Abstract Interstitial fluid between two approaching particles will give rise to an energy dissipation in the process of their collision due to the viscous effect. Compared with gas-solid fluidized bed, particles in the liquid-solid fluidized bed will generate more energy dissipation due to the viscosity of liquid being much higher than that of the gas. In the present study, the Discrete Element Method (DEM) was employed to simulate the hydrodynamics of the particle flow in a liquid fluidized bed. The interstitial fluid effect was taken into account by incorporating a dynamic coefficient of restitution for colliding particles into the damping coefficient. Probability distribution of particle velocity gradient was analyzed with variation of superficial liquid velocity for particles with different diameters. Effect of fluid properties on particle flow hydrodynamics was also studied. Simulated results show that particle velocity gradient and granular temperature are clearly affected when a dynamic coefficient of restitution is employed and the effects of interstitial fluid on the hydrodynamics of wet particle fluidization should be considered in numerical simulations. Simulated particle pressure agrees well with experimental data in the literature.

中文翻译：

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用CFD-DEM研究间隙流体对液-固流化床中颗粒流体动力学的影响

摘要 两个靠近的粒子之间的间隙流体，由于粘性效应，在碰撞过程中会产生能量耗散。与气固流化床相比，液固流化床中的颗粒会产生更多的能量耗散，因为液体的粘度远高于气体的粘度。在本研究中，离散元法 (DEM) 用于模拟液体流化床中颗粒流动的流体动力学。通过将碰撞粒子的动态恢复系数纳入阻尼系数来考虑间隙流体效应。对不同直径的颗粒，随着表观液体速度的变化，分析了颗粒速度梯度的概率分布。还研究了流体特性对粒子流动流体动力学的影响。模拟结果表明，当采用动态恢复系数时，颗粒速度梯度和颗粒温度明显受到影响，并且在数值模拟中应考虑间隙流体对湿颗粒流化流体动力学的影响。模拟粒子压力与文献中的实验数据非常吻合。