Dynamic study of streamer interaction with fluidized particles in a plasma fluidized-bed system

Exploration of the interaction dynamics between plasma and fluidized particles in a plasma fluidized-bed holds practical importance for elucidating the mechanism of plasma treatment of powders. In this study, we employed a 2D fluid model to investigate the effects of particle diameter, dielectric constant, and inter-particle spacing, with the primary aim of simulating the specific consequences of variations in particle size, material type, and gas-to-powder ratio (GPR) on the powder processing effect. The results indicate that particles with diameters below 300 μm exert less impact on streamer propagation, enabling complete plasma wrapping of the particle surface (100%). However, particles with a diameter of 400 μm induce branching, leading to a reduction in the treatment area to 46%. These observations imply a critical particle size range of 300–400 μm for achieving effective plasma treatment of the fluidized particles. Plasma treatment ensures a comprehensive surface coverage on particles with low dielectric constants (εr<4), while particles possessing a higher dielectric constant (εr>8) exhibit a diminished plasma-treated surface area (80%), meaning that longer treatment durations for high dielectric constant materials may be required to achieve a comparable treatment effect. Furthermore, as the inter-particle spacing increases from 10 to 500 μm, the plasma-treated surface area undergoes an initial increment, followed by a subsequent reduction. Notably, at 300 μm spacing, the streamer channel displays a root-like branching pattern, leading to a substantial expansion of the plasma-treated surface area. This indicates that an optimal GPR in the fluidized-bed system can enhance the powder treatment effect.