Abstract
Control of aggregation/dispersion behavior of fine particles in a suspension is important to improve characteristics of complex materials. The dispersion behavior of fine particles in a suspension was observed and analyzed in a flow across sudden contraction in a microchannel. The dispersed particle and media of the suspension were polystyrene (diameter: 3:5 μm) and 27:0 wt% aqueous glycerol solution. The volume fraction was 0.02. The suspension was introduced to the microchannel using syringe pump. The velocity and dispersion behavior of fine particles of the suspension were determined in the PIV and image analysis. As a result, the velocity profile was fully developed at x/H = 0:23. The profile of the mean number of particles in a cluster at x/H = 0:24 was equal to the profile at upper stream. At x/H = 0:74, the mean cluster size was smaller than that at x/H = 0:24 It indicates a difference in the entrance region of the velocity field and aggregation/dispersion characteristics.
