Micro-flow analysis by molecular tagging velocimetry and planar raman-scattering

TitleMicro-flow analysis by molecular tagging velocimetry and planar raman-scattering
Publication TypeJournal Article
Year of Publication2008
AuthorsRoetmann, K, Schmunk, W, Garbe, CS, Beushausen, V
JournalExp. Fluids

The two dimensional Molecular Tagging Velocimetry (2D-MTV) was used to measure velocity fields of the flow in a micro mixer. Instead of commonly used micro particles an optical tagging of the flow was performed by using a caged dye. The flow induces a deformation of the optically written pattern that can be tracked by laser induced fluorescence. The series of raw images gained this way were analyzed quantitatively with a novel optical flow based technique. Reference measurements have been carried out allowing to draw conclusions about the accuracy of this procedure. A comparison to the standard technique of uPIV was also conducted. Apart from measuring flow velocities in microfluidic mixing processes, the spatial distribution of concentration fields for different species were also measured. To this end, a new technique has been developed that allows spatial measurements from Planar Spontaneous Raman Scattering (PSRS). The Raman stray light of the relevant species was spectrally selected by a narrow bandpass filter and thus detected unaffectedly by the Raman stray light of other species. The successful operation of this measurement procedure in micro flows will be demonstrated exemplary for a mixing process of water and ethanol.

Citation Keyroetmann2007