Date of Award

Spring 2001

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering - (Ph.D.)

Department

Civil and Environmental Engineering

First Advisor

Jay N. Meegoda

Second Advisor

Denis L. Blackmore

Third Advisor

John R. Schuring

Fourth Advisor

Taha F. Marhaba

Fifth Advisor

Kauser Jahan

Abstract

The fractionation of particles by size or by density has many applications in a variety of technologies. Decontamination and separation of fine sediments is useful in treating sediments. The application of acoustic standing wave fields for the fractionation and segregation of suspended particles was studied.

The above technology was implemented at the bench scale by building a Plexiglas chamber. Two ultrasound transducers were fixed to opposite sides of the chamber to generate the acoustic standing wave field. The technology was evaluated using silica dioxide (Si02) (1-5 ~tm) and silicon carbide (SiQ (5-20 ~tm) particle suspensions in deionized water. Due to the acoustic force field, Si02 particles migrated towards the pressure nodes at half wavelength intervals within the channel at optimum frequency of 333 kHz and 40 W power.

The fractionation process was mathematically modeled, by deriving particle trajectonies and concentration. The SiC particle's displacements due to an acoustic force were used to be compared with the mathematical model predictions. For input power level between 3.0 to 5.0 W, the experimental data were comparable to mathematical model predictions. Also, based on the experimental data it was possible to develop a relationship between input power and acoustic energy in the resonance chamber. The proposed technology will provide viable alternatives to the classical fractionation methods.

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