矩形风管局部构件与直管段气溶胶粒子沉降速度比较分析  

Comparative analysis of aerosol particles' deposition velocities in constituent components and straight-forward sections of rectangular-shaped ventilation duct

作　　者：朱青松[1] 李念平[1] 付峥嵘[1] 倪吉[1] 苏锲[1] 

机构地区：[1]湖南大学土木工程学院,长沙410082

出　　处：《安全与环境学报》2007年第5期32-35,共4页Journal of Safety and Environment

基　　金：教育部高等学校博士学科点专项基金项目(20050532022)

摘　　要：气溶胶是影响室内空气质量的重要因素之一,室外的气溶胶粒子通过风管系统进入室内,严重危害人们的健康。本文用滑石粉模拟气溶胶粒子,对矩形风管系统(材料为镀锌钢板)的直管段、渐缩段和风阀等3个位置,测定了气溶胶粒子在不同风速和粒径下的表面沉降速度,分析了它们之间的关系。结果表明,风管断面的沉降速度随风速和粒径的增加而增加;同一风管断面上底面的沉降速度最大,侧壁面次之,顶面最小;渐缩段底面、侧壁面和顶面的沉降速度均比直管段大,风阀断面的沉降速度明显高于直管段。研究表明,风管系统底面及局部构件是积尘的主要部位,也是风管系统清洗的重点。Aerosol is one of the key factors of the indoor air quality due to the ventilation delay caused by the aerosol particles＇ deposition, particularly; in the rectangular duct sections in a building, which may bring about serious damage to human health. Therefore, this paper is inclined to present the results of our laboratory experiments in hoping to quantify the particle deposition velocities in a horizontally rectangular ventilation ducts made of HVAC materials （zinc-plated steel）. As we know, in a steel duct system, French chalk is usually adopted to simulate the aerosol particle activities. For this purpose, we have investigated the behaviors of polydisperse aerosol particles with their mean diameters being 11.46 μm, 3.63 μm, and air speeds of 2.5 m/s, 5.3 m/s and 8.8 m/s. Along with the deposition velocities of the different duct sections under different air speeds and different particle sizes to the straight sections, we have also determined the abrupt contraction sections and the wind valve of the rectangular ductwork while taking into account the relation between them. Our experiments have shown that the deposition velocities are highest at the duct floor, intermediate at the duct walls and lowest at the duct ceilings. The particle size or the air speed will be increased with the increase of the deposition velocities of a given surface. As compared with the straight sections, the abrupt contraction sections, the wall and ceiling surfaces may contain obvious increment of the deposition. In addition, the deposition velocity of the cross sections of ventilation valve would surely be higher than those of the horizontal straight ones. As to the horizontal straight floors and constituent components, the velocity can surely be predicted to control the loss in the duct system. Needless to say, in the presence of the HVAC filtration, ventilation ducts are playing a minor role in determining the indoor particle concentrations. However, such velocities are expected to be important for the ventilation system con

关 键 词：通风与空调 气溶胶粒子 沉降速度 风阀 渐缩段 

分 类 号：TU834[建筑科学—供热、供燃气、通风及空调工程]