A 2D transient mathematical model was established to separately describe the anode bubble dynamics and the bubbleinduced electrolyte motion in the rare earth electrolysis cell with horizontal electrode.Results indicat...A 2D transient mathematical model was established to separately describe the anode bubble dynamics and the bubbleinduced electrolyte motion in the rare earth electrolysis cell with horizontal electrode.Results indicate that with the increase in the anode inclined angle,the maximum bubble thickness is increased gradually.Furthermore,compared with the conventional anode,the inclined and chamfered anodes are conductive to the bubble length reduction and the bubble velocity improvement.Meanwhile,the bubble-induced electrolyte motion in the electrolysis cell can improve the distribution and transport process of oxyfluorides,thereby enhancing the current efficiency.Finally,a novel feeding method based on the electrolyte flow is proposed.展开更多
The paper first studies the analytical expression of electrical potential by a point current source in a uniform half-space medium,and then focuses on the distribution of electrical potential in a horizontally layered...The paper first studies the analytical expression of electrical potential by a point current source in a uniform half-space medium,and then focuses on the distribution of electrical potential in a horizontally layered half-space model by a point current source within the surface layer or the bottom layer.Finally,the electrical potential by a source electrode in any layer of a layered half-space model is presented.展开更多
Arc flashes pose significant hazards to personnel working with energised power lines due to their high thermal risk,quantified by incident energy(IE)in joules or calories per area.Accurate estimation of IE is crucial ...Arc flashes pose significant hazards to personnel working with energised power lines due to their high thermal risk,quantified by incident energy(IE)in joules or calories per area.Accurate estimation of IE is crucial for ensuring safety.The most widely employed method for estimating IE from an arc flash is outlined in IEEE Std 1584-2018,which applies exclusively to three-phase AC arc flashes.However,limited research has explored alternative methods due to the complexities,costs,and preparation involved.Numerical simulations offer a viable alternative for studying arc flashes.This paper introduces a multiphysics simulation approach for determining IE by modelling three-phase AC arc flashes using the magnetohydrodynamics(MHD)theory.This study exclusively investigates horizontal electrodes in open-air(HOA)configuration due to the specific characteristics of the local power system configuration,which predominantly features overhead power lines,and the available test setup in the laboratory.The IE derived from simulations is compared with measurements from an arc flash laboratory based on IEEE Std 1584-2018 and with the IE calculated by the standard itself.The results indicate a significant alignment between this innovative approach and other methods for estimating IE for three-phase arc flashes.展开更多
土壤非线性电离效应是影响接地体散流能力的重要因素。为了研究冲击电流作用下土壤非线性电离对接地体泄流能力的影响规律,以单根水平接地体为研究对象,采用三维时域有限差分(3-D FDTD)数值分析方法,基于L-D(Liew and Darveniza)提出的...土壤非线性电离效应是影响接地体散流能力的重要因素。为了研究冲击电流作用下土壤非线性电离对接地体泄流能力的影响规律,以单根水平接地体为研究对象,采用三维时域有限差分(3-D FDTD)数值分析方法,基于L-D(Liew and Darveniza)提出的土壤非线性电离效应模型;根据电磁场理论,建立了水平接地体仿真模型,然后从暂态冲击接地电阻、最大暂态地电位升(GPR)和电导率分布等接地体特性参数角度来研究水平接地体冲击散流的物理过程。研究表明:1雷电流在接地体及其周围土壤的散流是复杂的电磁暂态过程,接地体的散流极不均匀;2土壤非线性电离效应减小暂态冲击接地电阻,而且考虑了土壤非线性电离效应的最大暂态地电位升要远远低于未考虑土壤非线性电离的情况;3接地体端部附近土壤电离区域大于中部附近电离区域,具有明显的端部效应。展开更多
基金National Natural Science Foundation of China(52101165)Inner Mongolia Science and Technology Major Project(2020ZD0010)Key Research Program of the Chinese Academy of Sciences(ZDRW-CN-2021-3)。
文摘A 2D transient mathematical model was established to separately describe the anode bubble dynamics and the bubbleinduced electrolyte motion in the rare earth electrolysis cell with horizontal electrode.Results indicate that with the increase in the anode inclined angle,the maximum bubble thickness is increased gradually.Furthermore,compared with the conventional anode,the inclined and chamfered anodes are conductive to the bubble length reduction and the bubble velocity improvement.Meanwhile,the bubble-induced electrolyte motion in the electrolysis cell can improve the distribution and transport process of oxyfluorides,thereby enhancing the current efficiency.Finally,a novel feeding method based on the electrolyte flow is proposed.
基金funded under the key project,Study on Techniques of Medium and Short-term Earthquake Prediction for Tianjin and Its Nearby Areas(07ZCGYSF03100),of the Science & Technology Pillar Program of Tianjin Municipality
文摘The paper first studies the analytical expression of electrical potential by a point current source in a uniform half-space medium,and then focuses on the distribution of electrical potential in a horizontally layered half-space model by a point current source within the surface layer or the bottom layer.Finally,the electrical potential by a source electrode in any layer of a layered half-space model is presented.
基金CPFL Group,Grant/Award Number:PD-00396-3104/2024Federal University of Santa Maria+3 种基金Electrical Engineering Graduate Program of UFSMNational Institute of Science and Technology—Distributed GenerationSmart Grids Institute of UFSMCoordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brazil—Financing Code 001。
文摘Arc flashes pose significant hazards to personnel working with energised power lines due to their high thermal risk,quantified by incident energy(IE)in joules or calories per area.Accurate estimation of IE is crucial for ensuring safety.The most widely employed method for estimating IE from an arc flash is outlined in IEEE Std 1584-2018,which applies exclusively to three-phase AC arc flashes.However,limited research has explored alternative methods due to the complexities,costs,and preparation involved.Numerical simulations offer a viable alternative for studying arc flashes.This paper introduces a multiphysics simulation approach for determining IE by modelling three-phase AC arc flashes using the magnetohydrodynamics(MHD)theory.This study exclusively investigates horizontal electrodes in open-air(HOA)configuration due to the specific characteristics of the local power system configuration,which predominantly features overhead power lines,and the available test setup in the laboratory.The IE derived from simulations is compared with measurements from an arc flash laboratory based on IEEE Std 1584-2018 and with the IE calculated by the standard itself.The results indicate a significant alignment between this innovative approach and other methods for estimating IE for three-phase arc flashes.
文摘土壤非线性电离效应是影响接地体散流能力的重要因素。为了研究冲击电流作用下土壤非线性电离对接地体泄流能力的影响规律,以单根水平接地体为研究对象,采用三维时域有限差分(3-D FDTD)数值分析方法,基于L-D(Liew and Darveniza)提出的土壤非线性电离效应模型;根据电磁场理论,建立了水平接地体仿真模型,然后从暂态冲击接地电阻、最大暂态地电位升(GPR)和电导率分布等接地体特性参数角度来研究水平接地体冲击散流的物理过程。研究表明:1雷电流在接地体及其周围土壤的散流是复杂的电磁暂态过程,接地体的散流极不均匀;2土壤非线性电离效应减小暂态冲击接地电阻,而且考虑了土壤非线性电离效应的最大暂态地电位升要远远低于未考虑土壤非线性电离的情况;3接地体端部附近土壤电离区域大于中部附近电离区域,具有明显的端部效应。
