抄録
In this study, we have investigated the mixing properties in microchannels utilizing unstable flows generated with polymer solutions. Microchannels with abrupt contraction-expansion parts consisted of asymmetric rectangular block gates were tested and mixing procedure in it was visualized with combination of dyed and undyed polymer solutions. Dilute aqueous solutions of polyethylene oxide (PEO) were employed to generate unstable vortexes at the contraction flow parts. The degree of mixing (DM) was estimated from image processing of pictures taken. We have examined influence of pitch of the gates with equally-spaced pattern channels on the mixing properties and clarified that higher degree of mixing was obtained in the case of short pitch channels for wide range in Reynolds number. Influence of unequally-spaced gate patterns were also investigated with same solutions. Similar efficiency of the mixing to the short pitch channel were obtained even for the unequally ones having short and long pitch parts. It is considered that the short pitch part enhanced the contribution of the other parts in mixing properties.
