µ-PIV/PTV Measurement of Suspensions in Symmetric Diverging-Converging Micro-Channel

Single-camera micro-PIV and PTV measurements were performed in diverging-converging micro-channel to study the suspension flow. In micro-channel, the width of the left and right daughter branch constant at 200 µm. A small quantity of 1 µm dyed particles was mixed with the suspension to measure background fluid velocity with the micro-particle image velocimetry technique (μ-PIV), and a small quantity of dispersed particle (6 μm or 10 μm) dyed to measure particle-phase velocity profile and particle distribution using micro-particle tracking velocimetry (μ-PTV). A tip-valley-tip velocity profile was observed near the divergence, which gradually reduces to blunted profile at the outlet of the confluence section. We have qualitatively studied the concentration by using in-house developed particle counting MATLAB programme and from micro-PTV vector map. At the inlet locations of diverging section concentration profile was symmetric due to particle migration towards the centre of the channel which becomes asymmetric at the daughter branches. The profile becomes again symmetric due to additional particles migration towards the centre of daughter branches and in the outlet locations of converging sections.