基于CFD-PBM偏置短叶片式叶轮对浮选机性能的影响

Effect of short blade impeller on the performance of flotation machine based on CFD-PBM model

浮选机的吸气量和对气泡的破碎能力是评价其性能的关键指标,大量微细气泡可提高煤泥的选择性,提升精煤回收率。针对这一目的,提出并设计了一种偏置短叶片式叶轮,应用于煤泥浮选的自吸式机械搅拌浮选机中。采用基于CFD-PBM数值模拟的方法,与常规叶轮的浮选机进行对比。研究发现相较常规叶轮,偏置短叶片式叶轮可有效消减叶片吸力面回流涡产生的阻塞,叶轮的有效流道增加了8.3个百分点;短叶片可提高对气泡的切割能力,中、细粒级气泡数量显著增加,大粒级气泡仍维持在较低数量级;偏置短叶片式叶轮的吸气量提高了26.79%,浮选机槽体内含气率与气体分散特性明显提升,其可在原工况下替换常规叶轮,实现高效浮选。

The suction capacity and ability to crush bubbles of a flotation machine are key indicators for evaluating its performance.A large number of fine bubbles can improve the selectivity of coal slurry and enhance the recovery rate of clean coal.A biased short blade impeller was proposed and designed for this purpose,which was applied in a self-priming mechanical agitation flotation machine for coal slurry flotation.Using the CFD-PBM numerical simulation method,compared with the conventional impeller flotation machine,research finds that compared to conventional impellers,short blade impellers effectively reduce the blockage caused by backflow vortices on the suction surface of the blades,increasing the effective flow channel of the impeller by 8.3 percentage points.Short blades enhance the cutting ability of bubbles,significantly increasing the number of medium and fine-grained bubbles,while keeping large-sized bubbles at a lower level.The suction capacity of the biased short blade impeller has increased by 26.79%,and the gas content and gas dispersion characteristics in the flotation cell have been notably improved.It can replace conventional impellers under the original working conditions,achieving efficient flotation.