Investigations of the spreading of falling liquid films in inclined tubes
Investigations of the spreading of falling liquid films in inclined tubes
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DOI：
10.1016/j.ijheatmasstransfer.2017.11.142
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发表时间：
2018-04
影响因子：
5.2
通讯作者：
S. Eichinger;T. Storch;T. Grab;T. Fieback;U. Gross
中科院分区：
文献类型：
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作者：
S. Eichinger;T. Storch;T. Grab;T. Fieback;U. Gross
本文从大量的文献综述入手，研究了光滑管和结构管中降膜的膜扩展与管倾角（β= 0° ~ 20°）、质量流量和流体温度（263.15-293.15 K）的关系。实验是在等温条件下进行的，也是在部分膜蒸发条件下进行的。用摄像机目视观察液膜，该摄像机可以沿着液体的总流动长度移动，而不会对液体或气体流动造成实质性干扰。研究所用液体为丙烷（Pr = 3，Ka = 20· 10 10，Re = 20-950）。实验表明，所研究的内管表面的螺旋结构导致膜铺展的改善，甚至对于高达β= 20°的倾斜角。在一个开放的空气-水系统中的初步测试清楚地表明，槽结构的几何形状对初始润湿和膜铺展有影响。此外，从两个理论方法计算的毛细管输运的结果进行了比较，并相互适应。
Starting with an extensive literature review, in this study investigations of the film spreading of falling films inside smooth and structured tubes are presented in dependence of the tube inclination angle (β= 0° til 20° from the vertical), mass flow rate and fluid temperature (263.15–293.15 K). Experiments are conducted at isothermal conditions and at partly film evaporation as well. The liquid film is observed visually with a camera which can be moved along the total flow length of the liquid without essential disturbance of the liquid respectively gas flow. The liquid used for the investigations is propane (Pr≈ 3, Ka≈ 20· 10 10, Re smooth tube= 20–950). The experiments reveal that the investigated helically structuring of the internal tube surface leads to an improvement of film spreading even for inclination angles up to β= 20°. Preliminary tests in an open air-water system clearly showed that the groove structure geometry has an influence on initial wetting and film spreading. Further, the results of the calculated capillary transport from two theoretical approaches are compared and adapted to each other.