The presented Thesis deals on the nitrogen-hydrogen DC post-discharge observations by optical emission spectroscopy. The plasma was generated in Pyrex tube in flowing regime at pressure of 1 kPa at discharge current of 100 mA. The optical emission spectra were recovered at discharge times up to 50 ms in nitrogen containing 0 – 92 % of hydrogen; the gas mixture volume, i.e. the gas speed in the system was conserved for all mixtures. The experiments were carried out at two reactor wall temperatures at the spectra collecting point – at ambient temperature and at the wall temperature of liquid nitrogen (temperature in plasma was about 150 K). The nitrogen first and second positive and first negative spectral systems were identified in the spectra, the hydrogen atomic Balmer series lines were recorded, too. No molecular hydrogen emission was determined during the post-discharge. Some non-identified bands (but with high probability bands of nitrogen Herman infrared system) at 690 and 780 nm were detected, too, mainly at low temperature. The intensities of all determined radiating species decreased exponentially or more than exponentially with the decay time. The experimental data showed strong quenching of all nitrogen radiative states even at very a few percent hydrogen additions. The shape of the selected intensity dependencies on both hydrogen concentration, and the decay time are nearly the same for N2(C) and N2+(B) states, dependencies for N2(B) levels differs of them. The hydrogen line emission was nearly independent on the hydrogen content in the gas mixture up to about 50%, at highest hydrogen concentrations it slightly increased. The results obtained at the decreased wall temperature were very similar, only intensities of all nitrogen spectra increased by the factor about 3, the intensities of levels populated by the recombination of nitrogen atoms increased by factor about five. The atomic hydrogen alpha line (at 656 nm) was the most sensitive on temperature decrease; its intensity increased over one order in whole observed time interval. The obtained results will be confronted with numeric model of kinetic processes in the near future. After that, the specific conditions applicable for the technological applications of nitrogen-hydrogen gas mixtures under post-discharge conditions will be proposed.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:216805 |
| Date | January 2011 |
| Creators | Zedníčková, Petra |
| Contributors | Mazánková, Věra, Krčma, František |
| Publisher | Vysoké učení technické v Brně. Fakulta chemická |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/masterThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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