The suspension of spherical glass beads in water

Author

David Isert, New Jersey Institute of Technology

Document Type

Thesis

Date of Award

6-30-1962

Degree Name

Master of Science in Chemical Engineering - (M.S.)

Department

Chemical Engineering

First Advisor

George C. Keeffe

Second Advisor

Jerome J. Salamone

Third Advisor

Joseph Joffe

Abstract

The purpose of this investigation was to determine, for the first time, a correlation between mixing and fluidization in a system of spherical glass beads and water.

Mixing data for the spherical glass bead-water system was obtained experimentally and abstracted from previous studies.⁽¹⁾

Fluidization data for the spherical glass beadwater system was obtained from the literature.⁽²⁾

The terminal velocity and the Reynolds Number at terminalization was calculated for the mixing system from the data obtained in this investigation. The terminal velocity and Reynolds Number, as determined experimentally was obtained from the literature,⁽³⁾ A comparison of the terminal velocities and Reynolds Numbers obtained for the mixing and fluidization systems for the same size spherical glass beads indicated these parameters to be identical and agree within 3%. Thus, the terminal velocity and the Reynolds Number at terminalization are the correlating factors for the mixing and fluidization systems.

As a result of the conclusion that mixing and fluidization systems are identical at the terminalization point for spherical glass beads and water, a comparison of the two systems may be made directly. This further allows for the determination of the most efficient system necessary to accomplish a specific purpose.

A portion of this investigation was devoted to comparing various types of mixing systems. This study indicated that a marine impeller, pump down action, and baffled tank was the most efficient system, from the standpoint of power requirements, for the suspension of a given quantity of spherical glass beads of a specific size in water. However, these requirements were approximately 200 times the power requirements necessary to suspend the same size and quantity of spherical glass beads in water using the fluidization system as defined in the literature. ⁽⁴⁾

It has also been shown that in the relationship of horsepower required to suspend given weights of spherical glass beads, there is a region where for additional weights of spherical glass beads no additional expenditure of energy is required. It has been found that this is due to the baffling effect of the spherical beads in suspension, changing the currents in the mixing system.

In this investigation general mixing equations have been developed to determine shaft R.P.M. to suspend given weights of given particle diameters in a given system for spherical glass beads in water. These equations are

a) For a turbine impeller, baffled system, and spherical particle diameters below 200 microns N = 410 D_s^0.048 G_s^0.43/Ds0.52

b) For a turbine impeller, baffled system and spherical particle diameters equal to and greater than 200 microns N = 27 D_s^0.46 G_s^0.10/Ds0.78

c) For a marine impeller, baffled system and spherical particle diameters below 200 microns N = 360 D_s^0.046 G_s^2.6/Ds0.78

d) For a marine impeller, baffled system, and spherical particle diameters equal to or greater than 200 microns N = 2.5 D_s^0.84 G_s^2.65/Ds0.80

These equations are applicable from 0 to approximately 60 grams of spherical glass beads.

(1) References 1, 4

(2) Reference 2

(3) Reference 2

(4) Reference 9

Recommended Citation

Isert, David, "The suspension of spherical glass beads in water" (1962). Theses. 2985.
https://digitalcommons.njit.edu/theses/2985