空调启动阶段室内微生物气溶胶传播的数值模拟研究

发布时间：2018-12-18 07:05

【摘要】：中央空调系统由于其内部适宜的温湿度条件而极易滋生微生物,在空调启动阶段,随着对室内的持续送风,原来风管内部残留空气所携带的微生物气溶胶会进入室内,进而影响人体健康。针对这种问题,本论文基于前人所检测的具体数据,根据气溶胶颗粒运动的原理与方式,研究了风管内部微生物气溶胶进入室内后的传播情况。通过统计室内不同位置人员所接触到的气溶胶颗粒数量,以及对比不同气流组织形式下室内气溶胶的分布特点,为进一步研究改善集中式中央空调室内空气质量提供理论基础。通过数值模拟空调启动阶段室内微生物气溶胶的传播情况,得到的主要结论如下:(1)在空调开启15min后室内滞留的微生物气溶胶量已经很少,此时风管内部滞留空气所携带的微生物对人体的影响已经很小。4μm和15μm的微生物气溶胶颗粒的变化趋势比较一致,而30μm的微生物气溶胶在大约经历5min之后,室内数量基本保持不变,其主要的状态为沉积于地面。(2)在三种不同粒径的微生物气溶胶颗粒的对比中,15μm的颗粒物在每个时间段接触到人体的数量最多,可以推测15μm的气溶胶所携带的微生物对人体产生的危害相比另外两种最大。(3)在空调开启阶段的20s~80s时间段内人员接触到微生物气溶胶数量最多,在采用的三种气流组织模拟中人员平均的暴露量最大时间均为30s时间点,说明此时室内人员处在高密度的微生物气溶胶颗粒物环境中,期间假如微生物气溶胶所携带有高危细菌、病毒等,人员最容易接触而感染。净化器设备由于机械设备参与气流组织,室内的微生物气溶胶量减少速度快,所以人员的暴露量最大值与另外两种情况相比都小。(4)在所采用的三种不同的气流组织形式中,远离回风口的工作人员在空调开启阶段所接触的总体数量与其他位置相比都是最高的,而处于房间中间位置的工作人员,在整个过程中所接触到的微生物数量最少。采用开门窗通风的方式可以很大程度地减少房间内各个位置人员所接触到的微生物气溶胶颗粒的数量,而采用净化器的措施,可以在时间上快速反应,但是最终效果没有开门窗的方式明显。本课题基于非稳态情况下对室内微生物气溶胶污染物在房间的分布扩散特性进行数值模拟研究。根据不同时刻、不同位置微生物气溶胶的分布状态,可以预知室内空气质量较差的区域,提醒人员避免由于吸入过多的有害气体而损害健康。通过分析不同去除室内微生物污染的方式,对人们日常生活中室内空气质量的改善措施方面提供相关操作依据。
[Abstract]:The central air conditioning system is easy to breed microorganisms because of its suitable temperature and humidity conditions. In the starting stage of the air conditioning system, with the continuous indoor air supply, the microorganism aerosol carried by the residual air in the original air duct will enter the room. And then affect human health. In order to solve this problem, the propagation of microbial aerosol in air duct was studied according to the principle and mode of aerosol particle movement based on the specific data detected by predecessors. By counting the number of aerosol particles in different positions and comparing the distribution characteristics of indoor aerosols in different air distribution forms, this paper provides a theoretical basis for further research on the improvement of indoor air quality of centralized central air conditioning system. The main conclusions are as follows: (1) the amount of microorganism aerosol remaining in the room after 15min is turned on is very small. At this time, the microbes carried by the retained air in the duct have little effect on the human body. 4 渭 m and 15 渭 m microorganism aerosol particles have the same change trend, while the 30 渭 m microorganism aerosol has experienced 5min. The number of indoor particles remained basically unchanged, and the main state was deposition on the ground. (2) in the comparison of three kinds of microorganism aerosol particles of different diameters, 15 渭 m particles were most exposed to human body in each time period. It can be inferred that 15 渭 m aerosol carries the most harmful microbes than the other two. (3) the number of microorganism aerosols exposed to the aerosol is the highest in the 20s~80s period of the open air conditioning phase. In the three airflow simulation, the average maximum exposure time was 30 s, which indicated that the indoor personnel were in high density microorganism aerosol particulate environment. During the microbial aerosol carries high-risk bacteria, viruses and so on, personnel are most susceptible to contact and infection. Due to the participation of mechanical equipment in air distribution, the amount of microbial aerosol in the room decreases rapidly. Therefore, the maximum exposure of personnel is smaller than that of the other two cases. (4) in the three different airflow patterns used, The total number of workers away from the air outlet in the air conditioning opening stage is the highest compared with the other positions, while the staff in the middle of the room is the least exposed to the microorganism in the whole process. Opening doors and windows can greatly reduce the number of microbial aerosol particles exposed to people at various locations in the room, while the use of purifiers can react quickly in time. But the final effect is not obvious in the way doors and windows are opened. In this paper, the distribution and diffusion characteristics of indoor microbial aerosol pollutants in the room are numerically simulated based on the unsteady condition. According to the distribution state of microbial aerosol at different time and position, we can predict the area of poor indoor air quality, and remind people to avoid damaging health by inhaling too much harmful gas. By analyzing the different ways of removing indoor microbial pollution, this paper provides the relevant operation basis for the improvement of indoor air quality in people's daily life.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU83;X513

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