建材几何形状对VOCs散发特性影响的研究
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摘 要
如今人们越来越关注室内空气质量(Indoor Air Quality,IAQ),从办公室环
境到家居环境,从公共场所到私人空间,到处都充斥着室内装修材料所散发的挥
发性有机物(Volatile Organic Compounds,VOCs)。这些有机物有着刺鼻的气味,
而且其中含有大量影响着人们身心健康的有毒有害物质。本文研究了室内建材
VOCs 散发特性,有助于了解建材 VOCs 的散发规律,从而提出控制 VOCs 散发
的措施,改善室内空气环境。
本文基于传质理论建立了平面形建材和空心圆柱形建材 VOCs 散发的解析模
型和数值模型,模型中均考虑了 VOCs 在材料内部和边界层的扩散过程。解析模
型通过采用数学变换和广义积分变换法(GITT)求得,数值模型则通过计算流体
力学(CFD)技术计算求得。另外,本文采用 CFD 技术研究了建材扩散系数、建
材厚度和建材中 VOCs 初始浓度对建材 VOCs 散发的影响,影响研究中采用了平
面形和空心圆柱形建材。同时,本文在文献实验数据的基础上,建立了建材 VOCs
散发的热力学模型,并采用数据拟合方法验证了温度对建材 VOCs 初始可散发浓
度的影响。
研究结论表明,无论是平面形建材还是空心圆柱形建材,建材扩散系数、建
材厚度都影响 VOCs 的散发。扩散系数越大材料越薄时,材料中 VOCs 散发越快;
扩散系数越小材料越厚时,材料中 VOCs 散发越慢。因此,为使建材中 VOCs 较
快地散发出来,应尽量采用扩散系数较大的轻薄型建材。研究表明当厚度等其他
条件均相同时,空心圆柱形建材内 VOCs 比平面形建材内 VOCs 散发快。对于初
始VOCs 浓度不同的平面形建材或空心圆柱形建材,在相同扩散条件下,室内
VOCs 浓度几乎同时达到峰值。但是,初始浓度值越大,室内 VOCs 浓度最高值
越高,室内 VOCs 高浓度维持时间越长,散发达到平衡所需时间越长,平衡时室
内VOCs 体积平均浓度值越大。另外,实验数据表明温度影响建材内 VOCs 初始
可散发浓度值:随着温度的升高,初始可散发浓度值增大。经实验数据拟合表明,
温度与建材内 VOCs 初始可散发浓度的相关关系可用方程式表达。
关键词: VOCs 散发 解析模型 数值模型 建材形状
ABSTRACT
Nowadays People express more concern about indoor air quality (IAQ). From
office environment to home environment, from public space to private space, every
place is filled with volatile organic compounds (VOCs) emissions from interior
materials. The organics have pungent smell and contain a lot of toxic substances which
is harmful to human physical and mental health. This paper studies the emission
characteristics of VOCs from interior materials, which is helpful to know the emission
rule of VOCs from building materials. And measures of VOCs emission control are
presented in the paper to improve the indoor air environment.
Considering the diffusion of VOCs within the material and boundary layer, this
paper build the analytical and numerical models for predicting emission of VOCs from
hollow cylindrical building materials based on the theory of mass transfer. Analytical
model can be built based on mathematical transformations and generalized integral
transform technique (GITT), and numerical model can be calculated by computational
fluid dynamics (CFD) technology. In addition, this paper studies the effects of
diffusion coefficient, thickness and initial concentration on the emission of VOCs from
planar and hollow cylindrical building materials by CFD technology. Meanwhile, a
thermodynamic model for VOCs emission from building materials is established based
on the experimental data in literature. Through data fitting, the effect of temperature on
initial mobile concentration of VOCs from building materials is verified.
The results show that both the diffusion coefficient and thickness can affect the
VOCs diffusion whether the building material is planar or hollow cylindrical. VOCs
can diffuse faster when the material is thinner and diffusion coefficient is bigger.
Conversely, VOCs diffuse slower with a smaller diffusion coefficient when the
material is thicker. Therefore, using thinner building materials with bigger diffusion
coefficient is better to make the VOCs send out quickly. Studies show that when the
thickness and other conditions are the same, VOCs from the hollow cylindrical
building materials diffuse faster than the planar building materials. For planar and
hollow cylindrical building materials with different initial concentration of VOCs,
while under the same diffusion condition the concentration of indoor VOCs peaked at
almost the same time. However, when the value of initial concentration is lager, the
concentration of indoor VOCs is higher, the time VOCs remained at a high
concentration is longer, moreover, it needs more time to achieve balance and the
equilibrium concentration is higher. Additionally,Experimental data shows that
temperature has effect on the initial mobile concentration of VOCs from building
materials. With the increase of temperature, the initial mobile concentration increases.
Through the experimental data fitting, the correlativity between temperature and the
initial emittable concentration of VOCs from building materials can be expressed by
equation.
Key Word: VOCs emissions, analytical model, numerical model,
shape of building material
目 录
中文摘要
ABSTRACT
第一章 绪论 .................................................................................................................... 1
1.1 课题研究背景及意义 ............................................................................................ 1
1.1.1 室内空气质量 ................................................................................................. 1
1.1.2 研究建材 VOCs 散发意义 ............................................................................. 1
1.2 研究室内建材 VOCS散发的方法 ........................................................................ 3
1.2.1 直接测定散发参数法 ..................................................................................... 3
1.2.2 数值拟合法 ..................................................................................................... 4
1.2.3 同系物相似法 ................................................................................................. 6
1.2.4 散发模型法 ..................................................................................................... 6
1.3 CFD 技术求解建材 VOCS散发 ............................................................................ 7
1.4 本文研究内容及创新点 ........................................................................................ 8
1.4.1 研究内容 ......................................................................................................... 8
1.4.2 创新点 ............................................................................................................. 8
第二章 平面建材 VOCS 散发模拟 ............................................................................... 9
2.1 单室模型 ................................................................................................................. 9
2.1.1 模型建立 ......................................................................................................... 9
2.1.2 模型验证 ........................................................................................................ 11
2.2 数值模型 .............................................................................................................. 12
2.3 本章小结 .............................................................................................................. 17
第三章 空心圆柱形建材 VOCS 散发模拟 ................................................................. 18
3.1 单室模型 ............................................................................................................... 18
3.1.1 模型建立 ....................................................................................................... 18
3.1.2 GITT 求解 ...................................................................................................... 20
3.2 数值模型 .............................................................................................................. 22
3.3 模型验证 .............................................................................................................. 25
3.4 本章小结 .............................................................................................................. 26
第四章 不同条件对不同形状建材 VOCS 散发的影响 ............................................. 27
4.1 计算模型及方法 .................................................................................................. 27
4.2 扩散系数对不同形状建材 VOCS散发的影响 .................................................. 29
4.3 厚度对不同形状建材 VOCS散发的影响 .......................................................... 32
4.4 几何形状对建材 VOCS散发的影响 .................................................................. 34
4.5 初始浓度对建材 VOCS散发的影响 .................................................................. 37
4.6 温度对建材 VOCS散发的影响 .......................................................................... 39
4.6.1 模型推导 ....................................................................................................... 39
4.6.2 实验数据验证热力学模型 ........................................................................... 41
4.6.3 CFD 技术验证热力学模型 ........................................................................... 44
4.7 本章小结 .............................................................................................................. 45
第五章 结论与展望 ...................................................................................................... 47
5.1 结论 ...................................................................................................................... 47
5.2 展望 ...................................................................................................................... 48
参考文献 ........................................................................................................................ 49
在读期间公开发表的论文和承担科研项目及取得成果 ............................................ 54
致 谢 ............................................................................................................................ 55
第一章 绪论
1
第一章 绪论
1.1 课题研究背景及意义
1.1.1 室内空气质量
室内空气质量(Indoor Air Quality,IAQ)是衡量室内空气环境是否健康和适
宜居住的重要指标。研究之初,人们认为 IAQ 是指在一定时间和一定区域内,空
气中所含有各项检测物质达到一个恒定不变的检测值。其主要标准包括含氧量、
甲醛含量、水汽含量、颗粒物浓度等。1989 年,美国供热通风空调工程师协会颁
布了 ASRAE62-1989 标准,该标准表明:室内空气质量是指室内空气中已知污染
物的浓度在没有达到权威机构所规定的有害浓度情况下,同时在此空间内的绝大
多数人没有出现对空气感到不舒适的情况[1, 2]。在污染物浓度不超过阈值的基础上,
此概念强调了人体舒适度,对室内污染物的要求更加严格。
随着信息网络的发达,人们在室内工作时间越来越长,因而对室内空气环境
的要求越来越高,清新的空气有助于人们更好的工作、学习与休息[3]。科学研究
表明,室内空气污染与大气空气污染由于所处环境不同,其污染特征也不同,室
内空气污染具有以下三个特点:(1)累积性,室内空间是相对封闭的空间,随气
流由室外进入室内的污染物,以及由室内建材(包括人造板材、墙纸、涂料油漆、
家具、地毯等)释放的污染物要排放到室外都需要一段时间,随着时间的积累造
成室内污染物浓度高于室外污染物浓度;( 2)长期性,有调查显示,人的生活中
约有 80%-90%的时间都在室内度过。工作、学习、生活都离不开室内环境,即使
室内污染物浓度很低,也会严重影响到人的正常生活[4];( 3)多样性,室内污染
物的种类很多,既包括进入室内的大气中所含的污染物,又包含室内装修材料、
涂漆等建设材料所散发的污染物。总体来说,室内空气中存在着生物性污染物、
化学性污染物和放射性污染物。生物性污染物主要是细菌;化学性污染物主要是
指挥发性有机物(VOCs):包括甲醛、氨气、二氧化碳、二氧化硫、一氧化碳、
苯、甲苯等;放射性污染物主要有氡气[5,6]。
1.1.2 研究建材 VOCs 散发意义
当室内引入能释放有害物质的污染源或由于室内环境通风不佳而导致空气中
有害物质从数量或种类上不断增加时,可能引发一系列不适症状,如建筑物综合
症( Sick Building Syndrome,
SBS)、 建筑物关联症(Building Related Illness,
BRI)
和化学物质过敏症(Multiple Chemical Sensitivity,MCS)[7, 8]。近些年来,SBS
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作者:侯斌
分类:高等教育资料
价格:15积分
属性:58 页
大小:3.47MB
格式:PDF
时间:2025-01-09