Flow measurements in microspace using sub-micron fluorescent particles (proposal of spatial averaged time-resolved PTV considering Brownian motion of tracer particles)

A measurement technique for a flow field in a microchannel was developed using sub micron fluorescent particles. The present study focused on a novel measurement technique so called Spatial Averaged Time-resolved Particle Tracking Velocimetry (SAT-PTV) which is able to detect the temporal variation of a fluid flow eliminating the effect of Brownian motion of the sub-micron tracer particles. Velocity vectors of individual tracer particles were averaged within a local small area, instead of temporal aerage, to realize higher time resolution. SAT-PTV method was evaluated by synthetic particle images in both a uniform flow and a flow with linear velocity gradient and the method confirmed the reduction of the measurement errors associated with Brownian motion. The validation of the present technique was performed in a microchannel flow with the time resolution of 37 ms.