Microchannel cleaning by the external laminar flow

Abstract

The paper is devoted to study of the cleaning a microchannel contaminated by solute particles deposited on channel walls. The main and the most common cause of microchannel clogging is sorption of solute particles on channel walls or “physical sorption”. In this paper, we study the problem of the drift of solid non-interacting particles into a microchannel, which can stick to its walls due to Van der Waals interactions and break away from the wall due to viscous stress. A constant pressure drop is fixed between the inlet and the outlet of the channel. At the initial time moment, the channel walls are contaminated with adhering particles, i.e. the form of walls affects the formation of the flow structure through the channel. Over time, under the action of viscous stress the particles detach from the channel walls, thus cleaning occurs. The interaction of the detached particles with the flow is taken into account within the Stokes approximation. In addition, the model takes into account random walks caused by diffusion. The problem is solved numerically in the framework of the random walk model. The evolution of the fluid flow in the channel during its cleaning is obtained. The dependences of the concentration of settled particles on the flow rate and the strength of the Van der Waals interaction between particle and wall are determined. The dependence of the flow rate through the channel cross section on the concentration of settled particles was investigated. The channel cleaning time was estimated.