【作者】 李全鹏；

【导师】 刘俊杰；

【作者基本信息】 天津大学 ， 供热、供燃气、通风与空调工程， 2007， 硕士

【摘要】 21世纪初爆发的SARS以及禽流感等呼吸性传染病,严重威胁人们的正常生活和健康。同时,医院手术部、隔离病房、生物安全实验室、医药卫生、生物制药工程、食品工业等高新技术产业等领域对空气微生物的控制则有了更加严格的要求,因此室内空气微生物污染已经成为人们关注的热点。以过滤为主的空气微生物的去除和防护技术的研究则显得尤为重要。本课题首先从理论入手,借助物理气溶胶过滤的理论计算模型,结合空气微生物特性,建立纤维滤料对空气中微生物过滤的模型。另外,采用经典的Logistic模型对滤料上收集下的微生物的繁殖进行分析,最后根据纤维滤料上存活微生物二次污染模型确定空气微生物被过滤后产生二次污染的理论可能性。根据各个模型之间的关系,将上面相互独立的3个模型综合为一个适用于空调系统微生物过滤收集、繁殖存活、二次污染的整体评价模型,可以用来模拟在任意时刻过滤器上微生物的繁殖存活情况及可能的二次污染情况,分析微生物在空调系统中变化的规律。同时,通过搭建空气微生物过滤实验台,采用微生物实验的方法对过滤、繁殖模型进行验证,发现微生物过滤模型能够比较好地对纤维滤料的微生物过滤效率进行预测,而且如果精度要求不高或缺乏微生物大小及粒径分布等数据时,也可以利用物理气溶胶模型来预测微生物过滤效率。还用实验方法分析了过滤器在不同容尘量下,过滤收集到的微生物存活繁殖情况,通过Logistic模型,对不同营养状况下的滤料上的微生物繁殖情况进行了对比,发现Logistic模型可以比较好地反映沉积在滤料上的微生物的存活繁殖规律。最后,通过实验观察了在连续通风条件下,由于滤料的微生物繁殖污染,所能引起的微生物二次污染情况。实验结果发现虽然受到各种因素,如滤料效率、微生物繁殖程度以及风速等的影响,但是均在滤料的下游捕集到活性微生物,检测到微生物的二次污染,因此仅仅依靠空气过滤不能达到空气微生物长期防护的最终目的,应当进一步研究新型过滤杀菌技术。这些理论和实验数据为下一步的空气微生物过滤防护技术的研究提供了有益参考。更多还原

【Abstract】 In early 21st century, People’s life and health were seriously affected by the outbreaks of some severe respiratory diseases, such as Service Acute Respiratory Syndrome (SARS) and the bird flu (H5N1 Killer Flu). And some high-tech fields, such as operating room, isolation ward, biological safety laboratory, medical care system, biomedical pharmacy engineering, food industry, are stricter with the control of airborne microorganisms than before. So the issue of indoor microbe contamination gradually draws widely and highly attentions of the world, and more research on bioaerosols removal and protection, especially the way of air filtration, is more important to be carried out.At the beginning of the subject, a bioaerosols removal efficiency model was established by combining the classic inert aerosol removal efficiency mathematical model with the characters of airborne microorganisms to predict the bioaerosols removal efficiency of the fibrous filter media. A classic Logistic mathematical model was used to analysis and to evaluate the growth extent of the microorganisms collected on the filter media. And a reentrainment model was used for the collected microorganisms on fibrous filter media to predict the theoretical probability of the secondary contamination. After that, according to the inner relationship of the above three separated models, an overall model was integrated to simulate the airborne microorganisms collection, survival and growth, and secondary contamination on the filters in the air-conditioning systems.And experiments were taken to prove the models of filtration and growth for the fibrous filter media by establishing an airborne microorganisms testing system. It was found that the bioaerosols removal efficiency model was suitable to predict the bio-protection performance of the fibrous filter media. Under the situation of low accuracy or lack of the data of microorganism characters including size, shape, size distribution, etc., the inert aerosol filtration model also could be used to predict the bioaerosols removal efficiency of the filter media. Other experiments were taken to simulate the different stages of the filter dust holding and tested the survival and growth of the filtrated microorganisms. After compared the experimental results with the theoretical data of Logistic model, it was found that the model could be fit to evaluate the survival and growth of the microorganisms which were filtrated on the filter media with different nutrition.In addition, the experiments tested the secondary contamination of the filter media under the situation of continuous ventilation. It showed that the results were seriously affected by some parameters, such as removal efficiency, the growth extent of microorganisms, face velocity, etc. However, microorganisms were detected at all downstream tests of the contaminated filter media, and all of them caused the secondary contamination in the air-conditioning system. So bioaerosols filtration is not the termination for long term bio-protection, further study on the new sterilization technology should be carried out. So the above theory and the experimental data will facilitate the next research on the bioaerosols filtration protection.更多还原