喷淋液滴在空气环境下的运动特性

本文以喷淋液滴在空气环境下运动特性为工程背景，建立单个液滴在常温、常压空气环境中的动量方程，分析液滴沉降特性、追赶特性及运动轨迹行为。计算结果表明，不同喷淋液滴初始条件下，短时间内存在重力大于曳力和重力小于曳力两种情况，但最终减速液滴均会达到受力平衡状态；液滴离开喷淋头后，垂向位移均迅速增大，液滴粒径越大、初始速度越大，垂向位移增长的速率也越大，达到相同位移的用时越短；液滴尺寸、初始速度相差越大，液滴追赶所用的时间越短，追赶位移越小，液滴尺寸、初始速度越接近，液滴追赶所用的时间越长，追赶位移越大；液滴初始速度越大、初始直径越大、喷射角度越大，横向速度消失越慢，达到的横向位移越大，喷射液滴覆盖的面积也越大。计算结果有助于优化工程实际中喷淋系统的设计与布置。

Motion Characteristic of Spray Droplet in Air Environment

The motion characteristics of the spray droplet as the engineering background were investigated in this paper. The momentum equation of a single droplet in the air environment under room temperature and pressure was established to analyze the sedimentation characteristic, pursuit characteristic and motion trail. The calculation results show that under different initial conditions, there are two situations in which the gravity is greater than the drag force and the gravity is less than the drag force during the initial period of time. After the droplets leave the spray header, the vertical displacement increases rapidly. The larger the droplet size and the initial velocity are, the higher the vertical displacement growth rate is. The larger the difference between droplet size and initial velocity is, the shorter the chasing time and the smaller the chasing displacement will be. The closer the droplet size and initial velocity are, the longer the chasing time and the larger the chasing displacement will be. The larger droplet initial velocity, initial diameter and injection angle induce the slower the transverse velocity disappeared, the larger the lateral displacement reaches, and the larger the area covers by the spray droplet. The calculation results are helpful to optimize the design and layout of spray system in engineering practice.