为了增加电感式油液污染物检测传感器的稳定性, 提升对铁磁性和非铁磁性污染物的检测精度, 设计了一种内置磁性纳米材料的电感式油液污染物检测传感器, 螺线管线圈内部填充的磁性纳米粒子层可以提升检测区域磁场强度, 增强磁化涡流效应。模型材料制作300 μm的微通道穿过螺线管线圈和磁性纳米材料组成的传感单元, 当污染物通过传感单元时, 利用电感检测原理可以区分铁磁性和非铁磁性污染物。同时采用有无磁性纳米粒子层的两种传感器进行多组对比实验。实验结果表明, 磁性纳米粒材料的电感式油液检测传感器具有更高的检测信噪比以及更低的检测下限, 对于20~70 μm的铁磁性颗粒检测信噪比提升了20%~25%, 对于80~130 μm的非铁磁性颗粒的检测信噪比提升了16%~20%。该方法基于微流控检测技术, 具有体积小、检测信噪比高等优点, 同时为液压油污染物快速检测提供了技术支持, 对液压系统的故障诊断与寿命预测具有重要意义。

In order to increase the stability of the inductive oil contaminant detection sensor and improve the detection accuracy of ferromagnetic and nonferromagnetic contaminants, an inductive oil contaminant detection sensor with built-in magnetic nanoparticles was designed in this paper. The solenoid coil was filled with a nanoparticle layer which adsorbs the pollutant particles and enhanced the magnetic field strength of the detection area, enhancing the magnetization and eddy current effects. A 300 μm microchannel was made using the model material, which passes through the sensing unit. Ferromagnetic and non-ferromagnetic contaminants can be distinguished when contaminants pass through the microchannel through the sensing unit. At the same time, two sets of contrast experiments were carried out using two sensors with and without magnetic nanoparticle layers. The experimental results show that the inductive oil detection sensor of magnetic nanomaterial has higher detection accuracy and lower detection limit. The detection accuracy of ferromagnetic particles of 20-70 μm improved by 20%-25%, while that of nonferromagnetic particles of 80-130 μm improved by 16%-25%. The method is based on microfluidic detection technology, and has the advantages of small volume and high detection precision. At the same time, it provides technical support for the rapid detection of hydraulic oil contaminants, which has great significance for fault diagnosis and life prediction of hydraulic systems.