A framework for studying CO₂ microwave plasmas

This thesis presents a comprehensive framework for the study of CO₂ microwave plasmas, with a specific emphasis on determining gas temperature. The research aims to develop and refine tools for characterizing low-temperature plasmas, aligning with the step-by-step validation framework employed at N-PRIME.

The primary objectives of this work include developing frameworks focused on gas temperature characterization through modeling and the analysis of optical emission spectra, integrating zero-dimensional (0D) kinetic modeling with fluid descriptions to simulate experimental data related to gas temperature and CO₂ conversion, while analyzing the rotational spectra of C₂ and N₂⁺ bands by creating dedicated scripts for data extraction and conducting comparisons with existing simulation tools.

The thesis investigates various microwave plasma systems, including an atmospheric helium axial injection torch (AIT) used for validating fluid modeling. It also examines an atmospheric CO₂ coaxial plasma torch and an atmospheric coaxial N₂ reactor, both of which are analyzed through optical emission spectroscopy (OES) to determine rotational and vibrational temperatures. Additionally, the study explores low-pressure microwave CO₂ discharges in both the active and post-discharge regions to assess the combined model's capability to accurately represent spatial temperature distribution.

This research successfully establishes the proposed framework, demonstrating strong agreement with experimental data. The findings confirm the effectiveness of the developed methodologies in accurately characterizing gas temperatures and enhancing the understanding of microwave plasma behavior.