深海采矿混输泵内流场及粗颗粒运动特性

为了解决由于颗粒粒径大、流体相互作用复杂导致的混输泵内两相流动研究困难的问题,针对10 mm颗粒粒径的混输泵流动,使用标准k-ω模型,构建相同体积浓度、不同颗粒粒径的流动模型来研究粒径对于泵外特性的影响,并探究不同粒径颗粒在泵内的分布情况.同时,还结合熵产理论,研究不同流量下混输泵内的能量损失及泵内过流部件的局部熵产情况.结果表明,混输泵叶轮流道内,颗粒在叶轮入口处发生低速堆积现象,颗粒速度随径向距离增大而增大.另一方面,在两极之间,第2级叶轮入口颗粒堆积现象减弱.随着粒径减小,颗粒在叶轮流道内加速度增大,出口处小粒径颗粒速度较大,且小粒径颗粒贴叶片运动现象比较明显.对比熵产,两极之间第2级熵产损失明显较大,造成2级外特性差异.同时,对比熵产分布发现,第2级叶轮和导叶内的局部熵产生率较大.研究结果对深海采矿水力提升装置中粗颗粒混输泵内流动的研究具有一定的参考价值.

Characteristics of flow field and coarse particle motion in multiphase pump for deep-sea mining

Due to the large particle size and complex fluid interaction, it is difficult to study the two-phase flow in multiphase pump with coarse particle. Aiming at the flow of multiphase pump with 10 mm particle size, the standard k-ω model was used to construct flow models with the same volume concentration and different particle sizes to study the influence of particle size on the hydralic characteristics of the pump and the distribution of particles with different particle sizes in the pump. Combined with the entropy production theory, the energy loss and local entropy production of the flowing parts in the pump were studied at different flow rates. The result shows that the particles accumulate at low speed at the impeller entrance in the impeller passage of the multiphase pump, and the particle velocity increases with the increase of radial distance. Between the two poles, the particle accumulation at the entrance of the second stage impeller weakens. With the decrease of particle size, the acceleration of particles in the impeller passage increases, and the velocity of particles with small particle size at the exit is larger, and the movement phenomenon of particles with small particle size sticking to the blade is obvious. Compared with the entropy production, the loss of the second stage entropy production between the poles is obviously larger, resulting in the difference in the characteristics of the two stages. Meanwhile, compared with the distribution of entropy production, the LEPR in the second stage impeller and guide blade is larger. It provides reference value for the research of the flow in the multiphase pump of coarse particles in the hydraulic lifting device of deep-sea mining and for the research and application of the solid-liquid two-phase flow of coarse particles.