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

Abstract

In conventional chemical oxygen-iodine lasers (COIL) the 1.315μm transition in atomic iodine is pumped by a sequence of reactions of I2 and I with O2(Δ1) which is generated using liquid chemistry. Ongoing studies are investigating means to produce the O2(Δ1) precursor with an electric discharge (eCOIL) 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 O2. In previous investigations, the scaling of production of O2(Δ1) was investigated using global-kinetics and one-dimensional (1D) models. It was found that the production of O2(Δ1) scaled linearly with energy deposition for moderate loadings (a few eV∕O2 molecule). 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 O2(Δ1). We found that O2(Δ1) production generally does scale linearly with energy loading, however, the saturation of O2(Δ1) 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 O2(Δ1) production.