流化床浮选柱分布器优化的数值模拟

Numerical simulation on optimization of distributor structure of fluidized bed flotation cell

流化床浮选在粗粒分选领域具有较大的应用前景,通过液固两相流体模拟研究了多环桥联式流体分布器设计参数对流化床浮选柱流体动力学的影响。模拟结果表明:当入口表观水流速度为3 m/s时,流体分布器喷出水流速度主要为0.4~1.2 m/s,局部水流速度可为0 m/s或1.8 m/s;流化床内固相体积分数为26%~32%,中心区域颗粒以0.11~0.21 m/s速度上升运动,近壁区域颗粒呈静止或下降状态,速度均低于0.07 m/s。通过改变开孔数量增大流体分布器开孔率会导致内环喷出水量相对增大、布水非均匀性增大,而通过降低内/外环孔径比、提高开孔不均匀度能够抑制内环出水量,强化布水均匀性,同时降低床层内湍流强度和粗颗粒脱附概率。研究结果为流化床浮选柱的流体分布器设计提供了依据。

Fluidized bed flotation exhibits substantial potential for application in the field of coarse particle separation.The effect of the multi-ring bridge-connected fluid distributor’s design parameters on the fluid dynamics of fluidized bed flotation equipment via solid-liquid two-phase flow simulation was investigated.The simulation results reveal that,at inlet superficial water velocity of 3 m/s,the water jet velocity from the fluid distributor is primarily distributed between 0.4 and 1.2 m/s,with local velocities reaching 0 m/s and 1.8 m/s.The solid phase volume fraction in the fluidized bed is between 26%and 32%.In the central area,the particles move upwards at speed of 0.11 to 0.21 m/s,while in the near-wall area,the particles are in a stationary/descending state,with speeds below 0.07 m/s.By adjusting the number of openings,the aperture ratio of the fluid distributor is modified.The simulation results indicate that increasing the aperture ratio of the fluid distributor leads to a relatively increased water ejection from the inner ring,thereby decreasing the non-uniformity of the distributor’s water distribution.However,by reducing the inner/outer ring hole diameter ratio and increasing the unevenness of the opening,the water output from the inner ring can be suppressed,enhancing the uniformity of water jet velocity distribution.At the same time,this also reduces the turbulent intensity within the bed layer and the probability of detachment of coarse particles.The research findings provide a basis for the design of fluid distributors in fluidized bed flotation columns.