Analytical – FE simulation of a multi-jet electrospinning process to predict material flow

Electrospinning is a technology used for the production of nanometric fibers starting from a solution of material spun by a needle in an electrostatic field. The jet starts from a needle and its diameter is reduced thanks to the instability of the process that stretch the fiber till nanometric dimension. The productivity of a single needle is very low so multiple needles facing the same collector is the simplest and most used apparatus to achieve an adequate productivity. However jets so produced repel each other making their path diverge from the axis of the needles; this effect can be corrected introducing a system of electrostatic lenses. As soon as the diameter of the filament is commonly tens of nanometers the FE simulation of the process in the work area is nearly impossible due to the very large number of elements required. This paper presents an hybrid approach that couple together an analytical analysis with an FE approach in order to reduce the computational time. The developed model is able to predict the divergence of electrospun multi-jets with and without the corrective effect of an electrostatic lens. The developed approach has been validated thanks to laboratory experimental tests that has proven its accuracy. A simulated test campaign using the Design of Experiment approach has been performed to create a mathematical model to predict the deflection of the filaments with different process parameters.