Dimensional analysis for jet diameter prediction in electrospray: Integrating electric field and process parameters

In electrospray, understanding the formation of the Taylor cone and liquid jet is required for predicting the droplet size during liquid breakup. Existing models have not assessed the effect of the electric field and its interaction with process parameters and material properties, which is particularly relevant when needle-electrode experimental setups vary. This study proposes a mathematical model and experimentally validates the prediction of jet diameter through dimensional analysis, clarifying the strong relationship between dependent and independent dimensionless groups, and observing interactions among process parameters such as wetting diameter, flow, and electric field, reflecting the effects of applied voltage and needle-electrode arrangement, as well as material properties such as surface tension, electrical conductivity, dielectric constant, and viscosity. The derived mathematical expression for jet diameter prediction demonstrated an average error of 5% when tested with ethylene glycol, effectively addressing the influence of electric field and process parameters on the proposed scaling laws.