ABSTRACT
The unit operation of mixing is extensively involved in bioprocessing systems. Some of the keys to mixing operations include mixing to dissolve components of a buffer, culture media, refolding solution, dispersion of cell culture in bioreactors, and heating or cooling of liquids. In bioprocessing operations, two types of mixing are important: one that leads to the dissolution of solutes, and the other that provides a homogenous environment such as in a bioreactor or a refolding tank. In fluid dynamics, mixing length theory is a method attempting to describe momentum transfer by turbulent Reynolds stresses within a fluid boundary layer by means of an eddy viscosity. Laminar mixing, often encountered in fluids with high viscosities, originates from a longitudinal mixing where fluid motion is dominated by linear viscous forces. There are several distinct types of mixing systems currently available in bioprocessing where disposable mixing containers are used. These include: stirrer systems, oscillating systems, and peristaltic systems.
