Numerically studying the effects of discharge conditions on plasma-wall transition region of magnetized methane plasma

Abstract

By combining the global model for rf plasma discharge and the multi-component fluid model for the plasma-wall transition region, the effects of discharge conditions and reactor characteristics on the sheath and pre-sheaths of magnetized methane plasma are studied numerically. The global model determines the density of all species considered in the model as well as electron temperature for the given discharge conditions and reactor size, while the multi-component fluid model uses the parameters calculated by the global model to specify the distribution of potential and species densities in the transition region for a given magnetic field intensity and orientation. The results show that the transition region characteristics are affected by changing the discharge conditions and reactor size. As the sheath and the magnetized pre-sheath become narrower by increasing the input power and background gas pressure, their thicknesses increase with the increase in the electrode radius. Also, they become narrower by increasing the magnetic field intensity and the angle between the electric and magnetic fields.

The Effects of Pulse Shape on the Selectivity and Production Rate in Non-oxidative Coupling of Methane by a Micro-DBD Reactor

“…A global model that considers more reactions and species has been developed and its results was used to select these main reactions and species, they play main role in underlying reaction pathways of DBD methane plasma. The global model used here is an atmospheric-pressure version of the model presented in reference [39], which deals with low-pressure plasma. In this model, the balance equations for heavy species and electron energy equation as well as gas temperature equation are solved with considering species loss on reactor surface.…”

Study of plasma parameters and gas heating in the voltage range of nondischarge to full‐discharge in a methane‐fed dielectric barrier discharge

“…Also, the gas temperature must initially be fixed. All cross-section data and reaction considered here for methane plasma are the same as data used in our previous works [34,35] . Determining the C b is straightforward and it is given by:…”

Plasma-enhanced catalysis for the upgrading of methane: a review of modelling and simulation methods

“…However, these zero-dimensional codes evidently lack the capability of describing the spatial variation of a discharge. Therefore, plasma phenomena like space-charge sheaths 45 , streamer heads, and the filamentary nature of some dielectric barrier discharges, are not possible to be taken into account. The validity of the conclusions based on zero-dimensional modelling of a reactor are, generally, restricted to findings of qualitative trends; except potentially in the case of a spatially homogenous plasma bulk, as in some RF discharges and the column of large DC glows.…”

“…The latter can include charged species (anions, cations, and electrons), free radicals, stable and metastable molecules, excited states, all reacting through numerous processes. Using this type of detailed schemes has been employed for different gas discharges and different methane upgrading applications, ranging from oxidative [28][29][30][31][32][33][34][35] to non-oxidative 5,[36][37][38][39][40][41][42][43][44][45][46] and methane conversion in the presence of nitrogen. [47][48][49][50] Besides upgrading, methane plasma kinetic schemes have been employed for other purposes too, with the oldest occurrences being related to plasma-enhanced chemical vapour deposition, [51][52][53][54][55][56][57][58][59][60][61][62][63][64] and combustion and pyrolysis studies.…”