Effects of Inclination and Rolling on Interfacial Parameter Distributions of Bubbly Flow in a Rectangular Duct
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摘要: 借助高速摄像机,对倾斜和摇摆条件下矩形通道(43 mm×3.25 mm×2000 mm)内泡状流局部界面参数的横向分布特性进行实验研究,包括局部气泡比例、空泡份额及界面面积浓度(IAC)。实验结果表明,竖直、倾斜及摇摆条件下,局部气泡比例、空泡份额及IAC三者的横向分布形状相类似。竖直静止及摇摆至竖直位置时,通道内中间较大范围内各局部参数变化缓慢,在xi/(w/2)=±0.5(xi为以通道宽边中心轴线为原点到窄边内壁面的距离,w为宽边尺寸)附近出现峰值;随着倾斜和摇摆角度的增大,下壁面附近峰值被削弱,上壁面附近峰值被加强。实验摇摆参数范围内,摇摆时局部参数的横向分布与实验段倾斜至相同角度时的分布十分相近;主要原因为在横向上摇摆引起附加惯性浮力远小于气泡受到的浮力。Abstract: Effects of inclination and rolling on lateral distribution of interfacial parameters for bubbly flow were studied experimentally with the help of a high-speed camera. Local parameters such as bubble proportion, void fraction and interfacial area concentration(IAC) were obtained in the experiments, showing a similar character with each other. These local parameters change slightly in the central part of the duct and present peaks around positions of xi/(w/2)=±0.5(xi represents the distance from origin based on the central axis of wide side to the inner wall surface of the narrow side, w denotes the wide side) in vertical position for both motionless and rolling cases. The peak of local parameters near the lower wall region is weakened and that near the upper wall is enhanced with an increase in inclined or rolling angles. There exist no obvious differences of interfacial parameters in lateral distribution at the same angle under inclined and rolling conditions within the range of experimental rolling parameters, which is mainly due to that the additional inertial force in lateral direction induced by rolling motion is far more less than that of buoyancy.
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Key words:
- Bubbly flow /
- Rectangular duct /
- Inclination /
- Rolling motion /
- Interfacial parameter distribution
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