通过对不同形态磨粒的退磁因子、磁化强度以及磁化场的分析,研究磨粒形态对电感式磨粒传感器线圈等效电感的影响。以椭球磨粒和圆柱磨粒为例,分析了退磁因子随椭球轴长比和圆柱长径比的变化规律。建立了传感器线圈和磨粒的有限元计算模型,保持磨粒体积不变,分别计算了磨粒为球磨粒、4种不同轴长比的椭球磨粒和3种不同长径比的圆柱磨粒时线圈磁场分布和引起的线圈电感变化率。分析和计算结果表明,磨粒越趋向于细长状,其退磁因子越小,磁化后磁化场的磁感应强度越大,引起传感器线圈电感变化率也越大。因此磨粒体积相同情况下,电感式磨粒传感器对细长状磨粒的检测能力较大。同时试验研究的结果证明了理论分析和有限元计算的正确性。
After analyzing demagnetization factor and magnetization intensity of wear debris with different morphology, the effect of the wear debris morphology on the equivalent inductance of inductive wear debris sensor is studied. Taking ellipsoid wear debris and cylindrical wear debris for examples, the variation laws of the demagnetization factors of ellipsoid wear debris with different ratio of axis and cylindrical wear debris with different length to diameter ratio are analyzed. The finite element models of the sensor coil and the ferromagnetic wear debris are built. With same volume, spherical wear debris, 4 kinds of ellipsoid wear debris and 3 kinds of cylindrical wear debris are used in the model for computing. And the magnetic field distribution and the rate of change of the sensor coil inductance are got. Both theoretical analysis and computa- tional results show that slender wear debris has low demagnetization factor, high magnetization intensity and large rate of change of coil inductance. If ferromagnetic wear debris has same volume, the inductive wear debris sensor will have effective detection capability for slender wear debris. The results of the test prove that theoretical analysis and finite element computation are correct.