DROP BREAK-UP AND COALESCENCE IN A STIRRED TANK

Abstract

It is shown in the paper that drop size distribution in liquid-liquid dispersions is affected by both the fine-scale and the large-scale inhomogeneity of turbulence. Fine-scale inhomogeneity is related to the phenomenon of local intermittency and described using a multifractal formalism. Largescale inhomogeneity is related to inhomogeneous distributions of the locally averaged properties of turbulence, including the rate of energy dissipation and the integral scale of turbulence. Large-scale distributions of the properties of turbulence in a stirred tank are considered with a network of wellmixed zones. CFD methods are used to compute the properties of turbulence in these zones. A model taking into account inhomogeneity of both types explains the effect of the system’s scale on drop size; it predicts smaller maximum stable drop sizes than the classic Kolmogorov theory of turbulence. The model predictions agree well with experimental data.