Capillary-driven microfluidic devices are of significant interest for on-site analysis because they
do not require external pumps and can be made from inexpensive materials. Among capillary-driven devices,
those made from paper and polyester film are among the most common and have been used in a wide array
of applications. However, since capillary forces are the only driving force, flow is difficult to control, and
passive flow control methods such as changing the geometry must be used to accomplish various analytical
applications. This study presents several new flow control methods that can be utilized in a laminate
capillary-driven microfluidic device to increase available functionality. First, we introduce push and burst
valve systems that can stop and start flow. These valves can be opened by either pressing the channel or
inflowing other fluids to the valve region. Next, we propose flow control methods for Y-shaped channels
that enable more functions. In one example, we demonstrate the ability to accurately control concentration and in a second example, flow rate in the main channel is controlled by adjusting the geometry of the inlet
channel. Finally, the flow rate in the Y-shaped device as a function of channel height and fluid properties
such as viscosity and surface tension was examined. As in previous studies on capillary-driven channels,
the flow rate was affected by each parameter. The fluidic control tools presented here will enable new
designs and functions for low cost point of need assays across a variety of fields.
Effect of passive flow control on the aerodynamic performance, entropy generation and aeroacoustic noise of axial turbines for wave energy extractor
