Abstract: The drop size distribution in a spray tower was obtained by means of the photographic technique with air and water as the experimental media. The effects of spray flux and superficial gas velocity on Sauter mean diameter (SMD) of droplets at different heights of the absorption zone were investigated. The drop size distribution was analyzed theoretically. Dense droplets assembled at the top of the tower; on the contrary, droplets became sparse at the bottom. Small and uniform droplets could be formed in the falling process. With increasing spray flux, the SMD of droplets increased at the top of the tower, while decreased at the middle and lower zones. Average droplet diameter decreased with increasing superficial gas velocity. Theoretically, the decrease of droplet size was mainly accounted for by collision and breakup among droplets, which was primarily caused by diversity of droplet diameters. Dimensionless correlation of SMD was proposed, and the calculation results were in good agreement with the actual data. The specific surface area of spray tower with collision and breakup among droplets was about 70% larger than that without collision and breakup.

Key words: spray tower, collision, droplet, Sauter mean diameter, distributions

摘要： 以水和空气为实验介质,通过拍照法获得喷淋塔内液滴粒径分布,考察了不同喷淋量及空塔气速对塔内不同高度处液滴Sauter平均直径(SMD)的影响,并对液滴粒径分布进行了理论分析.结果表明,喷淋塔顶部液滴分布密集,底部稀疏,液滴群在下落过程中,平均粒径减小且趋于均匀化;塔顶处液滴SMD随喷淋量的增加而增大,处在塔中下部的液滴SMD则随喷淋量增大而减小,提高空塔气速,可减小平均粒径;理论分析认为,液滴粒径减小主要是由于发生了碰撞破碎的缘故,而塔内液滴大小不一是碰撞的主要原因;通过量纲1化拟合得到喷淋塔内液滴SMD经验关联式,其计算结果与实验值吻合较好;考虑液滴破碎的喷淋塔比表面积比不考虑破碎的比表面积大70%左右.

关键词: 喷淋塔, 碰撞, 液滴, Sauter平均直径, 分布