Particle aggregation rate in a microchannel due to a dilute suspension flow

Particle-laden flow in a microchannel results in cluster formation and growth on the channel surface and the cluster growth, due to aggregation of polystyrene microparticles, has been investigated in this study. In particular, the initial stage of cluster growth is examined, where particle-cluster interaction is the dominant growth mechanism. Both experimental measurements and theoretical considerations were utilized to explore the functional dependence of the cluster growth rate on the following parameters: suspension void fraction, flow shear strain rate, and channel-height to particle-diameter ratio. The growth rate of an average cluster is found to increase linearly with suspension void fraction which is consistent with previous reports. The growth rate coefficient is found to obey a power-law relationship with respect to the shear strain rate, and predictions based on the modernized flocculation theory agree well with the experimental results. Furthermore, the growth rate coefficient obeys a power-law relationship with respect to the channel-height to particle-diameter ratio as well, qualitatively similar to other reported studies. However, to our knowledge, the exponent value estimated in this study does not agree with any previously published values; this disagreement is likely due to differences in experimental conditions.