The effect of droplet size, channel length and the amount of electromagnetic actuation force on reciprocating movement of mercury droplets in the magneto mercury reciprocating (MMR) micropumps

Micropumps are regarded as one of the devices used in microsystems, which are responsible for pumping working fluid. The magnetic reciprocating micropump is an example of the existing micropumps in which the pumping agent includes three liquid metal droplets placed inside lateral channels and reciprocated by the electromagnetic force inside their channels. The working fluid located inside the main channel is pumped through due to the movement of these three droplets. The time duration in which the droplet traverses the sub-channel length is crucial in the operation of the suggested micropump. The present study aims to evaluate the effect of the length of sub-channels, moving droplet volume and the amount of actuation force on the droplet movement duration by imaging a droplet movement and analyzing the experimental results. Then, it will be shown that all results can be collapsed on one curve by non-dimensionalizing the results and defining an appropriate characteristic time. An empirical equation is presented for prediction of a droplet scrolling time, using the length of sub-channels, moving droplet volume and the amount of actuation force.