scholarly journals Numerical Simulation of the Fast Processes in a Vacuum Electrical Discharge

Author(s):  
Igor Uimanov

2018 ◽  
Vol 910 ◽  
pp. 72-77
Author(s):  
Ryo Henzan ◽  
Yoshikazu Higa ◽  
Osamu Higa ◽  
Ken Shimojima ◽  
Shigeru Itoh

The underwater shock-wave phenomenon has been applied in various fields such as manufacturing and food processing and was investigated using many experimental and numerical analyses in the past. An underwater shock-wave is produced by various methods, e.g., underwater wire explosion and pulse-gap electrical discharge. Therefore, clarifying the shock characteristics depending on the stored electrical energy, wire dimension and material is extremely important. However, predicting the pressure and its distribution induced by underwater electrical wire explosion is hard because the phenomena associated with an elementary process are significantly complicated. In this study, to predict the discharge characteristics induced by underwater electrical wire explosion, numerical simulation based on the “simplified model of underwater electrical discharge” was performed. The numerical results show good agreement with the experimental ones.





2014 ◽  
Vol 566 ◽  
pp. 403-408
Author(s):  
Hideki Hamashima ◽  
Seisaku Iwasa ◽  
Hironori Maehara ◽  
Shigeru Itoh ◽  
Kazuyuki Hokamoto

The basic behavior during underwater electrical discharge up to 10 kJ stored energy is investigated through both numerical analysis and optical-observation experiments. Since the authors have been investigating the use of underwater exploding phenomena for food processing and other applications, it is necessary to know the whole process which may affect the quality of the samples recovered. In the present investigation, the propagation of underwater shock wave was measured using a high-speed camera and compared with the numerically simulated results using LS-DYNA. Also, the motion of gas bubble, which is induced quite after the propagation of the shock wave, was measured and compared with the numerical simulation using the same code. The pressure of the bubble is not such high as the shock wave, but it is known that the impulse is not possible to be ignored due to its relatively long duration of the pressurization. Through a series of optical-observation experiments, it is confirmed that the numerical simulation is potentially possible to predict the whole phenomena for processing foods and other materials.



Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 577 ◽  
Author(s):  
Jun Wang ◽  
José. A. Sánchez ◽  
Borja Izquierdo ◽  
Izaro Ayesta

Wire Electrical Discharge Machining (WEDM) is a popular non-conventional machining technology widely used in high-added value sectors such as aerospace, biomedicine, and the automotive industry. Even though the technology is now ready to meet the requirements of the most complex components, certain fundamental aspects related to the discharge process and gap conditions are not yet fully explained and understood. Combining single discharge experiments with numerical simulation represents a good approach for obtaining a deeper insight into the fundamentals of the process. In this paper, a fundamental study of the WEDM through single discharge experiments and numerical simulation is presented. WEDM single discharge experiments are described with the aim of identifying the relation between crater dimensions, discharge gap, and part surface roughness. A thermal transient numerical model of the WEDM process is presented, and correlation with actual industrial material removal rates (MRR) is analyzed. Results from single discharge WEDM experiments show that crater volume is as much as 40% lower when discharging on a rough surface than when the discharge occurs on a flat surface. The proposed thermal numerical model can predict actual removal rates of industrial machines with great accuracy for roughing cuts, deviations with experimental values being below 10%. However, lager deviations have been observed for other WEDM conditions, namely trim cuts, thus confirming the need for future research in this direction.



2009 ◽  
Vol 21 (10) ◽  
pp. 106103 ◽  
Author(s):  
J. D. Parisse ◽  
L. Léger ◽  
E. Depussay ◽  
V. Lago ◽  
Y. Burtschell


Author(s):  
L.H. Bolz ◽  
D.H. Reneker

The attack, on the surface of a polymer, by the atomic, molecular and ionic species that are created in a low pressure electrical discharge in a gas is interesting because: 1) significant interior morphological features may be revealed, 2) dielectric breakdown of polymeric insulation on high voltage power distribution lines involves the attack on the polymer of such species created in a corona discharge, 3) adhesive bonds formed between polymer surfaces subjected to such SDecies are much stronger than bonds between untreated surfaces, 4) the chemical modification of the surface creates a reactive surface to which a thin layer of another polymer may be bonded by glow discharge polymerization.



2009 ◽  
Vol 00 (00) ◽  
pp. 090904073309027-8
Author(s):  
H.W. Wang ◽  
S. Kyriacos ◽  
L. Cartilier




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