【摘要】 涡轮式气流分级机是超细铁矿粉的主要生产设备,在分级精度和分级效率上一直不高。为此,结合转轮转速和入口风速匹配关系,对转轮入口速度三角形进行分析,运用CFD流体动力学及力学相对运动理论对叶片间压降进行分析,得出分级轮叶片间速度分布规律。并利用FLUENT软件对不同叶片数结构转轮进行建模和数值模拟。数值模拟结果表明:转轮叶片长宽厚和进风速度对入口处流体的运动速度有直接影响;提高转轮转速能获得更细粒径,但容易造成流场不均匀,降低分级精度;通过适当增加叶片数能改进流体速度的分布规律,从而提升分级效率;提出了增加叶片数的新转轮设计方法,通过数值模拟和物料试验证明该新结构在一定工况下流场分布均匀,分级效率提升。研究结果对涡轮式气流分级机的设计具有一定的指导作用。更多还原

【Abstract】 Turbine air classifier is the main production equipment for ultrafine iron ore fines, which usually has an inferior classification accuracy and efficiency. To address the problem, in consideration of the relationship between the rotating speed of the impeller and the inlet wind speed, the inlet speed triangle is analyzed. The pressure drop between the blades is analyzed based on CFD fluid dynamics and the theory of relative motion of the mechanics. The FLUENT software is used to model and numerically simulate the impeller with different number of blades. The numerical simulation results show that the length, width and thickness of the impeller blade and the inlet velocity have a direct influence on the velocity at the inlet. Increasing the rotation speed can obtain a finer particle size, but it is easy to cause uneven flow field to reduce the classification accuracy. Proper increase of the number of blades can improve the velocity distribution, thus improve the classification efficiency. A new design method of increasing the number of blades is proposed. The numerical simulation and test prove an evenly distributed flow field under certain working conditions and increased classification efficiency. The study results have a certain guiding effect on the design of the classifier.更多还原