Design Rule Evaluation for Micro-Scale Flow Restrictions: Comparing Experiment and Theory

Control of the direction of fluid flow within a network of flow paths in a microfluidic device is paramount to its proper operation. Pressure driven flow requires either active valving for control, or passive control through variation of the flow resistance of each intersecting channel by adjusting its geometry. In order to achieve rational design of passive flow control, an accurate model describing fluid flow in micron-scale devices must be available. In this report we compare the predictions of the Navier-Stokes equations with experimental results for three-port devices with flow restrictors. The good agreement seen indicates that flow restrictors with 1-µm dimensions can be designed using solutions to the Navier-Stokes equations.