Effect of Surface Roughness on Micro-channel Flow of Dilute Polymer Solutions

Abstract

In this study, we investigated the influence of wall surface roughness on the pressure drop in micro-channel flow of dilute polymer solutions with two different channel heights, 100 and 50 μm. Tested channel surface roughness are Ra = 0.2, 1.0, 1.6, 2.5, 4.7, and 10.0 μm. Moreover, we changed surface wettability on these surfaces, namely hydrophilic or hydrophobic. The experiment showed the pressure drop increased with an increase of surface roughness for all surface conditions. In case of Ra > 1.0 μm, the pressure drop on hydrophobic surfaces were lower than that on hydrophilic surfaces. The pressure drop of dilute polymer solutions decreased in the case of hydrophilic surface roughness comparing that of distilled water. On the other hand, for hydrophobic surface roughness, the pressure drop of dilute polymer solutions increased.