摘要
铁磁流体中存在一个不平衡旋度 ≠ 12 rotv,由此引起悬浮在顺磁性载液中磁偶极矩为 m的磁粒子的旋转摩擦 .原先以磁畴取向的磁粒子 ,在外磁场作用下 ,经历驰豫时间 τ改变其方向 .在高速 ( v≥ 7m/s)时 ,磁流体摩擦热致使其粘度和粒子磁性能下降 ,影响其密封性能 .选择牛顿内摩擦模型 ,Langevins和 Navier-Stokes方程导出了磁粒子的旋转摩擦功耗公式 ,并由实验进行了验证 .
A nonequilibrium vorticity Ω≠12rotv exists under stationary conditions in ferrofluids,so as to cause a rotational friction of the magnetic particles in the carrier liquids.Going through a relaxation time τ,the magnetic particles,which are oriented on domain,change direction on the outside magnetic fields.In high velocity( v ≥7 m/s) inner friction heat leads to a decrease of viscosity of the ferrofluids and a worsening of magnetic particles property.A formula of the friction power loss is derivated from Langevins formula and Navier Stokes equation by Newton inner friction modular and it is in good agreement with the experiments.
出处
《兰州大学学报(自然科学版)》
CAS
CSCD
北大核心
2003年第4期31-33,共3页
Journal of Lanzhou University(Natural Sciences)
基金
甘肃省自然科学基金资助项目 ( ZS981 -A2 2 -0 2 2 )
关键词
磁流体
密封
摩擦功耗
ferrofluids
sealing
friction power loss