荷尘状态单纤维过滤压降数值计算与分析

Numerical calculation and analysis of pressure drop of a single fiber under dust-loaded conditions

采用Monte Carlo法和Kuwabara单元模型,模拟了单纤维表面粉尘树枝结构的生长过程。在此基础上,考虑邻近粒子对粉尘树枝中单粒子阻力的影响,给出了荷尘状态单纤维过滤压降模拟模型。结果指出,对所有过滤情形,荷尘单纤维过滤压降随沉积量变化呈现两个阶段性特征;过滤风速、粒子大小和粉尘树枝形态结构对荷尘单纤维过滤压降影响显著;而纤维直径对荷尘单纤维过滤压降影响不明显。在获得单纤维过滤压降随沉积量变化关系后,求解了粒子在模型过滤器中的质量分布,建立了荷尘纤维过滤器过滤压降预测模型,并将模型计算结果与实验结果作了对比。结果表明,过滤风速在0.01～0.3m.s-1范围内时,计算值与实验结果吻合较好,模型可适用于荷尘纤维过滤器的压降预测。

The growth of particle dendrites on a single fiber during fibrous filtration was simulated by the Monte Carlo stochastic simulation and Kuwabara cell model.With the interactions between particles in the dendrites considered,the drag force contribution from each individual particle was calculated and analyzed.The results indicate that two steps may be distinguished in evolution of the pressure drop with deposit aspect for all filtration conditions studied.The variation of pressure drop is strongly depended upon filtration velocity,particle size and particle dendrite structure.However,in the range of fiber diameter concerned,there is no influence on the evolution of pressure drop.A new theoretical model for estimation of the pressure drop across the fibrous filter during clogging was developed with the understanding of the evolution of pressure drop for a dust-loaded fiber with deposit aspect.The model test shows that the calculated values are in good agreement with the experimental data for the filtration velocity from 0.01 m·s-1 to 0.3 m·s-1.It can be used for the prediction of pressure drop during fibrous filter clogging.