Λεπτομέρειες βιβλιογραφικής εγγραφής
| Τίτλος: |
Dynamics of iron oxide particle injection in a microwave plasma torch. |
| Συγγραφείς: |
Thiel, J1 (AUTHOR) jonas.thiel-n4w@rub.de, Kulik, L1 (AUTHOR), Böke, M1 (AUTHOR), Keudell, A von1 (AUTHOR) |
| Πηγή: |
Journal of Physics D: Applied Physics. 2026, Vol. 59 Issue 33, p1-25. 25p. |
| Θεματικοί όροι: |
*Plasma torch, *Particle dynamics analysis, *Plasma flow, *Ferric oxide, *Particle analysis, *Chemical reduction, *Plasma dynamics |
| Περίληψη: |
The hydrogen-based reduction of iron oxides in atmospheric plasmas is a promising approach to replace conventional methods that produce greenhouse gases. The in-flight reduction of hematite powder ( Fe 2 O 3 ) in an argon-hydrogen microwave plasma torch (MPT) confined in a quartz tube is studied. The MPT system utilizes an integrated particle feeder and provides extended optical access to the microwave resonator and plasma effluent. The particle trajectories in the MPT can be controlled by adjusting the gas-flow scenario, balancing an axial versus a swirl flow, which is used to shield the quartz tube from the hot central plasma, reaching more than 4200 K. Two CMOS (Complementary Metal-Oxide-Semiconductor) cameras were employed to track particle motion in three dimensions or to measure particle surface temperatures through two-color pyrometry. This is complemented by a fluid simulation in Ansys Fluent to model particle trajectories, gas velocities, temperature profiles of the plasma effluent, and heat transfer to particles. Space-resolved measurements of particle dynamics across various gas-flow scenarios revealed a strong dependence on the ratio between axial particle injection velocities and the swirl flow. Particles with higher axial injection velocities reached higher temperatures and velocities, experienced shorter cooling times, making them observable at greater distances from the resonator. In scenarios with increased swirl gas flow, the particles exhibited predominantly swirled trajectories. This resulted in lower axial velocities, with motion primarily within the outer perimeter of the confining quartz tube. X-ray diffraction measurements of the collected plasma-treated particles showed a more efficient reduction for particles from swirl trajectories compared to axial trajectories: on axial trajectories, the acquired particle surface temperatures are very high, reaching over 2500 K, leading also to evaporation rather than to reduction only; on swirl trajectories, the acquired temperatures of the particles stay moderate and their residence time is longer, which leads to a more optimal reduction. [ABSTRACT FROM AUTHOR] |
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