Numerical investigation on the electrohydrodynamic evolution in stretchable micropumps based on lattice Boltzmann method

The electrohydrodynamic behavior of stretchable interdigitated micropumps under transient operating conditions remains poorly understood. This study presents the first high-fidelity lattice Boltzmann simulation of a negatively charge-injected stretchable micropump with realistic geometry. The model accurately reproduced experimental hydrostatic pressure and hydrodynamic flow rates, while resolving previously inaccessible microsecond-scale dynamics. Key findings revealed that the micropump exhibited strong sub-millisecond flow reversals during startup under free-flow conditions, with oscillation amplitudes significantly exceeding steady-state values. These transients can be effectively suppressed by pre-establishing charge distribution before valve actuation. Furthermore, we have identified and explained the “charge-filtered effect” responsible for the emergence and upstream migration of charge voids, which governs vortex restructuring and leads to complex multi-vortex flow patterns. This work provides a validated computational framework for designing soft electrohydrodynamic devices in applications ranging from flexible robotics to implantable medical systems.