Breakage kernel turbulence

Fig. 9.5. A sketch of the breakage kernel of Luo and Svendsen [74]. An unequal daughter size distribution is predicted by this model. In this case the parent diameter size is, di = 0.006 (m), and the turbulent energy dissipation rate is set at, = 1 Reprinted with permission from [38], Copyright 2005 American Chemical...

The breakage and agglomeration kernels depend on mixing conditions. Optimizing the power input to the system which determines the turbulent kinetic energy it is possible to minimize breakage or agglomeration. 

However, in other cases the model predictions deviate much more from each other and were in poor agreement the experimental data considering the measurable quantities like phase velocities, gas volume fractions and bubble size distributions. An obvious reason for this discrepancy is that the breakage and coalescence kernels rely on ad-hoc empiricism determining the particle-particle and particle-turbulence interaction phenomena. The existing param-eterizations developed for turbulent flows are high order functions of the local... 

Venneker et al [118] made an off-line simulation of the underlying flow and the local gas fractions and bubble size distributions for turbulent gas dispersions in a stirred vessel. The transport of bubbles throughout the vessel was estimated from a single-phase steady-state flow fleld, whereas literature kernels for coalescence and breakage were adopted to close the population balance equation predicting the gas fractions and bubble size distributions. 

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