Mathematical model of a short arc at the blow-off repulsion of electrical contacts during the transition from metallic phase to gaseous phase

2021 ◽  
Author(s):  
Stanislav N. Kharin ◽  
Targyn A. Nauryz
Keyword(s):  
Mathematical Model ◽  
Gaseous Phase ◽  
Metallic Phase ◽  
Electrical Contacts ◽  
Short Arc

Influence of Contact Materials on Phenomena in a Short Electrical Arc

2012 ◽  
Vol 510-511 ◽  
pp. 321-329 ◽  
Author(s):  
S.N. Kharin ◽  
M. Sarsengeldin
Keyword(s):  
Mathematical Model ◽  
Gaseous Phase ◽  
Thermionic Emission ◽  
Metallic Phase ◽  
Arc Length ◽  
Material Transfer ◽  
Contact Materials ◽  
Contact Erosion ◽  
Flux Evaporation ◽  
Gas Ionization

Investigation of transition phenomena accompanying the evolution of metallic phase of electric arc into gaseous phase is very important for the further progress in such fields as plasma technologies, electrical apparatus, plasmatrons and other technical applications. Some aspects of this transition are considered in presented paper on the base of mathematical model described dynamics of phenomena in the arc column, near-electrode zones, anode and cathode solids. Cathode and anode phenomena such as ion bombardment, thermionic emission, inverse electron flux, evaporation, radiation, heat conduction etc. are considered in dependence on time, current, opening velocity, parameters of the gas and contact materials. The conditions of the arc transition from one phase to another are formulated in terms of above characteristics and increasing of gas ionization level. Special experiments with two contacts materials, and have been carried to verify the mathematical model. The results of calculation and experimental data enables us to conclude that in metallic arc phase (short arc length), which is characterized by material transfer from the anode to the cathode, the erosion of contacts is considerably small than erosion of contacts both for resistive and inductive circuits, while in gaseous arc phase (long arc length) with opposite material transfer the rate of erosion depends on the inductance. If the inductance, then contacts have smaller erosion in comparison with contacts, however for inductive circuits situation is quite different, thus use of contacts in the case of long arcs burning in gaseous phase is more preferable. It was found also that the addition of niobium diselenide (1%) and tantalum (5%) into silver contact material which are sublimating into arc plasma enables to change ionization potential, that leads to decreasing of the arc temperature, arc duration and contact erosion.

Investigation on Microstructure Transformation and Failure Behavior of Cu-Cd-Nb-CP Electrical Contact Material

2005 ◽  
Vol 475-479 ◽  
pp. 869-872
Author(s):  
Yu Sheng Cui ◽  
Wen Zhu Shao ◽  
L. Zhen ◽  
V.V. Ivanov
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Electrical Contact ◽  
Optical Microscope ◽  
Metallic Phase ◽  
Electrical Contacts ◽  
Failure Behavior ◽  
Contact Material ◽  
Electrical Contact Material ◽  
Micro Cracks

Dependence of microstructure upon transfer stability of the powder-metallurgy copperdiamond electrical contact material with Cr and Nb addition during type-test process is investigated by optical microscope and SEM observation. During making and breaking process, micro-cracks occurred along grain boundaries under electrical and mechanical forces. Addition of cadmium into the composite increases oxidizable capability of this material, and also leads to oxide accumulation along grain boundaries. These factors reduce the reliability of electrical contacts in practice. Arc erosion quantities during commutation operation processes relates with grain size of matrix and particle size of the second metallic phase. The optimal grain size is 20~50µm and 10~20 µm for niobium particles in these tests.

scholarly journals Computer Simulation of the Formation of Non-Metallic Precipitates During a Continuous Casting of Steel

2016 ◽  
Vol 61 (1) ◽  
pp. 335-340
Author(s):  
D. Kalisz ◽  
P.L. Żak ◽  
T. Tokarski ◽  
Ł. Wzorek ◽  
J. S. Suchy ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Chemical Composition ◽  
Computer Software ◽  
Casting Process ◽  
Metallic Phase ◽  
Back Diffusion ◽  
Continuous Casting Of Steel ◽  
Cast Ingot ◽  
Calculation Results ◽  
The Given

The authors own computer software, based on the Ueshima mathematical model with taking into account the back diffusion, determined from the Wołczyński equation, was developed for simulation calculations. The applied calculation procedure allowed to determine the chemical composition of the non-metallic phase in steel deoxidised by means of Mn, Si and Al, at the given cooling rate. The calculation results were confirmed by the analysis of samples taken from the determined areas of the cast ingot. This indicates that the developed computer software can be applied for designing the steel casting process of the strictly determined chemical composition and for obtaining the required non-metallic precipitates.

scholarly journals Mathematical model of heat transfer in opening electrical contacts with tunnel effect

Filomat ◽  
2018 ◽  
Vol 32 (3) ◽  
pp. 1003-1008
Author(s):  
Merey Sarsengeldin ◽  
Stanislav Kharin ◽  
Zhangir Rayev ◽  
Yermek Khairullin
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Analytical Solution ◽  
Moving Boundary ◽  
Thermal Contact ◽  
Electrical Contacts ◽  
Tunnel Effect ◽  
Heat Equations ◽  
Integral Error ◽  
The Mathematical Model

The mathematical model describing the dynamics of heating in opening electrical contacts is presented. It takes into account the imperfect thermal contact between anode and cathode due to tunnel effect. The model is based on the system of spherical heat equations in a domain with moving boundary. The analytical solution is found in the form of series containing the integral error functions.

scholarly journals Numerical Model of Sic Particle Interaction with Solidification Front in Az91/(SiCp) Composite

2017 ◽  
Vol 62 (3) ◽  
pp. 1625-1628
Author(s):  
P. L. Żak ◽  
D. Kalisz ◽  
G. Rączkowski
Keyword(s):  
Mathematical Model ◽  
Numerical Model ◽  
Velocity Gradient ◽  
Solidification Front ◽  
Particle Interaction ◽  
Metallic Phase ◽  
Local Velocity ◽  
Sic Particles ◽  
The Mathematical Model ◽  
Sic Particle

AbstractPresented work focused on the movement of SiC particles in the vicinity of the solidification front in AZ91/(SiC)P composite. Authors describe the mathematical model that governs this phenomenon. On the base of following numerical model own computer program was prepared. The behavior of a particle moving parallel to the solidification front was analyzed. Three variants of local velocity gradient of liquid metallic phase were analyzed for a particle of radius 10, 50 and 100 μm. At a bigger velocity gradient the SiC particle was observed to go down quicker and to move towards the solidification front. This effect was stronger for SiC particles, which had a bigger radius, i.e. 100 and 50 μm

Sign in / Sign up

Export Citation Format

Share Document