Out-scaling electrohydrodynamic atomization systems for the production of well-defined droplets

Industrial use of single-nozzle electrohydrodynamic atomization for producing aerosol particles of uniform size is limited by the small throughput of the method. To increase it, out-scaling by means of multiple nozzles is inevitable. We designed and tested a multi-nozzle system with a circular symmetry that provides a uniform flow rate and the same electric field intensity to all nozzles. Stability of particle production from multi-nozzle electrospray systems strongly depends on the precision of the liquid feeding system that typically requires high-cost pumps. A constant-head feeding system is a cost-effective alternative that can deliver the same performance. In order to describe the relation between flow rate and particle size in the constant-head operating mode, we developed a semi-empirical model that predicts the flow rate through the system. This model can be used with the conventional scaling law for predicting the diameter of the produced droplets.