Thöming, JorgHelmers, ThorbenThorbenHelmers2020-03-092020-03-092019-10-14https://media.suub.uni-bremen.de/handle/elib/1735This thesis deals with the movement of Taylor-droplets in microscopic multiphase flows and reports a phenomenological model to improve the description of the instantaneous droplet velocity. The chosen approach can be seen as a holistic-hybrid between measurement methodology, high-speed image averaging and semi-analytic greybox modeling. For the first time, the influential parameters on the excess velocity are described for squared microchannels. Different valuable benefits arose on this journey beside the final model: A novel noninvasive and cost-efficient measurement device based on near-infrared photometry is developed and successfully tested, the flow-induced Taylor-droplet cap deformation is correlated to the Ca-number and genetic algorithms are successfully adapted for model adjustment. Model validation drives the development of a novel refractive index matching (RIM) approach. The phenomenology of the model is subsequently validated using carefully performed microPIV measurements.eninfo:eu-repo/semantics/openAccessTaylor flowdroplet excess velocitymicrofluidicsgenetic algorithmsmicroscopic multiphase flowsparticle image velocimetry (PIV)refractive index matching (RIM)620Dissertationurn:nbn:de:gbv:46-00108560-19