Streamer propagation in air
Streamer propagation in air
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DOI：
10.1088/0022-3727/30/4/017
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发表时间：
1997-02-21
影响因子：
3.4
通讯作者：
Lowke, JJ
中科院分区：
文献类型：
--
作者：
Morrow, R;Lowke, JJ
给出了在大气压力下，空气中某一点突然施加正电压时第一流光发展的理论。用泊松方程同时求解了电子、正离子和负离子的连续性方程，包括电离、附着、复合、电子扩散和光致电离的影响。在50 mm的间隙上施加20千伏的电压时，流光不会到达阴极。在200 ns的时间内，强电场锋从点向缝隙传播到35 mm的距离。在接下来的7.5亩中，S只需将彩带再向缝隙中移动2毫米，彩带头部的电场就会崩溃。最后，只剩下远离点的正空间电荷，使点附近的电场在类似于S的10亩后恢复；自由电子因此可以在阳极附近产生二次放电。电场分布与以前发现的SF6的电场分布有很大的不同，因为流光柱中的电场通常只是电离等于附着的临界场的一小部分。与SF6相比，在空气中，给定电压下的流光具有更大的射程。空气的结果也适用于烟道气混合物，因为这两种气体的重要物质性质非常相似。
A theory is presented for the development of the first streamer when a positive voltage is abruptly applied to a point in air at atmospheric pressure. The continuity equations for electrons, positive ions and negative ions, including the effects of ionization, attachment, recombination, electron diffusion, and photoionization, are solved simultaneously with Poisson's equation. With an applied voltage of 20 kV across a 50 mm gap, the streamer does not reach the cathode. An intense electric field front propagates away from the point into the gap to a distance of 35 mm in 200 ns. During the next 7.5 mu s the streamer only moves a further 2 mm into the gap, and the electric field at the head of the streamer collapses. Finally, only positive space charge remains which moves away from the point, allowing the field near the point to recover after similar to 10 mu s; free electrons can thus give rise to a secondary discharge near the anode. The electric field distribution is shown to be quite different from that found previously for SF6 in that the electric field in the column of the streamer is generally only a fraction of the critical field for which ionization equals attachment. Streamers for a given applied voltage have a far greater range in air than in SF6. The results presented for air also apply to flue gas mixtures, since the important material properties of both gases are very similar.