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Numerical Simulation of Fluid Flow and Heat Transfer in a DC Non-Transferred arc Plasma Torch Operating Under Laminar and Turbulent Conditions

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Plasma Science and Technology 2011年第2期13卷 201-207页

作者：邓晶李要建徐永香盛宏至 Institute of Mechanics Chinese Academy of Sciences

In this work, a magnetic fluid dynamics （MHD） model is used to simulate the electromagnetic field, heat transfer and fluid flow in a DC non-transferred arc plasma torch under laminar and turbulent conditions. The electric current density, temperature and velocity distributions in the torch are obtained through the coupled iterative calculation about the electromagnetic equations described in a magnetic vector potential format and the modified fluid dynamics equations. The fluid-solid coupled calculation method is applied to guarantee the continuity of the electric current and heat transfer at the interface between the electrodes and fluid. The predicted location of the anodic arc root attachment and the arc voltage of the torch are consistent with corresponding experimental results. Through a specific analysis of the influence of mass flow rates and electric current on the torch outlet parameters, the total thermal efficiency, thermal loss of each part, and the laws of the variation of outlet parameters with the variation of mass flow rates and electric current was obtained. It is found that operation under a laminar condition with a limited area of the anode could increase the total thermal efficiency of the torch.

关键词： modeling arc plasma torch MHD arc root fluid-solid coupled method

Formation of a 40 A DC Current arc During the Opening of Silver Contacts

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Plasma Science and Technology 2014年第5期16卷 471-478页

作者： M'hammed ABBAOUI André LEFORT Erwann CARVOU Damien SALLAIS James Brian Alexander MITCHELL Noureddine BEN JEMAA Clermont Université Université d'AuvergneEA 3120LAEPTBP 10448F-63000 Clermont-FerrandFrance Equipe Contacts Electriques IPR(UMR CNRS 6251)Universite de Rennes 135042 Rennes CedexFrance

The erosion of silver contacts due to break arcs with length proportional to time and of variable duration has been measured by weighing the contacts following 5000 openings at a constant current equal to 40 A.The experimental results show that,for arc durations shorter than 60 μs,the transfer of metal from the anode to the cathode occurs,but after passing this stage,when the two electrodes are separated by greater distances,each will display erosion.This is the result of the diffusion of material outside the space between the two electrodes.In order to interpret these results,we have applied a classical model of the physical phenomena occurring at the root of the arc.Analysis of the experimental results shows that for an arc duration of less than15 μs,no distinct cathode root is seen to exist,but beyond this,several spots appear gradually on the cathode for arc duration up to 50 μs,after which they merge into a single spot.The comparison between experiment results and theoretical interpretation is reasonable up to 60 μs.

关键词： arc root cathode spot anode spot erosion contacts current density

Typical Motion and Extinction Characteristics of the Secondary arcs Associated with Half-Wavelength Transmission Lines

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Plasma Science and Technology 2014年第9期16卷 843-847页

作者：丛浩熹李庆民行晋源李劲松 School of Electrical Engineering Shandong University Beijing Key Lab of High Voltage and EMC School of Electric and Electronic EngineeringNorth China Electric Power University State Key Lab of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University

Secondary arc discharge is a complicated physical phenomenon and one of the key fundamental issues associated with ultra high voltage （UHV） half-wavelength transmission lines （HWTL）. With the establishment of a physicM simulation platform for the HWTLs, experiments were carried out regarding the motion and extinction characteristics of secondary arcs. The cathode arc root and the anode arc root were found to show an obvious polarity effect while the arc column was moving in a spirM, due to their different motion mechanisms. The extinction behavior was also recorded and experiments were designed with different compensation conditions. Results show that the arcing time can be greatly reduced if there exists an electrical compensation network. The research provides fundamentals for understanding the physics involved, especially the motion and extinction mechanisms of the secondary arcs.

关键词： secondary arc discharge arc root arc column motion mechanism

Geochronology and geochemistry of a suite of mafic rocks in Chencai area,South China:Implications for petrogenesis and tectonic setting

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Geochronology and geochemistry of a suite of mafic rocks in ...