Microfabricated continuous-flow, turbulent, microsecond mixer

We present a microfabricated, continuous-flow, turbulent mixing device that can mix two or more fluids to complete homogeneity on the molecular scale in the microsecond range. The current design is compact, portable, relatively simple to fabricate, adaptable for various measurement techniques, and consumes small sample volumes. The entire mixing process is observable and we use this feature to characterize the dependence of the progress of mixing on the flow velocity. We present details of the mixer's construction and optical data acquisition using fluorescence. Because the mixer is constructed using microfabrication technology, it is inexpensive and alterations are easy to explore. We show that the dependence of mixing times and pressure drop on the flow velocity agree well with theoretical expectations for turbulent pipe flow. This provides useful guidelines in predicting performance of this type of mixing device. (c) 2005 American Institute of Physics.