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基于群体平衡理论和CFD数值计算方法,考虑不同尺寸气泡及气泡间聚并与破碎,建立了气液两相流的CFD-PBM耦合模型。应用该模型和Fluent软件对某铝厂的KYFⅡ-40型机械搅拌充气式浮选机内的矿浆-气泡两相流进行数值模拟,获得了其两相流场、气含率和气泡尺寸分布等信息。模拟结果表明,在生产工艺条件下,浮选机内的流体在转子带动下形成上下两个循环流场;气含率保持在0.1左右,壁面附近及循环流场的中心处气含率偏高,并沿气液混合区向气液分离区减少;气液混合区的气泡变化以破碎为主,气泡较小,分离区的气泡变化以聚并为主,且气泡尺寸逐渐增大;气泡尺寸总体上呈多峰分布,其主峰对应的气泡直径位于3~4mm之间,有利于提高浮选生产效率。
Based on the population balance theory and CFD numerical calculation method, the CFD-PBM coupling model of gas-liquid two-phase flow was established considering the coalescence and fragmentation of bubbles of different sizes and bubbles. This model and Fluent software were used to simulate the two-phase flow field, the gas holdup and the bubble size distribution in the slurry-bubble two-phase flow in a KYFⅡ-40 mechanical stirred aeration flotation machine information. The simulation results show that under the conditions of the production process, the fluid in the flotation machine forms two upper and lower circulation flow fields driven by the rotor; the gas holdup is maintained at about 0.1, and the gas holdup near the wall surface and the center of the circulating flow field is high , And decreased along the gas-liquid mixing zone to the gas-liquid separation zone. The bubble changes in the gas-liquid mixing zone were mainly broken with smaller bubbles. The bubbles in the separation zone were mainly polygons, and the bubble size gradually increased. The bubble size In general, it has a multimodal distribution with the diameter of the bubble corresponding to the main peak located between 3 and 4 mm, which is beneficial to improve the production efficiency of flotation.