It was found that under laminar flow conditions, the A-
45PBT6 impeller led to formation of smallest IMRs at a given
Reynolds number, as evident from a/A vs. specific power data.
Alvarez et al. (2002) conducted the experiments based on the
time progression of fluorescent dye injection and they demonstrated
that the periodic perturbation caused by impeller
blades triggers chaos in laminar systems. The perturbation
introduced by the blades is thus the main factor causing
the reduction in IMR size in our experiments; therefore it is
not surprising to note that the impellers with more blades
(e.g. DT6 and 45-PBT6 here) have the smallest IMRs, owing to
the introduction of the greater perturbation by their blades.
However, it is unsure to us whether installation of more blades
in an impeller can actually lead to better mixing quality as it
approaches geometry similar to a disc. In addition, it should be
noted that the asymmetrical design of our impeller (A-45PBT6)
also contribute to the introduction of greater periodic perturbation,
and the more effective mixing results make it the first
option for liquid blending, regardless of baffled and unbaffled
conditions.