Analysis of Membrane Behavior of a Normally Closed Microvalve Using a Fluid-Structure Interaction Model

In this paper, membrane deflection against fluid flow and opening membrane (threshold) pressure were studied using fluid-structure interaction (FSI) analysis, and compared with experimental data obtained by Jaemin et al. In the current analysis, two different models (I-shaped and V-shaped) were used to perform the FSI simulation. In microvalve modeling, in order to reduce external actuator usage, interconnections are made between two similar microvalves. This typical interconnection creates a pressure distribution in a local environment. Furthermore, to differentiate the volume factor in a microvalve, a length/width (L/W) ratio term was used. Compared with higher- and lower-L/W-ratio models, the higher-L/W model eventually initiates more deflection in a low-pressure regime than the lower-L/W-ratio model. FSI simulations were performed for 4 μL/min, 6 μL/min, 8 μL/min, 10 μL/min, and 12 μL/min flow rates against membrane behavior, and performance evaluations of the microvalves were conducted. It was observed during an FSI simulation that the gate pressure applied to the lower surface deflects the membrane upward, thereby making contact with the wall. Two important parameters (material properties of the structural membrane and the inlet region height) were selected for analysis to evaluate changes in microvalve performance. These results are presented in the current study.