Understanding electrohydrodynamic (EHD) performance of corona discharge via particle image velocimetry (PIV)

Electrohydrodynamic (EHD) pumping through corona discharge has found many interesting applications, as it does not require any mechanical moving parts. However, understanding the EHD performance of the corona discharge is crucial for a controllable manipulation of the fluids. This study investigates the pumping performance of an in-house built corona discharge setup for inducing circular motions in the fluids. Silicone oils of different kinematic viscosities are used as the EHD fluid. The EHD performance/fluid characteristics are studied experimentally using particle image velocimetry (PIV) under different DC corona voltages and their results are verified using the continuity equation. Additionally, an analytical model is derived using the Navier–Stokes equations. A clear scaling effect of the corona voltage is seen for the EHD fluid. The EHD fluid exhibits higher velocities at high corona voltages with low perturbation frequency ( < 3 Hz) which is attributed to a sloshing motion in the fluid. This naturally occurring sloshing (out-of-plane) motion can be utilized when mixing is desired in the fluid. The results of this study can be used for contact-less and controllable manipulation of dielectric fluids (i.e., silicone oils) for potential applications in emulsion formation and separation. Graphical abstract