Dynamic behavior of anode arc jets in a cascade plasma torch with an external magnetic field

Hirokl Saito, Hikaru Matsumoto, Takayasu Fujino

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The voltage measurement and high-speed photography were conducted for a cascade plasma torch with an external magnetic field to study the voltage-current characteristics and key factors for suppressing the arc fluctuations in plasma torch. A ring-shaped permanent magnet was used to generate an external magnetic field of about 0.27 T at the center of the magnet. The operating current, the gas flow rate, and the anode-cathode distance were varied in the range 40-100 A, 10-40 L/min, and 0-10 mm, respectively. The width of a ring-shaped anode was set to 1 mm or 3 mm. The end-on images of the anode arc jets were captured by high-speed photography, and the associated arc voltage was measured. The time-averaged arc voltage of the cascade plasma torch shows a negative trend with the increase of the operating current with no external magnetic field applied. Higher time-averaged arc voltage is obtained by increasing the anode-cathode distance and applying the external magnetic field. The results of highspeed photography show that steep voltage drops are caused by successive arc root jumps on the anode. When an anode with 1 mm width is used, a periodic sine-like voltage waveform is observed at low gas flow rate. In that condition, an arc root rotates along the anode wall continuously with no observed breakdown process.

Original languageEnglish
Title of host publicationInternational Thermal Spray Conference and Exposition, ITSC 2019
Subtitle of host publicationNew Waves of Thermal Spray Technology for Sustainable Growth
EditorsF. Azarmi, Y. Lau, J. Veilleux, C. Widener, F. Toma, H. Koivuluoto, K. Balani, H. Li, K. Shinoda
PublisherASM International
Pages199-206
Number of pages8
ISBN (Electronic)9781510888005
Publication statusPublished - 2019 Jan 1
Externally publishedYes
EventInternational Thermal Spray Conference and Exposition: New Waves of Thermal Spray Technology for Sustainable Growth, ITSC 2019 - Yokohama, Japan
Duration: 2019 May 262019 May 29

Publication series

NameProceedings of the International Thermal Spray Conference
Volume2019-May

Conference

ConferenceInternational Thermal Spray Conference and Exposition: New Waves of Thermal Spray Technology for Sustainable Growth, ITSC 2019
CountryJapan
CityYokohama
Period19/5/2619/5/29

ASJC Scopus subject areas

  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

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