【作者】 王乐；

【导师】 王怡；

【作者基本信息】 西安建筑科技大学 ， 供热、供燃气、通风及空调工程， 2009， 硕士

【摘要】 近年来,由于大量含有有害物质的建筑材料的使用和建筑的不良通风,使得建筑空间内污染物的浓度增高,造成空气品质恶化,特别是对于具有高大空间的建筑,其特有的人员流动大、污染物种类复杂等的特点,污染问题尤为突出。所以研究不同送风方式和不同污染源位置情况下空间污染物浓度的分布对改善空间空气品质有着很重要的指导意义。首先,本文对国内外高大空间建筑进行了分类,对其建筑特征以及建筑送风方式的选择做了较为全面的总结,对置换通风和吹吸式通风两种机械通风方式的原理进行了说明和对比。其次,对建筑空间内污染物及其散发量的预测方法做了详细的归纳总结,选取了甲醛(HCHO)作为研究高大空间建筑污染物稀释的主要污染物质。最后,利用CFD技术对高大空间模型进行了模拟,对两种不同的通风方式和不同的污染源位置,分析了空间内的速度、温度和污染源位置等因素对空间污染物浓度的影响,分析了各个工况下的流场情况及污染物浓度分布情况。本文通过对高大空间机械通风类型对污染物控制的12种工况的对比分析研究,得出在相同的送风量和污染物扩散强度的条件下,下面三种方法对污染物浓度进行的评价:(1)置换式通风系统在工作区上部和工作区的污染物浓度要高于吹吸式通风系统;(2)对于空间在X、Y、Z各个断面上,置换通风的污染物浓度都要高于吹吸式通风;(3)对于空间的无因次浓度,吹吸式通风方式除靠近污染源附近的无因次浓度较高外,其他各个断面都较低,而置换通风除随着高度的不断升高,无因次浓度是不断增加,在Y方向上,无因次浓度也是增加的。更多还原

【Abstract】 Recently,with the application of building materials with harmful substances and poor ventilation,pollutant concentration in building increases which have greatly caused deterioration in air quality.Because of its distinctive characteristics such as frequently personnel flowing and complex pollution species,the problem of pollution is particularly outstanding in large space building.Therefore,the study on pollution distribution in large building space with different air supply modes at different positions is of great guiding significances.Firstly,based on the classification of large space buildings,the characteristics and way of air supply is summarized comprehensively,and two kinds of mechanical ventilation including displacement ventilation and push-pull ventilation are illustrated and compared in this paper.Secondly,formaldehyde(HCHO) is selected as the main pollutants in this paper. Introduction and summarization on predictive methods of pollution as well as its emission are detailed.Finally,in terms of simulation with CFD on large space model,the influences of velocity,temperature and position on pollutants concentration under the two kinds of ventilation are analyzed.Besides,the distribution of pollutant concentration and flow field under different conditions are also introduced.The ventilation efficiency respectively with displacement ventilation and push-pull ventilation is also compared.Through analysis of pollutant control on 12 kinds of conditions for mechanical ventilation,three methods are adopted to evaluate pollutant concentration on the condition that the rate of air supply and pollutant dispersion are the same:(1)pollutant concentration at working area and its upper part in displacement ventilation system is higher than that of push-pull ventilation system;(2)whether at section X,Y or Z,the pollutant concentration of displacement ventilation system is higher than that of push-pull system;(3) dimensionless concentration at some sections are very low in push-pull ventilation except for sections that close to pollution source.While for displacement ventilation,the dimensionless concentration increases ceaselessly with height rising.更多还原