• 关键词：多层复合纤维滤料  表面覆膜  过滤性能  数值模拟

• 基金项目：国家自然科学基金项目(No.50708001);安徽省教育厅自然科学基金重点项目(No.KJ2010A047);教育部科学技术研究重点项目(No.210094)

• 钱付平
• 安徽工业大学 建筑工程学院, 马鞍山 243002

• 王海刚
• 安徽工业大学 建筑工程学院, 马鞍山 243002

• 陈光
• 安徽工业大学 建筑工程学院, 马鞍山 243002

• 摘要：根据Matlab软件和数值计算前处理软件Gambit中的Journal文件建立了多层复合纤维滤料模型,利用计算流体动力学(CFD)技术对沿气流方向具有不同纤维填充密度及直径分布的滤料内部的气-固两相流动特性进行了数值研究,计算了不同运行条件下滤料的压力损失及过滤效率,并将数值计算值和经典模型及实验关联式的计算值进行了比较.结果表明,压力损失的数值计算预测值和实验关联式计算值吻合较好,误差在2%以内.随着迎面风速的增加,压力损失呈线性增加.相对于填充密度,纤维直径对压力损失和过滤效率的影响更显著.不同结构滤料过滤效率的数值计算结果和理论模型的计算值变化趋势基本一致.不同迎面风速下,过滤效率都是先减小后增大,对于颗粒直径d_p≤0.05μm的颗粒,随着风速的增大,过滤效率减小;对于d_p≥0.5μm的颗粒,过滤效率变化趋势正好相反.迎面风速不同,过滤效率最低点出现的位置也不同.对于小颗粒,风速越小,扩散作用起主导作用;而对于大颗粒,风速越大,惯性作用越明显.过滤效率最低点出现在扩散作用逐渐弱化,惯性作用刚刚开始加强的区域.多层复合滤料在结构上采用纤维直径逐层加大的梯次结构时,能够获得较高的过滤效率.而在多层复合滤料表面覆膜后过滤效率平均增加约13%.

• Abstract：Asimulation of a multi-layer fibrous filter media was established by combining Matlab and the Journal file in the preprocessing software,Gambit,in this study.The gas-solid two phase flow characteristics and filtration performances in multi-layer fibrous filter media with different fiber solid volume fraction(SVF) and diameter were simulated by computational fluid dynamics(CFD),and the predicted results were compared with the values of the theoretical models in the literature.The results indicate that the predicted values of the pressure drops are in excellent agreement with the experimental correlation and the error are less than 2%,and the pressure drop linearly increased with the face velocity.Compared with the SVF,the fiber diameter plays an important role in influencing the pressure drop and filtration efficiency of the fibrous filter media.The predicted values of the filtration efficiencies show similar tendencies to the theoretical model.The filtration efficiency first decreased and then increased with increasing face velocity.For the small particles(d_p≤ 0.05 μm),the filtration efficiency decreased with the face velocity,while for the large particles(d_p≥ 0.5 μm),the tendency is just the opposite.The least value of the filtration efficiency varied with the face velocity,i.e.,for the smaller particles,Brownian diffusion plays a significant role in the filtration process at low velocity,and for the large particles,inertial impaction becomes an important capture mechanism at high velocity.The filtration efficiency has the least value in the range in which Brownian diffusion and inertial impaction are both relatively weak.The structures of the multilayer composite fibrous filter media can obtain high filtration efficiency and long running life because its fiber diameter is increased gradually along the gas flow.In addition,the filtration efficiency is increased by 13% via coating a layer of membrane(ultrafine fiber) on the surface of the multi-layer fibrous filter media.

• Key words：multi-layer fibrous filter media  surface coating membrane  filtration performance  numerical simulation

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