The analysis of flow rate through orifices of MEMS valves with experimental results

In this paper, we study the flow rate through orifices of an electro-thermally actuated linear MEMS gate valve which consists of a surface-micromachined metal gate on top of bulk-micromachined through orifices on silicon wafer. Theoretical models are established and a dual-iteration method is presented to calculate the air flow rate through the orifices of the MEMS valve. To compare with another method, the flow rate is also calculated using the method which considers slip flow with slip boundary condition. Corresponding to each set of initial conditions in the theoretical analysis, we conducted experiments to measure actual flow rate. Two orifices with rectangular cross-sections were used in experiments: 50 μm × 1000 μm and 200 μm × 1050 μm. Comparisons between the theoretical predictions and experimental results are presented. Finally, the sources of error in modeling and simulation of flow rates were discussed. It is concluded that the dual-iteration method presented in this paper works well for estimating the air flow rate through rectangular orifices of MEMS valves for the purpose of design for MEMS valves with through orifices.