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| Numerical simulation of gas-liquid Taylor flow in mini/micro tubes |
| ZHANG Jing-zhi, LI Wei |
| Department of Energy Engineering, Zhejiang University, Hangzhou 310027, China |
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Abstract A numerical simulation of fully developed gas-liquid Taylor flow in mini/micro tubes with tube diameters of 0.5, 1, and 2 mm was conducted with the moving frame method. The bubble shape, bubble rising velocity, liquid film thickness, and pressure drop characteristics of Taylor flow were analyzed. The numerical data fit well with theresults in open literatures and empirical correlations.The results show that the unstable region nearthe bubble tail increases with increasing inlet Reynolds number. The length of Taylor bubbleand inner recirculation zone increases with increasing initial bubble void fraction.Thenormalized liquid film thickness and bubble rising velocityare proportional to capillary number, while they are independent on tube diameters and bubble void fraction. The correlation to predict normalized liquid film thicknessis amended with the data obtained from the present work and open literatures forcapillary number smaller than 0.01. The deviations ofthe predicted value from thenumerical data are less than ±15%. The frictionalfactorof the whole computation domain decreases with increasing Reynolds number and with increases in bubble void fraction. The separate model and flow pattern dependent model can predict frictional pressure dropgradients well.
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Published: 01 August 2015
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微小管径圆管气-液Taylor流动数值模拟
采用移动计算域方法,对微小圆管（管径为0.5、1、2 mm）内充分发展的气-液Taylor流动进行数值研究,分析Taylor气泡的形状、上升速度、液膜厚度及压降特性.将数值结果与文献数据及经验公式进行对比,吻合较好.模拟结果表明,随入口雷诺数增大,气泡尾部不稳定区域增大.气泡长度及内部回流区随气泡体积分数增大而增大.无量纲液膜厚度与气泡上升速度与毛细数正相关,与管径以及气泡体积分数关系较小.当毛细数小于0.01时,修正液膜厚度的预测公式、预测值与模拟结果的误差在±15%以内.计算域阻力因子随着入口雷诺数与气泡体积分数的增大而降低,分离模型以及流型依赖模型可以较好地预测本文模拟结果.
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