Effect of gas flow on the nanoparticles transport in dusty acetylene plasmas

Abstract

This article presents simulation results on the effects of neutral gas flow for nanoparticle transport in atmospheric-pressure, radio-frequency, capacitively-coupled, and acetylene discharge. The acetylene gas is set to flow into the chamber from the upper showerhead electrode. The internal energy of the gas medium therein is transferred into kinetic energy so the gas advection can be triggered. This is represented by the pressure volume work term of the gas energy converse equation. The gas advection leads to the gas temperature sink at the gas inlet, hence a large gas temperature gradient is formed. The thermophoresis relies on the gas temperature gradient, and causes the profile of nanoparticle density to vary from a double-peak structure to a single-peak one. The gas advection influences the properties of electron density and temperature as well and causes the drift-ambipolar mode profile of electron density asymmetric. In the bulk region, i.e. away from the inlet, the gas advection is more like one isovolumetric compression, which slightly increases the temperature of the gas medium at consuming its kinetic energy.