In order to develop a filtration device for sub-micron particles, we need to produce electrically charged water droplets which role is to collect negative sub-micron pollutant particles by electric coagulation. The droplets are produced by Electro-HydroDynamic Pulverisation (EHDP) in the cone-jet-glow mode, in air, at atmospheric pressure. We describe a number of electric and granulometric experiments to define some of the different modes of the water sprays according to the liquid properties (conductivity and flow rate) and according to the voltage, i.e. to the electrical field near the liquid related to electrical discharge phenomena (continuous or impulse). We found that:
- a continuous corona discharge current (glow) allows the EHDP of water in, what we decided to call the « cone-jet-glow » mode, leading to the production of unimodal sprays.
- a strong impulse discharge current (streamer) disturbs the continuous pulverisation in the « cone-jet-glow » mode to, what we decided to call, the « electric-dripping » mode. The disturbance is due to the impulse electric discharges (streamer) in the gas around the liquid mode, leading to the production of polymodal sprays.