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Experimental and theoretical studies on two-phase flows

Citation

Koh, Christopher James (1991) Experimental and theoretical studies on two-phase flows. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-06062005-103146

Abstract

This thesis, comprised of two parts, deals with the flow of suspensions. Part I concerns specifically with the stability of a single drop translating through a quiescent, unbounded suspending fluid at low Reynolds number. The evolution of the shape of an initially nonspherical drop as it translates is studied numerically and experimentally. For finite capillary numbers, it is shown that the drop reverts to a sphere provided that the initial deformation is small enough. However, beyond certain critical initial deformation, the drop deforms continuously. For initially prolate shapes, the drop elongates with the formation of a tail; for initially oblate shapes, the drop flattens with the formation of a cavity at its rear. Experiments extend the numerical results. It is found that initially unstable prolate drops break up into multiple droplets, while initially unstable oblate drops deform in double-emulsion drops.

Part II of this thesis considers the flow of high concentration solid suspensions through a rectangular channel. By adapting the well-known Laser Doppler Anemometry, an experimental technique is developed to measure the velocity as well as particle volume fraction of the suspension. A crucial element in these experiments is the reduction of the optical turbidity of the suspension. To accomplish this goal, a systematic method based on refractive-index-matching of the two phases is employed. Experimental results show that the velocity profile is blunted while the concentration profile has a maximum near the center. The qualitative features of the experimental data compare reasonably well with theoretical predictions based on the shear-induced particle migration theory.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:drops and bubbles stability; Laser Doppler Anemometry; suspension flow; Two-phase flow
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Leal, L. Gary
Thesis Committee:
  • Unknown, Unknown
Defense Date:4 February 1991
Author Email:planesmooth (AT) verizon.net
Record Number:CaltechETD:etd-06062005-103146
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-06062005-103146
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2472
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:06 Jun 2005
Last Modified:26 Dec 2012 02:51

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