异形纤维捕集颗粒过程的格子Boltzmann法数值模拟

Numerical Simulation of Particle Capture Process of Noncircular Fibers by Lattice Boltzmann Method

为了探究异形纤维的截面形状和放置角度对捕集效率、系统压降及除尘器综合性能的影响,对布袋除尘器中三角形、十字形及三叶形3种异形纤维捕集颗粒的过程进行研究;采用格子Boltzmann-元胞自动机气-固两相流模型定量描述颗粒的运动过程,计算扩散、拦截及惯性碰撞3种捕集机制下纤维的捕集效率,并且与相同体积分数的圆柱纤维进行比较。结果表明:对于十字形和三叶形纤维,当长短轴比越大时,捕集效率也越大;对于拦截机制占主导时较难捕集的中等大小颗粒,三角形和三叶形纤维放置角度为60°时更有利于捕集。

To find out the influence of cross-section shape and orientation angle of fibers on capture efficiency, pressure drop and comprehensive performance of filters, the particle capture process from three noncircular fibers of triangular, cross and trilobal in fibrous filters was studied. The lattice Boltzmann-cellular automation（LB-CA） gas-solid two-phase model was applied to quantitatively describe the motion of particles. The capture efficiency due to three capture mechanisms of diffusion, interception and inertial impaction were calculated and compared with the circular fibers with the same volume fraction. The results show that for the cross and trilobal fibers, the larger the aspect ratio is, the higher the capture efficiency can be achieved. For the particles with medium size when mainly dominated by interception mechanism, the triangle and trilobal fibers with orientation angle of 60° have higher capture efficiency.