中国物理B ›› 2017, Vol. 26 ›› Issue (8): 85207-085207.doi: 10.1088/1674-1056/26/8/085207

• PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES • 上一篇    下一篇

Characteristics of helium DC plasma jets at atmospheric pressure with multiple cathodes

Cheng Wang(王城), Zelong Zhang(张泽龙), Haichao Cui(崔海超), Weiluo Xia(夏维珞), Weidong Xia(夏维东)   

  1. 1 Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230027, China;
    2 Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
  • 收稿日期:2017-03-17 修回日期:2017-05-16 出版日期:2017-08-05 发布日期:2017-08-05
  • 通讯作者: Cheng Wang E-mail:awcheng@mail.ustc.edu.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11475174 and 11675177) and the Fundamental Research Funds for the Central Universities, China (Grant No. WK2090130021).

Characteristics of helium DC plasma jets at atmospheric pressure with multiple cathodes

Cheng Wang(王城)1, Zelong Zhang(张泽龙)1, Haichao Cui(崔海超)1, Weiluo Xia(夏维珞)2, Weidong Xia(夏维东)1   

  1. 1 Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230027, China;
    2 Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
  • Received:2017-03-17 Revised:2017-05-16 Online:2017-08-05 Published:2017-08-05
  • Contact: Cheng Wang E-mail:awcheng@mail.ustc.edu.cn
  • About author:0.1088/1674-1056/26/8/
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11475174 and 11675177) and the Fundamental Research Funds for the Central Universities, China (Grant No. WK2090130021).

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摘要：

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 high-temperature 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.

关键词: arc plasma jet, jet appearance, jet parameters distribution, zirconia coating

Abstract:

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 high-temperature 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.

Key words: arc plasma jet, jet appearance, jet parameters distribution, zirconia coating

中图分类号:  (Plasma torches)

  • 52.75.Hn
52.80.Mg (Arcs; sparks; lightning; atmospheric electricity) 52.70.-m (Plasma diagnostic techniques and instrumentation) 52.77.Fv (High-pressure, high-current plasmas)