Lagrangian models for the micromixing rate

One of the principal difficulties faced when employing Lagrangian micromixing models is the determination of tm based on properties of the turbulent flow fields. Researchers have thus attempted to use the universal nature of high-Reynolds-number isotropic turbulence to link tm to the turbulence time scales. For example, in the E-model (Baldyga and Bourne 1989) the engulfment rate essentially controls the rate of micromixing and is defined by 

Lu to r). One should thus proceed cautiously when applying (5.251) in CFD calculations of plant-scale reactors. 

One common difficulty when applying the E-model is the need to know the turbulent dissipation rate e for the flow. Moreover, because e will have an inhomogeneous distribution in most chemical reactors, the problem of finding e a priori is non-trivial. In most 

The importance of including mesomixing in the definition of tm has been demonstrated using jet-mixer scale-up experiments by Baldyga et al. (1995). In these experiments, the micromixing rate was found to scale as 

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