Multi-parametric study of sizes of dielectric barrier discharge setup and its effects on engineering of low temperature plasma jets

N.Jomaa, M. Yousfi[1], O. Eichwald, N.Merbahi
Page No. 12-29

This work is devoted to the optimization of a classical setup generating a low temperature plasma
jet launched in open air by using helium flow carrier gas through a glass tube. The dielectric
barrier discharge setup uses a tube wrapped by two thin cylindrical external electrodes powered by
a mono-polar pulsed high voltage supply. The optimization is based on a multi-parameter study
covering a wide range of the tube and electrode sizes and also the dielectric permittivity of the tube.
The aim is to analyze individually the effect of each of these tube parameters on the magnitude of
the geometric downstream electric field which is directly correlated to the efficiency of the
dynamics of the generated ionization waves or “plasma bullets”. Such correlations are shown by
using fluid modeling of plasma jet dynamics and experimental measurements of discharge current
and plasma jet length. Two distinct configurations of the plasma jet setup have been considered: a
standard configuration and an experimental optimized one. The optimization of plasma jet
characteristics has shown that for a fixed high voltage magnitude (5kV), the optimal jet length is
reached for the lowest dielectric permittivity, the smallest downstream electrode width, the largest
upstream electrode width, the thinnest electrode thickness, the smallest inter-electrode distance, the
thinnest tube thickness and the smallest tube diameter. This allows us to suggest a theoretical
optimal configuration that gives a maximum value of downstream electric field about 5 times higher
than the standard case. This theoretical optimal configuration enables to design electric power
supply using voltage about 5 times lower (1 kV) than the standard voltage (5kV)to generate the
same low temperature plasma jet.