Characteristics of a Hydroelectrical Bubble Generator

• Main Authors: Chih-hsiang Kuo, 郭志祥
• Other Authors: Yih-jiun Wang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/98891236407764870192

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 91 === Characteristics of a hydroelectrical bubble generator in deionized water and saline of concentration 100g/l have been studied experimentally. Vapor bubble was produced by means of high-voltage electrical discharge. Growth and collapse of the bubble were photographed using a high-speed camera and the images were employed to measure the maximum size of the bubble. Relationship between the discharge voltage and the size of bubble was determined. Influences of electrode gap and other possible factors on the reproducibility of the bubble size were also examined. In order to measure the impact force caused by the collapse of the bubble near a rigid boundary, the electrodes were placed close to the plate of the cuvette and a PVDF piezoelectric film was implemented. The output of the PVDF film was connected to a home-made operation amplifier to eliminate loading effects of the measurement system. The signal was then recorded by a digital oscilloscope. In addition to the magnitude of the impact force, time duration of the impact signal and the time interval, experimental results obtained in water with two different electrical conductivities were compared. It is hoped that the present study can help understand the characteristics of the hydroelectrical bubble generator and find applications in medical engineering, sush as the improvement of the reproducibility of the shock wave generator for extracorporeal lithotripsy.