Mechanism of charge injection-based electrohydrodynamic pump with interdigitated electrodes

The mechanisms of a charge injection-induced electrohydrodynamic pump using the lattice Boltzmann method are numerically investigated in this paper. The pump is composed of a dielectric liquid layer and two substrate layers with embedded electrodes. There are three possible flow modes found, which are associated with the generation of local convective rolls for different electrode arrangements, namely, modes associated with one and two vortices and an irrotational mode. For different flow modes, results are presented for both the transient development of the flow field and the steady-state total flow rate and pressure. A distinct four-state transition can be observed in the temporal record of the velocity field. Regarding pumping ability, it is found that the irrotational mode can lead to optimal performance, while the single-vortex flow mode gives the worst performance.