Roetmann Karsten, Schmunk Waldemar, Garbe Christoph S, Beushausen Volker
1Laser-Laboratorium Göttingen e.V., Göttingen, Germany.
2Interdisciplinary Center for Scientific Computing (IWR), University of Heidelberg, Heidelberg, Germany.
Exp Fluids. 2008;44(3):419-430. doi: 10.1007/s00348-007-0420-1. Epub 2007 Nov 4.
The two dimensional molecular tagging velocimetry (2D-MTV) has been used to measure velocity fields of the flow in a micro mixer. Instead of commonly used micro particles an optical tagging of the flow has been performed by using a caged dye. The pattern generation is done by imaging a mask for the first time. This allows to generate nearly any imaginable pattern. The flow induces a deformation of the optically written pattern that can be tracked by laser induced fluorescence. The series of raw images acquired in this way were analyzed quantitatively with a novel optical flow based technique. The reference measurements have been carried out allowing to draw conclusions about the accuracy of this procedure. A comparison to the standard technique of μPIV has also been conducted. Apart from measuring flow velocities in microfluidic mixing processes, the spatial distribution of concentration fields for different species has also been 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 has been 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.
二维分子标记测速技术（2D-MTV）已被用于测量微混合器中流体的速度场。通过使用笼形染料对流体进行光学标记，取代了常用的微粒。图案生成首次通过对掩膜成像来完成。这使得能够生成几乎任何可想象的图案。流体导致光学写入图案的变形，该变形可通过激光诱导荧光进行跟踪。以这种方式获取的一系列原始图像采用一种基于光流的新技术进行了定量分析。进行了参考测量，以便对该程序的准确性得出结论。还与μPIV标准技术进行了比较。除了测量微流体混合过程中的流速外，还测量了不同物质浓度场的空间分布。为此，开发了一种新技术，可通过平面自发拉曼散射（PSRS）进行空间测量。相关物质的拉曼杂散光通过窄带通滤波器进行光谱选择，从而不受其他物质拉曼杂散光的影响进行检测。将以水和乙醇的混合过程为例，展示该测量程序在微流体中的成功运行。
