ANALYTICAL STUDY OF THE MECHANISM OF DROPLET DEFORMATION AND BREAKUP IN SHEAR FLOWS


  • G.K. Ivanitsky Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine
  • B.Ya. Tselen Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine
  • N.L. Radchenko Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine
  • L.P. Gozhenko Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine
Keywords: shear flow, droplet deformation and fragmentation, modeling

Abstract

The problem of drop deformation and breakup in shear flow represents academic and practical interest and has attracted close attention over the intervening decades. Drop breakup is important for a wide range of engineering and biomedical applications including production and processing of emulsions, aerosols, etc. Although drop breakup operations are widely used in various industries, however, till quite presently there is no unequivocal treatment of the physical mechanism, which causes the fragmentation of dispersions in shear flows. In this paper the principles of constructing a mathematical model, which predicts the evolution of initially spherical droplet in shear flows of viscous liquid over a wide range of flow regimes as well physical parameters of both liquid phases, are considered. A mathematical model is presented that describes the deformation of a single drop suspended in another immiscible liquid under the combined action of three forces, namely, hydrodynamic force, capillary force and dissipative viscous force. The influence of each of these forces on the process of droplet deformation is discussed in the paper.

The focus of the study is to more deeply analyze the dynamics of droplet deformation in shear flows and the transitional effects associated with current droplet shapes. Particular attention is paid to the analysis of critical conditions for the onset of irreversible deformation of droplets, which leads to their destruction. The deformed droplet is assumed to be in the form of prolate ellipsoid of revolution. The drop deformation is regarded as motion of the centers mass of the half-drops, symmetrical with respect to the drop center.

The results of numerical calculations for droplet deformation in shear flows in comparison with experimental data of other authors are presented. A simple criterion for destruction of droplets in shear flows has been obtained. The results of the analysis confirm the reliability of the model and the competency of the assumption made. The model is able to predict the nature of droplet deformation and the conditions for their destruction in shear flows with known operating parameters with a greater degree of accuracy than the existing empirical relationships.

References

1. Taylor G.I. The formation of emulsions in definable fields of flow. // Proc. Royal. Soc. London, Ser.A.-1934.-Vol.146, P.501-523.
2. Bentley B.J., Leal L.G. An experimental investigation of drop break-up in two-dimension stationary flow. // J.Fluid Mech.-1986.-V.167, P.241-283.
3. de Bruijn R.A. Deformation and breakup of drops in simple shear flows. -Tech. University of Eindhoven.-1989. 274 p.
4. Wannaborworn S., Mackley M.R., Renardy Y. Experimental observation and matching numerical simulation for the deformation and breakup of immiscible drops in oscillatory shear. // J. Rheol. -2002. -Vol.46 (5), September/October.-P.1279-1293.
5. Cristinia V., Guido S., Alfani A., B?awzdziewicz J., Loewenberg M. Drop breakup and fragment size distribution in shear flow.// J. Rheol. -2003.-Vol 47(5), September/October. -P.1283-1298.
6. Lin Changzhi, Guo Liejin Experimental study of drop deformation and breakup in simple shear flows. //Chin. Jour. Chem. Eng. - 2007, Vol.1, N.5.-P.1-5.
7. A. Komrakova A., Shardt O., Eskin D., Derksen J. Lattice Boltzmann simulations of drop deformation and breakup in shear flow. // Int. J. Multiphase Flow. -2014.-Vol.59, P.24-43.
8. Torza S., Cox R.G., Mason S.G. Particle motions in sheared suspensions. XXVII. Transient and steady deformation and burst of liquid drops. //J. Colloid Interface Sci. - 1972. -Vol.38, P.395-411.
9. Ivanitsky G.K. [Modeling the processes of deformation and breakup of drops when moving in a liquid], Promyshlennaya teplotechnika, [Industrial heat Engineering], 1997, V.19, N1. P.8-16.

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Published
2021-03-04
How to Cite
Ivanitsky, G., Tselen, B., Radchenko, N., & Gozhenko, L. (2021). ANALYTICAL STUDY OF THE MECHANISM OF DROPLET DEFORMATION AND BREAKUP IN SHEAR FLOWS. Thermophysics and Thermal Power Engineering, 43(1), 30-37. https://doi.org/https://doi.org/10.31472/ttpe.1.2021.4
Section
Heat and Mass Transfer Processes and Equipment, Theory and Practice of Drying