【作者】 王艳辉；

【导师】 王德真；

【作者基本信息】 大连理工大学 ， 等离子体物理， 2006， 博士

【摘要】 均匀大气压介质阻挡放电由于其显著的优点和巨大的工业应用前景，自1988年第一次被报道以来就一直倍受人们的关注。近年来对均匀大气压介质阻挡放电的实验和模拟研究已被广泛进行，人们对这种放电的性质也有了一定的了解和认识。但是在这样一个具有强烈非线性的空间扩展耗散型放电系统中，放电行为是非常复杂的，有许多方面仍然处于研究讨论之中。在本论文中，我们采用一维流体力学模型，分别对纯氦气、氦一氮混合气体及纯氮气中均匀大气压介质阻挡放电特性及放电模式进行了数值模拟研究，具体包括以下几个方面：（a）对纯氦气中均匀大气压放电的行为和性质进行了研究，其中包括氦气放电的基本特性、氦亚稳态在放电中的行为和作用、多脉冲放电的形成原因、条件和性质及均匀大气压介质阻挡放电的工作模式；（b）针对不同的放电模式，研究了微量杂质对氦气放电的电学性质及放电空间结构的影响；（c）研究了氮气均匀介质阻挡大气压放电的特点、主要机制及多脉冲放电行为等；（d）研究了氦气均匀介质阻挡大气压放电中的复杂非线性动力学行为：倍周期分岔和混沌。 模拟结果显示，对于纯氦气中的均匀大气压介质阻挡放电，在通常的条件下，表现为狭窄的单脉冲放电，放电的空间结构具有低气压辉光放电特点，即存在明显的阴极位降区、负辉区、法拉第暗区和等离子体正柱区。放电脉冲的幅度直接受外部参数的影响。氦亚稳态原子在放电中起重要作用。它们主要产生于放电阶段，且最大产生率出现在高场强的阴极区，并在整个放电空间内都保持相对高的密度。亚稳态之间的碰撞电离不仅为放电提供种子电子，而且也产生了高浓度的氦的分子离子He₂⁺。亚稳态的时空行为随着放电条件而改变。放电空间亚稳态密度的下降，将导致带电粒子密度的减小，从而可以引起放电模式的改变。在放电间隙较小的情况下，在外加的电压的每半个周期内可以出现多个电流脉冲。多脉冲放电形成的主要原因是由于介质表面积累电荷增加而导致的空间电荷场的增强。多脉冲放电的发生通常需要较小的放电间隙，较低的驱动频率，或较高的电压幅度。其中小的放电间隙是形成多脉冲放电的必要条件。半个周期内放电脉冲的数目和幅度取决于驱动电压的幅度和频率。我们发现，在一定的条件下，对于氦气中的均匀大气压介质阻挡放电，无论是单脉冲放电还是多脉冲放电，都可以存在两种放电模式，即汤森和辉光模式，甚至在多脉冲放电的同一击穿序列中两种放电模式也可以并存。两种放电模式具有完全不同的电学性质和放电结构，在合适的参数下两种模式可以相互转换。 对氦—氮混合气体放电的研究发现，由于氮分子与氦亚稳态原子之间有效的潘宁电离过程，即使微量的氮杂质也可以对均匀大气压放电产生很大的影响。而且，在不同的更多还原

【Abstract】 Uniform atmospheric-pressure discharge （APD） controlled by dielectric barriers has attracted considerable attention since its inception because of its advantageous properties for industrial applications. In recently years, experimental and modeling studies on uniform APD have been carried out and some preliminary insights into uniform APD have been obtained. But, in such a spatially extended dissipative system with strong nonlinearity, the discharge behaviors are more complicated than that has been reported. . Many aspects still remain the subject of debate. An in-depth investigation on homogenous APD, especially its complex nonlinear dynamic behaviors, is indispensable to its farther development. In this paper, one-dimensional fluid models for the homogenous barrier discharges at atmospheric pressure have been developed, respectively in helium, helium mixed small impurities and nitrigon. Based on these models, we finish the studies of （a） the behaviors and mechanisms of uniform APD in pure helium including the elementary characteristics of the discharge, the role of helium metastable atoms in the discharge, the forming reasons and properties of multiple-pulse discharge, as well as the operation modes of uniform APD; （b） the influence of small nitrogen impurities on the electrical characteristics and space structures of uniform APD in helium under different discharge modes; （c） the period doubling events and chaotic behavior of homogeneous dielectric-barrier discharge at atmospheric pressure in helium; （d） the plasma dynamics characteristics , dominant mechanisms and structures of uniform APD in nitrogen.The simulaton results show that the homogeneous dielectric-barrier discharge at atmospheric pressure in helium is usually characterized by one current peak per half cycle of the applied voltage. The space structure of this discharge is similar to that of low pressure glow discharge, i.e. there exist four specific regions: the cathode fall; the negative glow; the Faraday dark space; and the positive column. The properties of discharge current are determined by the external conditions. The metastable helium atoms play an important role in the discharge. They mainly produced in the active phase of the discharge and keep its relatively high concentration throughout the discharge. Not only can metastable atom collisions provide seed electrons for discharges, but also produce much more He₂⁺ ions. The behaviors of metastable atoms change with the discharge parameters. A reduction of matestable atom density results in the drop of charged particle densities and causes a qualitative change of discharge patterns. In the case of smaller gap width, multiple current pulses can be formed in each half-cycle of the applied voltage duo to the increases of surface density of the accumulation charges leading to the enhancement of the induced electric field. The development of multiple current peaks usually requires smaller gap width, lower更多还原