Numerical and experimental research on the hydro-electromagnetic levitation micropump

Abstract

Micropump is the core component of the microfluidic systems. However, most mechanical micropumps are using the traditional contact bearings that are troubled by wear-out failure. Hydraulic levitation, which can make the rotating components levitate without any solid-solid contact, provides efficient solution to this long-standing challenge. Nevertheless, the current hydraulic levitation technology must utilize micron microgroove structure to produce thrust forces, therefore enlarging the assemble difficulty and manufacture cost. Alternatively, a novel kind of hydro-electromagnetic levitation micropump (HELP) without grooved thrust bearing is designed in this study. Taking advantage of the coupling behavior between the electromagnetic force and hydraulic force, the rotor of the HELP can levitate in the working fluid in all directions. Thereafter, the mechanisms of levitation forces formation are elucidated by the simulations of fluid flow and motor. Results indicate that the levitation bearing can provide sufficient load capacity in all working conditions, especially in high speeds. Based on the hydro-electromagnetic levitation principle, the HELP prototype is manufactured, whose overall size is as large as a coin, but can output the hydraulic performance of over 3160ml/min and 90.5 kPa at 20000 RPM, which is several times over other micropumps. To verify the rotor levitation performance, the levitation trajectory test benches are built on the basis of laser displacement sensors. Results prove that the designed HELP can levitate stably in all directions at all rotational speeds. The proposed levitation micropump may be an excellent choice for powering the liquid cooling systems with high performance and high reliability.