袋式除尘器喷吹过程气流行为的三维数值模拟

Three-dimensional Numerical Simulation of Airflow Behavior in Bag Filter Injection Process

脉冲喷吹清灰是袋式除尘器常用的清灰方式之一,更好地了解喷吹过程中清洁气流的气流量在滤袋间的分布及射流的行为特征对提高袋式除尘器的工作效率至关重要。该研究通过瞬态三维CFD数值模拟的方式分别对使用高压和低压脉冲喷吹系统的袋式除尘器的喷吹过程进行分析。结果表明,清洁气流的气流量在滤袋间的分布并不均匀,进入中部几个滤袋的气流量占比较高,且其中较大部分为二次气流;尽管高压系统中喷嘴出口处射流的质量流量较高,但进入滤袋中的气流量在2个系统中的分布情况相似;受主要气流压力波的影响,喷嘴出口处的射流均存在偏移,偏移程度沿吹扫管逐渐减小,且高压系统中的偏移程度均小于低压系统,这表明喷嘴位置与喷吹压力会对射流产生影响。

Pulse jet cleaning is one of the commonly used cleaning methods of bag filter.It is very important to know better the distribution of clean air flow between filter bags and the behavior characteristics in the process of jet cleaning to improve the working efficiency of bag filter.In this study,the blowing process of bag filter using high-pressure and low-pressure pulse blowing system was analyzed by transient 3D CFD numerical simulation.The results show that the air flow of clean air flow is not evenly distributed among filter bags,and the air flow entering several filter bags in the middle is relatively high,and most of them are secondary air flow.Although the mass flow rate of jet at the outlet of nozzle is high in high pressure system,the distribution of air flow into filter bag is similar in the two systems.Under the influence of the main air pressure wave,the jet at the nozzle outlet is offset,and the offset degree decreases gradually along the purge pipe,and the offset degree in the high-pressure system is smaller than that in the low-pressure system,which indicates that the nozzle position and injection pressure will have an impact on the jet.