Controlling the breakdown delay time in pulsed gas discharge

2021 ◽  
Author(s):  
Irina V Schweigert ◽  
Matthew Hopkins ◽  
Ed V Barnat ◽  
Michael Keidar
Keyword(s):  
Delay Time ◽  
Time Delays ◽  
Pulse Discharge ◽  
Gas Discharge ◽  
Pulsed Discharge ◽  
Cathode Sheath ◽  
Stochastic Nature ◽  
Breakdown Process ◽  
Pulsed Gas Discharge ◽  
Three Stages

Abstract In experiment and 2D3V PIC MCC simulations, the breakdown development in a pulsed discharge in helium is studied for U=3.2 kV and 10 kV and P=100 Torr. The breakdown process is found to have a stochastic nature, and the electron avalanche develops in different experimental and simulation runs with time delays ranging from 0.3 to 8 μs. Nevertheless our experiments demonstrate that the breakdown delay time distribution can be controlled with a change of the pulse discharge frequency. The simulation results show that the breakdown process can be distinguished in three stages with a) the ionization by seed electrons, b) the ions drift to the cathode and c) the enhanced ionization within the cathode sheath by the electrons emitted from the cathode. The effects of variation of seed electron concentrations, voltage rise times, voltage amplitudes and ion-electron emission coefficients on the breakdown development in the pulsed gas discharge are reported.

Research on the influence of the discharge breakdown process on the crater formation during EDM

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wenchao Zhang
Keyword(s):  
Mathematical Model ◽  
Discharge Channel ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Single Pulse ◽  
Crater Formation ◽  
Content Type ◽  
Breakdown Process ◽  
Positive Ions ◽  
Fluid Coupling

PurposeThis paper aims to study the breakdown, oscillation and vanishing of the discharge channel and its influence on crater formation with simulation and experimental methods. The experiment results verified the effect of the oscillating characteristics of the discharge channel on the shape of the crater.Design/methodology/approachA mathematical model that considers the magnetohydrodynamics (MHD) and the discharge channel oscillation was established. The micro process of discharging based on magnetic-fluid coupling during electrical discharge machining (EDM) was simulated. The breakdown, oscillation and vanishing stage of the discharge channel were analyzed, and the crater after machining was obtained. Finally, a single-pulse discharge experiment during EDM was conducted to verify the simulation model.FindingsDuring the breakdown of the discharge channel, the electrons move towards the center of the discharge channel. The electrons at the end diverge due to the action of water resistance, making the discharge channel appear wide at both ends and narrow in the middle, showing the pinch effect. Due to the mutual attraction of electrons and positive ions in the channel, the transverse oscillation of the discharge channel is shown on the micro level. Therefore, the position of the discharge point on the workpiece changes. The longitudinal oscillation in the discharge channel causes the molten pool on the workpiece to be ejected due to the changing pressure. The experimental results show that the shape of the crater is similar to that in the simulation, which verifies the correctness of the simulation results and also proves that the crater generated by the single pulse discharge is essentially the result of the interaction between transverse wave and longitudinal wave.Originality/valueIn this paper, the simulation of the discharge breakdown process in EDM was carried out, and a new mathematical model that considers the MHD and the discharge channel oscillation was established. Based on the MHD module, the discharge breakdown, oscillation and vanishing stages were simulated, and the velocity field and pressure field in the discharge area were obtained.

Intermediate Products Analysis of Phenol Degradation in Aqueous Solution Caused by Pulsed Discharge

2012 ◽  
Vol 518-523 ◽  
pp. 3146-3149
Author(s):  
Sheng Lan ◽  
Zhen Xing Zhang ◽  
Yong Bin Yuan ◽  
Abdus Samee
Keyword(s):  
Aqueous Solution ◽  
Degradation Mechanism ◽  
Pulse Discharge ◽  
Phenol Degradation ◽  
Reaction Products ◽  
Pulsed Discharge ◽  
Dc Voltage ◽  
Intermediate Products ◽  
Phenethyl Alcohol ◽  
Products Analysis

Abstract. In this paper we have presented the degradation of Phenol in aqueous solution which is caused by pulse discharge. The reaction products in the wastewater dissolved phenol under pulsed discharge were tested using GC-MS. Based on the experimental results intermediate products include 2,4hydroxyphnel, polyhydroxy phenethyl alcohol and so on. The final products are carbon dioxide and water. In addition, the theoretical analysis has been conducted These results will be helpful for further studying degradation mechanism of wastewater dissolved phenol under pulsed discharge, using either AC or DC voltage.

Theory of the Cathode Sheath in a Low-Density Gas Discharge

1958 ◽  
Vol 111 (4) ◽  
pp. 1017-1028 ◽  
Author(s):  
P. L. Auer ◽  
H. Hurwitz ◽  
S. Tamor
Keyword(s):  
Gas Discharge ◽  
Low Density ◽  
Cathode Sheath

Calculation of cascade lasing due to 0001–0200–0110 transitions in CO2molecules pumped by a pulsed gas discharge

1982 ◽  
Vol 12 (8) ◽  
pp. 1107-1109 ◽  
Author(s):  
D Yu Zaroslov ◽  
R Sh Islamov ◽  
Nikolai V Karlov ◽  
I O Kovalev ◽  
Yu B Konev ◽  
...  
Keyword(s):  
Gas Discharge ◽  
Pulsed Gas Discharge

Soft x-ray emission from a pulsed gas discharge in a pseudosparklike electrode geometry

2008 ◽  
Vol 103 (12) ◽  
pp. 123304 ◽  
Author(s):  
Klaus Bergmann ◽  
Felix Küpper ◽  
Markus Benk
Keyword(s):  
Gas Discharge ◽  
Electrode Geometry ◽  
X Ray ◽  
Pulsed Gas Discharge
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