UC Davis

In recent years, electrohydrodynamic flow applications have gained popularity due to their ability to control flow characteristics by subjecting them to an electric field. A prime example of this is electrospray thruster for electric propulsion applications. The useful ability to carefully control the operating regimes of an electrospray device with properties such as flow rate and voltage has proved beneficial for the small satellite industry.

With the use of the open-source software OpenFOAM, a numerical solver capable of successfully capturing multiphase electrohydrodynamic phenomena has been implemented. The solver takes advantage of the existing OpenFOAM infrastructure to couple the dynamic interplay between electric fields and fluid dynamic. The numerical simulations employ sophisticated algorithms to elucidate the intricate behavior of charged droplets, shedding light on key parameters such as cone-jet length, jet diameter, and droplet diameter. Additionally, a selection of validation test cases is showcased to assess the solver’s accuracy and validity. In this work, electrospray simulations with varying liquid flow rate and applied voltages are presented. With heptane as the working fluid, results show that the solver produces comparable results to those simulated by competing numerical approaches. Moreover, the results from these simulations demonstrate satisfactory agreement with both experimental data and analytical solutions. Qualitatively, the simulations performed in this study accurately show the cone-jet formation and breakup of droplets normally seen in experimental works. By competently simulating electrospray phenomena in the steady cone-jet regime, this research contributes valuable insights that can inform the design and optimization of electrospray systems in various applications, spanning from drug delivery to electric propulsion.