The dependence of residence time distribution on flow in co-axial cylinder devices

Numerical simulations are presented showing the effects of operating and geometrical parameters on the transition of laminar to Taylor vortex flaw for induced Ta rotational-axial flow in the gap of a pair of rotating cylinders. These simulations indicate that annular rotational flow becomes more stable in the presence of a small degree of axial flow and as gap width increases. The effect of rotational speed on the breakdown of laminar flow is more complex and for given radius ratio and axial flow rate depends on both the speed ratio and the direction of the rotation of the cylinders, counter-rotating how generally producing a more stable flow than co-rotating. Limited experimental data are provided on the residence time distribution for flow of Newtonian liquids through the gap of two rotating cylinders. The data include results from experiments in which flow transition occurred from laminar to Taylor vortex flow. The findings from these experiments are successfully analyzed and assessed using the simulations studies.