MICRO-ELECTRO-MECHANICAL-SYSTEMS (MEMS) AND FLUID FLOWS

TLDR

Micromachining technology from the late 1980s enables micron‑sized sensors and actuators that, when integrated with signal conditioning, form MEMS capable of real‑time distributed control, but the large surface‑to‑volume ratio in these miniature devices causes surface effects to dominate fluid flow, presenting challenges for fundamental flow‑science research. The study aims to reexamine surface forces in the momentum equation for MEMS‑scale fluid flows. Because MEMS‑scale gas flows have large Knudsen numbers, the authors modify boundary conditions to account for altered surface forces. The resulting capability opens a new territory for flow control research.

Abstract

▪ Abstract 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-electro-mechanical-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.