A collapsing bubble-based micropump for viscous liquids

During the collapse of a bubble near a rigid plate/wall, a liquid jet forms that is directed toward the plate/wall. For perforated plates, part of the jet flow passes through the hole, so the bubble jet acts as a pump transporting liquid from one side of the plate to the other. A distinct advantage of this particular micropump is its absence of any moving components coupled with its exceptionally rapid response time. The transport process is highly complex, time dependent, and influenced by various parameters, including bubble–hole distance, plate thickness, and hole geometry. The objective is to numerically simulate the pumping of a viscous liquid through a truncated cone hole made in a rigid plate. The numerical method is based on the volume of fluid method, which employs a single-field formulation of the Navier–Stokes equations to model immiscible two-phase flows and considers the influences of surface tension and viscosity. The results are presented in terms of bubble shape, pressure and velocity fields, and mass flow through the hole. It was found that cone angle, standoff distance, plate thickness, and liquid viscosity have a significant role in the pumping effect of the bubble. Specifically, as each of these parameters increases, the net mass pumped decreases.