Generation of high-power ultrasound by spark discharges in water
Generation of high-power ultrasound by spark discharges in water
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DOI：
10.1109/tps.2005.856411
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发表时间：
2005-10-01
影响因子：
1.5
通讯作者：
MacGregor, SJ
中科院分区：
文献类型：
--
作者：
Mackersie, JW;Timoshkin, IV;MacGregor, SJ
从传统机电声源获得所需的功率和带宽组合是不切实际的。然而，这些特性需要通过使用脉冲功率技术产生高功率超声波（HPU）来实现。高压脉冲引起水的电击穿，由此产生的气泡形成和破裂产生高功率和频率的声波。火花产生气泡的动力学被公式化以预测气泡半径随时间的发展，并且描述了产生一致的球对称 HPU 声波源的实验系统。检测到由于气泡形成和破裂而产生的压力脉冲，尽管它们的相对幅度变化，但它们的频谱没有显着差异。对于高达 25 J 的施加脉冲能量，声输出的幅度急剧上升，但效果饱和，表明使用高能脉冲增益很小且效率较差。发现电极分离形式的源拓扑变化是声输出中最重要的因素。检测到的 HPU 随着源变大而增加，但随着电极间隔的三分之二幂而增加，从而显示出逐渐减弱的增强。声信号的频率内容似乎不随施加的脉冲能量或电极间隔而变化。
It is impractical to achieve the desired combination of power and bandwidth from conventional electromechanical acoustic sources. However, these characteristics call be achieved by the use of pulsed power technology to generate high-power ultrasound (HPU). High-voltage pulses induce the electrical breakdown of water and the resulting bubble formation and collapse produce acoustic waves of high power and frequency. The dynamics of spark generated bubbles are formulated to predict the development of the bubble radius with time and an experimental system to produce a consistent source of spherically symmetric HPU acoustic waves is described. Pressure pulses due to both bubble formation and collapse were detected and, although their relative amplitudes varied, their frequency spectra did not differ significantly. The amplitude of the acoustic output rises sharply for applied pulse energies up to similar to 25 J but the effect saturates indicating little gain and poor efficiency by using high-energy pulses. Variation of the source topology in the form of the electrode separation was found to be the most important factor in the acoustic output. The detected HPU increased as the source became larger but as the two-thirds power of the electrode separation, thereby showing progressively diminishing enhancement. The frequency content of the acoustic signal did not appear to vary with either applied pulse energy or the electrode separation.