Characteristics of helium DC plasma jets at atmospheric pressure with multiple cathodes
A novel DC plasma torch with multiple cathodes is developed for generating laminar, transitional and turbulent plasma jets. The jet＇s characteristics, including jet appearance, voltage fluctuation, thermal efficiency, specific enthalpy, and distributions of temperature, pressure, and velocity, are e...
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| Published in | Chinese physics B Vol. 26; no. 8; pp. 299 - 307 |
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| Main Author | |
| Format | Journal Article |
| Language | English |
| Published |
01.08.2017
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| Subjects | |
| Online Access | Get full text |
| ISSN | 1674-1056 2058-3834 |
| DOI | 10.1088/1674-1056/26/8/085207 |
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| Summary: | A novel DC plasma torch with multiple cathodes is developed for generating laminar, transitional and turbulent plasma jets. The jet＇s characteristics, including jet appearance, voltage fluctuation, thermal efficiency, specific enthalpy, and distributions of temperature, pressure, and velocity, are experimentally investigated. The results show that as the gas flow rate increases, the plasma jet transforms first from the laminar state to the transitional state and second to the turbulent state. Compared with the transitional/turbulent jet, the laminar jet possesses not only a better stability and a longer hightemperature zone but also a higher average/core temperature and a higher specific enthalpy at the nozzle＇s outlet. With the change of jet states from the laminar to the turbulent flow, the core pressure and velocity at the nozzle＇s outlet increase,while the decaying rates of temperature/pressure/velocity along the jet＇s axial direction increase sharply. Furthermore, applications of laminar, transitional and turbulent jets for zirconia spray coating are described. The test results indicate that the long laminar jet is favorable for the deposition of a high-quality coating because the powder particles injected into the laminar jet may have better heating and lower kinetic energy. |
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| Bibliography: | Cheng Wang1, Zelong Zhang1, Haichao Cui1, Weiluo Xia2, and Weidong Xia1（ 1 Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230027, China 2Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China） A novel DC plasma torch with multiple cathodes is developed for generating laminar, transitional and turbulent plasma jets. The jet＇s characteristics, including jet appearance, voltage fluctuation, thermal efficiency, specific enthalpy, and distributions of temperature, pressure, and velocity, are experimentally investigated. The results show that as the gas flow rate increases, the plasma jet transforms first from the laminar state to the transitional state and second to the turbulent state. Compared with the transitional/turbulent jet, the laminar jet possesses not only a better stability and a longer hightemperature zone but also a higher average/core temperature and a higher specific enthalpy at the nozzle＇s outlet. With the change of jet states from the laminar to the turbulent flow, the core pressure and velocity at the nozzle＇s outlet increase,while the decaying rates of temperature/pressure/velocity along the jet＇s axial direction increase sharply. Furthermore, applications of laminar, transitional and turbulent jets for zirconia spray coating are described. The test results indicate that the long laminar jet is favorable for the deposition of a high-quality coating because the powder particles injected into the laminar jet may have better heating and lower kinetic energy. arc plasma jet, jet appearance, jet parameters distribution, zirconia coating 11-5639/O4 |
| ISSN: | 1674-1056 2058-3834 |
| DOI: | 10.1088/1674-1056/26/8/085207 |