F103 EXPERIMENTAL STUDY ON THE HELICAL FLOW FIELD IN A CONCENTRIC ANNULUS WITH ROTATING INNER CYLINDER(Heat transfer in complex system-1)

概要

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This experimental study concerns the characteristics of transitional flow in a concentric annulus with a diameter ratio of 0.52, whose outer cylinder is stationary and inner one rotating. The pressure losses and skin friction coefficients have been measured for the fully developed flows of water and that of glycerine-water solution (44%), respectively at inner cylinder rotational speeds of 0 〜 600rpm. The transitional flow has been examined by the measurement of pressure losses and visualizations of flow field, to reveal the relation between the Reynolds and Rossby numbers with the skin friction coefficients and to understand the flow instability mechanism. The occurrence of transition has been checked by the gradient change of pressure losses and skin friction coefficients with respect to the Reynolds numbers. Consequently, the critical (axial-flow) Reynolds number decreases as the rotational speed increases. Thus, the rotation of inner cylinder promotes the onset of transition due to the excitation of Taylor vortices.
一般社団法人日本機械学会の論文
2000-10-01