Thesis-1997-Yuan.pdf (3.69 MB)
Studies of electric discharges and their interactions with gases
thesis
posted on 2016-07-25, 10:36 authored by Qiulin YuanMeasurements of the effect of increasing the
discharge column voltage gradient were investigated using
argon based mixtures with nitrogen, oxygen and sulphur
hexafluoride in a plasma torch. The theoretical
calculation of the voltage gradient and the electron number
density was based on the Saha equation which was modified
for application to the gas mixtures. The investigations
showed that a mixture of Ar and SF6 was most effective and
increased the voltage gradient to 0.5 V/mm from 0.3 V/mm.
The best mixture was 89% Ar, 10% N2 , 1% SF6 based on the
highest increase of the voltage gradient and the least
added gas. A model has been developed to illustrate the
effects of dissociation, excitation, ionisation of gases
and their effects on the discharge column voltage gradient:
The mode of an electric discharge in Ar was
investigated using spectroscopy. The study showed that for
a glow discharge the 520.0 nm line and for an arc discharge
the 427.1 nm line were unique. These lines were used to
investigate a Glydarc electric discharge which was shown to
be a mixture of the glow and the arc discharges.
Measurements of the transition of the glow to arc in
Ar with discharge current ranging from 0.1 A to 1.0 A at
atmospheric pressure showed that at the lower value of
discharge current (O. 25 A) the spectral lines were
dominated by the near infra-red lines whereas at the higher
value of discharge current (1.0 A) the spectral lines were
included from the near infra-red to the near UV.
The Glydarc electric discharge has been studied in
still and fast air flows at atmospheric pressure over a
range of discharge currents from 100 mA to 3 A. The results
showed that the increase of the discharge voltage with
increasing discharge current was due to increase of the
discharge column length which varied with time and the air
flow rate and was not due to a positive dynamic
characteristic.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Publisher
© Qiulin YuanPublisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/Publication date
1997Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.Language
- en