磁流变液中磁性颗粒成链与团聚的临界特征分析

热运动对纳米级磁流变液系统的颗粒团聚行为和宏观流变特性扰动影响不可忽视.为研究施加外磁场后系统微结构与热运动间的关系，探讨在不同颗粒粒径情况下热运动能量在系统总能量中的占比.采用CCD设计方法，分析Monte Carlo仿真获取的颗粒位形信息，生成关于外磁场磁感应强度、颗粒粒径和体积分数的系统热耦合系数<λ>回归模型;成链团聚的临界颗粒粒径计算值比文献经验值高出约23%，证实在考虑系统内多因素的综合影响下，纳米级磁流变液具有更严格的流变现象临界发生条件.

Chain Formation and Agglomeration Characterization of Magnetic Particles in Magnetorheological Fluids

Thermal motion behavior has an unneglectable disturbing effect on the agglomeration and rheological characteristics of nano-size magnetorheological fluids(MRFs).To discover the relationship between microstructure and thermal motion in MRFs with external magnetic fields applied， the thermal proportion of total energy with different diameters of carbonyl iron particles (CIPs) was discussed. The CCD method was employed to analyze the CIPs’ position data set calculated by Monte Carlo simulation， and a systematic thermal coupling coefficient<λ>regression model related to magnetic induction intensity， CIPs’ diameter and volume concentration was built. The threshold particle diameter value calculated by the model is 23% higher than the empirical value in the literature， which proves that rheological characteristic has a stricter precondition with multiple factors considered in MRFs.