The definition of mixing efficiency can mean many different things, depending on whether the process is liquid blending for formulation, mixing intensity for chemical reaction, solids suspension, gas dispersion.  Geometric similarity is also vague, especially if it includes different types of impellers.  Different types of impellers can mean different performance, both with respect to quantity of motion and direction of motion.  A definition of the process objective, and description of both scales of equipment is needed to provide a reasonable estimate.  Scale-up without geometric similarity is quite possible, but with different answers for different situations.

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