An experimental study of the co-flow of Newtonian and non-Newtonian fluids in a T-shaped microchannel*

Microfluidic mixers and separators often concern flow of non-Newtonian fluids through a T-junction. The flow dynamics at the junction plays an important role on the performance of such devices. Some previous studies have focused on the topic with same fluids flowing through the T-junction in an opposing configuration. However, many of the real applications may use fluids with dissimilar rheological properties. In this work, we experimentally investigate the co-flow of Newtonian and non-Newtonian fluids through a planar T-shaped microchannel. Several types of polymer solutions with diverse shear-thinning and elastic properties are tested. Our preliminary results indicate the development of different vortical/nonvortical and unstable flow regimes at the T-junction based on the fluid rheology.