Simulation and Experiments on a Valveless Micropump With Fluidic Diodes Based on Topology Optimization

Micropumps are microelectromechanical system (MEMS) devices that pump small quantities of liquids. They are used in many applications such as electronics cooling and drug delivery. Valveless fluid diode micropumps with no moving parts have recently attracted great interest in the MEMS community. In this paper, topology optimization is used to design two-dimensional, fixed-geometry, fluidic diodes of high diodicity, which is the ratio of pressure drops of forward to reverse flows. One of the fluidic diodes, of the Tesla type, shows a diodicity of over five. Another is of the nozzle-diffuser type. Both are experimentally and computationally demonstrated herein. Then the numerical simulation was applied to simplify the structures, and the two-dimensional geometry was converted into three-dimensional model for micropumps. Three-dimensional and unsteady numerical analyses of micropump fluid flow with optimized diodes were conducted for pumps of each of the two diode designs. The micropump with the Tesla-type fluidic diode reached a measured flow rate of 34 ml/h, consistent with the computed results and 2.2 times that of the nozzle-diffuser type micropump. The performance results show a high dependence on internal channel geometry. The two types show highest flow rates with an internal channel thickness of
$200 ~\mu \text{m}$
. Demonstrated good repeatability and precise flow control show positive prospects for application. [2021-0144]