SF6/N2 mixtures is considered as a practical alternative proposal of SF6 in GIS and GIL. Simulating particle transportations and chemical reactions during the positive streamer propagation in SF6/N2 mixtures assists in the insulation performance optimization of SF6/N2 mixtures. This paper presents a fluid dynamic model coupled with the chemical reaction system for the positive streamer propagation in SF6/N2 mixtures. The Townsend coefficients of the 20%SF6/80%N2 mixture derived from the proposed chemical reaction system are in accordance with the measurement results. Based on this model, the propagation of the positive streamer in a 1 mm needle-plate gap in the 20%SF6/80%N2 mixture is simulated. Simulated results indicate that there exists a negative space charge region in the streamer channel. It can be attributed to the increasing attachment rates of SF6 yielding SF5⁻ and SF6⁻, and the reduction of the ionization rates of N2 and SF6 in the streamer channel. Besides, it is noted that the ionization activities of N2 and SF6 at the streamer head are equally important to support the continuous propagation of the positive streamer. The ionization of N2 in the streamer channel serves as an important factor to supply electrons and avoid the accumulation of the negative space charge.

中文翻译：

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非均匀场下SF6/N2混合物中正流注传播和化学反应的数值模拟

顺丰6/N2 混合物被认为是 SF 的实用替代方案6在 GIS 和 GIL 中。模拟 SF 中正流光传播过程中的粒子传输和化学反应6/N2 混合物有助于 SF 的绝缘性能优化6/N2混合物。本文提出了流体动力学模型与化学反应系统耦合，用于 SF 中的正流注传播6/N2混合物。20%SF 的汤森系数6/80%N2来自建议的化学反应系统的混合物与测量结果一致。基于此模型，正流光在 20%SF 中 1 mm 针板间隙中的传播6/80%N2混合物被模拟。模拟结果表明，在流光通道中存在负空间电荷区。这可以归因于SF的附着率不断增加6 产生SF5^-和SF6⁻，以及 N 电离率的降低2 和顺丰6在主播频道。此外，注意到 N 的电离活动2 和顺丰6在流光头处支持正流光的连续传播同样重要。N的电离2 流光通道中的电荷是提供电子和避免空间负电荷积累的重要因素。