Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 12, 2022 - November 13, 2022
Effects of surface roughness on microchannel gas flow are significant since the surface roughness of a microchnnel is relatively large compared to conventional size tubes. Therefore, in this study, the effects of surface roughness on friction factors of nitrogen gas flow through stainless steel microtubes experimentally investigated under atmospheric back pressure and variable inlet pressure. The experiments were carried out with six different diameters stainless steel microtubes whose diameters range from 256 to 867 μm. The average values of Mach number and Fanning & Darcy friction factors between the inlet and outlet considering decrease in gas temperature were obtained from measured stagnation temperatures & pressures and mass flow rates. The effects of surface roughness on the compressibility effect were described with Fanning and Darcy friction factor correlations as a function of Mach number. The arithmetic mean height of the surface (Ra) of the microtube was also measured with a 3D laser scanning confocal microscope for profilometry. Comparing the measured Ra and the equivalent sand grain surface roughness (Ks) determined from Colebrook-White correlation, a correlation between Ra and Ks was obtained.
