Investigation of the effects of parallel electric field on fog dissipation

Abstract Fog dissipation by charge and electric field has become a research hotspot due to its affordability and high efficiency compared with traditional technologies. However, the mechanism by which the electric field affects the temporal variation of droplet concentration is unclear. Therefore, a cylinder fog chamber with a radius of 0.15 m and a height of 1 m is established to analyze the influence of electric field on the concentration change of partially charged fog (50% of fog droplets are charged). The distribution of electric field in the fog chamber is simulated by an electrostatic model in COMSOL, and the electric field in the fog chamber is regarded as a parallel electric field. A percentage concentration α, the ratio of the real droplet concentration n, and the initial droplet concentration n 0 are introduced to describe the effects of fog dissipation. The results show that visibility can increase from 10 m to 150 m after applying the electric field. The shortest time is 12 s, which is much smaller than the natural settling time (102 s). Furthermore, α first increases, then decreases, and finally gets close to zero with electric field E regardless of the charged state (neutral or partially charged) at the beginning of applying the electric field (t = 60 s). Besides, α without charging is smaller than that with partially charging. Finally, α decreases with electric field E regardless of the charged state at the end of the applied electric field (t = 240 s). These findings can be explained by the relative strength of electrostatic force effect induced by the electric field on neutral and charged droplets and gravitational effect, which are quantified by the calculation analysis of various forces. The results can be used to guide and optimize the structure of experimental setups for outdoor fog dissipation in the future.