Investigation on Microcosmic Characteristics of Trichel Pulse in Bar-Plate DC Negative Corona Discharge Based on a Novel Simulation Model

摘要

An improved multi-component two-dimensional hybrid model is presented for the simulation of Trichel pulse corona discharge in dry air (O_2:N_2=1:4). The model is based on the plasma hydrodynamics and the chemical models, in which 12 species (e, O, O_2, O_3, O_2~+, O_4~+, O_2~ˉ, O~ˉ, N_2, N_2~+, N_4~+, and N_2O_2~+) and 27 collision reactions between them are considered. In addition, the photoionization and secondary electron emission effect are also incorporated within the model as well. The simulation is established with a bar-plate electrode configuration with an inter-electrode gap of 3.3 mm where the negative DC voltage applied to the bar is 5.0 kV, the pressure in air discharge is fixed at 1.0 atm, and the gas temperature is assumed to be a constant (300 K). Based on the novel model, a few key microcosmic characteristics such as electric field distribution, net charge density distribution, electron density distribution at 5 typical time points during a process of Trichel pulse are discussed emphatically. What is more, the investigation on electron generation and disappearance rates, as well as positive ion, negative ion and neutral particle distribution characteristic along the axis of symmetry in the later Trichel pulse cycle are also detailed. The obtained results will provide valuable insights to the physical mechanism of negative corona discharge in air.