Drop Dispersion in Turbulent Flow

In contrast to laminar flow, there are numerous studies of drop dispersion in practical turbulent flows, particularly for dilute systems, when coalescence can be neglected. Data are relatively easy to acquire, since water and other nontoxic Newtonian fluids serve as the continuous phase and waste disposal issues are 

We begin by considering mechanistic theories that allow correlation of equilibrium mean drop size in dilnte systems. An example of their application is given. Drop size distributions are then discussed. The predictive approach is extended to other contacting devices and to moderately concentrated noncoalescing systems. Some additional factors are considered, followed by a discussion of transient effects and time to achieve equilibrium. 

1 Mechanistic Modeis and Correiation of Mean Drop Size. Mechanistic models for maximum stable drop size in tmbulent flow are based on arguments put forth by Kolmogoroff (1949) and Hinze (1955). The stress acting to deform a drop of size d is given by 

For energy dissipation rates that commonly occur in stirred vessels, final drop sizes are small compared to the turbulence macroscale but large compared to the Kolmogoroff microscale, defined by 

Therefore, eddies that interact with the drops to determine the ultimate DSD fall within the inertial subrange of turbulence. These eddies are locally isotropic and E(k) can be described by Kolmogoroff s (1941a,b) theory of local isotropy  

---