Abstract
The coalescence efficiency of two Newtonian droplets submerged in a Newtonian fluid subjected to a simple shear flow was investigated experimentally and theoretically. The experimental investigation was based on observing collisions between two droplets under a microscope. The theoretical investigation considered three drainage models: immobile, partially mobile and mobile interfaces. Both the experimental results and the theoretical analysis showed that a critical approach angle exists below which the colliding droplets separate. Above this critical angle the collision leads to coalescence. Knowledge of the critical angle permits calculation of the coalescence efficiency. The dependence of the coalescence efficiency on various dimensionless groups such as the flow number, the capillary number and the viscosity ratio was studied. The theoretical analysis indicated that the coalescence efficiency decreases as the capillary number and the flow number increase. The experimental results showed that the coalescence efficiency goes through a minimum as the value of the flow number increases. The discrepancy between the experimental and the theoretical results was attributed to some mechanism that enhances coalescence and that is not accounted for in the equation used for the critical thickness for film rupture. Both the experimental and the theoretical results indicated that the coalescence efficiency decreases as the viscosity ratio decreases.
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References
Groeneweg F, van Voorst Vader F, Agterof WGM (1993) Chem Eng Sci 48:229
Arp PA, Mason SG (1976) Can J Chem 54:3769
Guido S, Simeone M (1998) J Fluid Mech 357:1
Jaeger PT, Janssen JJM, Groeneweg F, Agterof WGM (1994) Colloids Surf 85:255
Abid S, Chesters AK (1994) Int J Multiphase Flow 20:613
Chesters AK (1991) Trans Inst Chem Eng 69:259
de Bruijn RA (1989) PhD thesis. Eindhoven University, Eindhoven, The Netherlands
Tomotika S (1935) Proc R Soc Lond Ser A 153:302
Mikami T, Cox RG, Mason SG (1975) Int J Multiphase Flow 2:113
van de Ven TGM, Mason SG (1977) Colloid Polym Sci 255:468
van de Ven TGM (1982) Adv Colloid Interface Sci 17:105
Patlazhan SA, Lindt JT (1996) J Rheol 40:1095
Wang H, Zinchenko AZ, Davis RH (1994) J Fluid Mech 265:161
Brazier-Smith PR, Jennings SG, Latham J (1972) Proc R Soc Lond Ser A 326:393
Rother MA, Zinchenko AZ, Davis RH (1997) J Fluid Mech 346:117
Wright H, Ramkrishna D (1994) AIChE J 40:767
Kumar S, Kumar R, Gandhi KS (1993) Chem Eng Sci 48:2025
Muralidhar R, Ramkrishna D (1986) Ind Eng Chem Fundam 25:554
Adler PM (1981) J Colloid Interface Sci 83:106
Mousa H, van de Ven TGM (1991) Colloids Surf 60:39
Chesters AK, Bazhlekov IB (2000) J Colloid Interface Sci 230:229
Klaseboer E (1998) PhD thesis. Institute National Polytechnique de Toulouse
Allan RS, Mason SG (1962) J Colloid Interface Sci 17:383
Bazhlekov IB, Chesters AK, van de Vosse FN (2000) Int J Multiphase Flow 26:445
MacKay, Mason SG (1963) Can J Chem Eng 41:203
Zhang X, Davis RH (1991) J Fluid Mech 230:479
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Mousa, H., Agterof, W., Mellema, J. (2001). Theoretical and experimental investigation of the coalescence efficiency of droplets in simple shear flow. In: Koutsoukos, P.G. (eds) Trends in Colloid and Interface Science XV. Progress in Colloid and Polymer Science, vol 118. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-45725-9_46
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DOI: https://doi.org/10.1007/3-540-45725-9_46
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