摘要
工业生产过程中颗粒物输送系统输运过程存在大量粉尘逸散的问题,其中溜槽是关键部件之一,成为了工作场所大气污染的源头。为了解溜槽内颗粒物的运动及流场情况,首先通过试验数据验证了Discrete Phase Model的适用性,之后利用Fluent软件对溜槽内粒径为300～500μm、密度为700～2 800 kg/m^3的颗粒及斜抛初速度为2～6 m/s的不同工况进行了数值计算。结果表明,斜抛初速度对卷吸空气流场影响不大;初速度越大料流核心区颗粒物质量浓度衰减越慢,密度越小质量浓度衰减越快;整个斜抛过程中,颗粒速度先急剧减小,再急剧增大,最后保持稳定。溜槽下皮带落料点两侧形成正压区容易造成粉尘逸散,通过研究溜槽内颗粒物的运动规律及流场特性,为控制溜槽内粉尘逸散的工艺通风优化设计提供了理论依据。
In order to control the dust dissipation in the transfer point chute,the present paper has calculated the different working conditions in the particle diameters of 300-500μm and the density of 700-2 800 kg/m^3 at the initial velocity of 2-6 m/s in the chute via the discrete phase model of Fluent.For the above purposes,the author has worked out the motion law and the flow field features of the particles by changing the initial velocity of the particles in their own diameter and density.The results of our simulation show that,the initial velocity of the oblique projectile has little effect on the air entrainment flow field.However,when the initial velocity of the particles has increased from 2 m/s to 6 m/s,the maximum air entrainment velocity would like to increase from 1.1 m/s to 1.25 m/s.And,then,the particle diameter may have a certain effect on the entrained air velocity.Actually,the smaller the particle diameter,the greater the maximum velocity of the entrained air would be.On the other hand,the smaller the particle density,the more vigorous the entrainment air disturbance:What is more,the greater the density,the more stable the entrained air distribution would be.In addition,the greater the initial velocity of the oblique projectile,the slower the particle concentration decay in the core region of the particle stream.Thus,in turn,the bigger the particle diameter,the more difficult for the particles to escape from the core region of the particle stream.Therefore,it can be said that the particle density enjoys a great effect on the horizontal movement distance of the particle current.And,actually,the particle velocity changes during the oblique projectile process can be divided into 3 phases.That is,the deceleration phase comes about because of the upward oblique projectile movement,which is opposite to the direction of the gravity,for the initial velocity of the particle movement tends to reduce quickly to 0.And then,in the acceleration phase,when the particles reach the highest point in their movement,they t
作者
孙宏发
李安桂
SUN Hong-fa;LI An-gui(School of Building Services Science and Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China;College of Civil Engineering and Mechanics,Xiangtan University,Xiangtan 411105,Hunan,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2019年第2期713-722,共10页
Journal of Safety and Environment
基金
国家自然科学基金项目(51678469)
关键词
环境工程学
大气污染
斜抛运动
卷吸空气
料流核心区
通风
environmental Engineering
air pollution
oblique projectile motion
air entrainment
the core region of the material flow
ventilation
