bubble impingement with particle

Diapositiva 1

Universit degli Studi di Napoli Federico IIDipartimento di Ingegneria Chimica, dei Materiali e della Produzione IndustrialeTesi di Laurea Magistrale in Ingegneria ChimicaImpingement of gas bubbles in liquid matrices in the presence of a solid particle

Candidato:Alessandro EspositoMatricola: M55/418RelatoreCh.mo Prof.Ing. Gaetano DavinoCorrelatoreDott.Ing. Massimiliano Maria Villone

the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpressFoamsFoams are dispersions of gas in a liquid or a solid matrix

liquid foampolyurethane foammetallic foam

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the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpressFoam structureFoams may have different structure, in relation to their production processFoam realization steps [1]:

Open and closed cell structure

Nucleation &Single bubble growthImpingementRuptureRetractionKey steps to determine the final structure are the rupture and the consequent film retraction[1] Tammaro et al., Chem. Eng. J., 2016Open and closed cell foam

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the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpress

How the presence of a solid particle can influence the foam structure?Investigation through 3D numerical simulationsBasic problem: two gas bubbles in a liquid matrix in the presence of a solid particleObjective of the workRupture may be induced by different factors:CrystallizationPresence of solid objects (filled polymeric foams)

OBJECTIVE

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LLdR0R0RpLB1B2PProblem formulationGeometrical domain:Assumptions:

Newtonian liquid matrixIncompressible flowSingle, rigid, spherical particleCreeping flow regime (Re > R(t) such that bubbles are not affected by domain boundariesxzy

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the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpressMathematical modelFluid motion equationsParticle motion equationsNB: since we impose that bubble growth is driven by a constant pressure difference between gas and ambient fluid, no mass balance equation is solved for the gas phase[2][2] Favelukis et Al. Bubble growth in viscous newtonian and non-newtonian liquids

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the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpressBoundary conditions

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ParametersDimensionless parameters

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Results

Two bubbles growth without solid particle:bubble dynamicsmesh visualization (remeshing)

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the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpressStrain rate

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Results

Two bubbles growth with solid particle: two possible scenarios

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the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpressStrain rate

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Strain rate

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Symmetry

xzyOn the y-z plane each radial position of the particle is symmetrical.

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the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpressAttraction basins

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the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpressConclusionsThe results found shows that the presence of the solid particle can induce:

- Higher values of strain rate.

- Bubble edge deformation nearby the particle.

The influence of the solid particle is relevant if it is actually trapped between the bubbles. Parameters like particle radius and the bubble distance, (concentration) can influence the attraction basins of the particle, driving the system to different structures

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the soft matter engineering group @uninadicdot16.ingchim.unina.it/wordpressFuture developements - Remove the assumptions of Newtonian fluid and approach different constituive equation (UCM, Oldroyd B)

- Consider multiple bubble interactions

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Thank you for your attention

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bubble impingement with particle

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