On the Influence of the Specific Dissipation Rate Distribution on the Efficiency of Mass Transfer in Apparatuses with Liquid-Phase Media

A theoretical analysis of the influence of the distribution of the local specific energy dissipation rate on the specific interfacial area, the surface and volumetric mass transfer coefficients in apparatuses with heterophase processes and a liquid continuous phase, as well as the quality of mixing in apparatuses with homophase reactions in the liquid phase, is performed. It is shown that the average value of the specific energy dissipation rate over the volume of the device is not a full-fledged criterion for assessing the useful effect since it does not take into account, on the one hand, the local level of energy dissipation in the active zones and, on the other hand, the features of the flow structure and the local residence time in the active zones, depending on the geometry of the device and the method of energy input into it. Limiting cases are discussed: (1) uneven energy distribution in the presence of a small volume with a high specific dissipation rate and (2) ideally uniform energy distribution throughout the entire volume of the device. In the first case, a significant part of the volume is used inefficiently; in the second case, an excessive amount of energy is spent. In this regard, the concepts of dosed distributed energy input for long-term processes and maximum energy concentration in a microvolume for fast-flowing processes are considered.