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中文核心期刊

横向振动立管上升流中球形单颗粒运动特征

CHARACTERISTICS OF A SPHERICAL PARTICLE MOTION IN AN OSCILLATING RISER WITH UPWARD FLOW

  • 摘要: 深海采矿过程中, 输送矿石颗粒的立管在复杂海洋环境作用下会产生运动响应, 这会对管道中矿石颗粒的运动行为产生重要影响, 从而影响矿石提升效率, 甚至可能危及整个采矿系统的安全. 结合颗粒运动方程和软球碰撞模型, 对横向振动立管中的球形单颗粒运动特征进行研究, 主要分析了立管振动参数、颗粒与流体密度比以及颗粒与立管直径比对立管中单颗粒运动的影响. 研究表明, 随振动频率和幅度、颗粒与流体密度比以及颗粒与立管直径比的增加, 颗粒垂向平均速度减小. 颗粒与管壁之间无碰撞发生时, 颗粒与立管之间横向相对速度幅值、颗粒运动与立管之间横向速度的相位差以及颗粒垂向速度波动幅值, 与立管振动的频率和振幅、颗粒与流体密度比以及颗粒与立管直径比呈正相关. 然而, 当颗粒与立管之间有碰撞发生时, 颗粒与立管间的横向速度的相位差减小, 而颗粒垂向速度波动幅值显著增大. 另外, 随着密度比和直径比的增大, 颗粒与管壁之间更容易发生碰撞, 而碰撞会减弱密度比和直径比对颗粒横向速度和垂向速度的影响.

     

    Abstract: In deep-sea mining, vibrations can be induced when the lifting risers subject to ocean waves and currents, and these vibrations have an impact on the lifting efficiency and ores motion transported inside the risers. Here, by using the governing equation for motion of a spherical particle and the soft sphere collision model, the particle movement in a riser with upward flow and oscillating in the lateral direction is investigated. Validations are conducted based on comparisons of our data with numerical and experimental results. Then, the motion of a single particle in the vibrating riser is explored, considering the effects of the frequency and amplitude of the riser vibrations, the density ratio of the particle to the fluid, and the diameter ratio of the particle to the riser. It is found that the average of the vertical velocity of the particle decreases with the vibrational frequency and amplitude of the riser, density ratio and diameter ratio increasing. In addition, without the occurrence of collision between the particle and riser wall, as the vibrational frequency and amplitude, density ratio and diameter ratio increase, the amplitude of relative lateral velocity between the particle and riser in the vibrational direction, the phase difference between the particle velocity and riser velocity as well as the fluctuation amplitude of the vertical velocity shows an increasing trend. Compared to the absence of collisions, a sharp increase in the fluctuation amplitude of the particle vertical velocity can be caused by the collision between the particle and riser wall. In addition, an increase of the density and diameter ratios can lead to the early appearance of collision between the particle and the riser wall, making collisions more likely to occur, while the effects of the density ratio and diameter ratio on the lateral velocity and vertical velocity can be decreased.

     

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