Multiphysics simulation of the initial stage of plasma discharge formation in liquids
Multiphysics simulation of the initial stage of plasma discharge formation in liquids
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液体中等离子体放电形成初始阶段的多物理场模拟
DOI：
10.1088/1361-6595/ab51e3
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发表时间：
2020
影响因子：
3.8
通讯作者：
Farouk, Tanvir
中科院分区：
文献类型：
--
作者：
Aghdam, Ali Charchi;Farouk, Tanvir
模拟了均匀液体中等离子体在∼3.0-5.0 ns电压脉冲作用下的起爆过程。数值模拟采用了由可压缩流体解算器、带电物种守恒和泊松方程解算器组成的内部数值框架。对具有线性和指数增长两种不同电压分布的针状供电电极进行了模拟。模型预测表明，在纳秒电压升高的影响下，液体在电极附近形成负压区，并超过空化阈值压力。空化位置开始于亚微米区域，然后扩展到几个微米。电动力是静电、极化和电致伸缩有质动力的组合，对介质空化和形成低密度区有重要作用。有重量动力的影响最大，其次是两极分化力量。只有当形成足够的自由电荷时，静电力的影响才变得明显。尽管形成了低密度区，但电离过程仍然主要受场相关电离-齐纳隧道效应的驱动；因为跨越亚微米到微米级的电场不足以使电子碰撞电离显著。对最大驱动电压和电压分布进行了参数研究。结果表明，在较高电压下，指数型和线性型电压分布均在介质中形成压缩波和相应的高密度区。压缩波的大小并不能代表冲击波。当最大驱动电压提高2.5~15kV时，流体的整体速度可达每秒数百米，但仍保持在亚音速状态，说明在较高的电场条件下会形成类似激波的条件。
Plasma initiation simulations in homogenous liquids in response to∼ 3.0–5.0 ns voltage pulse is conducted. An in-house numerical framework consisting of a compressible fluid solver together with charged species conservation and Poisson's equation solver is employed for the simulations. The simulations are conducted for a needle-like powered electrode with two different voltage profiles—linear and exponential increase. The model predictions show that under the influence of nanosecond voltage rise the liquid experiences the formation of negative pressure region near the vicinity of the powered electrode and surpasses the cavitation threshold pressure. The cavitation locations initiate as sub-micron regions and then extends up to a few microns. The electrical forces which is a combination of electrostatic, polarization and electrostrictive ponderomotive forces contributes significantly in cavitating the medium and forming low-density region. The ponderomotive forces have the highest impact followed by the polarization forces. The effect of electrostatic forces only become significant when sufficient free charges are formed. Despite the formation of low-density region, the ionization process is still predominantly driven by field dependent ionization—Zener tunneling; as the electric field across the sub-micron to micron scale low-density regions are not sufficient for electron impact ionization to be significant. A parametric study on maximum driving voltage and voltage profile is conducted. The results indicate that at higher voltage both the exponential and linear voltage profile form a compression wave and an associated high-density region in the medium. The magnitude of the compressive waves is not representative of shock waves. The bulk liquid velocity can reach hundreds of meters per second but maintains subsonic conditions when the maximum driving voltage is increased by a factor of 2.5–15 kV suggesting shock like conditions will be formed under higher electric field conditions.
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DOI：
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发表时间：
1952
期刊：
影响因子：
--
作者：
I. Jacobs;A. W. Lawson
通讯作者：
A. W. Lawson
DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
V. E. Vinogradov
通讯作者：
V. E. Vinogradov
论密集媒体中的流媒体动态
DOI：
--
发表时间：
2001
期刊：
影响因子：
--
作者：
N. Babaeva;G. Naidis
通讯作者：
G. Naidis
非均匀脉冲电场中的介电流体。
DOI：
--
发表时间：
2013
期刊：
Physical review. E, Statistical, nonlinear, and soft matter physics
影响因子：
--
作者：
M. Shneider;M. Pekker
通讯作者：
M. Pekker
DOI：
10.1063/1.168744
发表时间：
1998-11-01
期刊：
COMPUTERS IN PHYSICS
影响因子：
--
作者：
Weller, HG;Tabor, G;Fureby, C
通讯作者：
Fureby, C