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Self-similar particle-size distributions during coagulation: theory and experimental verification

Published online by Cambridge University Press:  20 April 2006

James R. Hunt
Affiliation:
Division of Sanitary, Environmental, Coastal, and Hydraulic Engineering, University of California, Berkeley, California 94720

Abstract

A quantitative theory for particle coagulation in continuous particle size distributions is presented and experimentally verified. The analysis, following Friedlander (1960a, b), assumes a local equilibrium in the size distribution maintained by a particle flux through the size distribution, Only particle collisions caused by Brownian motion, fluid shear and differences in settling velocities are considered. For intervals of particle size where only one coagulation mechanism is dominant, dimensional analysis predicts self-similar size distributions that contain only one dimensionless constant for each mechanism. Experiments were designed to test these predictions with clay particles in artificial seawater sheared in the gap between concentric rotating cylinders. Particle-size distributions measured over time were self-similar in shape and agreed with the Brownian- and shear-coagulation prediction in terms of shape and dependence on fluid shear rate and particle volume flux through the size distribution.

Type
Research Article
Copyright
© 1982 Cambridge University Press

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References

Adler, P. M. 1981 Heterocoagulation in shear flow. J. Colloid Interface Sci. 83, 106115.Google Scholar
Batchelor, G. K. 1953 The Theory of Homogeneous Turbulence. Cambridge University Press.
Batchelor, G. K. 1959 Small-scale variation of convected quantities like temperature in turbulent fluid. Part 1. General discussion and the case of small conductivity. J. Fluid Mech. 5, 113133.Google Scholar
Birkner, F. B. & Morgan, J. J. 1968 Polymer flocculation kinetics of dilute colloidal suspensions. J. Am. Water Works Assoc. 60, 175191.Google Scholar
Drake, R. L. 1976 Similarity solutions for homogeneous and nonhomogeneous aerosol balance equations. J. Colloid Interface Sci. 57, 411423.Google Scholar
Edzwald, J. K., Upchurch, J. B. & O'Melia, C. R.1974 Coagulation in estuaries. Environ. Sci. Technol. 8, 5863.Google Scholar
Friedlander, S. K. 1960a On the particle-size spectrum of atmospheric aerosols. J. Met. 17, 373374.Google Scholar
Friedlander, S. K. 1960b Similarity considerations for the particle-size spectrum of a coagulating, sedimenting aerosol. J. Met. 17, 479483.Google Scholar
Friedlander, S. K. 1977 Smoke, Dust and Haze: Fundamentals of Aerosol Behaviour. Wiley - Interscience.
Gelbard, F. & Seinfeld, J. H. 1979 The general dynamic equation for aerosols, theory and application to aerosol formation and growth. J. Colloid Interface Sci. 68, 363382.Google Scholar
Honig, E. P., Roebersen, G. J. & Wiersema, P. H. 1971 Effect of hydrodynamic interaction on the coagulation rate of hydrophobic colloids. J. Colloid Interface Sci. 36, 97109.Google Scholar
Hunt, J. R. 1980a Coagulation in continuous particle size distributions; theory and experimental verification. Ph.D. thesis, California Institute of Technology, Pasadena (Rep. no. AC–5–80, W. M. Keck Laboratory of Environmental Engineering Science, California Institute of Technology).
Hunt, J. R. 1980b Prediction of oceanic particle size distributions from coagulation and sedimentation mechanisms. Adv. Chem. Ser. 189, 243257.Google Scholar
Jeffrey, D. J. 1981 Quasi-stationary approximations for the size distribution of aerosols. J. Atmos. Sci. 38, 24402443.Google Scholar
Kerr, P. F. Et Al. 1949–50 Reference Clay Minerals: Am. Petroleum Inst. Res. Proj. 49. Preliminary Rep. nos. 1–8. Columbia University.
Lawler, D. F., O'Melia, C. R. & Tobiason, J. E.1980 Integral water treatment plant design: From particle size to plant performance. Adv. Chem. Ser. 189, 353388.Google Scholar
Lichtenbelt, J. W. Th., Pathmamanotharan, C. & Wiersema, P. H. 1974 Rapid coagulation of polystyrene latex in a stopped-flow spectrophotometer. J. Colloid Interface Sci. 49, 281285.Google Scholar
Manley, R. St J. & Mason, S. G. 1955 Particle motions in sheared suspensions. III. Further observations on collisions of spheres. Can. J. Chem. 33, 763773.Google Scholar
Mason, B. J. 1971 Physics of Clouds, 2nd edn. Clarendon.
Mccave, I. N. 1975 Vertical flux of particles in the ocean. Deep-Sea Res. 22, 491502.Google Scholar
Overbeek, N. Th. G. 1977 Recent developments in understanding of colloid stability. J. Colloid Interface Sci. 58, 408422.Google Scholar
Pruppacher, H. R. & Klett, J. D. 1978 Microphysics of Clouds and Precipitation. Reidel.
Pulvermacher, B. & Ruckenstein, E. 1974 Similarity solutions of population balances. J. Colloid Interface Sci. 46, 428436.Google Scholar
Riley, J. P. & Skirrow, G. 1965 Chemical Oceanography, vol. 1. Academic.
Smoluchowski, M. 1917 Versuch einer mathematischen Theorie der Koagulationkinetik kolloider Lösungen. Ann. Physik. Chem. 92, 129168.Google Scholar
Spielman, L. A. 1970 Viscous interactions in Brownian coagulation. J. Colloid Interface Sci. 33, 562571.Google Scholar
Spielman, L. A. 1977 Particle capture from low-speed laminar flows. A. Rev. Fluid Mech. 9, 297319.Google Scholar
Swift, D. L. & Friedlander, S. K. 1964 The coagulation of hydrosols by Brownian motion and laminar shear flow. J. Colloid Sci. 19, 621647.Google Scholar
Tambo, N. & Watanabe, Y. 1979 Physical characteristics of flocs – I. The floc density function and aluminum floc. Water Res. 13, 409419.Google Scholar
Taylor, G. I. 1936 Fluid friction between rotating cylinders. Part I. Torque measurements. Proc. R. Soc. Lond. A 157, 546564.Google Scholar
Van De Ven, T. G. M. & Mason, S. G. 1977 The microrheology of colloidal dispersions VII. Orthokinetic doublet formation of spheres. Colloid Polym. Sci. 255, 468479.Google Scholar
Van Olphen, H. 1977 An Introduction to Clay Colloid Chemistry, 2nd edn. Wiley-Interscience.
Wang, C. S. & Friedlander, S. K. 1967 The self-preserving particle size distribution for coagulation by Brownian motion. II. Small particle slip correction and simultaneous shear flow. J. Colloid Interface Sci. 24, 170179.Google Scholar
Zeichner, G. R. & Schowalter, W. R. 1977 Use of trajectory analysis to study stability of colloidal dispersions in flow fields. A.I.Ch.E. J. 23, 243254.Google Scholar