Optical diagnostics for determining gas temperature of reactive microdischarges in a methane-fed dielectric barrier discharge

Abstract

The gas temperature of reactive microdischarges has been extensively investigated in a methane-fed dielectric barrier discharge (DBD) configured by a two parallel plate reactor with 0.5 mm gap spacing. Emission spectroscopy of the rotational bands of CH(2Δ→2Π) coupled with heat transfer experiments have been employed for this purpose. Stationary and space-averaged gas temperature between the discharge gap was estimated from the heat transfer experiment; thus heat capacity and enthalpy gained by the feed gas stream resulted in a ≈20 K temperature increase. The rotational temperature showed fairly good sensitivity to the inlet gas temperature variation in the range 370-670 K. However, the local gas temperature increase inside the microdischarges represented an additional 100 K above the average gas temperature, indicating one order of magnitude higher value than the theoretically expected gas temperature increase (5-10 K) for a single microdischarge. High-frequency operation (80 kHz) is responsible for memory effect, thus such a high gas temperature increase was the result of multiple microdischarges rather than a single one.

Alkane Activation at Ambient Temperatures: Unusual Selectivities, CC, CH Bond Scission versus CC Bond Coupling

“…This is not enough to resolve the individual rotational lines of the Q, R and P branches of the CH band. [24] Thus, rotational temperature, which reflects the gas temperature inside the filamentary discharge, was predicted comparing the CH band shown in Figure 1 with those in the spectra simulated as a function of the rotational temperature using LIFBASE software. [25] Spectrometer resolution was the only input used for the software.…”

An in-Depth Investigation of Toluene Decomposition with a Glass Beads-Packed Bed Dielectric Barrier Discharge Reactor

“…[30][31][32] This temperature is determined by analysis of the rotational structure of a nitrogen molecular band in the second positive system, namely the 0-0 vibrational band of N 2 (C 3 Π u − B 3 Π g ) emission at a wavelength of 337.1 nm.…”

Plasma diagnostics in plasma processing for nanotechnology and nanolevel chemistry

“…According to their definition, the APG is spatially uniform, and in this respect, it is different from the typical, i.e. streamer-like DBD that is a group of streamers of micrometer order [6]. In order to obtain APG instead of the typical DBD, it is already found that Penning ionization or cumulative ionization of ions should be the essential process for ionization.…”

“…In order to elucidate the difference in the gas temperature distribution between the electrodes, they carried out optical emission spectroscopy (OES) measurement for the electronic transition (A 2 D-X 2 P, v 0 Zv 00 Z0) of CH radical, and evaluated the rotational temperature, which gives an approximate value of the gas temperature of the plasma due to the short relaxation time of rotational and translational motion [6]. They discussed the precise value of average increase in the gas temperature of the plasma [7].…”