条形磁铁几何构形对层流中磁性颗粒分离行为影响的数值研究

增强磁场对流体中磁性颗粒或团聚物的分离回收作用是开梯度磁分离技术中的关键问题。通过建立数值模型，研究条形磁体4种排列方式（轴向交替、轴向并发、横向交替和横向并发）及不同磁端间距对颗粒捕获率的影响，并结合颗粒运动轨迹和磁场力分布情况对颗粒捕获结果进行分析，同时研究了磁体长宽比、颗粒磁化率、流体流速、磁体磁化强度对颗粒捕获率的影响。结果表明:对于条形磁体，当磁端间距足够远时，轴向布置优于横向布置；在小磁端间距下，轴向交替排列方式最优；对于横向交替排列，在同等磁通量和截面面积的矩形磁体下，长宽比为1:1的方形磁体对颗粒的捕获作用最优。该成果可为多磁体组合的磁分离器设计提供理论参考。

NUMERICAL STUDY ON EFFECT OF STRIP MAGNET GEOMETRIC CONFIGURATION ON SEPARATION BEHAVIORS OF MAGNETIC PARTICLES IN LAMINAR FLOW

Enhancing the separation and recycling of magnetic particles or agglomerates in fluid by the applied magnetic field is a key problem in the open gradient magnetic separation technology. By establishing a numerical model, the effects of four arrangement modes of strip magnets (the axial alternating arrangement, the axial concurrent arrangement, the transverse alternating arrangement, and the transverse concurrent arrangement) and different magnetic end spacings on the particle capture rate were studied, and also the particle capture results were analyzed, in combination with the particle trajectory and the magnetic force distribution. At the same time, the ratio of magnet length to width, the effects of particle susceptibility, the fluid flow velocity, and the magnet magnetization on particle capture rate were studied. The results showed that, for strip magnets, when the magnetic end spacing was far enough, the axial placement was better than the transverse placement; for a low magnetic end spacing, the axial alternating arrangement was the best; for the rectangular magnets with the same magnetic flux and cross-sectional area, the square magnet with the aspect ratio of 1:1 had the best trapping effect on the particles. The results could provide theoretical guidance for the design of a multi-magnet magnetic separator.