Dynamic Sealing Using Magnetorheological Fluids

One obstacle in developing micropumps is their extremely low efficiency, compared to their macroscale counterparts. Thus the authors explore a dynamic sealing method for microhydraulic systems, using magnetorheological (MR) fluids: To minimize backflow under particular conditions, they identify the optimal combination of parameters, which occurs at the transition from attached to detached plug flow. This leads to a design space for gear pumps that can achieve high efficiency and accuracy, using current mechanical architectures and tolerances. Also, the optimal magnetic field intensity is investigated for different working conditions, and a metric for effectiveness is proposed.