植物滞尘分析及其数学表达模式  

A mathematical model on the dust-retention effect on the growth of the plants

作　　者：吴桂香[1] 吴超[1] 

机构地区：[1]中南大学资源与安全工程学院,长沙410083

出　　处：《安全与环境学报》2015年第2期272-277,共6页Journal of Safety and Environment

基　　金：国家自然科学基金项目(50974132)

摘　　要：在植被的树冠结构分析、植物滞尘机理和粉尘沉降速度半经验公式的基础上,建立了植物滞留大气颗粒物的数学表达式。利用Beta功能函数φθ(X)、叶面的投影面积、叶面积密度a(z)、叶投影面积分布参数Kx、Kz等描述不同植被冠层的结构特征,并分析了冠层内的空气动力变化和树冠内气溶胶的平衡公式。借鉴Slinn的颗粒物沉降半经验公式、Petroffa等的阔叶滞尘计算模式,植物滞尘沉降通量数学表达式以树冠中树叶的位置为变量、由颗粒物在单片树叶上的各物理机制的沉降速度积分而成。结合国内外植物上沉降速度的试验结果和植物滞尘沉降通量公式的分析结果对影响植物滞尘的主要因素进行了比较分析。This paper is dedicated to the introduction to a mathemati- cal model of the dust-retention effect on the growth of the plants by taking China＇ s urban areas as a case study sample. As a matter of fact, the pollution situation caused by the atmospheric particulate matters has been ever increasing serious in China＇ s urban conditions, which has brought about tremendous effects on the healthy growth of different species of plants. Nevertheless, little has been done on the quantitative study of the relation between the capability of the detain- ing dust and the plant regular growth. Coming from the urgent need and using the corresponding parameters of the current pollution statis- tics, we have brought about a detailed description of the canopy structure of the plants, such as the Beta-function, the projected sur- face st on the horizontal plane and the projected surface sx on the plane perpendicular to the flow direction, the density a （z） of the fo- liage area, the parameters of the angular distribution（ Kx , Kz） , so as to analyze the aerodynamic changes in the canopy. In so doing, we have resorted to the aid of the mechanisms and regularities of the dust retention by plants to represent the aerosol balance within the canopy in the following equation： Э/Эz （-Kp（z） Эn/Эz - Vgn ＋ a（z）Vsn =0 . Since the different mechanical processes tend to produce depo- sition of the particulate matters, mainly the brown diffusion, the in- terception, the inertial impact and sedimentation, it is necessary to take into account the collected effects of the isolated leaves in hoping to derive the associated elemental collective velocity （ Vk ） from the experience of other models for reference, such as Slinn＇ s model and Alexandre Petroffa＇ s model, which have to be relied on the parame- ters whose values statistically vary within the reference spheres. More clearly speaking, the deposition density is closely related to the aver- age concentration rate through the average collection velocities Vk

关 键 词：环境工程学 叶面 颗粒物 树冠 沉降速度 数学表达式 

分 类 号：X513[环境科学与工程—环境工程]