Analysis of polarity effects in the electrical breakdown of liquids
Analysis of polarity effects in the electrical breakdown of liquids
复制标题
DOI：
10.1088/0022-3727/39/2/018
复制
发表时间：
2005-03
期刊：
影响因子：
--
通讯作者：
J. Woodworth;J. Qian;R. Joshi;E. Schamiloglu;J. Gaudet;J. Lehr
中科院分区：
文献类型：
--
作者：
J. Woodworth;J. Qian;R. Joshi;E. Schamiloglu;J. Gaudet;J. Lehr
对响应亚微秒（~ 100 - 200ns）电压脉冲的液体进行了电击穿模拟。这个模型建立在我们之前的分析基础上，并特别关注在点平面几何实验中看到的极性效应。数值实现采用通量校正输运法。我们的模型充分解释了击穿前电流波动、流光传播和分支的实验观察，以及阳极和阴极极性之间保持电压和击穿起始时间的差异。结果表明，极性效应主要是由电子和离子之间较大的迁移率差异引起的。较高的电子迁移率导致更大的电荷涂抹和扩散，从而影响局部电场分布。数密度、电场和电荷产生率之间的非线性耦合共同影响电离通道的形成及其时间动力学。
Electrical breakdown simulations are carried out for liquids in response to a sub-microsecond (∼100–200 ns) voltage pulse. This model builds on our previous analysis and focuses particularly on the polarity effect seen experimentally in point–plane geometries. The flux-corrected transport approach is used for the numerical implementation. Our model adequately explains experimental observations of pre-breakdown current fluctuations, streamer propagation and branching as well as disparities in hold-off voltage and breakdown initiation times between the anode and cathode polarities. It is demonstrated that polarity effects basically arise from the large mobility difference between electrons and ions. The higher electron mobility leads to greater charge smearing and diffusion that impacts the local electric field distributions. Non-linear couplings between the number density, electric field and charge generation rates then collectively affect the formation of ionized channels and their temporal dynamics.