水平采样直管内颗粒传输特性的研究  

The study of transmission characteristics of particles in Straight horizontal sampling tube

作　　者：丛晓春[1] 王成[1] 曲京华[1] 

机构地区：[1]山东科技大学山东省土木工程防灾减灾重点实验室,山东青岛266590

出　　处：《河北工程大学学报（自然科学版）》2016年第2期78-81,112,共5页Journal of Hebei University of Engineering:Natural Science Edition

基　　金：国家科技支撑计划项目(2013BAK12B08)

摘　　要：以0.1～20μm的单分散颗粒为研究对象,利用数值模拟的方法,对在层流状态下,颗粒在内径为4、7和10 mm,长度为0.2、0.5、1.0和1.5 m的水平采样直管内的运动特性进行模拟,得到水平采样直管内的流场及颗粒的浓度分布,通过对模拟结果的整理分析得到颗粒在水平采样直管内的传输效率。数值模拟发现,粒子的损失主要来源于重力和扩散作用;颗粒的传输效率要受到粒径、管长、管内径的影响;在层流状态下,0.1～1.0μm颗粒的传输效率几乎达到100%,不受管内径、管长和重力、布朗扩散力的影响;2.5～20μm颗粒的传输效率随粒径、管内径、管长的增大而减小。分析可得,通过减少采样管的输送长度或者在流量一定的基础上减小管内径均可提高颗粒在水平采样直管内的传输效率。通过对比分析模拟结果与理论公式,可以近似认为颗粒在水平采样直管内的传输效率等于在重力和扩散力单独作用下颗粒传输效率的乘积。This paper chooses 0. 1 μm ～ 20 μm monodisperse particles as the research object. We adopted numerical simulation methods to study the transmission characteristics of particles in the straight horizontal sampling tube under laminar flow. Diameters of tube are 4 mm,7 mm and 10 mm.The lengths of tube are 0. 2 m,0. 5 m,1. 0 m and 1. 5 m. We got the flow field of the tube and the particle concentration distribution. Through the analysis of simulation results,we obtained the transport efficiency of particles in the straight horizontal sampling tube. Based on the numerical simulation of particle transmission characteristics within the straight horizontal sampling tube,it is found that the particle loss is mainly from gravity and diffusion. Simultaneously,the particle transport efficiency is influenced by particle size,tube length and inner diameter. Under laminar flow,the transport efficiency of 0. 1 μm ～ 1. 0 μm particles is almost 100%,without the influence of inner diameter,tube length,gravity and Brownian diffusion force. The transport efficiency of 2. 5 μm ～ 20 μm particles decreases with the increasing of particle size,tube length and inner diameter. Through the analysis,it will improve the transport efficiency of particles by reducing the length of the sampling tube or the inner diameter on the basis of a flow. The simulation results compared with the theoretical formula,it can be approximated that the transport efficiency of particles is equal to the product of particle transport efficicency respectively under the action of gravity and diffusion.

关 键 词：颗粒物 采样管 数值模拟 传输效率 

分 类 号：X851[环境科学与工程—环境工程]