Application of yield stress - pseudoplastic fluid models to pipeline transport of sludge

摘要

In a sewage treatment plant, particularly for large municipalities, pumping sludge from one location to another through a pipeline system is an important operation. The design and day-to-day running of such a system is not trivial, because sludge is a rheologically complex fluid which exhibits a yield stress - a minimum shear stress needed to start the fluid flowing. The Bingham fluid model (yield stress plus Newtonian flow behavior) is the simplest and most widely used model for prediction of the flow characteristics (pressure drop vs. flow rate) of sludges. However, it is also widely known that most sludges do not exhibit Newtonian behavior in flow. Thus, a more complex model, the yield stress - pseudoplastic fluid model (Herschel-Bulkley), has also been proposed for this problem.