Effects of pipe diameter on interfacial and wall friction factors of swirling annular flows in a vertical pipe

Q3 Engineering

Multiphase Science and Technology Pub Date : 2023-01-01 DOI:10.1615/multscientechn.2023050392

Ryoya Koto, Ryo Kurimoto, Kosuke Hayashi, Akio Tomiyama

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Abstract

Interfacial and wall friction factors, fi and fw, of swirling annular flows in a vertical pipe of 20 mm in diameter D were measured for comparison with those in a vertical pipe of D = 30 mm. A three-fluid model was applied to evaluate the friction factors. Measurements were carried out in two sections, one near the swirler and the other far downstream the swirler. The swirl intensity of the flow was evaluated by the interfacial swirl number si defined by the ratio of the azimuthal to the axial components of interfacial wave velocity. The interfacial swirl numbers were smaller in the smaller pipe. The ratio of fi in swirling annular flows to that in non-swirling annular flows decreased to unity with decreasing si* which is the arithmetic mean value of si for 0 < z* (= z/D) < 3.8, where z is the axial coordinate in the test section, and is higher in D = 20 mm than in D = 30 mm. The ratio of fw in swirling annular flows to that in non-swirling annular flows decreased to less than unity with decreasing si* and is higher in D = 20 mm than in D = 30 mm.

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管径对垂直管内旋流环空流动界面和壁面摩擦因数的影响

测量了直径为20 mm的垂直管道中旋转环形流的界面和壁面摩擦系数fi和fw，并与直径为30 mm的垂直管道中的摩擦系数进行了比较。采用三流体模型对摩擦系数进行了评价。测量分两个部分进行，一个靠近旋流器，另一个位于旋流器的下游。流动的旋流强度由界面波速的方位角分量与轴向分量之比定义的界面旋流数si来评价。管道尺寸越小，界面旋流数越少。旋转环空流与非旋转环空流的fi之比随着si*的减小而趋于一致，即si在0 < z* (= z/D) < 3.8时的算术平均值，其中z为试验段轴向坐标，且在D = 20 mm时比D = 30 mm时更高。随着si*的减小，旋流环空流与非旋流环空流的流量之比减小到小于1，且在D = 20 mm时比D = 30 mm时更高。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Multiphase Science and Technology Engineering-Engineering (all)

CiteScore

0.80

自引率

0.00%

发文量

期刊介绍： Two-phase flows commonly occur in nature and in a multitude of other settings. They are not only of academic interest but are found in a wide range of engineering applications, continuing to pose a challenge to many research scientists and industrial practitioners alike. Although many important advances have been made in the past, the efforts to understand fundamental behavior and mechanisms of two-phase flow are necessarily a continuing process. Volume 8 of Multiphase Science and Technology contains the text of the invited lectures given at the Third International Workshop on Two-Phase Flow Fundamentals sponsored by the Electric Power Research Institute (EPRI) and the U. S. Department of Energy (DOE).