Simulations of plasma-assisted combustion flames in coaxial microwave reactors

The atmospheric coaxial direct-coupled microwave torch configuration offers a convenient experimental format for validating multiphysics simulations of plasma-assisted combustion (PAC). The optical accessibility of this configuration allows for the application of various diagnostics to the PAC flame such as planar laser-induced fluorescence (PLIF) to determine quantitative two-dimensional density distributions of radicals (e.g. OH, CH, NO), Rayleigh scattering thermometry (RST) for temperature profiles, and particle image velocimetry (PIV) to characterize the flame flow-field, as well as assessment of plasma nonequilibrium effects via probe measurements and spectroscopic emission measurements. Furthermore, the flexible system enables premixed and non-premixed configurations to be addressed, and the most recent modifications have added tangential swirling flows. Here, recent changes to the experimental apparatus to combine PAC with swirl-stabilization are overviewed, and initial PLIF measurements of OH radicals are presented, as well as measurements of flame stability limits and acoustics. Cold flow simulations of the swirl-stabilized chamber using BLAZE Multiphysics simulation suite are presented.