内管旋转的垂直同心环形管内单相流动特性的试验研究

分别以空气、油、水为工作介质对内管旋转的垂直同心环形管内的单相流动特性进行了系统的试验研究。首先在100 Re 70000的范围内对内管不转的环形管内的摩擦阻力进行了试验测定,并与几种摩阻关系式进行了比较,得出同心环形管内紊流摩擦系数比圆管摩擦系数约高6%~10%,Sadatomi的关系式可用于4000 Re 70000的范围内的紊流计算。采用测量轴向摩擦压降的方法,对内管旋转的环形管内的流动离心不稳定性以及摩阻进行了试验研究,得出了直径比小于0.8时,层流向层流+Taylor涡旋的转换边界及紊流+Taylor涡旋向紊流的过渡边界,并针对不同流型给出了适用于较大环形间隙环形管的摩阻关系式。

Test Study on the Flowing Behavior of Single - Phase Flow in the Vertical Concentric Annular Pipe with Rotating Inner Pipe

Using air, oil, and water as working medium, a test study is conducted to discover the flowing behavior of the single-phase flow in the vertical concentric annular pipe, which contains rotating inner pipe. The frictional resistance in the annular pipe is firstly measured, with the static inner pipe, when 100 Re 70000; and then compared with several other frictional resistance formulas. It is concluded that frictional coefficient of turbulence is about larger 6%~10% than laminar in a concentric annular pipe. By measuring the axial frictional pressure drop, the centrifugal instability and the frictional resistance in the annular pipe is investigated, when the inner pipe is rotating. The converting boundary from laminar flow to laminar plus Taylor vortex, and turbulence plus Taylor vortex to turbulent flow is obtained when the diameter ratio is lower than 0.8, and a new frictional resistance formula is also presented for different flowing type in the concentric pipe of larger annular.