Modeling of helium plasma jets emerged into ambient air: Influence of applied voltage, jet radius, and helium flow velocity on plasma jet characteristics

2012 ◽  
Vol 112 (10) ◽  
pp. 103304 ◽  
Author(s):  
G. V. Naidis
Keyword(s):  
Flow Velocity ◽  
Applied Voltage ◽  
Plasma Jet ◽  
Ambient Air ◽  
Plasma Jets ◽  
Helium Plasma ◽  
Helium Flow ◽  
Jet Characteristics ◽  
Plasma Jet Characteristics

scholarly journals What do we know about long laminar plasma jets?

2006 ◽  
Vol 78 (6) ◽  
pp. 1253-1264 ◽  
Author(s):  
Xi Chen ◽  
Wenxia Pan ◽  
Xian Meng ◽  
Kai Cheng ◽  
Dong-Yan Xu ◽  
...  
Keyword(s):  
Plasma Jet ◽  
Ambient Air ◽  
Low Noise ◽  
Plasma Jets ◽  
Metallic Surface ◽  
Ideal Object ◽  
Wide Range ◽  
Laminar Plasma Jet ◽  
Jet Characteristics ◽  
Plasma Jet Characteristics

Silent and stable long laminar plasma jets can be generated in a rather wide range of working parameters. The laminar flow state can be maintained even if considerable parameter fluctuations exist in the laminar plasma jet or if there is an impact of laterally injected particulate matter and its carrier gas. The attractive special features of laminar plasma jets include extremely low noise level, less entrainment of ambient air, much longer and adjustable high-temperature region length, and smaller axial gradient of plasma parameters. Modeling results show that the laminar plasma jet length increases with increasing jet inlet velocity or temperature and the effect of natural convection on laminar plasma jet characteristics can be ignored, consistent with experimental observations. The large difference between laminar and turbulent plasma jet characteristics is revealed to be due to their different laws of surrounding gas entrainment. Besides the promising applications of the laminar plasma jet to remelting and cladding strengthening of the metallic surface and to thermal barrier coating preparation, it is expected that the laminar plasma jet can become a rather ideal object for the basic studies of thermal plasma science owing to the nonexistence of the complexity caused by turbulence.

Expansion dynamics of atmospheric pressure helium plasma jet in ambient air

2020 ◽  
Vol 384 (19) ◽  
pp. 126497 ◽  
Author(s):  
G. Veda Prakash ◽  
Kiran Patel ◽  
Narayan Behera ◽  
Ajai Kumar
Keyword(s):  
Atmospheric Pressure ◽  
Plasma Jet ◽  
Ambient Air ◽  
Helium Plasma

scholarly journals The Influence of Anode Inner Contour on Atmospheric DC Plasma Spraying Process

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Kui Wen ◽  
Min Liu ◽  
Kesong Zhou ◽  
Xuezhang Liu ◽  
Renzhong Huang ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
Thermal Efficiency ◽  
Plasma Jet ◽  
Measured Temperature ◽  
Arc Voltage ◽  
Cylindrical Nozzle ◽  
Jet Characteristics ◽  
Plasma Spraying Process ◽  
Spraying Process ◽  
Plasma Jet Characteristics

In thermal plasma spraying process, anode nozzle is one of the most important components of plasma torch. Its inner contour controls the characteristics of plasma arc/jet, determining the motion and heating behaviors of the in-flight particles and hence influencing the coating quality. In this study, the effects of anode inner contour, standard cylindrical nozzle, and cone-shaped Laval nozzle with conical shape diverging exit (CSL nozzle) on the arc voltage, net power, thermal efficiency, plasma jet characteristics, in-flight particle behaviors, and coating properties have been systematically investigated under atmospheric plasma spraying conditions. The results show that the cylindrical nozzle has a higher arc voltage, net power, and thermal efficiency, as well as the higher plasma temperature and velocity at the torch exit, while the CSL nozzle has a higher measured temperature of plasma jet. The variation trends of the plasma jet characteristics for the two nozzles are comparable under various spraying parameters. The in-flight particle with smaller velocity of CSL nozzle has a higher measured temperature and melting fraction. As a result, the coating density and adhesive strength of CSL nozzle are lower than those of cylindrical nozzle, but the deposition efficiency is greatly improved.

scholarly journals Excitation mechanisms in a nonequilibrium helium plasma jet emerging in ambient air at 1 atm

2018 ◽  
Vol 36 (4) ◽  
pp. 04F406 ◽  
Author(s):  
Tam Nguyen ◽  
Eduardo Hernandez ◽  
Vincent M. Donnelly ◽  
Demetre J. Economou
Keyword(s):  
Plasma Jet ◽  
Ambient Air ◽  
Helium Plasma ◽  
Excitation Mechanisms

scholarly journals Tailoring the Chemistry of Plasma-Activated Water Using a DC-Pulse-Driven Non-Thermal Atmospheric-Pressure Helium Plasma Jet

Plasma ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 127-137 ◽  
Author(s):  
Oh ◽  
Szili ◽  
Hatta ◽  
Ito ◽  
Shirafuji
Keyword(s):  
Hydrogen Peroxide ◽  
Atmospheric Pressure ◽  
Pulse Width ◽  
Plasma Jet ◽  
Plasma Jets ◽  
Helium Plasma ◽  
Uv Absorption Spectroscopy ◽  
Pulse Polarity ◽  
Plasma Activated Water

We investigate the use of a DC-pulse-driven non-thermal atmospheric-pressure He plasma jet in the regulation of hydrogen peroxide (H2O2), nitrite (NO2−), nitrate (NO3−), and oxygen (O2) in deionized (DI) water. The production of these molecules is measured by in situ UV absorption spectroscopy of the plasma-activated water (PAW). Variations in the pulse polarity and pulse width have a significant influence on the resultant PAW chemistry. However, the trends in the concentrations of H2O2, NO2−, NO3−, and O2 are variable, pointing to the possibility that changes in the pulse polarity and pulse width might influence other plasma variables that also impact on the PAW chemistry. Overall, the results presented in this study highlight the possibility of using DC-pulse-driven plasma jets to tailor the chemistry of PAW, which opens new opportunities for the future development of optimal PAW formulations across diverse applications ranging from agriculture to medicine.

scholarly journals How Hydrogen Admixture Changes Plasma Jet Characteristics in Spray Processes at Low Pressure

2020 ◽  
Author(s):  
Georg Mauer
Keyword(s):  
Thermal Conductivity ◽  
Plasma Jet ◽  
Low Pressure ◽  
Atmospheric Conditions ◽  
Hydrogen Atoms ◽  
Electron Densities ◽  
Radial Temperature ◽  
Jet Characteristics ◽  
Plasma Enthalpy ◽  
Plasma Jet Characteristics

AbstractIn plasma spraying, hydrogen is widely used as a secondary working gas besides argon. In particular under low pressure, there are strong effects on the plasma jet characteristics even by small hydrogen percentages. Under such conditions, fundamental mechanisms like diffusion and recombination are affected while this is less relevant under atmospheric conditions. This was investigated for argon–hydrogen mixtures by optical emission spectroscopy (OES). The small electron densities under the investigated low pressure conditions implied specific difficulties in the application of several OES-based methods which are discussed in detail. Adding hydrogen to the plasma gas effected an increased plasma enthalpy. Moreover, the jet expanded radially as the reactive part of the thermal conductivity was enhanced by recombination of atomic hydrogen so that the shock waves were less reflected at the cold jet rims. In the jet cores, the lowest temperatures were found for the highest hydrogen admixture because the energy consumption due to the dissociation of molecular hydrogen outbalanced the increase of the plasma enthalpy. Variations in the radial temperature profiles were related to the jet structure and radial thermal conductivity. The local hydrogen–argon concentration ratios revealed an accumulation of hydrogen atoms at the jet rims. Clear indications were found, that higher hydrogen contents promoted the fast recombination of electrons and ions. However, it is assumed that the transport properties of the plasma were hardly affected by this, since the electron densities and thus the ionization degrees were generally small due to the low pressure conditions.

scholarly journals Studying the non-thermal plasma jet characteristics and application on bacterial decontamination

2018 ◽  
Vol 12 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Ali F. Al-rawaf ◽  
Fadhil Khaddam Fuliful ◽  
Mohammed K. Khalaf ◽  
Husham. K. Oudah
Keyword(s):  
Thermal Plasma ◽  
Plasma Jet ◽  
Thermal Plasma Jet ◽  
Non Thermal Plasma ◽  
Jet Characteristics ◽  
Plasma Jet Characteristics

Localized DLC etching by a non-thermal atmospheric-pressure helium plasma jet in ambient air

2014 ◽  
Vol 50 ◽  
pp. 91-96 ◽  
Author(s):  
Jun-Seok Oh ◽  
Yoshiaki Kakuta ◽  
Yuki Yasuoka ◽  
Hiroshi Furuta ◽  
Akimitsu Hatta
Keyword(s):  
Atmospheric Pressure ◽  
Plasma Jet ◽  
Ambient Air ◽  
Helium Plasma
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