Numerical analysis of the NO and O generation mechanism in a needle-type plasma jet

Abstract

In this paper we study two cold atmospheric pressure plasma jets, operating in Ar + 2% air, with a different electrode geometry but with the same power dissipated in the plasma. The density profiles of the biomedically active NO and O species throughout the plasma jet, previously obtained by laser diagnostics, are calculated by means of a zero-dimensional semi-empirical reaction kinetics model. A good agreement between the calculated and measured data is demonstrated. Furthermore, the most probable spatial power distribution in an RF driven plasma jet is obtained for the first time by comparing measured and calculated species density profiles. This was possible due to the strong effect of the power distribution on the NO and O density profiles. In addition the dominant reaction pathways for both the NO and the O species are identified. The model allows us to obtain key information on the reactive species production inside the jet, which is difficult to access by laser diagnostics in a coaxial geometry. Finally, we demonstrate that water impurities in the order of 100 ppm in the gas feed can have a significant effect on the spatial distribution of the NO and O density.

Identification of the biologically active liquid chemistry induced by a nonthermal atmospheric pressure plasma jet

“…The model has as input experimentally obtained gas temperature profiles, power distribution derived from emission profiles as described in detail in Ref. 27 and a separately calculated flow field which includes air admixing in the core jet.…”

“…The modeling results have been compared with in situ measurements of NO, O, and O 3 with excellent agreement. 27 Note that the results are obtained for a free jet and local disturbances of the flow by the solution have not been considered. The modeling outcomes should thus be seen as a semiquantitative representation of the actual measurement conditions.…”

“…The model calculations for the Ar/O 2 and Ar/air RF plasma have been compared with gas phase species density measurements. 23,27 The plasma conditions are the same as used in Fig. 8; however, the calculations are made for a free jet without the disturbance of the flow field by the liquid.…”

Physical Parameters and Chemical Composition of a Nitrogen DC Discharge with Water Cathode

“…The integration of J ee gives zero. The relations (8)(9)(10)(11)(12) allow calculating the energy fraction inputted to every process, d, as the ratio of power density of appropriate process to total power density. Also, it allows checking the accuracy of EEDF calculations.…”

“…Simulation of the NO and O formation-loss mechanism in the RF atmospheric pressure needle-type plasma jet (Ar ? 2 % of air) was carried out in study [11]. For the model verification, the concentrations of NO molecules and O atoms, measured experimentally were used.…”