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dc.contributor.authorKeshavarz, Bavand
dc.contributor.authorMcKinley, Gareth H
dc.date.accessioned2020-07-31T12:37:46Z
dc.date.available2020-07-31T12:37:46Z
dc.date.issued2020-03-05
dc.date.submitted2019-09
dc.identifier.issn2469-990X
dc.identifier.urihttps://hdl.handle.net/1721.1/126459
dc.description.abstractWe study the dynamics of fragmentation for Newtonian and viscoelastic liquids in rotary atomization. In this common industrial process centripetal acceleration destabilizes the liquid torus that forms at the rim of a spinning cup or disk due to the Rayleigh-Taylor instability. The resulting ligaments leave the liquid torus with a remarkably repeatable spacing that scales inversely with the rotation rate. The fluid filaments then follow a well-defined geometrical path-line that is described by the involute of a circle. Knowing the geometry of this phenomenon we derive the detailed kinematics of this process and compare it with the experimental observations. We show that the ligaments elongate tangentially along the involute of the circle and thin radially as they separate from the cup. We use these kinematic conditions to develop an expression for the spatial variation of the filament deformation rate and show that it decays away from the spinning cup. Once the ligaments are sufficiently far from the cup, they are not stretched sufficiently fast to overcome the critical rate of capillary thinning and consequently undergo capillary-driven breakup forming droplets. We couple these kinematic considerations with the known properties of several Newtonian and viscoelastic test liquids to develop a quantitative understanding of this commercially important fragmentation process that can be compared in detail with experimental observations. We also investigate the resulting droplet size distributions and observe that the appearance of satellite droplets during the pinch-off process lead to the emergence of bidisperse droplet size distributions. These binary distributions are well described by the superposition of two separate Γ distributions that capture the physics of the disintegration process for the main and satellite droplets, respectively. Furthermore, as we consider more viscous Newtonian liquids or weakly viscoelastic test fluids, we show that changes in the liquid viscosity or viscoelasticity have a negligible effect on the average droplet size. However, incorporation of viscous/viscoelastic effects delays the thinning dynamics in the ligaments and thus results in broader droplet size distributions. The ratio of the primary to satellite droplet size increases monotonically with both viscosity and viscoelasticity. We develop a simple physical model that rationalizes the observed experimental trends and provides us a better understanding of the principal dynamical features of rotary fragmentation for both Newtonian and weakly viscoelastic liquids.en_US
dc.publisherAmerican Physical Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1103/PhysRevFluids.5.033601en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourceAmerican Physical Societyen_US
dc.titleRotary atomization of Newtonian and viscoelastic liquidsen_US
dc.typeArticleen_US
dc.identifier.citationKeshavarz, Bavand et al. “Rotary atomization of Newtonian and viscoelastic liquids.” Physical review fluids, vol. 5, no. 3, 2020, article 033601 © 2020 The Author(s)en_US
dc.contributor.departmentMassachusetts Institute of Technology. Hatsopoulos Microfluids Laboratoryen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Mechanical Engineeringen_US
dc.relation.journalPhysical review fluidsen_US
dc.identifier.mitlicensePUBLISHER_POLICY
dc.identifier.mitlicensePUBLISHER_POLICY
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dc.date.updated2020-03-05T21:07:11Z
dc.language.rfc3066en
dc.rights.holderAmerican Physical Society
dspace.date.submission2020-03-05T21:07:11Z
mit.journal.volume5en_US
mit.journal.issue3en_US
mit.licensePUBLISHER_POLICY
mit.metadata.statusComplete


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