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Acoustic emulsification. Part 1. The instability of the oil-water interface to form the initial droplets

Published online by Cambridge University Press:  19 April 2006

M. K. Li
Affiliation:
Department of Chemical Engineering, University of Michigan, Ann Arbor Present address: General Electric Corporate Research and Development, Schenectady, New York.
H. S. Fogler
Affiliation:
Department of Chemical Engineering, University of Michigan, Ann Arbor

Abstract

A technique has been developed to study the phenomenon of ultrasonic emulsification in which oil is dispersed as a fine suspension into water at 20 kHz. It was found that the emulsification takes place in two stages. In the first stage, oil droplets of the order of 70 μm are formed from the instability of interfacial waves. In the second stage these large droplets are successively broken into small droplets by cavitation until a stable droplet size is reached. In this paper, the criterion for the instability of the interfacial waves is developed from a linearized stability analysis of the planar oil-water interface exposed to acoustic excitation. The characteristic droplet diameter produced by the instability is related to the induced capillary wavelength at the interface.

The amplitude of the ultrasonic transducer and the theoretical amplitude of vibration necessary for the instability of the interfacial waves were found to be in agreement. In addition, the sizes of the large droplets present in the suspension systems at short irradiation times agree closely with the predicted droplet diameters.

Type
Research Article
Copyright
© 1978 Cambridge University Press

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References

Christiansen, R. M. & Hixon, A. N. 1957 Ind. Engng Chem. 49, 1017.Google Scholar
Doyle, A. W., Mokler, B. V., Perron, R. R. & Little, A. D. 1962 Am. Petrol. Inst. Publ. no. 1701, New York.Google Scholar
Eisenmenger, W. 1959 Acustica 9, 327.Google Scholar
Fogler, H. S. 1971 Chem. Engng Prog. Symposium Series, vol. 67, no. 109, p. 1.Google Scholar
Hayashi, C. 1953 Forced Oscillation in Non-linear Systems. Tokyo: Nippon Printing and Publishing Co.Google Scholar
Lamb, H. 1945 Hydrodynamics. Dover.Google Scholar
Lang, R. J. 1962 J. Acoust. Soc. Am. 34, 6.Google Scholar
Li, M. K. 1976 Ph.D. thesis, The University of Michigan.Google Scholar
Mclachlan, N. W. 1947 Theory and Application of Mathieu Functions. Oxford University Press.Google Scholar
Marinesco, N. 1946 Chem. Ind. 55 (2), 87.Google Scholar
Neduzhii, S. A. 1964 Sov. Phys. Acoust. 9, 195.Google Scholar
Neduzhii, S. A. 1965 Sov. Phys. Acoust. 10, 390.Google Scholar
Peskin, R. L. & Raco, R. J. 1963 J. Acoust. Soc. Am. 35, 1378.Google Scholar
Pohlman, R. 1969 Fraunhofer-Ges. (Examples of Applied Research), p. 136.Google Scholar
Potsis, A., Yeager, E. & Hovorka, F. 1958 J. Acoust. Soc. Am. 30, 678.Google Scholar
Sollner, K. 1938 J. Phys. Chem. 42, 1071.Google Scholar
Sollner, K. 1944 Colloid Chemistry (ed. J. Alexander), vol. 5. Reinhold.Google Scholar
Sollner, K. & Bondy, C. 1935 Trans. Farad. Soc. 31, 835.Google Scholar
Sorokin, V. I. 1957 Sov. Phys. Acoust. 3, 281.Google Scholar
Stamm, K. 1965 Tech. Mitt. 58 (3), 109.Google Scholar
Tyler, E. 1933 Phil. Mag. 16, 504.Google Scholar
Wood, R. W. & Loomis, A. L. 1927 Phil. Mag. 4, 417.Google Scholar
Yeager, E., Potsis, A. & Hovorka, F. 1961 Proc. 3rd Int. Cong. on Acoustics, vol. 2, p. 1276, Amsterdam-London-N.Y.Google Scholar
Yih, C. S. 1969 Fluid Mechanics. McGraw-Hill.Google Scholar