【作者】 王友君；

【导师】 亢燕铭；

【作者基本信息】 东华大学 ， 供热、供燃气、通风及空调工程， 2012， 博士

【摘要】 由于现代社会人们大部分时间都在建筑室内外环境中度过,所以,研究建筑室内外空气污染物输运特性对于控制和改善其空气质量具有重要意义。基于这一背景,本文利用数值模拟或现场监测相结合的方法对室外典型街谷空气污染特性、建筑室内外污染物相关性和室内典型封闭空间空气污染特性等方面的几个重要问题进行了系统的研究和分析。实测数据表明,街谷两侧绿化和建筑物对空气污染物扩散的阻碍有重要影响。因此,引入约束物(建筑或绿化)高度(H)与约束物距机动车道中心距离(D)之比(即高远比H/D)来表征这些约束物对街谷内空气污染物扩散的阻滞作用。街谷局部实测地点的总有效高远比(H/DT)等于单体约束物高远比(Hi/Di)的最大值。静风条件下,街谷总有效高远比(H/DT)越大,约束效应越强,即越不利于空气污染物的扩散。本文引入街谷整体换气次数(ηt,)和局部换气次数(ηl)的概念评估街谷内外空气交换能力。数值模拟结果显示,建筑布局对街谷气流组织结构、风速梯度分布及空气交换能力的影响很大。尤其是当组成街谷的建筑错列布置,并且上风侧缺口数量多,宽度大时,街谷局部换气次数(ηl)较大,有利于街谷内外空气交换和污染物稀释。街谷各沉积面上颗粒物平均沉积速度主要与流场特点、粒径大小和沉积面的位置有关。关于沉积速度的分布规律,较大值一般出现在建筑棱边附近,从棱边往沉积面中心方向逐渐降低。棱边附近沉积速度梯度变化显著,而沉积面中心基本没有梯度变化。实测数据显示,由于典型乡村(鲁西南)建筑的气密性较差,室内外污染物浓度相关性十分密切：取暖设备运行方式、燃料类型和居民日常活动规律对乡村建筑室内外污染物浓度变化规律有很大的影响。春节燃放烟花爆竹会产生大量的颗粒物和气态污染物,其污染程度与烟花爆竹类型和燃放高度有关。人工气候室实验结果表明,建筑室内外颗粒物浓度相关性主要与通风类型和粒子尺度谱分布等因素有关。如机械通风房间室内外颗粒物浓度关系最为密切；自然通风房间室内颗粒物浓度变化滞后于室外；空调通风房间的初效过滤器对小粒子室内外浓度关系几乎没有影响；供暖渗透通风房间通风效果最差,室内外颗粒物浓度变化曲线的一致性最差。置换通风房间是一种典型室内封闭空间。数值模拟结果显示,气溶胶粒子污染源位置、送风温度和送风口位置对其室内颗粒物浓度空间分布和清除效率具有十分强烈影响。当污染源位置较低时,垂直方向上出现浓度分层现象。送风温度和送风口的垂直位置虽然对置换通风房间上部的气流组织影响不大,但是对下部气流组织的影响却很明显。轨道交通系统是另一种典型封闭空间。上海轨道交通系统代表性车站的实测信息表明：站外污染物浓度与局部交通环境和车站周围建筑布局特点有关;站内空间CO2浓度与客流密度、背景浓度和通风系统多种因素有关；而站内空间CO和颗粒物浓度与客流密度基本无关,却与室内外源和通风系统关系密切。尤其是,地下空间内部(如3号线上海火车站和上海南站站厅)污染程度十分严重,而且很有可能有CO室内污染源。上海轨道交通系统列车内空气品质监测参数的变化因其种类、监测(即列车运行)方向及工作日与周末的不同而存有差异。各种监测参数与客流密度相关性的强弱顺序依次是CO2,温度和湿度。而颗粒物浓度主要取决于背景,受客流密度的影响较弱。此外,9号线从地上高架过渡到地下隧道过程中,车厢内所有监测参数均有不同程度的变化。相同客流密度条件下,3号线车厢内CO2浓度约为9号线的3.6倍。更多还原

【Abstract】 People spend most of their time in built-environment in modern society. Study on the transportation characteristics of air pollutants in and out buildings has special significance for controlling and improving indoor or outdoor air quality. Therefore, some important problems about air pollution features in outdoor typical street canyons, relationships of pollutants between indoor and outdoor building environment, and pollutants dispersion characteristics in typical enclosure spaces are investigated and analyzed systemetically by employing numerical simulation and field measurement.The field measurement data shows that tree planting along street canyons is as important as buildings on the block effect of air contaminants dispersion. Therefore, ratio of the height of restrictive objects (buildings or tree planting) to the distance of them to the center of motor vehicles driveways, ratio of height to distance (H/D), is introduced to denote the constraint effect of street canyon obstacles. The total effective ratio of height to distance (H/DT) of the local street canyon monitoring site is equal to the maximum among those of all the individual restrictive objects (Hi/Di). On the condition of calm wind, the higher the H/DT, the stronger the restriction effect of the objects to the disadvantage of air contaminants dispersion.The total air exchange rateηt and local air exchange rateη1 are introduced to evaluate the air exchange level of street canyons. The numerical simulation results show that air flow structure, velocity gradient distribution and air exchange level are tremendously changed by buildings layout. Especially, when the buildings are stagger arrangement, and there are more interspaces, larger interspaces width among upwind buildings, the local air exchange rateη1 of street canyon will be larger, which is good for the air exchange and pollutants dilution. Particles average deposition rate on each surface of street canyons is mainly associated with flow field, particle diameter and location of the surface. About distribution of particles deposition rate on surfaces of street canyons, the largest ones appear near the edges of buildings, and they decrease gradually from the edges to the center of surface. The remarkable gradient variation exists near the edges, while almost no gradient variation in the surface center.The field measurement data indicates that there is closely correlation between indoor and outdoor air contaminant concentrations, for the terrible obturation feature of rural building in the southwest of Shandong Province. The types of heating facilities, fuel type and habit of resident daily activity have great effects on the variations of pollutant concentrations indoor and outdoor. Fireworks during the Spring Festival can produce large number of particles and gaseous contaminants, and the consequent pollution level depend on their form and height of blowing up.The experiment data in climate chamber indicates that the correlation of particle concentration between indoor and outdoor of a building is greatly affected by ventilation type and particle size distribution. For example, particle concentration in a mechanical ventilation room is directly affected by the outdoor concentration. Indoor particle concentration of a natural ventilation room changes with a time delay comparing to outdoor concentration. The primarily efficient filter of air conditioning room has a little influence on the correlation of fine particle concentration between indoor and outdoor environment. The consistency of particle concentration curves indoor and outdoor of a heating room is the worst among which mentioned above.Displacement ventilation (DV) room is one of the typical enclosure spaces. The numerical simulation indicates that the aerosol source location, temperature and vertical location of the inlet supply air have strong impact on the spatial distribution and removal rate of indoor particles. When the aerosol source location is low, there will be the satisfying vertical concentration stratification. The temperature and vertical location of inlet supply air do not greatly affect the air distribution in the upper part of a DV room, but could significantly influence the airflow pattern in the lower zone of the room.Rail transit system is another typical enclosure space. The monitoring information of representative stations of Shanghai Rail Transit System shows that air pollutant concentrations outside the stations are related to local traffic environment and layout features of buildings around stations. CO2 concentration inside stations is connected with density of passenger flow, background concentration and ventilation system. However, CO and particle concentration inside stations are not associated with density of passenger flow, but with sources inside and outside stations as well as their ventilation system. Specially, the underground spaces of stations, halls of Shanghai Railway Station and South Station of line 3, are polluted seriously, and there could be CO sources in all probability. The variations of monitored parameters of air quality in carriages of Shanghai Rail Transit System differ from their kinds, traveling direct, weekends and workdays. The correlation level between the monitored parameters and density of passenger flow from the strongest to the weakest is CO2, temperature and humidity in proper sequence. However, particle concentration in carriages primarily depends on the background concentration, and influence the density of passenger flow is relativily weak. In addition, the monitored parameters in carriages on line 9 vary at different extent when the train travels from the over ground elevated road to subterranean tunnel. Under the condition of the same density of passenger flow, CO2 concentration in carriages of line 3 is about 3.6 times higher than that of line 9.更多还原