同心二重管の内管から環状部への流れに関する研究 : 損失ヘッドと流の可視化  [in Japanese] Study on the Turning of Inner Pipe Flow into Outer Annulus Flow in a Concentric Double Pipe : Head Loss and Flow Visualization  [in Japanese]

The present study gives its experimental data using various types of concentric double pipes, in particularly, giving the loss of total head through a turning flow region from the outlet of inner pipe to the inlet of the annulus between the inner and the outer pipes. They are given in terms of a nondimensional clearance length L/d_i between the outlet of the inner pipe and the bottom of the outer pipe for various values of area ratio and Reynolds number. It should be noted that all curves of coefficient of head loss against L/d_i have the maximum value at L/d_i≒0.875 and the misimum value at L/d_i≒0.500. But due to the plate attached to the outlet of a inner pipe, the head loss for the clearance length ratio L/d_i=0.750〜1.00 decreases remarkably.