Numerical study of microscale gas pump based on surface acoustic waves

The concept of microscale fluidic pump based on microchannel with surface acoustic waves (SAWs), propagating along one of its walls, has been extensively studied in the last decade with possible application to lab-on-chip projects. Meanwhile, any mentions of the application of such device to gas medium seem absent in the literature. The present paper aims to fill this gap by investigating the possibility of using microchannel with SAWs as a microscale gas pump. The numerical study is performed using the modification of the direct simulation Monte Carlo method. It was shown that the pumping effect occurs mainly in the area covered by SAW, while the upper layers of gas are almost still in average. The pumping effect demonstrates weak dependence on gas rarefaction, decreases with the SAW speed, and is lower for a low amplitude to channel height ratios. Finally, it is shown that the propulsion intensity in the open system decreases with a decreasing microchannel height, while the compression ratio in the closed system, on the contrary, increases.