Effect of the Vortex Formed by the Electrohydrodynamic Flow on the Motion of Particles in a Needle-plate Electrostatic Precipitator

This work numerically simulates the effect of the electrodynamic (EHD) flow on particle motion in a single-needle-plate electrode configuration. The interaction between the primary-secondary flow, and the trajectory of particles in a 3D environment is analyzed. In addition, the effects of the needle-shaped discharge electrode structure on the electric field and the flow field distribution are explored. The results show that the sharp tip of the needle emits a high-intensity discharge that generates a nearby high-speed ionic wind, which can reach a velocity of 9.028 m s–1 at an applied voltage and an inlet velocity of –60 kV and 1 m s–1, respectively. This ionic wind near the needle tip potentially increases the migration speed of particles. Moreover, 90% of the 1 µm particles penetrate the surface of the outlet, indicating that the EHD flow negatively affects the capture of fine particles. The relationships between the injection position, the residence time, and the escape velocity of the particles further confirm that the secondary flow significantly inhibits fine-particle capture. These findings can be applied to optimize an electrode design that efficiently uses high-speed ionic wind to capture particles, including the fine fraction.