Transient Performance and Coupled Acoustic Structural and Electrostatic Modeling of a Multistage Vacuum Micropump

This paper describes the theoretical analysis used to design of a multistage peristaltic vacuum micro pump, comprising of two parts. First, three different designs for a 16 stage micropump to achieve a vacuum of 250 torr are investigated. One design produces an equal pressure distribution across each stage at steady state. A second design has equal volume ratio across each stage. The third design is a combination of the other two. The transient behavior of these designs is analyzed using a reduced order model. In the first two designs when the pressure difference across the pump is low most pumping occurs across the first few stages, while for the third design the load is almost equally distributed across all stages. The opposite is observed when the pressure difference across the pump is high. In the second part of the paper, the reduced order model is further developed to account for the effects of electrostatic actuation and membrane dynamics. A non-linear model is proposed for the motion of the membrane and used to study the steady state performance and resonance of a multistage vacuum micro pump as a function of input voltage. It is found that near the acoustic frequency, a lower voltage is required to produce a greater flow.