Rotation Speed Of Inner Cylinder Research Articles

Synthesis of Monodisperse Silica Particles using Rotating Cylinder Systems

Monodisperse silica nanospheres were synthesized by Stober method using rotating cylinder systems with batch or continuous manner. The particle size could be controlled by adjusting the reactant compositions such as the amount of monomer, catalyst, and water in the reaction mixture. The size and monodispersity of the ceramic particles could be controlled by changing the reaction medium with different alcohols other than ethanol or changing the reaction temperature. The effect of Taylor number (Ta) on the average diameter and standard deviation of silica particles were also studied by adjusting the rotation speed of inner cylinder, and the maximum diameter of particles was observed at Ta ? 3,000.

Pharmaceutical crystallization in Couette-Taylor crystallizer: A case study of polymorphism of amino acid L-glutamic acid

The influence of intensity Taylor vortex flow in Couette-Taylor crystallizer on the crystallization of polymorphic amino acid L-glutamic acid was investigated in cooling crystallization. Here, the L-glutamic acid was chosen as the model crystal product, where it has two kinds of polymorphism including the unstable phase α-form and stable phase β-form crystal. In cooling crystallization, the α-form crystal transformed to the β-form crystal corresponding to the phase transformation of α-form to β-form crystal. The present study found that the selective polymorphism of α-form and β-form crystal as well as the phase transformation significantly depended on the intensity of turbulent Taylor vortex flow in Couette-Taylor crystallizer. Here, the selective β-form nucleation and phase transformation were remarkably promoted as increasing the rotation speed of inner cylinder in Couette-Taylor crystallizer. By comparison with the conventional stirred tank (ST) crystallizer, the Couette-Taylor (CT) crystallizer was at least 2.0 times more effective as regards the selective β-form polymorphism and phase transformation time. The advantage of CT crystallizer over the conventional ST crystallizer was explained in terms of the high shear stress and mass transfer of turbulent Taylor vortex flow in CT crystallizer. Here, the shear stress of Taylor vortex flow in CT crystallizer was at least 23.0 times higher than that of fluid motion in conventional ST crystallizer, whereas the mass transfer of Taylor vortex flow in CT crystallizer was at least 1.2 times higher than that of fluid motion in conventional ST crystallizer. As such, the high turbulent shear stress of Taylor vortex flow was expected to promote the β-form nucleation via the effective molecules alignment, whereas the high mass transfer of Taylor vortex flow facilitated the dissolution rate of α-form and growth rate of β-form crystal, resulting in an acceleration of phase transformation rate.

1603 液晶マイクロモータ駆動に関する数値シミュレーション(OS16-1 非ニュートン流体の流動現象,オーガナイズドセッション)

We have numerically simulated the liquid crystalline micromotor, using the Leslie-Ericksen continuum theory. When an electric field is applied between concentric cylinders, the liquid crystalline flow called the back-flow is induced due to the reorientation of the liquid crystalline molecules. The flow causes the shear stress at inner cylinder surface and the rotation of the inner cylinder occurs. The rotation speed of inner cylinder increases with decrease of the inner cylinder radius.