Study on cavern evolution and performance of three mixers in agitation
of yield-pseudoplasitc fluids
Abstract
The hydrodynamic performance of the three mixers (single shaft central
mixer, single shaft off-centred mixer, dual shaft off-centred mixer,
i.e. SSC, SSO, DSO), was investigated in the mixing of
yield-pseudoplastic fluids (xanthan gum solutions) in the laminar
regime. Computational Fluid Dynamics was employed to simulation the
apparent viscosity distribution, mixing time and the flow pattern in the
stirred tank. The influence mechanism of the rotational speed and fluid
rheology on the cavern evolution was explored deeply. The results
verified that the faster the rotating speed, the greater influence of
the fluid rheology was obtained on the cavern evolution. Moreover, the
Nt95 of DSO was nearly 42.8% and 6.1% shorter than that of SSC and SSO
at the same Re*, respectively. These data also revealed that the DSO was
more efficient than SSC and SSO in mixing of yield pseudoplastic fluids
with regard to the mixing time and power drawn.