Coupled Electrostatics-Structures-Fluidic Simulations of a Bead Mesopump

Abstract

A novel microfluidic pump called bead mesopump was analyzed using numerical tools for performance predictions. An electrostatically actuated diaphragm produces pumping action, with appropriately placed inlet and outlet channels for flow rectification. For the first time ever, coupled, transient electrostatics-structures-flow simulations were successfully performed on this complex problem. Simulation data compare well with the available experimental test data. Simulations clearly show the presence of squeeze film flow, and its effects on actuation times and voltages. Simulations of different chamber and electrode designs were also completed to assess effects on pump performance. Numerical simulation tools for MEMS are thus shown to be of significant use in future for analysis of new pump designs, and device optimization.

Analytical model for an electrostatically actuated miniature diaphragm compressor

“…The pump provided a maximum flow rate of 30 ml min −1 at a pressure rise of 2 kPa, and had a power consumption of 8 mW. An array of Cabuz et al [10] Athavale et al [12] Zengerle et al [13] Shannon et al [14] Saif et al [15] Model 2 × 3 × 2 pumps with dimensions of 4.5 × 3.5 × 0.4 cm 3 was shown to pump 230 ml min −1 of air at an actuation voltage of 160 V. Athavale et al [12] proposed a bidirectional diaphragm pump based on electrostatic actuation for pumping gases at large flow rates. The pump consisted of two chambers with one inlet and two outlets, which were controlled independently.…”

“…While these researchers [10][11][12][13] investigated the ability of electrostatic actuation to pump fluids, Shannon et al [14] developed an electrostatically actuated diaphragm compressor for pressurizing refrigerant R134a vapor as part of a miniature cooler circuit designed for cooling off military personnel in hot environments. Each cooler circuit was designed to provide 3 W of cooling.…”

“…Equation ( 16) provides the required pull-down voltage for each segment. The areas and heights of the segments are estimated based on the segmentation described using equations ( 9) through (12). The elastic and gas forces for each segment are calculated using equations ( 13) and ( 14), respectively.…”

Comments on the size effect on the microcantilever quality factor in free air space

“…The validity of these simplified models needs to be further investigated. On the other hand, the numerical simulation of fluid-structure interaction (FSI) has been extensively employed in the macro world [16], and has been successfully applied to some MEMS applications [17,18] as well. The numerical calculation that minimizes the approximations could not only simulate the dynamic behavior of the microcantilevers more accurately but also provide more insight into the problem of structure-fluid interaction through scientific visualization.…”