Flow behavior of liquid falling film on a horizontal rotating tube
Flow behavior of liquid falling film on a horizontal rotating tube
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DOI：
10.1016/j.expthermflusci.2006.05.004
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发表时间：
2007-02-01
影响因子：
3.2
通讯作者：
Mohamed, A. M. I.
中科院分区：
文献类型：
--
作者：
Mohamed, A. M. I.
水平管外表面的液膜下降是换热器中重要且常用的传热过程。通过实验研究了管的旋转速度对降膜模式跃迁、膜厚度和无量纲波长的影响。实验表明，当液体降膜落在水平旋转管上时，转变从低雷诺数开始。为避免管子旋转过程中不稳定的落膜，管子的旋转速度不应超过最大旋转速度。随着转速的增加，薄膜厚度的值略有下降。在雷诺数为 285 且转速为 300 rpm 时，观察到水膜的膜厚度减少了约 12%。由于高粘度流体管的转速增加，无量纲波长 lambda* 明显减小。另一方面，对于低粘度流体（水以及 50% 水和 50% 乙二醇的混合物）观察到较小的影响。 (c) 2006 Elsevier Inc. 保留所有权利。
Falling liquid film on outside surface of a horizontal tube is an important and commonly used heat transfer process in heat exchangers. Experimental study has been conducted to investigate the effect of the rotation speed of the tube on the falling film mode transitions, film thickness and dimensionless wavelength. Experiments have been indicated that, when a liquid falling film falls on a horizontal rotating tube, the transition starts at low Reynolds number. To avoid instable falling film during rotation of the tube, the tube speed of rotation should not exceed the maximum speed of rotation. The value of the film thickness has been slightly decreased by increasing the rotation speed. A reduction of the film thickness was observed at about 12% for water film at Reynolds number of 285 and 300 rpm rotating speed. A clear reduction of the dimensionless wavelength, lambda*, has been occurred due to the increase of the rotating speed of the tube for high viscosity fluids. On the other hand, a small effect has been observed for low viscosity fluids (water and mixture of 50% water and 50% ethylene glycol). (c) 2006 Elsevier Inc. All rights reserved.