Liquid-Phase Mixing in Stirred Vessels:  Turbulent Flow Regime

Abstract

The published literature on the liquid-phase mixing in a turbulent flow regime has been critically reviewed and analyzed. Experimental techniques for mixing time have been described together with their relative merits. The effects of the impeller design (blade number, blade angle, blade and disk dimensions, and blade shape), the location of the impeller (off-bottom clearance, distance from the vessel center, i.e., eccentricity), and the vessel size on the liquid-phase mixing have been critically analyzed. The mixing performance dependency on the internals such as baffles (number, dimension, and position) and the draft tube has been presented in detail. Further, an extensive review on the mathematical models proposed for the liquid-phase mixing has been presented, and the utility of the computational fluid dynamics modeling for the mixing optimization has been illustrated. Finally, suggestions have been made for the selection of an energy-efficient impeller-vessel configuration, and directions have been given for future studies.

Unsteady Mixing Characteristics in a Vessel with Forward‐Reverse Rotating Impeller

“…According to the turbulence model, the mixing time for various impellers (in the same vessel and for the same D/T ratio) is constant [29,30]. This relation is expressed by:…”

Mixing Time—Experimental Determination and Applications to the Modelling of Crystallisation Phenomena

“…A comprehensive review of available experimental techniques and influence of various parameters has been given by Nere et al (2003) and Ghotli et al (2013). Experimental In this work the laser-induced fluorescence has been used.…”

“…The characteristic mixing times associated with each of these three ranges of scales are different. Nere et al (2003) and Ghotli et al (2013) wrote an expanded review of mixing time models and divided them into five categories: (a) semi-empirical correlations based on experimental data, (b) models based on bulk flow, which assume that the process is controlled by the bulk or convective flow, (c) dispersion based models, (d) models that segregate the whole stirred vessel into a network of interconnected zones, and (e) CFD models. The characteristics of those types of models were extensively discussed by Nere et al (2003) and Ghotli et al (2013).…”

Stochastic Simulation of Droplet Interactions in Suspension Polymerization of Vinyl Chloride

“…The initial droplet size distribution is affected by the collision, coalescence and breakage frequencies. These frequencies were calculated using the expressions and parameters by Alopaeus et al [22] while the energy dissipation rate, influenced by some properties of the impeller such as impeller speed, impeller diameter, power number of impeller, and naturally the properties of mixed phase, the volume and density of the mixture was computed as discussed by Nere et al [23]. Figure 3 represents the monomer droplet size distribution computed for impeller speed is 350 rpm and dispersed phase volume fraction is 0.3.…”