Effect of Electrical Conductivity on Atomization Characteristics of Electrospray

This study experimentally investigated various spraying modes in electrospraying, an atomization method in which a high voltage is applied to the auxiliary device at the tip of the nozzle. The spraying modes were generated depending on the experimental parameters (voltage, current, and flow rate) and characteristics of two test solutions (S and C), which were a mixture of ethanol, glycerol, citric acid, and water. Solution C had a higher electrical conductivity than solution S. Eleven spray modes were identified in the study. From a comparison of the spray modes, a maximum Sauter mean diameter (SMD) of the cone jet of solution S was 1.7 times that of solution S. The standard deviation of SMD for the unstable, rotating-jet, and pulsed-jet modes were more than two times that for the cone-jet mode. With an increase in flow rate in the cone jet, the SMD and SMD standard deviation of solution C increased linearly, and the SMD value of solution C was ~5% lower than that of solution B. The SMD standard deviations for both S and C solutions were small at low flow rates, and the standard deviation for solution C (with high conductivity) was smaller than that of solution S. For a given SMD, the current associated with solution C was higher than that associated with solution S. The study presented the comprehensive data for SMD, SMD standard deviation, and current in an electrospray system for the two fluids of different electrical conductivities under various experimental conditions.