scholarly journals COMPARISON OF SPARK CHANNEL EXPANSION IN HYDROGEN, OXYGEN AND NITROGEN

2020 ◽  
pp. 165-168
Author(s):  
K.V. Korytchenko ◽  
Yu.V. Kashanskyi ◽  
O.V. Cherkashyn ◽  
D.Yu. Belyuchenko ◽  
A.V. Maksimov ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Discharge Current ◽  
Spark Discharge ◽  
Detonation Initiation ◽  
Species Concentration ◽  
Gas Dynamic ◽  
Channel Expansion ◽  
Spark Channel

The results of the spark channel expansion simulation in various gases such as hydrogen, oxygen and nitrogen have been presented. Difference in thermodynamic properties of the various gases has been taken into account. Influence of a type of gas on the discharge current, the spark resistance, the energy deposited in the spark and the spark gas-dynamic expansion has been found out. Influence of initial species concentration in mixture of nitrogen, hydrogen and oxygen on detonation initiation by spark discharge has been discussed.

scholarly journals Numerical simulation of gap length influence on energy deposition in spark discharge

2021 ◽  
pp. 35-43
Author(s):  
K.V. Korytchenko ◽  
O.V. Shypul ◽  
D. Samoilenko ◽  
I.S. Varshamova ◽  
А.A. Lisniak ◽  
...  
Keyword(s):  
Total Energy ◽  
Linear Relationship ◽  
Discharge Current ◽  
Energy Input ◽  
Discharge Channel ◽  
Spark Discharge ◽  
Gas Dynamic ◽  
Spark Gap ◽  
Deposited Energy ◽  
Spark Channel

The aim of the work is to study the influence of the length of the spark gap on energy input into the discharge channel during its gas-dynamic expansion. Methodology. The research is carried out by numerical modeling of the process of spark discharge development at variable values of the discharge gap length and at invariable other discharge conditions. The length of the gap was set in the range from 1 mm to 20 mm. The study was conducted using a numerical model of spark development, which takes into account the processes of nonstationary gas-dynamic expansion of the spark channel, the transient process in the electric circuit, nonequilibrium chemical processes, gas ionization, heat transfer and electrons thermal conductivity. The simulation was performed in atmospheric pressure nitrogen. The calculation was performed for various parameters of the RLC circuit, such as capacitance, inductance, resistance and voltage across the capacitor. Results. The study evaluates the influence of the spark length on the discharge current, the resistance of the spark channel, the energy deposited in the spark channel, and the distribution of thermodynamic parameters of the gas during the development of the spark discharge. It is confirmed that increasing the length of the gap increases the resistance of the spark. The deviation from the linear relationship between the deposited energy or the radiated energy and the length of the spark gap is estimated. Scientific novelty. A linear relationship between the gap length and the deposited energy is revealed when the total energy is above tens of Joules. Deviations from the linear dependence were detected in the discharge circuit when the total energy is below one of Joules. Practical value. The research results allow predicting the effect of the spark gap length on the energy input into the discharge channel under conditions of a slight change in the discharge current. In the conditions of essential change of amplitude of discharge current it is expedient to apply numerical researches for specification of changes in the energy deposited into a spark discharge.

Plasma and Gas-Dynamic Near-Electrode Processes in the Initial Phase of a Microstructured Spark Discharge in Air

2020 ◽  
Vol 46 (8) ◽  
pp. 737-740 ◽  
Author(s):  
K. I. Almazova ◽  
A. N. Belonogov ◽  
V. V. Borovkov ◽  
V. S. Kurbanismailov ◽  
G. B. Ragimkhanov ◽  
...  
Keyword(s):  
Initial Phase ◽  
Spark Discharge ◽  
Electrode Processes ◽  
Gas Dynamic

Third Paper: Comparison of the Behaviour of Different Sheet Materials Formed by the Underwater Spark Discharge Method

1964 ◽  
Vol 179 (1) ◽  
pp. 234-239 ◽  
Author(s):  
J. L. Duncan ◽  
W. Johnson
Keyword(s):  
Discharge Current ◽  
Spark Discharge ◽  
Discharge Process ◽  
Electrical Parameters ◽  
Aluminium Sheet ◽  
Material Thickness ◽  
Sheet Materials ◽  
Discharge Method ◽  
Underwater Spark Discharge

The effect of certain electrical parameters on the forming of flat circular aluminium sheet specimens clamped at their periphery and formed by means of the underwater spark discharge process as described in a previous paper (40) is extended to cover a number of different materials. Experimental observations on the effect of stand-off distance and material thickness on deformation and deflection are included and the speed of movement during the deflection of specimens of different materials is compared. The variation with polar deflection of strain at a particular radius is presented and the nature of the discharge current is also discussed.

scholarly journals NUMERICAL SIMULATION OF INITIAL PRESSURE EFFECT ON ENERGY INPUT IN SPARK DISCHARGE IN NITROGEN

2019 ◽  
Author(s):  
K.V. Korytchenko ◽  
R.S. Tomashevskyi ◽  
I.S. Varshamova ◽  
D.P. Dubinin ◽  
A.A. Lisnyak ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Energy Input ◽  
Energy Deposition ◽  
Pressure Effect ◽  
Initial Pressure ◽  
Spark Discharge ◽  
Atmospheric Conditions ◽  
Energy Correlation ◽  
Average Value ◽  
Spark Channel

An influence of initial gas pressure on energy deposited by spark discharge in nitrogen during the spark channel expansion is evaluated. Influence of the pressure on efficiency of energy deposition and emitted energy in a discharge channel is simulated. Dependencies of dynamic of energy input and an energy correlation coefficient on the pressure are found out. It was suggested to use an average value of the correlation coefficient to model a load of spark channel by the any initial pressure when a spark load is formed by atmospheric conditions.

Impacts of Spark Discharge Current and Duration on Flame Development of Lean Mixtures Under Flow Conditions

2018 ◽  
Author(s):  
Zhenyi Yang ◽  
Xiao Yu ◽  
Shui Yu ◽  
Jianming Chen ◽  
Guangyun Chen ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Discharge Current ◽  
Propagation Speed ◽  
Spark Ignition ◽  
Spark Discharge ◽  
Current Level ◽  
Ignition Process ◽  
Flame Kernel ◽  
Flame Development ◽  
Discharge Duration

Lean or diluted combustion has been considered as an effective strategy to improve the thermal efficiency of spark ignition engines. Under lean or diluted conditions, the combustion speed is reduced by the diluting gas. In order to speed up the combustion, in-cylinder flow is intentionally enhanced to promote the flame propagation. However, it is observed that the flow may make the spark ignition process more challenging due to the shortened discharge duration, the frequent re-strikes of spark plasma and the more complicated interactions between the flow and the flame. In this research, the effects of spark discharge current level and discharge duration on flame kernel development and flame propagation of lean methane air mixture are investigated under flow velocity of about 25 m/s and background pressure of 4 bar abs in an optical combustion chamber. A dual coil ignition system and an in-house developed current management module are used to create different discharge current levels. The average discharge current levels range from 55 mA, 190 mA, up to 250 mA. Detached flame kernel is observed under some test conditions. The flame propagation speed with the detached flame is generally slower than the flame developed from a flame kernel attached to the spark plug. The flame detachment is related to both the discharge current level and the discharge duration. When the discharge current level is high at 250 mA, the detached flame is observed at shorter discharge duration of 0.8 ms, while when the discharge current is low at 190 mA, detached flame can happen at longer discharge duration of 1.3 ms. Various discharge current and discharge durations are adopted to initiate the combustion in a single-cylinder engine operating with lean gasoline air mixture. It is shown from the results that a higher discharge current level and longer discharge duration are beneficial for controlling the combustion phasing and improving the operation stability of the engine.

Ignition of Combustible Dust Clouds by Strong Capacitive Electric Sparks of Short Discharge Times

2017 ◽  
Vol 231 (10) ◽  
pp. 1683-1707 ◽  
Author(s):  
Rolf K. Eckhoff
Keyword(s):  
Blast Wave ◽  
Dust Cloud ◽  
Life Time ◽  
Spark Discharge ◽  
Dust Concentration ◽  
Time Interval ◽  
Industrial Dust ◽  
Dust Clouds ◽  
Spark Channel ◽  
Spark Energy

Abstract It has been known for more than half a century that the discharge times of capacitive electric sparks can influence the minimum ignition energies of dust clouds substantially. Experiments by various workers have shown that net electric-spark energies for igniting explosive dust clouds in air were reduced by a factor of the order of 100 when spark discharge times were increased from a few μs to 0.1–1 ms. Experiments have also shown that the disturbance of the dust cloud by the shock/blast wave emitted by “short” spark discharges is a likely reason for this. The disturbance increases with increasing spark energy. In this paper a hitherto unpublished comprehensive study of this problem is presented. The work was performed about 50 years ago, using sparks of comparatively high energies (strong sparks). Lycopodium was used as test dust. The experiments were conducted in a brass vessel of 1 L volume. A transient dust cloud was generated in the vessel by a blast of compressed air. Synchronization of appearance of dust cloud and spark discharge was obtained by breaking the spark gap down by the dust cloud itself. This may in fact also be one possible synchronization mechanism in accidental industrial dust explosions initiated by electrostatic sparks. The experimental results for various spark energies were expressed as the probability of ignition, based on 100 replicate experiments, as a function of the nominal dust concentration. All probabilities obtained were 0%<p<100%. A tentative mathematical model could be fitted to all the data, assuming that the life time of the spark channel as an effective ignition source increased with the spark energy, that the minimum time of contact between the spark and the dust cloud for ignition to occur was a function of spark energy and nominal dust concentration, and that the stochastic element was the statistical distribution of the time interval between spark appearance and re-establishment of contact between spark channel and dust cloud, following detachment of the dust cloud from the spark by the shock/blast wave emitted by the spark discharge.

scholarly journals Influence of Ag Electrodes Asymmetry Arrangement on Their Erosion Wear and Nanoparticle Synthesis in Spark Discharge

2021 ◽  
Vol 11 (9) ◽  
pp. 4147
Author(s):  
Kirill Khabarov ◽  
Maxim Urazov ◽  
Anna Lizunova ◽  
Ekaterina Kameneva ◽  
Alexey Efimov ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Current Pulse ◽  
Discharge Current ◽  
Nanoparticle Synthesis ◽  
Spark Discharge ◽  
Anode Surface ◽  
Electrode Gap ◽  
Discharge Current Pulse ◽  
The Asymmetry ◽  
Constant Polarity

For nanoparticle synthesis in a spark discharge, the influence of the degree of electrode asymmetry in the rod-to-rod configuration, using the example of silver electrodes, on the energy efficiency and nanoparticle composition is studied. The asymmetry degree was determined by the angle between electrodes’ end faces. Two types of discharge current pulses were used: oscillation-damped and unipolar, in which electrodes changed their polarities and had a constant polarity during a single discharge, respectively. A significant influence of the asymmetry degree of the electrode arrangement on the synthesized nanoparticle size, agglomeration and concentration, and on the synthesis energy efficiency, has been established. An increase in the degree of the electrode asymmetry with the oscillation-damped discharge current pulse led to an increased mass production rate and energy efficiency of nanoparticle synthesis, a significant fraction of which had large dimensions of more than 40 nm. The effect of the transfer of synthesized nanoparticles to the opposite electrode at the unipolar discharge current pulse led to the appearance of electroerosive instability, manifested in the formation of a protrusion on the anode surface, around which spark discharges, leading to its further growth and electrode gap closure.

The Early Stages of Spark Channel Expansion

1959 ◽  
Vol 74 (3) ◽  
pp. 309-315 ◽  
Author(s):  
J M Somerville ◽  
J F Williams
Keyword(s):  
Early Stages ◽  
Channel Expansion ◽  
Spark Channel
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