On the excess velocity of Taylor-droplets in square microchannels
File | Description | Size | Format | |
---|---|---|---|---|
00108560-1.pdf | 42.47 MB | Adobe PDF | View/Open |
Other Titles: | Zur Exzessgeschwindigkeit von Taylortropfen in quadratischen Mikrokanälen | Authors: | Helmers, Thorben | Supervisor: | Thöming, Jorg | 1. Expert: | Thöming, Jorg | Experts: | Dreyer, Michael | Abstract: | This 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. |
Keywords: | Taylor flow; droplet excess velocity; microfluidics; genetic algorithms; microscopic multiphase flows; particle image velocimetry (PIV); refractive index matching (RIM) | Issue Date: | 14-Oct-2019 | Type: | Dissertation | Secondary publication: | no | URN: | urn:nbn:de:gbv:46-00108560-19 | Institution: | Universität Bremen | Faculty: | Fachbereich 04: Produktionstechnik, Maschinenbau & Verfahrenstechnik (FB 04) |
Appears in Collections: | Dissertationen |
Page view(s)
380
checked on Nov 21, 2024
Download(s)
289
checked on Nov 21, 2024
Google ScholarTM
Check
Items in Media are protected by copyright, with all rights reserved, unless otherwise indicated.