【作者】 刘树森；

【导师】 朱能；

【作者基本信息】 天津大学 ， 供热、供燃气、通风及空调工程， 2007， 博士

【摘要】 目前,室内微生物污染问题已经受到国内外学者广泛而高度的重视。大量资料及研究成果已经证明病毒和细菌等生物颗粒物可以随空气传播,在室内以及人员密集的封闭空间,人们更容易接触和感染病菌,因此对生物颗粒物在室内的运动和传播规律进行研究极为重要。而人体做为室内微生物的主要来源之一,是本文研究的重点内容。本课题首先从理论入手,借助物理气溶胶运动的理论计算模型,结合空气微生物特性,建立室内微生物颗粒传播模型,考察微生物气溶胶在室内的传播规律。以拉格朗日方法为基础建立室内蒙特卡罗随机游走模型,分析室内喷射速度,环境风速,通风形式,发生的微生物颗粒的大小等等因素对于微生物气溶胶运动的影响。同时考虑微生物自身蒸发、死亡特性,给出微生物气溶胶室内传播路径的预测方法。参考普通物气溶胶室外扩散模型,结合本课题特点对扩散模型进行修正分析。给出一种较为准确的预测方案。同时,建立了一套能够模拟人体散发微生物颗粒的实验系统,该系统不论是在发生气溶胶的粒径分布,还是数量以及含菌量上都与人体散发的情况基本吻合。在国内首次通过大量不同场合,不同条件下室内人体散发微生物气溶胶传播的实验研究,对微生物颗粒在室内的运动问题进行了实验验证。模拟不同发生数量,不同传播速度,不同室内洁净程度,不同环境风速等情况下微生物颗粒的运动情况,给出相应的实验结论。通过实验分析,如果忽略外界环境风速、温度等对微生物颗粒的影响,咳嗽状态发生的微生物颗粒能够在室内传播1米左右的距离,而打喷嚏的传播距离则更远。然后,通过FLUENT流体力学计算软件对微生物颗粒在室内的传播情况进行分析研究,将模拟结果与实验结果进行对比分析,在认定模拟结果可信的前提下对微生物颗粒在室内传播情况进行了大量的分析研究,考察了不同粒径、不同发生速度,不同环境因素对其传播的影响。首次提出室内微生物气溶胶生命龄的概念,指出不同粒径大小的微生物颗粒在室内的存在时间以及致病能力都不相同的,并给出防治微生物颗粒室内污染的方法。最后,通过VB程序编写了室内微生物颗粒传播的寻源问题程序,对寻源问题进行初步探索,并提出改进的方案。更多还原

【Abstract】 The issue of indoor microbe contamination gradually draws widely and highly attentions of scholars all around the world. It has been proved by the results of enormous researches that the bio-particles containing virus and microbe, etc. can spread through air. Especially in the room or other sealed spaces which are crowded with people, the potential to contact with virus and then be infected is much higher. Thus the research on movement and transport of bio-particles indoor is critical and indispensable. Human body much as mouth, as the main source of indoor bio-aerosols, is discussed in this paper.The physics aerosol transport model as the basic analysis method is used combined with bio-aerosols character to build bio-particle transport mechanism. Basing on the Lagrangian equation, the Monte Carlo (MC) modeling method will be coupled into this simulation program to describe the bio-particle transport mechanism indoor. Many influent factors such as indoor airflow velocity,ventilation system model , the bio-aerosol generator velocity , particle diameter , and evaporation and death are considered synthetically in this paper. Consulting the normal aerosol outdoor dispersion model, the indoor bio-aerosol dispersion model is given. Compared with the experiment result, this bio-aerosol dispersion model is more accuracy.Meanwhile, a human emanation bio-aerosol simulation system is built in this paper. Under the experiment proved, the number of aerosol, the diameter distributing, and microbe content in the aerosol are same to the real condition. Though different location and different air condition experiment discussion, the transport result of bio-particle produced by mouth under different generator velocity, different indoor cleanness degree and different airflow velocity is given. As a result of each cough, the affected area extended as far as 2m, and the bio-particle produced by sneeze can transport farther distance.Using FLUENT to simulate bio-particle produced by human transport mechanism. First the simulation result and the experiment results are compared to prove the accuracy of the simulation. Then, more simulation cases are given to analysis different airflow condition, different ventilation system, different particle diameter’influence of indoor transport. Last, a new conception of indoor bio-aerosol life age is given to illustrate that the different particle size bio-aerosol’s indoor survival time and influence ability are different. Building indoor environment regular and emergency control strategies and methods are developed.Additionally, reverse search source of bio-particle method is given using the VB program.更多还原