Design And Research Of Oil Metal Particle Sensor Based On Electromagnetic Induction

As an important technical means of equipment condition monitoring and fault diagnosis,on-line oil monitoring has been widely used in the field of lubrication safety of large-scale equipment.The friction pair of mechanical equipment will produce metal abrasive particles during operation.These metal abrasive particles contain rich tribological information of friction pairs of mechanical equipment.Through detection and analysis,not only can the fault location of mechanical equipment be diagnosed,but also the life of mechanical equipment can be predicted.Therefore,the research on the detection of metal particles in oil is of great significance to the condition monitoring and operation and maintenance of mechanical equipment.Inductive metal abrasive sensors can not only measure the size and concentration of metal abrasive particles,but also determine the properties of the particles.However,the detection accuracy of online wear debris sensors currently on the market is not high,and can only detect magnetic particles above 100μm and non-magnetic particles above 150μm.Aiming at this problem,based on the Guangzhou Huangpu International Science and Technology Cooperation Project,this paper studies an inductive oil wear debris sensor using LC resonance frequency measurement.Based on theoretical analysis,finite element simulation,and experimental verification,the feasibility of the sensor is verified.The main research contents of this paper are as follows:(1)The research background and significance of the detection technology of wear debris in oil are introduced.A theoretical analysis is carried out on the detection principle of the inductive sensor,the relationship between the wear debris and the sensor coil under the time-harmonic quasi-static electromagnetic field,and the distribution law of the magnetic field inside the inductive coil.(2)Based on Maxwell’s equations,combined with the finite element simulation software COMSOL Multiphysics,the effects of excitation frequency,coil inner diameter,coil turns,and coil length on the magnetic field uniformity and detection sensitivity are analyzed.The simulation results show that when the ratio of the inductance coil radius to length is less than 0.4,the magnetic field uniformity of the coil test surface reaches more than 90%,and the magnetic field can be considered uniform at this time;The detection sensitivity of the sensor can be improved by increasing the excitation frequency,reducing the coil inductance or reducing the number of turns of the coil,and reducing the inner diameter of the coil.(3)According to the simulation results,the structure design and circuit design of the sensor are carried out,and the sensor test bench is built.The experimental results show that the detection of magnetic particles of 64.57μm and non-magnetic(copper)particles of 82.83μm can be achieved in a 4mm aperture flow channel.The sensor realizes the detection of tiny magnetic particles and non-magnetic particles under a large aperture,and especially improves the detection ability of non-magnetic particles.