Bottom Drainage Port

Some scale-up methods emphasize geometric similarity. This refers to holding constant the impeller geometry, the impeller dimensional ratios (such as D/T, W/D, C/T), the liquid height/tank diameter ratio, and baffling. There are many situations when complete geometric similarity is not feasible for example, when the aspect ratio of commercial scale tanks needs to be larger than the laboratory tank. 

There are two commonly used scale-up criteria based on holding power per unit volume (P/V) or torque per unit volume (Tq/V) constant on scale-up. 

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