The Simulation of Dispersed-Phase Breakage Phenomena

Abstract

Droplet breakage in emulsification occurs as the result of work performed against surface tension by dynamic pressure fluctuations while deaggregation in biological wastewater treatment occurs in response to hydrodynamic stresses imposed by aeration, recirculation, and mixing. Such size reduction in the latter case leads to solids carry-over and poor process performance due to reduced sludge age. Laboratory observations of the disintegration process have shown how the hydrodynamic environment causes breakup and lean, batch breakage studies have indicated the most probable sizes of fragments. A Monte-Carlo type simulation has been used successfully to model the breakage process in both liquid-liquid and solid-liquid systems under high dissipation condi tions.

Floc Breakage Analysis— A Simulation Approach

“…Figures 2 and 3 show the typical transient floc size distribution generated by SIMA and SIMB, respectively. Characteristic common to these figures is that the movement of the distribution curve is rather fast at the early stage of the deflocculation process; this behavior is consistent with the eiperimental results (see, e.g., Hsu and Glasgow, 1984). illustrate the transient means and the corresponding variances, respectively, of the floc size distributions generated by SIMB.…”

“…Two algorithms have been examined in detail. The first algorithm, SIMA, has been described at length by Hsu and Glasgow (1984) and needs no further elaboration. In the second algorithm, SIMB, the number of daughter particles produced upon breakage is assumed to be an uniformally distributed random variable on the range (1, N,,,).…”

“…The characteristics of SIMB along with a previously investigated algorithm (Hsu and Glasgow, 1984), SIMA, have been examined in-depth.…”