Speaker
Youssef Morabit
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.3015.pdf
Quantitative insights in to the fluid interactions downstream of an
atmospheric pressure dielectric barrier plasma jet.
Y. Morabit1, J. L. Walsh1, M. I. Hasan1, R. D. Whalley2
1
Centre for plasma Microbiology, University of Liverpool, L69 3GJ, Liverpool, UK
2
School of Mechanical and Systems Engineering, Newcastle University, NE1 7RU,
Newcastle, UK
Low-temperature atmospheric pressure plasma jets are dielectric barrier discharges
generated in thin dielectric tubes. The gas flowing through the capillary, typically Helium or
Argon, is ionized, emerges into the quiescent ambient air creating a variety of reactive
chemical species. The spatial separation between the region of plasma generation and species
creation makes the plasma jet configuration unique, facilitating a stable source of short and
long lived reactive oxygen and nitrogen species (RONS) under ambient conditions.
Understanding the complex interaction between the discharge and the background gas is the
key to understanding the RONS chemistry arriving at a downstream sample.
Recently, considerable progress has been made in understanding the complex fluid
interaction at play in a plasma jet configuration. Many studies have demonstrated dramatic
changes to the structure of the flowing gas, which initiate turbulent fluctuations, both gas
heating and electrohydrodynamic forces have been cited as possible mechanisms behind
these observations [1, 2, 3].
In this investigation, a particle imaging velocimetry (PIV) was used to provide quantitative
insights in to the complex fluid interactions at the orifice of a helium plasma jet. By capturing
the velocity profile of both the flowing and background gas the impact of plasma generation
parameters on the flow structure were identified. It was observed that key plasma parameters,
such as the applied voltage, have little impact on the velocity of the flowing gas. This finding
implies that the early onset of turbulence in the plasma jet is not attributed to an increased
velocity, but is more likely a consequence of a periodic perturbation to the jet shear layer
introduced by the discharge.
[1] Robert, E. et al. Rare gas flow structuration in plasma jet experiments. Plasma Sources Science and
Technology, 23(1), 12003 (2014).
[2] Whalley, R. D., & Walsh, J. L. Turbulent jet flow generated downstream of a low temperature dielectric
barrier atmospheric pressure plasma device. Scientific Reports 6, 31756 (2016).
[3] Hasan, M. I., & Bradley, J. W. Reassessment of the body forces in a He atmospheric-pressure plasma jet: A
modelling study. Journal of Physics D: Applied Physics, 49 055203 (2016).
