点击次数：

论文类型：期刊论文

发表时间：2018-01-01

发表刊物：PHYSICS OF PLASMAS

收录刊物：SCIE、EI、Scopus

卷号：25

期号：1

ISSN号：1070-664X

摘要：Atmospheric dielectric barrier discharge (DBD) was found to be promising in the context of plasma chemistry, plasma medicine, and plasma-assisted combustion. In this paper, we present a detailed fluid modeling study of abundant radical species produced by a positive streamer in atmospheric dense methane-air DBD. A two-dimensional axisymmetric fluid model is constructed, in which 82 plasma chemical reactions and 30 different species are considered. Spatial and temporal density distributions of dominant radicals and ions are presented. We lay our emphasis on the effect of varying relative permittivity (epsilon(r) = 2, 4.5, and 9) on the streamer dynamics in the plasma column, such as electric field behavior, production, and destruction pathways of dominant radical species. We find that higher relative permittivity promotes propagation of electric field and formation of conduction channel in the plasma column. The streamer discharge is sustained by the direct electron-impact ionization of methane molecule. Furthermore, the electron-impact dissociation of methane (c + CH4 = >c + H + CH3) is found to be the dominant reaction pathway to produce CH3 and H radicals. Similarly, the electron-impact dissociations of oxygen (c + O-2 = >c + O +O(D-1), c + O-2 = >c + O + O) are the major routes for O production. Published by AIP Publishing.