离线清灰袋式除尘器气流均匀性数值模拟分析

Numerical Simulation Analysis of Airflow Uniformity of Bag Dust Collector with Off-line Ash Removal

针对离线清灰方式袋式除尘器的不同工作状态,采用工程实际应用的某5单元单排袋式除尘器作为分析对象,运用CFD数值模拟方法分析在不同运行工况(清灰前、清灰状态、清灰后)下各除尘单元气流分配,仓室除尘空间及滤袋处过滤气流的分布情况。结果表明,整个离线清灰过程中运行阻力和仓室处理负荷变化频繁。清灰前各仓室过滤阻力相差较小,气流分配均匀。清灰状态下处理风量增加,袋底冲刷和粉尘二次返混严重。清灰后最大不均幅值为0.65,除尘空间内气流组织不均匀,近壁面处滤袋过滤风速达到1.9 m/min,严重影响滤袋寿命。模拟结果对进一步研究和优化离线清灰方式有一定参考价值。

For the different working conditions of the bag filter with the off-line cleaning method,a 5-unit single-row bag filter applied to the project is used as the analysis object.The CFD numerical simulation method was used to analyze the air distribution of each dust removal unit and the dust collection space in the unit compartment and the distribution of the filtered airflow at the filter bag under different operating conditions(before cleaning,during cleaning,and after cleaning).The results show that the running resistance and chamber processing load change frequently during the entire off-line cleaning process.The difference in filtration resistance between chambers before ash cleaning is small,and air flow distribution is uniform.The increase of air volume in the state of clean ash caused the bottom flushing and dust backmixing.The maximum uneven amplitude after cleaning is 0.65,and the air flow is not uniform in the dust removal space.Near the wall surface filter bag filter wind speed reached 1.9 m/min,seriously affecting the filter bag life.The simulation results have certain reference value for further research and optimization of off-line cleaning methods.