Flow visualization in an annulus between co-axis rotating cylinders with a circular jet on stationary outer cylinder

This work experimentally investigated the effects of jet flow and flow outlet configuration on the fluid flow in an annulus between co-axis rotating cylinders. By using the incense and the laser light, smoke flow visualization in a rotating annulus can be obtained. Firstly, the flow behavior in a rotating annular without jet flow and flow outlet was investigated. When Taylor number (Ta) exceeded 1708, the well-known Taylor vortices were successfully observed. Subsequently, the flow characteristics in a rotating annular with a jet flow and various flow outlet configurations were investigated. The circle jet nozzle was located at the middle position of the stationary outer cylinder. In addition, two flow outlet configurations were employed. One was the model of single outlet at the right side of the annulus, the other was the model of double outlets at both side of the annulus. The jet Reynolds number (Re) was 1351. The Taylor number (Ta) varied from 545 to 24,217. When the impinging force and the inertia force from the jet flow interacted with the Coriolis force and the centrifugal force due to rotation, the fluid flow should become very complicated. The experimental results indicated that the rapid rotation broke the original stream line of the jet flow. On the other hand, when the jet flow turned 90° to be the axial flow, it would suppress the onset of Taylor vortices. Finally, fixing the Re and Ta, the model of single outlet more suppressed the onset of Taylor vortices than the model of double outlets did.