一种气流分级机端面密封特性研究

Research on end face sealing characteristics of air classifier

涡轮气流分级机是应用十分广泛的超细分级设备,但是仍存在分级机端面跑粗现象。本文通过实验探究分级机端面间隙对不同物料分级效果的影响,并在传统迷宫密封的基础上设计一种气密封装置,探究不同气封压力对不同物料分级效果的影响,并以相对分级精度为评价指标。利用Ansys Workbench 15.0软件,对气流密封的流体区域进行了数值模拟,得出了压力场和速度场的分布情况。模拟及实验结果表明:相对分级精度随着分级机端面间隙的增大而减少,当间隙保持在3mm左右时,相对分级精度较高且分级机亦可正常运转;在分级机端面间隙为3mm以下时,增加气流密封,相对分级精度随气封压力的增加先增大后减小,当气密封压力为0.15MPa时,粉煤灰和矿渣的相对分级精度最高;气流密封的失效压力为0.05MPa;在相同间隙的情况下,增加气密封,粉煤灰和矿渣的相对分级精度分别从0.202、0.187增加到0.458、0.408,分级机性能得到提高,分级效果更为良好。

Turbo air classifier was an ultra-fine grading equipment broadly applying in ultrafine classifying industry. However,the leakage phenomenon of coarse powder about classifier with traditional labyrinth seal was not eliminated. In this paper,impacts of end face sealing gap and gas sealing pressure change to different material classification effects were investigated,and the relative classification precision to evaluate the quality of classifying was used. Gas sealing fluid field was simulated by Ansys Workbench 15.0. The distribution of the gas sealing fluid field was presented by its velocity field and pressure field. Numerical simulation and experimental results showed that the relative classification precision decreased along with the increase of end face sealing gap. Optimum relative classification precision was obtained. Classifier could be normal operated under the condition of 3mm of end face sealing gap. The relative classification precision first increased then decreased along with the increase of gas sealing pressure under the condition of 3mm of end face sealing gap with gas seal. When gas sealing pressure was 0.15 MPa,the relative classification precision of fly ash and slag was the highest. The failure of gas sealing pressure was 0.05 MPa. The performance of classifier and classification effect was betterunder the condition of the same end face sealing gap and used gas seal. The relative classification precision of fly ash and slag increased from 0.202,0.187 to 0.458 and 0.408.