The effect of conductivity on the spraying of dielectric liquids

The atomisation of liquids by high electrostatic fields-usually obtained by applying high potentials to sharp electrodes-is a familiar phenomenon. Despite considerable recent research activity, there is a paucity of data relating atomised droplet size to applied potential, liquid flow rate and liquid conductivity, particularly for a multi-ligament spray. An experiment is described in which the spraying characteristics of a liquid with conductivity controlled over several orders of magnitude by adding ethanol to hexane, has been examined. The experimental data obtained are presented and discussed in terms of modern theoretical models. It is concluded that control of liquid conductivity and flow rate together with careful nozzle design offers means for the production of droplets of precise size over a wide range of liquid throughput. These techniques have application in high quality coating, low energy injection systems for chemical reaction and precise solid particle production.