Analysis Applied to Mixing Liquids

An important number of factors having a key influence on this unit operation [6.19, 6.20], together vith the examples described above, show how difficult it is to formulate a complete and unitary mixing theory responding to the various technical questions such as mixing time, distribution of the residence time, power consumption, heat and mass transfer kinetics in mixed media, scaling-up of a laboratory mixing plant etc. 

In order to simplify the problem, we will apply dimensional analysis to liquid mixing in a particular case. The studied example will take into account the interactions showing  

The first necessary condition [6.21] to be taken into account in all particularization cases is the use of general mixing parameters (factors related to the geometry of agitation, the properties of liquid media, the type of agitators and rotation speed) as well as the use of the specific factors of the studied application. For example, in the case of suspended solid dissolution, we can consider the mass transfer coefficient for dissolving suspended solids, the mean dimension of the suspended solid particles, and the diffusion coefficient of the dissolved species in the liquid. 

In this chapter, we present two particularizations the first concerns the dependence of the power consumption on the considered influencing factors the second shows the relationship between the mixing time and its affecting factors. 

In order to establish the list of variables, we use the explicative Fig. 6.4 in both cases. It especially shows the geometry of agitation, allowing the introduction of geometric, material and dynamic factors. 

---