空气中单丝和丝阵电爆炸特性的比较

本文开展了500 J储能下、大气空气介质中微秒脉冲电流源驱动平面型铜丝阵负载电爆炸放电特性研究,并与铜单丝电爆炸进行了比较.实验中保持铜电极间距2 cm不变,选择2-16根直径100μm的铜丝组成平面型铜丝阵,同时选择直径50-400μm的单根铜丝作为对照,对电爆炸过程中负载电压、回路电流与光辐射强度进行测量,计算得到电功率、沉积能量等参数,研究质量变化对铜导体电爆炸过程的影响规律;特别地,对于相同质量下单丝与丝阵负载情况进行比较.实验结果表明,随着质量增加,单丝电爆炸气化与电离过程变缓,宏观表现为电压峰值时刻延后、半高宽增大(约0.07μs增至约0.64μs);与之不同,虽然丝阵电爆炸时刻随质量增加延后,但气化与电离持续时间变化不明显,电压峰半高宽稳定在0.11±0.01μs,且击穿发生前丝阵负载沉积能量低于同质量单丝负载.光辐射强度方面,丝阵电爆炸光辐射强度比三次同质量下单丝电爆炸分别强约28%,49%和52%.造成单丝与丝阵电爆炸过程差异的原因可能有两个方面:一是比表面积的差异使得细丝的相变过程更加迅速,表现为相同质量下细丝丝阵比粗单丝爆炸过程快;二是电热/磁流体不稳定性在丝阵与单丝中发展程度不同,表现为光强-时间曲线的差异.

Comparison of electrical wire explosion characteristics of single wire and wire array in air

In this paper,discharge characteristics of a planar copper wire array explosion driven by a microsecond pulsed current source(500 J stored energy)in atmospheric air medium were studied.Meanwhile,controlled experiments were performed with single wire cases.With a 2 cm distance between electrodes,2-16 copper wires with a diameter of 100μm were selected to form planar copper wire arrays,and single copper wires with diameter of 50-400μm were selected for comparisons.Load voltage,circuit current and light radiation intensity were measured.Electric power and deposited energy were calculated.The experimental results show that for the single wire case,with the increase of mass(diameter),the process of vaporization and ionization become slower,manifested as a delay of the voltage peak and an increase of the full width half maximum(FWHM)of the voltage pulse from 0.07μs to 0.64μs.In contrast,although the explosion time of wire array load was delayed with the increase of mass,the duration of vaporization and ionization did not change significantly with a FWHM of 0.11±0.01 ps.In addition,the deposited energy of wire array load before breakdown was lower than that of single wire load with the same mass.As for the optical radiation intensity,under three cases with the same mass,the peak intensity of wire array explosion is about 28%,49%and 52%higher than that of single wire explosion.There may be two reasons which cause the difference between the single wire load and wire array load.First,the larger specific surface area of the wire array load makes faster phase transitions.Second,the development of thermal or magneto hydrodynamics for the two kinds of loads was different,which should be responsible for the differences in energy deposition and optical emission.