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Analysis of the Backflow Recirculation in Flow Blurring Nozzles via Lagrangian Coherent Structures

Ates, Cihan; Giovannoni, Valerio; Bürkle, Niklas; Keller, Marc; Okraschevski, Max ORCID iD icon; Koch, Rainer; Bauer, Hans-Joerg


The liquid atomization process relies on the disturbance of the liquid surface by various forces. In the case of “flow-blurring” (FB) atomization, this is achieved by inducing turbulence near the liquid channel exit. In this study, we analyze the underlying dynamics of these coherent turbulent structures and their role in the primary atomization within the FB regime. For that purpose, Smoothed Particles Hydrodynamics (SPH) simulations have been conducted using the geometry of an FB atomizer, which was also studied experimentally. An in-house developed visualization and data exploration platform (postAtom) was used to capture the time-resolved, Lagrangian coherent structures ($\mathrm{LCSs}$) via the finite-time Lyapunov exponent ($\mathrm{FTLE}$) fields. The results indicate that the design of the mixing chamber can trigger an oscillatory behavior at the nozzle exit, which has a direct impact on the evolution of the micro-ligaments and the consecutive primary atomization. It is further shown how the $\mathrm{FTLE}$ fields can be used as a guide to optimize the nozzle geometry.

Zugehörige Institution(en) am KIT Institut für Thermische Strömungsmaschinen (ITS)
Publikationstyp Proceedingsbeitrag
Publikationsdatum 29.08.2021
Sprache Englisch
Identifikator KITopen-ID: 1000137259
Erschienen in ICLASS 2021, 15th, Triennial International Conference on Liquid Atomization and Spray Systems, Edinburgh, UK, 30 Aug. - 2 Sept. 2021
Veranstaltung 15th Triennial International Conference on Liquid Atomization and Spray Systems (ICLASS 2021), Online, 30.08.2021 – 02.09.2021
Externe Relationen Abstract/Volltext
Schlagwörter Primary breakup, flow blurring nozzle, shadowgraph, smoothed particle hydrodynamics, Lagrangian coherent structures
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