Memoirs of the Graduate School of Engineering Kobe University, No. 1, pp. 48-51, 2009

Observation of Inertial Particle Motion in Laminar Flow in a Stirred Vessel

Nami NISHIOKA1, Alatengtuya2, Norihisa KUMAGAI2, Takafumi HORIE2, Naoto OHMURA2

1Graduate School of Science and Technology, Department of Chemical Science and Engineering
2Graduate School of Engineering, Department of Chemical Science and Engineering

(Received September 28, 2009; Accepted January 14, 2010; Online published January 21, 2010)

Keywords: Stirred Vessel, Laminar Flow, Particle Motion, Solid-Liquid Flow, Nonlinear Dynamics

Inertial particle motion in a stirred vessel with no baffle plate was observed experimentally and numerically at low Reynolds numbers. Several particles were captured on a torus orbit within one of the IMRs and kept traveling around the impeller. The particles captured in the IMRs enhance the exchange of material with the outside active mixing region. The primary and secondary circulation flow directions were defined φ- and θ-direction respectively. Initially, particle orbit obtained by Poincaré section shows that the particle motion covers the full surface of the torus orbit and the ratio of the period for one round of a particle in φ-direction to that in θ-direction, Pθ /Pφ, is irrational, while after a long time, the circular orbit on the Poincaré section converges on three discrete points and Pθ /Pφ is rational. Numerical simulation revealed thsat even after a particle seemed to have almost settled on a final orbit, the diameter of secondary circulation was not constant. After a particle has been captured, the drag force frequently works on the surface of the particle since the particle always exists near the impeller

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