错流内滤式滤芯脉喷清灰的数值模拟

Numerical simulation of cross-flow inside-out filter element pulse jet cleaning

错流式过滤除尘技术利用切向风流抑制尘饼生长变厚,具有过滤阻力上升缓慢的优点,采用脉喷气流撞击设置在滤芯外的横向挡板并产生局部静压可实现内滤式滤芯的清灰。构建CFD数值模拟考察了喷吹气流的分布,分析了喷嘴入口处的喷吹压力和挡板位置对脉冲喷吹性能的影响,设计并考察了挡板往复式喷吹策略。结果表明:滤芯压力随喷嘴入口压力升高而增加,确定了最佳喷嘴入口压力为5000 Pa;挡板位置的变化显著影响清灰的有效区,对于1000 mm长的滤芯,挡板位置为500 mm和350 mm分别实现350~500 mm和0~350 mm区域的有效清灰;相比普通喷吹,设计的挡板往复式喷吹(挡板位置依次为350、500、650、500 mm)可实现滤芯喷吹压力增大1.57倍、均匀性提升7.17倍。该研究结果可为内滤式滤芯脉喷清灰提供参考。

Cross-flow filter dust removal technology uses tangential air flow to suppress the growth and thickening of dust cake and has the advantage of slow rise of filtration resistance.The inside-out filter element can be cleaned by using pulse jet flow to impact the transverse baffle set outside the filter element and generate local static pressure.In this paper,CFD numerical simulation was constructed to investigate the distribution of jet flow,analyze the influence of the injection pressure at the nozzle entrance and the position of baffle on the performance of pulse jet,and design and investigate the baffle reciprocating injection strategy.The results showed that the filter element pressure increased with the increase of nozzle inlet pressure,and the optimal nozzle inlet pressure was 5000 Pa.The effective cleaning area was significantly affected by the change of baffle position.For the 1000 mm long filter element,the effective cleaning area of 350~500 mm and 0~350 mm could be achieved with the baffle position of 500 mm and 350 mm,respectively.Compared with the ordinary injection,1.57 times increase in filter element injection pressure and 7.17 times increase in uniformity were achieved by the designed baffle reciprocating injection(baffle position at 350,500,650,500 mm in order).The results of this study can provide a reference for pulse jet cleaning of inside-out filter element.