ENVIRONMENTAL PROTECTION USING CAVITATION

在空化泡破裂的最后阶段的高能量集中导致超过1GPa的非常高的压力。这有时会对液压机械造成不利影响。然而，我们可以利用高压来保护环境。在本研究计划中，我们进行了以下四个研究课题。1.杀死浮游生物湖泊和池塘中浮游生物数量的异常增加会破坏其生态环境。另一个重要课题是远洋船舶的压载水排放问题。压载水含有浮游生物和鱼卵。当它们被排放到离它们生活的地方数千英里的地方时，它们可能会破坏生态环境。实验结果表明，带靶体的空化射流对海洋生物具有很好的杀伤作用。2.溢油扩散溢油事故对海洋环境具有灾难性的影响。机械采油是最理想的方法。但是，由于各种原因，它可能变得困难，例如 ...更多信息 恶劣天气油分散是第二好的解决方案，并使用分散剂。然而，分散剂可能会产生副作用。空化射流分散油液是本课题新开发的一种独特而有效的方法。3.杀菌是人类生活中最重要的环节之一。加热是最流行和最常用的灭菌方法。然而，它需要相当多的能量，并且有时待灭菌材料的性质变得更差。化学品是其他流行的消毒方法，但化学品可能会对人体产生副作用。空化流对细菌的杀灭是有效的。我们测试了两种不同类型的细菌，枯草芽孢杆菌作为革兰氏阳性菌的典型例子，大肠杆菌作为革兰氏阴性菌的典型例子。4.有机化合物的氧化空化射流对于有害有机化合物的氧化也是有效的。我们进行了系统的实验，四种有机化合物，1，4-二氯苯，联苯，二苯并呋喃，二苯并二恶英。结果表明，随着喷射压力的增加和空化数的减小，分解速率几乎呈线性增加。少

The high concentration of energy at the final stage of a cavitation bubble collapse causes very high pressure of more than 1 GPa. This sometime causes a detrimental effect to hydraulic machinery. However, we can use the high pressure for environmental protection. In this research project we performed the following 4 research subjects.1.Killing PlanktonAn abnormal increase in the amount of plankton in lakes and ponds can destroy their ecological environment. Another important subject is the discharge of ballast water from ocean-going ships. The ballast water contains plankton and fish eggs. They may destroy the ecological environment, when discharged thousands miles away from where they live. It was found that the cavitating jet with a target body was effective to killing plankton.2.Dispersing Spilled OilOil spill accidents have a disastrous effect on the ocean environment. Mechanical recovery of oil is the most desirable method. But, it can become difficult for various reasons, such as … More bad weather. The oil dipersion is the second-best solution, and dispersants are used. However, the dispersant may cause side effects. The dispersion of oil by cavitating jet is a unique and effective method, which was newly developed in the present project.3.Sterilization of BacteriaSterilization of bacteria has been one of the most important procedures in human life. Heating is the most popular and common method of sterilization. However, it needs considerable amount of energy, and sometimes the nature of the material to be sterilized becomes worse. Chemicals are other popular sterilization method, but the chemicals may cause side effects to human body. The cavitaing flow is effective for the sterilization of bacteria. We tested two different types of bacteria, the Bacillus Subtilis as a typical example of the Gram-positive bacteria, and the Escherichia Coli as a typical example of the Gram-negative bacteria.4.Oxidation of Organic CompoundsThe cavitating jet is also effective for oxidation of harmful organic compounds. We performed systematic experiments for four organic compounds, 1,4-dichlorobenzene, biphenyl, dibenzofuran, and dibenzo-p-dioxin. It was found that the decomposition rate increased almost linearly with increasing injection pressure and with decreasing cavitation number. Less