Improved 3D Numerical Model for EHD Printing Processes

Electrohydrodynamic (EHD) printing provides new opportunities in a variety of applications including high-resolution printing for flexible electronics devices. Detailed numerical simulations of the EHD printing process can provide deeper insights into the dynamics of the physical phenomena involved, the latter occurring on a very short time-scale which makes them difficult to be investigated experimentally. The present study presents an improved numerical solver for the three-dimensional problem. The solver builds on the well-known OpenFOAM solver interflow enhanced by the incorporation of electrohydrodynamic effects and viscoelastic fluid behavior based on a single-mode Giesekus model. The solver, referred to as "veInterFlowEHD," has previously been validated using various simplified test cases and has so far been limited to axisymmetric configurations. Key features include adaptive mesh refinement, dynamic load balancing across processors, and mitigation of numerically-induced charge leakage. Simulation results demonstrate good agreement with experimental data, assuring the accuracy of the newly developed 3D solver. Present simulation results also demonstrate the importance of proper spatial resolution and minimization of numerical charge leakage in order to arrive at reliable results. Future research will explore additional fluid systems (relevant to specific applications) and time-varying boundary conditions, such as pulsed electric fields.