Influence of the constriction angle on the clogging of dilute and dense suspensions*

Suspensions flowing through confined systems are present in various applications, from additive manufacturing to filtration processes. However, the passage of a suspension through a constriction, where a reduction of the cross-section of a channel occurs, is particularly prone to clogging. In this study, we consider the clogging by bridging, i.e., through the formation of a stable arch of particles at a constriction that hinders the transport of particles downstream of the clog. To characterize the role of the angle of the constriction on the clogging dynamics, we study the flow of suspensions of non-Brownian particles through quasi-bidimensional 3D-printed millifluidic devices that allow us to track the particles as they flow and form arches at a constriction. We report the conditions for clogging by bridging when varying the constriction width to particle diameter ratio for different angles of the constriction for both dilute and dense suspensions. Understanding the role of the channel geometry in the formation of clogs is an important step for optimizing engineering design and developing more reliable dispensing systems.