纳米铁粉Fe_3O_4含量对磁流变液正应力特性的影响

Effect of Fe_3O_4 Nanoparticles Content on Normal Stress Characteristics of Magnetorheological Fluid

设计了测试磁流变液正应力性能的试验装置,搭建了相应的测试系统,通过实验来研究不同纳米级Fe_3O_4颗粒含量对传统磁流变液正应力的影响。实验结果表明,当电流在0~1.5 A,剪切速率给定时,当纳米Fe_3O_4粒子的质量分数从0%~7%变化时,微纳米磁流变液的正应力与传统磁流变液的正应力相比会随着纳米颗粒含量的增大而迅速增大;当磁感应强度在320 m T时,微纳米磁流变液的正应力将达到最大值,然而随着纳米粒子的质量分数从7%~16%变化时,微纳米磁流变的正应力逐渐降低。

The testing device for testing normal stress characteristics of the magnetorhological（ MR） fluid is designed,and a set of testing system is built accordingly. The effect of the different contents of nano magnetic particles on the normal stress of MR fluid was investigated. The experimental results indicate that given a constant shear rate,in a small range of currents（ 0 ~ 1. 5 A）,when the mass content of Fe3O4 nano magnetic particle changes from 0% to 7%,with the mass content of nano magnetic particle increasing,the normal stress will also increase rapidly,compared with the traditional MR fluid. Furthermore,when the applied magnetic induce intensity at 320 m T,the increment of normal stress produced by micro-nano MR fluid reaches the maximum. However,when the mass content of nano magnetic particle changes from 7% to 16%,the normal stress is decreased gradually.