Microfluidic turn-down valve

Flow visualisation and numerical flowfield computations were used in the development of a microfluidic valve for control of reaction product in microreactors. The flow rate is modulated by headon collision with an opposed flow of control fluid. This principle makes possible unique capability of turn-down (rather than diverting) control at very low operating Reynolds numbers (- design valueRe=75). The planar layout with shallow constant-depth cavities is suitable for microfabrication, especially by one-sided etching.