O 2 ( Δ 1 ) production in flowing He∕O2 plasmas. II. Two-dimensional modeling

Abstract

In conventional chemical oxygen-iodine lasers ͑COIL͒ the 1.315 m transition in atomic iodine is pumped by a sequence of reactions of I 2 and I with O 2 ͑ 1 ⌬͒ which is generated using liquid chemistry. Ongoing studies are investigating means to produce the O 2 ͑ 1 ⌬͒ precursor with an electric discharge ͑eCOIL͒ to enable a totally gas phase system. Due to the thermodynamic and power loading requirements, the plasma in eCOIL systems is sustained in a flow of a rare-gas diluent and the O 2 . In previous investigations, the scaling of production of O 2 ͑ 1 ⌬͒ was investigated using global-kinetics and one-dimensional ͑1D͒ models. It was found that the production of O 2 ͑ 1 ⌬͒ scaled linearly with energy deposition for moderate loadings ͑a few eV/ O 2 molecule͒. In this paper, these previous investigations are extended to two-dimensions using a plasma hydrodynamics model. The goal of this investigation is to determine if multidimensional considerations affect energy scalings for production of O 2 ͑ 1 ⌬͒. We found that O 2 ͑ 1 ⌬͒ production generally does scale linearly with energy loading, however, the saturation of O 2 ͑ 1 ⌬͒ production occurs at lower-energy loadings than predicted with global and 1D models. This trend is a result of the more accurately depicted and more localized energy deposition afforded by the two-dimensional model, and emphasizes the need for volumetrically uniform power deposition to optimize O 2 ͑ 1 ⌬͒ production.

Continuous processing of polymers in repetitively pulsed atmospheric pressure discharges with moving surfaces and gas flow

“…The velocity flow field for the neutral gas, which is treated as a single fluid, is calculated using a newly developed incompressible flow option within the fluid dynamics model described in [25]. This option is implemented using an artificial compressibility [26,27] technique in which the momentum equation is solved with a pseudo-continuity equation having pressure p acting as a relaxation parameter.…”

Pressure scaling of an electro-discharge singlet oxygen generator (ED SOG)

“…However the energy efficiency of the O 2 (a 1 g ) production drops to ∼10-12% because the electron energy starts to dissipate into other channels, mostly in O 2 dissociation. Nevertheless the highest O 2 (a 1 g ) yields were experimentally obtained just in rf discharges [1,[8][9][10][11][12][13][14][15][16][17]. It stimulated us in the experimental and theoretical study of rf discharges to obtain the highest O 2 (a 1 g ) yield at an increased oxygen pressure [3, 9-11, 15, 16].…”

Production of O2(Δ1) in flowing plasmas using spiker-sustainer excitation

“…The long lifetime of O 2 ͑ 1 ⌬͒ ͑60 min͒ and robustness against quenching enables transport over long distances to the laser cavity. [10][11][12][13][14][15][16][17][18][19][20][21][22] Recently, positive gain was reported in atomic iodine resulting from electric discharge produced O 2 ͑ 1 ⌬͒, 23,24 followed by laser demonstrations. 8,9 Recent and ongoing investigations have shown that substantial yields of O 2 ͑ 1 ⌬͒ can be generated by an appropriately tailored electric discharge, typically in mixtures with rare gas diluents such as He.…”