AUTHOR=Li Deming , Yang Ruixue , Cao Hui , Yao Feng , Shen Chaoqun , Zhang Chengbin , Wu Suchen 

TITLE=Experimental Study on Gas Flow in a Rough Microchannel

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.863733

DOI=10.3389/fenrg.2022.863733

ISSN=2296-598X

ABSTRACT=The shape and relative roughness of rough surface have important influence on micro-scale flow and heat transfer. In this paper, a rectangular silicon microchannel (0.8mm of width and 11.9μm of height) with large width-depth ratio is fabricated by MEMS micromachining process. The silicon surface of microchannel and the two-dimensional rough contours of the glass surface are measured and the fractal dimensions, which is taken as the only quantitative parameter of the surface morphology, are calculated. The three-dimensional morphology of the silicon surface is measured by confocal laser microscope and atomic force microscope. On this basis, a micro-scale gas flow performance test system is designed and built, and the flow characteristics of nitrogen and helium in rough silicon microchannel are experimentally studied. The experimental results show that the rough profiles of the silicon surface and the glass surface have possesses the self-affine  characteristics. Both nitrogen and helium show a certain degree of boundary slip when they flow in microchannel, and the degree of slip of helium flow is larger than that of nitrogen flow, which verifies the rarefied effect of micro-scale gas flow.