Two-dimensional mapping of absolute OH densities in an atmospheric pressure plasma effluent via planar laser-induced fluorescence: effects of He/H 2 O and He/O 2 mixtures in N 2 and air, with and without solid targets
Year: 2025
Type: article
Abstract: Planar laser-induced fluorescence (LIF) was employed to measure the absolute density of hydroxyl radicals (OH) in the effluent of the COST Reference Microplasma Jet for two feed gas mixtures: He/H 2 O and He/O 2 . Experiments were conducted with the effluent propagating into air and N 2 environments. For the He/H 2 O case, measurements were also performed with the effluent impinging on a solid target at varying distances from the jet nozzle. Calibration of the OH-LIF signal from the COST-Jet was achieved by comparing it to a reference signal generated by the photofragmentation of H 2 O 2 . Results demonstrated that OH densities were sustained longer when the effluent propagates in a nitrogen environment compared to air, particularly with water added to the feed gas. The broader OH distribution in N 2 suggests slower consumption due to the absence of oxygen, which accelerates OH depletion in air via reactions involving O 2 and HO 2 . Even when water was not added to the feed, as in the He/O 2 case, appreciable OH densities were observed, due to gas impurities and reactive species interactions with atmospheric humidity, forming reaction fronts that delineate the gas flow. Two-dimensional fluid dynamics simulations elucidated the influence of atmospheric gas entrainment and solid targets on the OH distribution. Experimental trends were further compared with a zero-dimensional chemistry model to explore OH production and consumption mechanisms in air and nitrogen environments.
Authors: María J Herrera Quesada, Sebastian Pfaff, Jordyn Polito, Grayson Gall, Mark J Kushner, Jonathan H Frank, Katharina Stapelmann
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,325
Funders: National Science Foundation, U.S. Department of Energy, Directorate for Engineering, Office of Science, National Nuclear Security Administration, Division of Physics, Division of Chemical, Bioengineering, Environmental, and Transport Systems, Fusion Energy Sciences, Sandia National Laboratories
Awards: G11630931, G129537217, G2214935549, Collaborative Research: ECLIPSE: Exploring Non-Oxidative Reaction Pathways of Atmospheric Pressure Plasmas, G280414146, G2909835193, G3644859417, G4114058267, G413247060, G4771968897, G4903105778, G5339743583, G5373082618, CENTER FOR LOW TEMPERATURE PLASMA INTERACTIONS WITH COMPLEX INTERFACES, G623394839, G6338696783, CENTER FOR LOW TEMPERATURE PLASMA INTERACTIONS WITH COMPLEX INTERFACES, G7846141903, Collaborative Research: ECO-CBET: Methane Conversion by Merging Atmospheric Plasma with Transition-Metal Catalysis, G855168022, G8922552302
OpenAlex ID: W4408515950