MICRO ELECTRO MECHANICALSYSTEMS MEMS AND FLUID FLOWS
The micromachining technology that emerged in the late 1980s can provide micron-sized sensors and actuators. These micro transducers are able to be integrated with signal conditioning and processing circuitry to form micro-electromechanical-systems (MEMS) that can perform real-time distributed control. This capability opens up a new territory for ﬂow control research. On the other hand, surface effects dominate the ﬂuid ﬂowing through these miniature mechanical devices because of the large surface-to-volume ratio in micron-scale conﬁgurations. We need to reexamine the surface forces in the momentum equation. Owing to their smallness, gas ﬂows experience large Knudsen numbers, and therefore boundary conditions need to be modiﬁed. Besides being an enabling technology, MEMS also provide many challenges for fundamental ﬂow-science research.
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