the distribution of particle diameters of liquid droplets. In this connection, a mathematico-statistical method was employed to analyze the change in jet flow length and the distribution of particle diameters of liquid droplets. It has been found from the analysis that a jet flow emerges when its speed is greater than 1.14 m/s and the fluctuations in the jet flow length at various flow speeds assume a random and non-periodic character. Moreover, with an increase of the jet flow speed the mean value and variance of the jet flow length show an overall variation tendency of “first increase and then decrease'. With the jet flow speed being 6.58 m/s, which is a turning point, a spherical or conical jet-flow top is formed at the peak point of the jet flow length fluctuations. This is the main reason why there emerged a difference in magnitude of the particle diameters of liquid droplets and their movement routes showed signs of wobbling. At various flow speeds, the distribution of particle diameters of the liquid droplets is in very good agreement with Rosin-Rammler distribution. The research results provide a reliable basis for controlling the distribution of particle diameters of liquid droplets resulting from atomization during the actual operation of a liquid-liquid circulating fluidized bed.

关 键 词：液-液循环流化床 液-液雾化 射流 液滴 粒径分布 

分 类 号：TB657.1[一般工业技术—制冷工程]