A Study on Ultra-Highspeed Micro-Flow

超高速微流研究

• 批准号: 04402024
• 负责人: OBA Risaburo
• 金额: $ 11.39万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04402024/
• 关键词: Micro-flow; Ultra-highspeed-flow; Ultra-pure-water; Nozzle; Caviation; Jet; Bubble; Erosion; 渦; マクロ液流; はく離; 空気含有度

In order to make clear the flow characteristics and the dynamics in the ultra-highspeed micro-flow, we examined the cavitation characteristics of the ultra-highspeed flow. Then, we systematically observed the flow pattern in the nozzle and near the nozzle-outlet as well as the cavitating jet in a narrow watercourse, and also tried to simulate the cavitating flow numerically. The obtained results are summarized as follows :1. We tested the ultra-pure water, whose resistance rate is more than 18 MOMEGA/cm. And, we made clear that the relative air content rates of the water, which is an important factor on the cavitation inception and develops, are considerably higher than that of tap-and still water. Then we made a special facility to degas the air within the ultra-pure water by using a special filtering membrane in order to avoid polluting the ultra-pure water, and we got the special ultra-pure water, whose relative air content rates are less than 0.2.2. In order to make clear the flow … More pattern of ultra highspeed flow systematically, we carried out the observation and the erosion test on ultra highspeed water jets in the air and in the water. In the case of the jets in the water, it is shown that the jets are periodically shedding the cavitation bubble clouds. And also the erosion intensity is closely related to the cavitation bubble clouds.3. The above-mentioned the erosion characteristics induced by the cavitation around the submerged highspeed water jets are systematically examined, the submerged water jets are very useful for cleaning and peening. Since the cavitation-impulse-pressures at the bubble collapsing can be effectively used on the cleaning and the peening, in the case of the submerged water jets. And also the suitable injection condition is shown for several nozzles.4. In order to clarify the ultra highspeed flow pattern in a narrow watercourse, the cavitating jet in a narrow watercourse is carefully observed by means of a highspeed video camera, whose maximum framing rate is 40,500 frames per second and a digital image processing technique. The cavitation bubble clouds in the narrow watercourse are periodically shedding as same as the above-mentioned cavitation clouds associated with severely erosive cavitation. Less

为了研究超高速微流场中的流动特性和动力学特性，本文对超高速流场的空化特性进行了研究。在此基础上，系统地观察了喷嘴内、喷嘴出口附近的流态以及狭窄河道中的空化射流，并对空化流进行了数值模拟。主要研究结果如下：1.我们测试了超纯水，其电阻率大于18 MOMEGA/cm。并且，我们明确了水的相对含气率，这是一个重要的因素，空化的开始和发展，是相当大的比自来水和静水。为了避免超纯水的污染，我们制作了一种特殊的装置，用一种特殊的滤膜对超纯水中的空气进行脱气，得到了相对含气率小于0.2.2的特种超纯水。为了使流程清晰 ...更多信息 系统地研究了超高速水流的流态，并对超高速水射流在空气和水中的冲刷进行了观测和试验研究。在水中的射流的情况下，它表明，射流周期性脱落的空化泡云。空蚀强度与空蚀泡云有密切关系.本文系统地研究了高速淹没水射流周围空蚀的上述冲蚀特性，认为高速淹没水射流在清洗和喷丸方面是非常有用的。由于气泡溃灭时的空化脉冲压力可以有效地用于清洗和喷丸，所以在淹没水射流的情况下。并给出了几种不同类型喷嘴的适宜喷射条件.为了研究窄水道中的超高速水流流态，利用最大帧频为40,500帧/秒的高速摄像机和数字图像处理技术，对窄水道中的空化射流进行了细致的观测。窄水道中的空泡云与上述严重冲蚀空泡的空泡云一样，也是周期性脱落的。少

项目成果

K.Hokkirigawa: "SEM Studies of Particles Produced by Cavitation Erosion" Int.Conf.Pump and Systems,Beijing. 193-202 (1992)

K.Hokkirikawa：“空化侵蚀产生的颗粒的扫描电镜研究”国际泵与系统会议，北京。

横田源弘: "微小ノズルのキャビテーション特性に対するポリマ添加の影響" ウォータージェット. 10. 3-13 (1993)

Minahiro Yokota：“聚合物添加对微喷嘴空化特性的影响”Waterjet。10. 3-13 (1993)。

山内由章: "高速水中水噴流の壊食の発達過程" 日本機械学会論文集(B). 60. 736-743 (1994)

Yoshiaki Yamauchi：“高速水下水射流侵蚀的发展过程”，日本机械工程师学会会刊 (B) 60. 736-743 (1994)。

Y.Yamauchi: "The Suitable Region of High- Speed Submerged Water-Jets for Cutting and Peening" Trans.JSME. Vol.59. 16-22 (1993)

Y.Yamauchi：“高速水下喷射切割和喷丸的适宜区域”Trans.JSME。

H.Soyama: "Behavior of the Erosion- Standoff- Distance Curves for High- Speed Water- Jets in Air" Trans.JSME. Vol.59. 707-712 (1993)

H.Soyama：“空气中高速水射流的侵蚀-间隔-距离曲线的行为”Trans.JSME。