Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-10T07:36:00.305Z Has data issue: false hasContentIssue false

An experimental investigation of concentrated suspension flows in a rectangular channel

Published online by Cambridge University Press:  26 April 2006

Christopher J. Koh
Affiliation:
University of California, Santa Barbara, Department of Chemical and Nuclear Engineering, Santa Barbara, CA 93106, USA
Philip Hookham
Affiliation:
University of California, Santa Barbara, Department of Chemical and Nuclear Engineering, Santa Barbara, CA 93106, USA
L. G. Leal
Affiliation:
University of California, Santa Barbara, Department of Chemical and Nuclear Engineering, Santa Barbara, CA 93106, USA

Abstract

An experimental adaptation of the well-known laser-Doppler anemometry technique is developed for measuring the velocity and concentration profiles in concentrated suspension flows. To circumvent the problem of optical turbidity, the refractive indices of the solid and liquid phases are closely matched. The residual turbidity, owing to small mismatches of the refractive indices, as well as impurities in the particles, allows a Doppler signal to be detected when a particle passes through the scattering volume. By counting the number of Doppler signals in a period of time, the local volume fraction is also measured.

This new technique is utilized to study concentrated suspension flows in a rectangular channel. The general behavior of the suspension is that the velocity profile is blunted while the concentration profile has a maximum near the centre. Comparisons are made with theoretical predictions based on the shear-induced particle migration theory.

Type
Research Article
Copyright
© 1994 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abbot, J. R., Tetlow, N., Graham, A. L., Altobelli, S. A., Fukushima, E., Mondy, L. A. & Stephens, T. S. 1991 Experimental observations of particle migration in concentrated suspensions: Couette flow. J. Rheol. 35, 773.Google Scholar
Adrian, R. J. 1978 Laser velocimetry. T. & M Rep. 442. University of Illinois, Dept of Theoretical and Applied Mechanics, Urbana, IL, USA.
Adrian, R. S. & Earley, W. 1976 Evaluation of LDV performance using Mie scattering theory. Minnesota Symposium on Laser Anemometry Proceedings, Oct. 22–24, 1975, Bloomington, MN. University of Minnesota, Dept of Conferences, Minneapolis.
Conaghan, B. F. & Rosen, S. L. 1972 The optical properties of two-phase polymer systems: single scattering in monodisperse, non-adsorbing systems. Polymer Engng Sci. 2, 12.Google Scholar
Drain, L. E. 1972 Coherent and noncoherent methods in Doppler optical beat velocity measurement. J. Phys. D Appl. Phys. 5, 481.Google Scholar
Drain, L. E. 1980 The Laser Doppler Techniques. John Wiley and Sons.
Durani, T. S. & Greated, C. A. 1977 Laser Systems in Flow Measurements. Plenum Press.
Fahraeus, R. & Lindquist, T. 1931 The viscosity of the blood in narrow capillary tubes. Am. J. Physiol. 96, 562.Google Scholar
Gadala-Maria, F. & Acrivos, A. 1980 Shear-induced structure in a concentrated suspension of solid spheres. J. Rheol. 24, 799.Google Scholar
Gauthier, F., Goldsmith, H. L. & Mason, S. G. 1971 Particle motions in non-Newtonian media II. Poiseuille flow. Trans. Soc. Rheol. 15, 297.Google Scholar
Happel, J. & Brenner, H. 1965 Low Reynolds Number Hydrodynamics. Prentice-Hall.
Hookham, P. A. 1986 Concentration and velocity measurements in suspensions flowing through a rectangular channel. PhD thesis, California Institute of Technology.
Jenkins, J. T. & McTigue, D. F. 1990 Transport processes in concentrated suspensions: the role of particle fluctuations. In Two-Phase Flows and Waves. ed. D. D. Joseph & D. G. Schaeffer, pp. 7079. Springer.
Jenkins, J. T. & McTigue, D. F. 1993 Viscous fluctuations and the rheology of concentrated suspensions. J. Fluid Mech. submitted.Google Scholar
Karnis, A., Goldsmith, H. L. & Mason, S. G. 1966 The kinetics of flowing dispersions: I. concentrated suspension of rigid particles. J. Colloid Sci. 22, 531.Google Scholar
Karnis, A. & Mason, S. G. 1967 Particle motions in sheared suspensions. XIX. Viscoelastic media. Trans. Soc. Rheol. 10, 571.Google Scholar
Kim, S. & Karrila, S. J. 1991 Microhydrodynamics. Butterworth-Heinemann, Boston, MA.
Koh, C. J. 1991 Experimental and theoretical studies on two-phase flows. PhD thesis, California Institute of Technology.
Kowalewski, T. A. 1980 Velocity profiles of suspension flowing through a tube. Arch. Mech. 32, 857.Google Scholar
Kowalewski, T. A. 1984 Concentration and velocity measurements in the flow of droplet suspensions through a tube. Exps Fluids 2, 213.Google Scholar
Kowalewski, T. A. 1987 An experimental study of the lateral migration of a droplet in a creeping flow. Exps Fluids 5, 43.Google Scholar
Krieger, I. M. 1972 Rheology of monodisperse lattices. Adv. Colloid Interface Sci. 3, 111.Google Scholar
Leal, L. G. 1980 Particle motions in a viscous fluid. Ann Rev. Fluid Mech. 12, 435.Google Scholar
Leighton, D. & Acrivos, A. 1987 The shear-induced migration of particles in concentrated suspensions. J. Fluid Mech. 181, 415.Google Scholar
McMahon, T. A. & Parker, R. R. 1975 Particles in tube flow at moderate Reynolds number. Trans. Soc. Rheol. 19, 445.Google Scholar
Nott, P. R. & Brady, J. F. 1993 Pressure-driven flow of suspensions: simulations and theory. J. Fluid Mech. submitted.Google Scholar
Nouri, J. M., Whitelaw, J. H. & Yianneskis, M. 1986 An investigation of refractive-index matching of continuous and discontinuous phases. Third Intl Symp. on Applications of Laser Anemometry to Fluid Mech. Portugal.
Phillips, R. J., Armstrong, R. C., Brown, R. A., Graham, A. & Abbot, J. R. 1992 A constitutive equation for concentrated suspensions that accounts for shear-induced particle migration. Phys. Fluid A 4, 30.Google Scholar
Segré, G. & Silberberg, A. 1962 Behaviour of macroscopic rigid spheres in Poiseuille flow. Parts 1 and 2. J. Fluid Mech. 14, 115, 136.Google Scholar
Segré, G. & Silberberg, A. 1963 Non-Newtonian behavior of dilute suspensions of macroscopic spheres in a capillary viscometer. J. Colloid Intl Sci. 18, 312.Google Scholar
Sinton, S. W. & Chow, A. W. 1991 NMR flow imaging of fluids and solid suspensions in Poiseuilleflow. J. Rheol. 35, 735.Google Scholar
Timmermans, L. 1965 Physico-Chemical Constants of Pure Organic Compounds. Vol. 2. Elsevier.
Van de Hulst, H. C. 1957 Light Scattering by Small Particle. Wiley.