Continuously Variable on-Chip Flow Switcher Utilizing Vortex Generations

We propose a continuously variable on-chip flow switcher (CVS) by utilizing vortex generations. Unlike previous no-moving-part valves, CVS can change the flow resistance to forward and backward flow with regulating the vortex generations, thereby allowing to rectify the oscillatory flow to the desired directions with variable rectification efficiency. In this presentation, we demonstrate the flow switching by constructing the microfluidic system enabling the high-speed flow control with the on-chip membrane pump. In this system, we generated continuous flow of less than 587 and 306 μl/min to forward and backward direction, respectively, by changing the amplitude/frequency of the oscillatory flow. Additionally, we achieved variable diodicity of 0.73 to 1.32 which indicated that rectification efficiencies are more than 10% in both directions. Especially, the revealed relationships between Reynolds number and diodicity offer the design strategy for constructing CVS networks for multidirectional microfluidic control system.