TY - THES ID - 135113205 TI - CFD and PIV investigation of Flow Patterns and Particle Behavior in Swirling Jets AU - Ogus, Güven AU - Baelmans, Martine AU - Vanierschot, Maarten AU - KU Leuven. Faculty of engineering technology. Department of mechanical engineering PY - 2018 PB - Leuven KU Leuven. Faculty of Engineering Technology DB - UniCat UR - https://www.unicat.be/uniCat?func=search&query=sysid:135113205 AB - Swirling flows are widely observed in nature as well as in man-made machines from tornadoes to tip vortices of airplane wings. In industry, they are utilizedin many applications such as cyclone separators and pumps. In this study, it is aimed to propose a new area of utilization of swirling flows: life sciences<br />applications. As swirling jets were used for particle concentration control to increase combustion efficiency successfully in the past, this research aims tosuggest a new concept to use this particle concentration ability in life sciences applications. An annular jet swirl burner, which operates in turbulent conditions,is used as a base for a novel flow cell design to be used in biomedical diagnostics devices. This requires scaling down the size and the flow rate of this deviceto laminar conditions. Firstly, how the annular jet swirl burner behaves underlaminar conditions at a Reynolds number of 180 is investigated. The flowpatterns that are possible to achieve are determined with numerical simulations (CFD), validated with particle image velocimetry (PIV). The hysteresis betweendifferent flow states, that was previously observed for fully turbulent flows was also found to be present in laminar conditions and the hysteretic behavioris mapped with respect to the swirl rate. Secondly, the influence of vortex breakdown on the flow structures in the annular jet was investigated. Severalfeatures of flow patterns near breakdown were observed for the first time. The large scale instability frequencies are determined and the 3D structures of thevortices in these states are visualized by further investigation with numerical and experimental tools. A spiral vortex breakdown is proved to exist by S-PIVmeasurements and the flow scales at different flow and swirl rates are calculated in detail. Moreover, the largest and smallest length scales in the flow are mappedversus the swirl number. Finally, the knowledge obtained by investigating the spiral vortex breakdown is used to design a small scale annular swirling nozzle,inspired from the investigated swirl burner. The flow cell is designed for usage in life sciences applications together with a flow cell based on a standard vesselwidely used in biomedical applications. The aimed application is to use this flow type with a surface plasmon resonance fiber optic sensor (FO-SPR) which works by detecting the refractive index difference between liquids that have high and low concentration of biological molecules. The flow was simulated to understandthe flow patterns and the particle behavior. For further investigation, optical experiments by laser induced fluorescence were performed. Finally, the designeddevice was built for usage with a FO-SPR sensor and liquid with a known concentration of bovine serum albumin (BSA) was fed to the flow cell to provethe concept. The output of this research is, firstly, flow maps for laminar conditions in annular jet flows, secondly, reporting the flow scales of spiral vortex breakdownforming inside the annular jet and finally, a new concept design of a flow cell that can be used in life sciences applications for artificially increase solid particleconcentration in a biological specimen. Even though the design is still in the concept stage, it is promising to be commercialized with further research. ER -