Many chemical reactions are carried out using stirred tanks, and the
efficiency of such systems depends on the quality of mixing, which has been a
subject of research for many years. For solid-liquid mixing, traditionally
the research efforts were geared towards determining mixing features such as
off-bottom solid suspension using experimental techniques. In a few studies
that focused on the determination of solids concentration distribution, some
methods that have been used have not been accurate enough to account for some
small scale flow mal-distribution such as the existence of dead zones. The
present review shows that computational fluid dynamic (CFD) techniques can be
used to simulate mixing features such as solids off-bottom suspension, solids
concentration and particle size distribution and cloud height. Information on
the effects of particle size and particle size distribution on the solids
concentration distribution is still scarce. Advancement of the CFD modeling
is towards coupling the physical and kinetic data to capture mixing and
reaction at meso- and micro-scales. Solids residence time distribution is
important for the design; however, the current CFD models do not predict this
parameter. Some advances have been made in recent years to apply CFD
simulation to systems that involve fermentation and anaerobic processes. In
these systems, complex interaction between the biochemical process and the
hydrodynamics is still not well understood. This is one of the areas that
still need more attention.
CFD simulation of solids suspension in stirred tanks: Review
