Comparative measurements on thermal plasma jet characteristics in atmospheric and low pressure plasma sprayings

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · IEEE Transactions on Plasma Science

OSTI ID:137068

Kim, H J; Hong, S H ^[1]

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1. Seoul National Univ. (Korea, Republic of). Dept. of Nuclear Engineering

The ion and electron temperature and plasma flow velocities are measured and compared between atmospheric and low pressure plasma spraying systems. The measurements of ion temperature for two systems are carried out by an optical emission spectroscopy which uses the relative emissivities of isolated Ar 1 emission lines. The electron density and temperature are measured by a Langmuir probe rotating across the plasma jets. The ion saturation currents collected by a Mach probe at two orientations, perpendicular and parallel to the plasma jet, determine the flow velocity. The spatial distributions of electron density, plasma flow velocity, and the associated shock activity in thermal plasma jets are discussed in conjunction with their direct dependency upon the ambient pressures as well as the torch powers. Measurements on temperatures and velocity profiles of thermal plasma jets reveal the general features of the LPPS jet characteristics, i.e., higher velocity flow with lower temperature, longer heating zone of expanded flame, and more extended accelerating zone compared with those of the APS jets. The shock activity clearly exists in the form of standing shock waves in the plasma jet of LPPS in view of flow compression and abrupt velocity drop which are appeared in the results of measurements on the variations of electron density and flow velocity along the plasma jet. In the center of the plasma jet of APS, the electron density is high enough to reach the LTE criterion, and the difference between ion and electron temperatures becomes insignificant as the torch input power increases.

• OSTI ID: 137068
• Journal Information: IEEE Transactions on Plasma Science, Journal Name: IEEE Transactions on Plasma Science Journal Issue: 5 Vol. 23; ISSN ITPSBD; ISSN 0093-3813
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ARGON IONS
COMPARATIVE EVALUATIONS
MATERIALS
PLASMA ARC SPRAYING
PLASMA DIAGNOSTICS
PLASMA GUNS
PLASMA JETS
PRESSURE DEPENDENCE