电工技术学报2025，Vol.40Issue(21)：6795-6805,11.DOI:10.19595/j.cnki.1000-6753.tces.250129
大气压微尺度电弧放电近阴极区能质输运机理
Energy and Mass Transport Mechanism of Atmospheric Micro-Scale Arc Discharge in the Near-Cathode Region
摘要
Abstract
For atmospheric micro-scale arc discharge,the near cathode region plays a crucial role in exploring the energy transport of arc plasma from the arc column region to the cathode surface with significant non-local equilibrium and space charge accumulation phenomenon.Detailed description of the kinetic characteristics of thermal microplasma in the near-cathode region is the key to understanding the micro-scale arc discharge mechanism.Recently,significant progress has been made in exploring the current transfer between arc plasma and refractory cathode by using fluid method.This method took the heat flux of plasma to the cathode surface as the nonlinear boundary condition to calculate the cathode temperature based on the heat conduction equation.However,due to the complex physical mechanism and small spatial scale in the near-cathode region,the experimental research is very difficult and the understanding of the energy transfer process involved in the cathode is not clear.Therefore,there is still no unified model and a generally accepted theory that can accurately calculate the cathode and near-cathode region. In this work,the energy and mass transport mechanism of atmospheric micro-scale arc discharge in the near-cathode region was studied.Firstly,a unified model including cathode and near-cathode region driven by a current source coupled with external circuit and nonlinear heat conduction was constructed.The changes of cathode temperature with total current density and heat flux with current were compared with the existing work for atmospheric DC argon arc discharge and atmospheric free burning arc to verify the model correctness.An implicit particle-in-cell coupled Monte Carlo collision(PIC-MCC)method was used to investigate the energy exchange process between thermal microplasma and cathode and between cathode and ambient gas.The temperature distribution of the cathode surface was calculated consistently,and the effects of radiation heat dissipation,natural convection heat dissipation,Joule heating and charged particle deposition heating on the energy transport characteristics of charged particles and the temperature of the cathode surface were quantitatively analyzed.The main conclusions can be drawn as follows: (1)Taking 2 000 K as the boundary temperature,the cathode temperature increases linearly in the region less than 2 000 K and nonlinearly in the region greater than 2 000 K.The electron emission current density increases exponentially on the cathode surface and reaches maximum at the right end of the cathode.The particle energy distribution function deviates from the Maxwell distribution in the sheath.EEDF shows the multi-peak distribution and IEDF shows the dual-energy group distribution. (2)When the total current densities were 5×106 A/m2 and 107 A/m2,the potential fall in the near cathode region is about 16.62 V and 18.21 V,which is consistent with the typical characteristics of low voltage and high current density of arc plasma.The maximum ion average temperature occurs at the cathode,which is 3.46 eV and 11.75 eV respectively,which is much higher than the cathode temperature. (3)The heating of charged particles deposited on the cathode surface is the main factor to increase the cathode temperature.The heat flux of ions deposited on the cathode is higher than that of electrons,indicating that the heating effect of ions on the cathode is larger than that of electrons.The heat flux of charged particles deposited on the cathode and heat flux carried away by electron emission increase exponentially with increasing cathode temperature. (4)Energy exchange between the cathode and the ambient gas include radiation and natural convection.In the region with electron emission,the energy loss caused by radiation is more prominent.In the region without electron emission,the energy loss by natural convection is more significant.关键词
微尺度电弧放电/近阴极区域/能质输运机理/隐式PIC-MCC方法Key words
Micro-scale arc discharge/near-cathode region/energy and mass transport mechanism/implicit PIC-MCC method分类
物理学引用本文复制引用
孙丽,严嘉彤,徐鸣,吕瑞东..大气压微尺度电弧放电近阴极区能质输运机理[J].电工技术学报,2025,40(21):6795-6805,11.基金项目
国家自然科学基金青年基金资助项目(52407186). （52407186）
