Numerical Analysis of Density-Driven Reactive Flows in Hele-Shaw Cell Geometry

  • S. Bekkouche Department of Mechanical Engineering, University Freres Mentouri Constantine 1, Algeria
  • M. Kadja Department of Mechanical Engineering, University Freres Mentouri Constantine 1, Algeria
Keywords: liquid-liquid reactive system, Hele-Shaw cell, diffusion, chemo hydrodynamic patterns

Abstract

In this paper, a two-dimensional numerical simulation of the unsteady state of a two non-isothermal immiscible liquids layer system filling a reactor formed by two closely spaced parallel glass sheets, which is called an Hele-Shaw cell, vertically oriented, with an expected neutralization reaction between an acid and a base in the lower layer, under the action of gravity, is studied. Attention is given on the general behavior of the complete temporal pattern evolution (velocity, temperature, and concentration profiles) and the identification of the exothermic reaction’s role in giving birth to chemo-hydrodynamic patterns that occur because of concentration gradients. The effects of gravity and changes in initial acid and base concentrations on the formed patterns were studied. The mathematical model governing the phenomenon was solved numerically by the CFD software package COMSOL Multiphysics, with the finite element method and a comparison with the experimental data was made. The results show that this numerical tool is promising for the understanding of the reactive instabilities happening when two immiscible fluids come into contact.

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References

Y. Shi, E. Kerstin, “Orientation-dependent hydrodynamic instabilities from chemo-marangoni cells to large scale interfacial deformations”, Chinese Journal of Chemical Engineering, Vol. 15, No. 5, pp. 748-753, 2007

E. Bodenschatz, W. Pesch, G. Ahlers, “Recent developments in Rayleigh-Benard convection”, Annual Review of Fluid Mechanics, Vol. 32, pp. 709-778, 2000

A. Thess, M. Bestehorn, “Planform selection in Benard-Marangoni convection: l hexagons versus g hexagons”, Physical Review E, Covering Statistical, Nonlinear, Biological, and Soft Matter Physics, Vol. 50, No. 6, pp. 6358-6367, 1995

G. I. Taylor, “The instability of liquid surfaces when accelerated in a direction perpendicular to their planes. ”, Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 201, No. 1065, pp. 192-196, 1950

C. Almarcha, P. M. J. Trevelyan, L. A. Riolfo, A. Zalts, C. El Hasi, A. D'Onofrio, A. De Wit, “Active role of a color indicator in buoyancy-driven instabilities of chemical fronts”, The Journal of Physical Chemistry Letters, Vol. 1, pp. 752–757, 2010

D. A. Bratsun, A. De Wit, “On Marangoni convective patterns driven by an exothermic chemical reaction in two-layer systems”, Physics of Fluids, Vol. 16, No. 4, pp. 1082–1096, 2004

D. A. Bratsun, A. De Wit, “Buoyancy-driven pattern formation in reactive immiscible two layer systems”, Chemical Engineering Science, Vol. 66, pp. 5723–5734, 2011

D. A. Bratsun, Y. Shi, K. Eckert, A. De Wit, “Control of chemo-hydrodynamic pattern formation by external localized cooling”. Europhysics Letters, Vol. 69, No. 5, pp. 746–752, 2005

K. Eckert, M. Acker, Y. Shi, “Chemical pattern formation driven by a neutralization reaction. I. Mechanism and basic features”, Physics of Fluids, Vol. 16, No. 2, pp. 385-399, 2004

A. Grahn, K. Eckert, “Plume and finger regimes driven by an exothermic interfacial reaction”, Physical Review Letters, Vol. 82, pp. No. 22, 4436–4439, 1999

E. V. Aitova, D. A. Bratsun, K. G. Kostarev, E. A. Mosheva, “Convective instability in a two-layer System of Reacting Fluids with concentration dependent diffusion”, Journal of Applied Mechanics and Technical Physics, Vol. 57, No. 7, pp. 1226–1238, 2016

D. A. Bratsun,“On Rayleigh-Benard mechanism of alignment of salt fingers in reactive immiscible two-layer systems”, Microgravity Science and Technology, Vol. 26 No. 5, pp. 293-303, 2014

S. Kalliadasis, J. Yang, A. De Wit, “Fingering instabilities of exothermic reaction-diffusion fronts in porous media”, Physics of Fluids, Vol. 16, No. 5, pp. 1395-1409, 2004

D. Villers, J. K. Platten, “Coupled buoyancy and Marangoni convection in acetone: Experiments and comparison with numerical simulations”, Journal of Fluid Mechanics, Vol. 234, pp. 487-510. 1992

A. De Wit, “Chemo-hydrodynamic patterns and instabilities”, Annual Review of Fluid Mechanics, Vol. 52, pp. 531-555, 2020

Y. Shi, K. Eckert, “Acceleration of reaction fronts by hydrodynamic instabilities in immiscible systems”, Chemical Engineering Science, Vol. 61, No. 17, pp. 5523-5533, 2006

A. Zalts, C. El Hasi, D. Rubio, A. Urena, A. D’Onofrio, “Pattern formation driven by an acid-base neutralization reaction in aqueous media in a gravitational field”, Physical Review E, Covering Statistical, Nonlinear, Biological, and Soft Matter Physics, Vol. 77, Article ID 015304, 2008

C. Almarcha, P. M. J. Trevelyan, P. Grosfils, A. De Wit, “Thermal effects on the diffusive layer convection instability of an exothermic acid-base reaction front”, Physical Review E, Covering Statistical, Nonlinear, Biological, and Soft Matter Physics, Vol. 88, Article ID 033009, 2013

C. Almarcha, P. M. J. Trevelyan, P. Grosfils, A. De Wit, “Chemically driven hydrodynamic instabilities”, Physical Review Letters, Vol. 104, Article ID 044501, 2010

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