Macromixing and micromixing

Mixing between mutual-soluble liquids is usually carried out by the action of certain external forces, e.g. agitation. Mixing occurs at various scales and the segregation scale varies with time. An idealized model of the mixing between a black liquid and a white liquid is illustrated in Fig. It). I. 

The status of micromixing is described by the parameter characteristic time constant for micromixing , fM, which can be simply called micromixing time. It represents the time needed to achieve completely uniform micromixing, and is correlated to the microscale A by 

The obvious inference that can be made is that both macro- and micro-mixing are closely related to the flow configuration in the device considered. 

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Macromixing vs Micromixing. Mixing in an agitated tank is considered to occur at two levels, macromixing and micromixing. 

In what follows, both macromixing and micromixing models will be introduced and a compartmental mixing model, the segregated feed model (SFM), will be discussed in detail. It will be used in Chapter 8 to model the influence of the hydrodynamics on a meso- and microscale on continuous and semibatch precipitation where using CFD, diffusive and convective mixing parameters in the reactor are determined. 

Considerations of Macromixing and Micromixing in Semi-Batch Stirred Bioreactors... 

Until 10 to 15 years ago the combined approach of macromixing and micromixing models was very widely used in the field of CRE but gradually CFD-based strategies have replaced the first mentioned strategy. In this respect it should be noted that this change also introduced big conceptual differences because the traditional CRE approach is usually formulated in the age space of fluid parcels whereas in CFD approaches a Eulerian framework is often adopted. Subsequently a brief overview of CFD-based approaches for reacting flows is presented and the current limitations are also indicated. 

Coalescence and redispersion models applied to these reaction systems include population balance equations, Monte Carlo simulation techniques, and a combination of macromixing and micromixing concepts with Monte Carlo simulations. Most of the last two types of models were developed to... 

F. Type III Interaction Models Use of Macromixing and Micromixing Concepts... 

FIGURE 5.5 Extent of macromixing and micromixing and suitability of reactor models. 

Localization of physical Macromixing and micromixing Equipment can be selected for... 

Let us consider the effect of macromixing and micromixing on the conversion in CSTR and PFR systems. 

Dispersed phase interaction models (1.Population balance techniques,2.Monte Carlo simulation models and 3.Models using macromixing and micromixing concepts)... 

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