Relationship between Wear Profile of Pantograph Contact Strip and Arc Discharge Energy Distribution

2018 ◽  
Author(s):  
Yoshitaka Kubota
Keyword(s):  
Energy Distribution ◽  
Arc Discharge ◽  
Discharge Energy ◽  
Contact Strip

scholarly journals A Novel Way to Enhance the Spark Plasma-Assisted Ignition for an Aero-Engine Under Low Pressure

2018 ◽  
Vol 8 (9) ◽  
pp. 1533 ◽  
Author(s):  
Shengfang Huang ◽  
Zhibo Zhang ◽  
Huimin Song ◽  
Yun Wu ◽  
Yinghong Li
Keyword(s):  
High Altitude ◽  
Penetration Depth ◽  
Power Supply ◽  
Arc Discharge ◽  
Burning Velocity ◽  
Discharge Energy ◽  
Aero Engine ◽  
Multichannel Discharge ◽  
Spark Plasma ◽  
Long Endurance

Finding a new ignition strategy for ignition enhancement in a lean-burn combustor has always been the biggest challenge for high-altitude, long-endurance unmanned aerial vehicles (UAVs). It is of great importance for the development of high-altitude, long-endurance aircraft to improve the secondary ignition ability of the aero-engine at high altitude where the ignition capability of the aero-engine igniter rapidly declines. An innovative ignition mode is therefore urgently needed. A novel plasma-assisted ignition method based on a multichannel discharge jet-enhanced spark (MDJS) was proposed in this study. Compared to the conventional spark igniter (SI), the arc discharge energy of the MDJS was increased by 13.6% at 0.12 bar and by 14.7% at 0.26 bar. Furthermore, the spark plasma penetration depth of the MDJS was increased by 49% and 103% at 0.12 bar and 0.26 bar, respectively. The CH* radicals showed that the MDJS obtained a larger initial spark kernel and reached a higher spark plasma penetration depth, which helped accelerate the burning velocity. Ignition tests in a model swirl combustor showed that the lean ignition limit was extended 24% from 0.034 to 0.026 at 25 m/s with 20 °C kerosene and 17% from 0.075 to 0.062 at 12 m/s with −30 °C kerosene maximally. The MDJS was a unique plasma-assisted ignition method, activated by the custom ignition power supply instead of a special power supply with an extra gas source. The objective of this study was to provide a novel multichannel discharge jet-enhanced spark ignition strategy which would help to increase the arc discharge energy, the spark plasma penetration depth and the activated area without changing the power supply system and to improve the safety and performance of aero-engines.

Effect of Discharge Energy Distribution on Flame Kernel Development

2020 ◽  
Author(s):  
Hua Zhu ◽  
Xiao Yu ◽  
Linyan Wang ◽  
Ming Zheng ◽  
Liguang Li ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Combustion Process ◽  
Operating Conditions ◽  
Discharge Energy ◽  
Energy Strategy ◽  
Ignition Energy ◽  
Lean Burn ◽  
Flame Kernel ◽  
Constant Volume Combustion Chamber ◽  
Initial Flame

Abstract The early flame kernel initiation and development are essential to a successful combustion process, especially under lean burn/EGR diluted conditions. Multiple ignition sites strategy has shown promise to secure the flame kernel initiation under extreme engine operating conditions. Two factors are considered to contribute to the enhanced ignition capability, i.e. the higher ignition energy and the multiple initial flame kernels. However, the mechanism why the multiple ignition sites help combustion is less understood. In this work, the impacts of the ignition energy distribution strategy on the flame inception process are investigated in a constant volume combustion chamber. A multi-coil ignition system, along with a sparkplug with three high-voltage electrodes, is used to adjust the discharge energy from 10 mJ to 240 mJ, as well as the energy deposition strategies. Experimental results have shown that the distributed energy strategy with sufficient discharge energy can establish a bigger initial flame kernel, leading to faster flame growth rates, as compared to the concentrated energy strategy.

Effect of the vibration on friction and wear behavior between the carbon strip and copper contact wire pair

2012 ◽  
Vol 226 (8) ◽  
pp. 722-728 ◽  
Author(s):  
HJ Yang ◽  
GX Chen ◽  
SD Zhang ◽  
WH Zhang
Keyword(s):  
Wear Rate ◽  
Wear Mechanism ◽  
High Speed ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Arc Discharge ◽  
Discharge Energy ◽  
Friction And Wear Behavior ◽  
Contact Wire ◽  
Arc Erosion

This article reports an experimental study on the friction and wear behavior of carbon strip sliding against copper contact wire under strong electric current utilizing a high-speed block-on-ring tester. The dynamic mechanism of electric arc generation was investigated. Scanning electron microscopy was used to observe morphology of worn surfaces of the carbon strips. The results show that arc discharge has a certain correlation with low-frequency vibration of the carbon strip. The arc discharge frequency and the average single arc discharge energy initially decrease and then tend to stable with increasing normal load at different speeds. The wear rate increases first and then decreases and has the minimum when the load is equal to 100 N especially. Moreover, the wear rate steadily increases with increase in arc discharge energy and is almost directly proportional to arc discharge energy. Arc erosion was a dominant wear mechanism occurred in carbon strip sliding against copper contact wire at a low load, accompanying with adhesive wear and material transferring. However, mechanical wear was a main wear mechanism at a high load. Severe arc erosion weakened the conductivity of the carbon strip.

Effect of Discharge Energy Distribution on Flame Kernel Development

2021 ◽  
Author(s):  
Hua Zhu ◽  
Xiao Yu ◽  
Ming Zheng ◽  
Liguang Li ◽  
Mengzhu Liu ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Discharge Energy ◽  
Kernel Development ◽  
Flame Kernel

Energy Distribution of a Prototype KSTAR Neutral Beam Ion Source for 300 s Arc Discharge

2008 ◽  
Vol 47 (2) ◽  
pp. 1076-1078 ◽  
Author(s):  
Doo-Hee Chang ◽  
Seung Ho Jeong ◽  
Byung-Hoon Oh
Keyword(s):  
Energy Distribution ◽  
Arc Discharge ◽  
Ion Source ◽  
Neutral Beam

Energy Distribution in Electron Beams

1972 ◽  
Vol 30 ◽  
pp. 568-569
Author(s):  
Tamotsu Ohno
Keyword(s):  
Electron Beam ◽  
Energy Distribution ◽  
Cross Section ◽  
Integral Curve ◽  
Electron Beams ◽  
Electron Gun ◽  
Angular Divergence ◽  
Apparent Increase ◽  
Integral Width ◽  
The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

Preparation and characterization of thin films of carbon nitride

1995 ◽  
Vol 53 ◽  
pp. 104-105
Author(s):  
L. Wan ◽  
R. F. Egerton
Keyword(s):  
Carbon Nitride ◽  
Arc Discharge ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Reactive Sputtering ◽  
Vacuum Arc ◽  
Specimen Preparation ◽  
Bonding Structure ◽  
Electron Energy Loss

INTRODUCTION Recently, a new compound carbon nitride (CNx) has captured the attention of materials scientists, resulting from the prediction of a metastable crystal structure β-C3N4. Calculations showed that the mechanical properties of β-C3N4 are close to those of diamond. Various methods, including high pressure synthesis, ion beam deposition, chemical vapor deposition, plasma enhanced evaporation, and reactive sputtering, have been used in an attempt to make this compound. In this paper, we present the results of electron energy loss spectroscopy (EELS) analysis of composition and bonding structure of CNX films deposited by two different methods.SPECIMEN PREPARATION Specimens were prepared by arc-discharge evaporation and reactive sputtering. The apparatus for evaporation is similar to the traditional setup of vacuum arc-discharge evaporation, but working in a 0.05 torr ambient of nitrogen or ammonia. A bias was applied between the carbon source and the substrate in order to generate more ions and electrons and change their energy. During deposition, this bias causes a secondary discharge between the source and the substrate.

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