Numerical Analysis of Charged Particles Transport in Air Based on Vortex Rings

Charged particles are widely used in the fields of defogging, haze removal and artificial rainfall. A novel transport strategy of charged particles based on the vortex rings is presented in this paper, to expand the effective action region and enhance the effect of charged particles. Transport distance and transport velocity (TV) of charged particles are the crucial two evaluation indexes. For the vortex rings generated by a piston-cylinder device, the transport velocity is closely related to Reynolds number and formation time. Based on the k-ω turbulence model, this paper verifies the relationship between vortex ring circulation, transport velocity and Formation Number in air by finite element methods, and studies the influence on the formation of vortex rings of an insulating bell mouth placed at the outlet of cylinder. The simulation results show that the Formation Number of vortex rings in the air is 4.0 ~ 5.0, and the growth rate of transport velocity of vortex ring slows down when the formation time is larger than Formation Number. The study also indicates that the bell mouth has little effect on the velocity of the vortex ring, when the bell mouth angle is greater than 45° and the length of generatrix is between 0.2 m and 1.0 m. Therefore, the research results can provide a reference for the design and optimization of a vortex ring generator for transporting charged particles to a certain target area.