Qualitative gas temperature distribution in positive DC glow corona using spectral image processing in atmospheric air

Abstract

An experimental method of determining a qualitative two-dimensional image of the gas temperature in stationary atmospheric nonthermal plasma by spectral image processing was presented. In the experiment, a steady-state glow corona discharge was generated by applying a positive DC voltage to a rod-plane electrode in synthetic air. The changes in the gas temperature distribution due to the amplitude of applied voltage and the ambient gas pressure were investigated. Spectral images of a positive DC glow corona were taken using a gated ICCD camera with ultranarrow band-pass filters, corresponding to the head and tail of a N2 second positive system band (0–2). The qualitative gas temperature was obtained from the emission intensity ratio between the head and tail of the N2 second positive system band (0–2). From the results, we confirmed that the gas temperature and its distribution of a positive DC glow corona increased with increasing applied voltage. In particular, just before the sparkover voltage, a distinctly high temperature region was formed in the positive DC glow at the tip of the rod electrode. In addition, the gas temperature decreased and its distribution spread diffusely with decreasing ambient gas pressure.

Estimation of electric field distribution of Hermstein’s glow corona discharge by spectral image processing

“…T g of Hermstein's glow corona discharge was acquired from the intensity ratio between the tail and head of the N 2 second positive system band (0, 2) [SPS(0, 2)tail/SPS(0, 2)head]. 25,26) The rotation temperature of N 2 is usually equivalent to the T g under atmospheric conditions. SPS(0, 2)tail/SPS(0, 2)head was calculated for each pixel to acquire the T g distribution of Hermstein's glow corona discharge based on the previously determined relationship between SPS(0, 2)tail/SPS(0, 2)head and T g .…”

“…SPS(0, 2)tail/SPS(0, 2)head was calculated for each pixel to acquire the T g distribution of Hermstein's glow corona discharge based on the previously determined relationship between SPS(0, 2)tail/SPS(0, 2)head and T g . 25,26) This experiment was adopted to the ultra-narrow band pass filters. The center wavelength and full width at half maximum of the filter for SPS(0, 2)tail were 379.2 nm and 1.17 nm, respectively, while those for SPS(0, 2)head were 380.5 nm and 1.07 nm, respectively.…”

“…Spectral image processing can be applied to the spatial distributions of specific spectra. [22][23][24][25][26] In this study, we acquired spectral images by using an intensified chargecoupled device (ICCD) camera with ultra-narrow band pass filters. This method is advantageous for revealing the fine details of distributions at which discharge occurs, and the measurement time is shorter than for OES.…”

Revisiting the theory of positive glow corona with a comprehensive kinetic scheme

“…Positive glow corona is a typical low-temperature nonequilibrium discharge [24]. The gas temperature and the vibration temperature of nitrogen molecule in the related chemical reaction rates are set to constants, namely T 0 = 300 K, T v = 4000 K [23].…”