脉冲袋式除尘器喷吹管内压缩气流喷吹均匀性的数值模拟

Numerical simulation on injection uniformity of compressed air in pulse-jet injection pipe of bag filter

运用计算流体力学(CFD)的方法,对大型脉冲袋式除尘器清灰时喷吹管内压缩气流喷吹的均匀性进行了数值模拟研究。在对传统等直径喷嘴的喷吹管出口的平均质量流量、流量偏差和喷嘴内气流的速度场进行分析的基础上发现,通过改变喷嘴直径和形状可以提高喷吹管系统的清灰均匀性。其中,采用锥形变径喷嘴时,喷吹管喷出的压缩气流的流量偏差降到2%以内,喷嘴内气流合速度方向与径向夹角几乎为零,到达滤袋的速度明显增大,极大改善了喷吹管喷吹气流的均匀性,有效提高滤袋的清灰强度,为袋式除尘器清灰系统的优化设计提供了依据。

The injection uniformity of compressed air in an injection pipe of a large-scale pulse-jet bag filter was simulated using the computational fluid dynamics（ CFD） method. The average mass flow rate and its deviation in the outlet of the injection pipe with the same diameter nozzle were investigated. In addition,the velocity field of air flow in nozzles was studied. The results indicated that the cleaning uniformity of the pulse jet system could be improved by altering the diameter and shape of the nozzle. Typically,with a cone-shaped nozzle,the deviation of the flow rate in the outlet of the injection pipe decreased to less than 2%. Moreover,the jet angle was close to zero with the cone-shaped nozzle,which significantly increased the velocity reaching the bag filter.The uniformity of air flow in the outlet of the injection tube and the dust-cleaning strength were significantly improved. The simulation results offer a reference for the design of a dust-cleaning system of a bag filter.