Microscope PIV for velocity-field measurement of particle suspensions flowing inside glass capillaries

We assembled an experimental arrangement for the measurement of the velocity field of glycerol suspensions, in the diametric plane, inside glass capillaries with internal diameter of the order of 200 µm. Glass spheres of mean diameter of 10 µm were used to seed the flow. The velocity fields were determined by the particle image velocimetry (PIV) method, whereby, in contrast to the usual implementations of this method based on light-sheet imaging, a forwards-scattering technique with the entire volume flow illuminated was used and the plane of interest was determined by the objective lens of a microscope. Statistical analysis of acquired experimental results was performed and possible limitations of the proposed technique were investigated. The method, with its present implementation, was used to measure velocities up to 4 mm s -1 and seems to be promising for similar measurements in glass capillaries or in microcirculation.