转轮式分级器切割粒径的预测模型

针对转轮式分离器，建立不同结构参数及操作参数下的切割粒径预测模型有助于指导其设计和运行。基于相似理论以及对颗粒分离过程的分析，提出一种考虑结构参数的半经验模型，确定了模型参数，并通过实验以及文献报道的数据验证了模型的可靠性。与前人工作相比，此模型在不同的转轮分离器结构下显示出较好的通用性；此外，模型可以复现切割粒径随叶轮转速增大而先减小后增大的非单调关系，这是原有的半理论模型不能实现的。对不同结构转轮分离器性能的系统分析表明，较大的分离器入口面积及较小的导流角度可确保入口产生强旋流气流，进而使切割粒径对转速的敏感段在低转速区；而较小的分离器入口面积，或较高的入口风速可以提高对细颗粒的分离能力。对运行参数的研究表明，增大颗粒流率会减小切割粒径；调整叶轮转速可以灵活地改变切割粒径，适应不同的工作需求。

Prediction model for cut size in turbo air classifiers

It is important to establish the prediction model of the cut size with different structural and operational parameters for the design and operation of the turbo air classifiers. Based on similarity theory and analysis of the separation process, a new semi-theoretical model considering the effect of the classifier structure parameters was proposed. The model parameters were acquired according to experimental results. The model was validated by both the experimental work and the data reported in literatures. The model is applicable for the classifiers with different structures. The cut size increases first and then decreases with the increasing impeller rotating speed. The model in this paper can reproduce this non-monotonic relation, while the previous semi-theoretical model cannot. The results indicated that a larger inlet area and a smaller inlet angle is necessary to generate a strong swirl flow, which ensures that the cut size is sensitive to a low impeller rotating speed. When the inlet area is smaller or the inlet velocity is larger, the separation efficiency of the fine particles will be improved. The cut size will decrease with the increase of the particle feed rate. Adjusting the impeller rotating speed can change the cut size to meet different demands.