水下放电同相位多气泡动力学实验研究

Experimental Study on the Dynamics of Multiple Bubbles in the Same Phase of Underwater Discharge

等离子体震源通过多电极发射阵进行电声转换,而多气泡动力学对声学特性影响显著,在发射阵的设计中电极间距是关键参数。为此开展了多电极水下同步放电实验,探究不同电极间距下放电过程的电特性与气泡动力学特性的变化。结果表明:当电极间距γ(无量纲数)小于1.3时,气泡之间的距离对气泡的形状、等效半径和气泡能量效率都有较明显的影响,气泡周期也随着电极间距的增大而增大;当电极间距继续增大时,气泡之间的影响减弱,气泡开始呈现较为规则的球形;当储能电容为2μF、充电电压为–4.72 kV时,双电极的气泡等效半径稳定在11.2 mm,气泡能量效率稳定在5.2%;三电极的气泡等效半径稳定在9.4 mm,气泡能量效率稳定在4.7%;四电极的气泡等效半径稳定在8.1 mm,气泡能量效率稳定在4.1%。

Electro-acoustic energy conversion of plasma sparker is accomplished by the multi-electrode emission array, and the dynamics of multiple bubbles has a significant impact on the acoustic characteristics, hence, the electrode distance is a key parameter in the design of the emission array. In this paper, the synchronous discharge on the multi-electrode array was generated to investigate the electrical characteristics and bubble dynamics under different electrode distances. The results show that when the dimensionless electrode distance γ is less than 1.3,the electrode distance has a significant impact on the shape, size, and bubble energy efficiency.In addition, the bubble period increases with the increase of electrode distance. When the electrode distance continues to increase, the interactions between the bubbles become small and the bubble’s shape is more spherical. When the capacitance and charging voltage are 2 μF and-4.72 k V, respectively, the stable bubble equivalent radius of the two-electrode discharge is 11.2 mm and the bubble energy efficiency is 5.2%, and those of three-electrode discharge are 9.4 mm and 4.7%, for the four-electrode discharge, the stable bubble equivalent radius and bubble energy efficiency are 8.1 mm and 4.1%, respectively.