An investigation of microstructure and microdynamics of fluid flow in mems

This paper reviews x-ray imaging, visualization and analysis technologies which were utilized in an investigation of microstructure and micromotion in fluidic microsystems. These systems include fluidic microvalves, silicon v-groove microchannels and capillary tubes. Specifically, we have visualized the 3-D internal microstructure of Redwood Microsystems Fluistor microvalves and EG&G IC Sensors bimetal microvalve using x-ray microtomography and a massively parallel supercomputer. In other experiments, microradiography was used to image fluid transport through the valves as well as actuation. To better understand the microdynamics of flow, we have also studied the displacement of fluids in Si v-grooves and found that capillarity effects may be dominant. Finally, we discuss methods to visualize and measure steady-state flow in microchannels through the use of emulsions. The detailed flow patterns are directly viewable by the motion of the droplets. Computer vision motion analysis is used to recover the corresponding flow fields and velocity profiles.