In many disperse systems of practical importance (e.g. paints, dairy products), one observes, under certain circumstances, aggregation of the suspended particles. Aggregation phenomena are also an important issue in many solid-liquid separation processes as mineral processing or waste water treatment, where one has to deal with both colloidal and non-colloidal particles. In another application field colloidal or non-colloidal particles (organized in 2D structures) are used as stabilizing agents of foams and emulsions (known as Pickering emulsions) encountered in many industrial and natural processes such as food, cosmetic and pharmaceutical products. To improve the properties of these products or the efficiency of these processes one needs a detailed knowledge of the behavior and properties of the aggregates involved. The behavior of an aggregate in shear flow can be quite complex. The aggregate may deform, restructure or break-up. Our goal is to find the relationship between the behavior of an aggregate and the shear flow to which it is subjected. In this thesis an experimental study of 2D aggregates (as a model for 3D structures) in shear flow is presented. We are interested in the critical shear rate at which the aggregate will break-up, but also in the structural changes that the aggregates undergo due to the applied shear flow. We investigate single aggregates, in this way only the disintegration of the aggregate is considered and the process of aggregation is negligible.
|Award date||25 Aug 2006|
|Place of Publication||Enschede|
|Publication status||Published - 25 Aug 2006|