https://doi.org/10.1140/epjd/e2003-00211-9
Axial variation of electron number density in thermal plasma spray jets
Laser and Plasma Technology Division,
B.A.R.C., Mumbai-400 085, India
Corresponding author: a nkjoshi@apasara.barc.ernet.in
Received:
21
July
2002
Revised:
6
January
2003
Published online:
22
July
2003
The electron number density has been measured in a plasma spray torch using Stark
broadening of H
and Ar-I (430 nm) line. A small amount of hydrogen (1% by volume in
argon gas) was introduced to study the H line profile. Axial variation of electron
number density has been determined up to a distance of 20 mm from the nozzle exit point
of spray torch. The plasma torch was operated at 5 and 10 kW power level and flow of
argon was kept at 25 liters per minute. Using the measured excitation temperature data
under same experimental conditions, the electron number density has also been calculated
using Saha equation. Comparison of electron number densities measured from Stark
broadening with those derived from excitation temperature measurements under the
assumption of local thermodynamic equilibrium (LTE) in thermal plasma jets indicate
about the deviation from LTE in thermal plasma jets. The electron number density
measurement using Stark broadening of Ar-I (430 nm) line will be particularly useful
when only argon gas is used in thermal plasma jets.
ptical (ultraviolet, visible, infrared) measurementslasma applicationslasma properties
PACS: 52.70.Kz – O / 52.77.-j – P / 52.25.-b – P
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003
