中文摘要：

在电感式磨粒传感器中，铁磁质磨粒主要通过磁化作用改变传感器线圈的磁场分布，进而改变线圈的等效电感．建立了线圈中含有铁磁质磨粒时的磁场模型，得出了磨粒磁化场关于退磁因子的磁感应强度表达式．以球磨粒为例，通过计算球磨粒磁化场，得到球磨粒引起线圈电感变化率的解析式，并用有限元法计算了线圈的磁场，分析后发现：理论计算解与数值分析解相符，所建模型可以反映客观实际；磨粒的磁化强度由其磁导率和退磁因子共同决定，球磨粒的磁化强度可近似认为与磁导率无关；球磨粒引起的传感器线圈电感变化率随线圈单位长度上匝数的增加而减小，并趋向于一极限值；传感器线圈的电感变化率与球磨粒半径的三次方成正比，球磨粒半径在100μm以内，电感变化率在10^-7数量级．本研究结论可为电感式磨粒传感器的设计提供理论指导．

英文摘要：

When ferromagnetic wear debris was in the coil of inductive wear debris sensor, the magnetic field distribution of the coil was changed through magnetization, and hence the equivalent inductance of the coil was changed. The magnetic model of the coil containing ferromagnetic wear debris was built. The expressions between demagnetization factor and induction density were deduced. Taking spherical wear debris for examples, the analytic expression of the rate of change of inductance was obtained by computing the magnetization field of spherical wear debris. The magnetic field of coil was also computed by finite element method. After analyzing the model and computing the magnetic field, the theoretical analysis was consistent with the numerical computation. It means that the model was reasonable. The magnetization intensity of wear debris depended on magnetic permeability and demagnetization factor, and the magnetization intensity of spherical wear debris could be approximately regarded as a constant that had no reference to its magnetic permeability. The rate of change of sensor coil inductance induced by ferromagnetic spherical wear debris decreased with increasing number of turns per unit length, and approached a limit. The rate of change of inductance was proportional to the cube of the radius of the wear debris. When the radius was less than 100 μm, the rate of change of inductance was of 10^-7 order. The conclusions of this study provide theoretical direction for design of inductive wear debris sensor.