Dynamics of Gas Heating in the Afterglow of Pulsed CO2 and CO2–N2 Glow Discharges at Low Pressure
The time-dependent evolution of the energy transfer into gas heating in the afterglow of pulsed CO2 and CO2–N2 glow discharges produced in cylindrical tubes at low pressures (1–5 Torr) is theoretically investigated, by developing a self-consistent model that couples the time-dependent gas thermal balance equation with the vibrational kinetics. The modelling predictions are in good agreement with recently published experimental data on gas temperature, obtained via time-resolved in situ Fourier transform infrared spectroscopy. The cooling of the gas in the afterglow is found to be strongly dependent on the thermal conductivity and the wall temperature. It is verified that wall and volume deactivation of CO2 vibrationally excited species influences the gas heating along the afterglow, in different proportions depending on the pressure of the gas. The time-resolved contributions of each of these cooling and heating mechanisms are discussed in detail. The new results bring an additional validation of a set of mechanisms and rate coefficients for vibrationally-energy transfers previously proposed.
KeywordsCO2 plasmas Low-temperature plasma Kinetic modelling Gas temperature Gas heating mechanisms
This work was partially supported by the Portuguese FCT, under Projects UID/FIS/50010/2019 and PTDC/FIS-PLA/1420/2014 (PREMiERE), and Grant PD/BD/105884/2014 (PD-F APPLAuSE).
- 5.Capitelli M, Colonna G, Ammando GD, Pietanza LD (2017) Self-consistent time dependent vibrational and free electron kinetics for CO2 dissociation and ionization in cold plasmas. Plasma Sources Sci Technol 26:1–17Google Scholar
- 19.Klarenaar BLM, Engeln R, van den Bekerom DCM, van de Sanden MCM, Morillo-Candas AS, Guaitella O (2017) Time evolution of vibrational temperatures in a CO2 glow discharge measured with infrared absorption spectroscopy. Exp Methods Plasma Sources Sci Technol 26:1–11Google Scholar
- 26.Premathilake D, Outlaw RA, Quinlan RA, Byvik CE (2018) Oxygen generation by carbon dioxide glow discharge and separation by permeation through ultrathin silver membrans. Earth Space Sci 6:1–8Google Scholar
- 38.Chase MW (1998) NIST-JANAF thermochemical tables. J Phys Chem Ref Data 9:1–1951Google Scholar
- 40.Blauer JA, Nickerson GR (1973) A survey of vibrational relaxation rate data for processes important to CO2–N2–H2O infrared plume radiatiion Technical Report. AFRPL-TR-73-57 Ultrasystems, IncGoogle Scholar
- 42.Hirschfelder JO, Curtis CF, Bird RB (1964) Molecular theory of gases and liquids. Wiley, New YorkGoogle Scholar
- 43.Black G, Wise H, Schechter S, Sharpless RL (1974) Measurements of vibrationally exctited molecules by raman scattering. J Phys D Appl Phys 60:3526–3536Google Scholar