Two-dimensional simulation and experiments of helium discharge between parallel-plate electrodes in short gaps at atmospheric pressure |
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Authors: | Qi You Yan Zhou Xingnan Liu Ni Mo |
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Affiliation: | 1. Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, China;2. Collaborative Innovation Center of Advanced Nuclear Energy Technology, Beijing, China;3. The Key Laboratory of Advanced Reactor Engineering and Safety, Ministry of Education, Beijing, Chinahttps://orcid.org/0000-0002-1968-468X;4. The Key Laboratory of Advanced Reactor Engineering and Safety, Ministry of Education, Beijing, China;5. The Key Laboratory of Advanced Reactor Engineering and Safety, Ministry of Education, Beijing, Chinahttps://orcid.org/0000-0002-0389-8472 |
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Abstract: | ABSTRACTHelium gas is used as the coolant in high temperature gas-cooled reactor while its insulation property is not good and brings big challenges to insulation design work. In this paper, breakdown voltages of two parallel-plate electrodes in millimeter-scale gaps at atmospheric pressure are calculated numerically with a two-dimensional hydrodynamic model. The Finite-Difference Flux-Corrected Transport method (FD-FCT) is used to avoid spurious oscillation caused by convection and diffusion restrictions. The simulation results are in good agreement with our experimental work. Different discharge characteristics are presented for a breakdown or a non-breakdown voltage. Importantly, when a breakdown is applied, ground-state ionization will make up the most in early stages while later accumulation of metastable atoms and molecules will prompt fractions of penning ionization to increase rapidly. It is predicted that penning ionization will eventually become comparable with ground-state ionization, especially near the anode, as the current density keeps increasing to order of 1 A. Some other simulation results are presented such as time evolutions of the distribution of electrons, ions, field strength and axial potential, etc. Attainment of these breakdown voltages and characteristics of helium discharge is going to help with insulation design work of electric equipment in reactor engineering. |
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Keywords: | Helium discharge hydrodynamic model FD-FCT breakdown voltage penning ionization |
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