Ideal plug-flow properties of taylor vortex flow

Abstract

Mixing properties of Taylor vortex flow with small constant axial flow rates were investigated in an annulus between two concentric rotating cylinders by injecting a salt-solution tracer or by suspending small soluble particles. Longitudinal intermixing of fluid elements between the neighboring vortices was examined by a method of two-point measurement. Circumferential mixing in each cellular vortex was also evaluated by comparing two successive time variations of concentration at a certain point in the case of no axial flow. The modes of flow were mapped in terms of Taylor number and Reynolds number. This vortex flow has been found to be an ideal plug-flow for the range of 51.4 < Ta < 640 and 0< Re < 90. Each cellular vortex marches through the annulus in single file without intermixing over the cell boundary, whereas the toroidal motion of fluid elements causes highly effective radial mixing in the vortex. When Taylor number exceeds 640, the plug flow cannot be maintained owing to the occurrence of longitudinal intermixing over the cell boundary, which is attributable to the transition from singly to doubly periodic flow. © 1975, The Society of Chemical Engineers, Japan. All rights reserved.