同轴受限水射流空化对生水中常见细菌灭杀机理研究

Bacteria disinfection is of considerable importance on drinking water security. Presently, the most popular disinfection method, chlorination, will produce chemical by-product which is harmful to human health. On the contrast, the cavitation method especially the hydraulic cavitation method generates no chemical by-products, while the corresponding cost and energy consumption is relatively high. So, a new hydralic cavitation disinfection technique, the confined coaxial jet cavitation method, is firstly presented in this application. It takes the advantages of fierce cavitation, no toxic by-products,low energy consumption and easy controlling. Based on the theory of confined co-axial jet cavitation, bubble dynamics and cell morphology, the project will focus on the development of the confined co-axial cavitation, the characteristics of bubble collapse as well as the mechanism of cell disruption within the jetting cavitation flow. The aims of the research will be: (1)to establish the correlation between cavitation level and the structural and flow parameters of the confined co-axial jet cavitation; (2) to reveal the mechanism of cell disruption in confined co-axial jet cavitation flow; (3) to propose an optimization design criterion of the confined co-axial jet cavitation reactor considering both energy consumption and sterilization rate. The expected results can advance the common knowledge of the confined co-axial cavitation flow in jet pumps, enrich the hydraulic cavitation disinfection method, present technical support for its industrial application and offer reference to wastewater treatment by cavitation method.

杀菌消毒对保障饮水安全至关重要。当前普遍使用的氯化法会产生对人体有害的化学残留物，空化特别是水力空化无毒副产物，但能耗和成本过高。本申请首次提出一种基于同轴受限射流空化的水力空化杀菌新方法，它具有无毒副产物、空化强度大、能耗低、控制方便等优点。申请将结合同轴受限水射流空化、空泡动力学、细菌细胞的形态分析等，重点研究同轴受限射流空化流动及空泡溃灭的规律、不同程度空化对细菌细胞的破坏作用，揭示同轴受限射流几何与流动参数对空化程度的影响、同轴受限水射流空化作用下细菌细胞的破碎机制，并提出综合考虑能耗与杀菌率的同轴受限射流空化发生器的优化设计准则。其成果可加深对射流泵内同轴受限射流空化机理的认识，丰富水力空化杀菌方法，为其大规模应用提供技术支撑，并为空化污水处理提供有力参考。

利用空化方法处理水中的细菌，实现对细菌细胞的破碎或灭杀，是一种高效、节能、环保的物理杀菌方法。水力空化作为新型的空化杀菌技术具有能耗低、空泡输运性强、杀菌效果好、处理量大等特点，具有广阔的应用前景。本课题采用实验研究、数值模拟相结合的方法，开展同轴受限水射流空化流动特性及其对水中细菌灭杀效果的机理研究，取得的主要成果如下：（1）对同轴受限射流空化发生器全流动工况下外特性变化和内部空化流动特性进行了系统的研究，将外特性参数变化与内部流动规律关联起来，扩展了其工作范围，深化了对同轴受限射流空化发生器内空化发生、发展规律及其控制方法的认识；（2）对影响同轴受限射流空化发生器性能的几何与动力因素进行了深入的研究，得到了工作压力、吸入压力、出口压力、面积比、喉管长度和结构、扩散管角度等对其空化性能的影响规律；（3）对同轴受限射流空化处理大肠杆菌细胞进行了较为系统的研究。分析了处理时间、空化状态、初始浓度、面积比等对杀菌率的影响，给出了处理大肠杆菌细胞的合适工作范围和对应能耗关系，初步分析了细菌细胞的破碎机制，提出了综合考虑能耗和杀菌率的同轴受限射流空化发生器的设计准则。.在本项目执行期间，共发表论文22篇，其中SCI检索论文16篇，EI检索论文17篇，授权专利4项。培养博士生2名，硕士生3名。参加国际学术会议4次，国内学术会议11次。研究成果加深了对同轴受限水射流空化流动机理以及对细菌细胞灭杀机理的认识，对完善同轴受限射流空化发生器的设计理论具有关键作用，对水力机械空化的研究具有重要参考价值。