Research On The Negative Magnetophoresis-Based Magnetic Levitation Technology And Its Performances

Negative magnetophoresis is the phenomenon where diamagnetic or weakly paramagnetic objects suspended in a magnetic fluid move away from the magnetic sources under the magnetic force produced by the magnetization difference between the objects and solution.The magnetic control technology based on negative magnetophoresis gets rid of the restriction that the objects should be magnetic in positive magnetophoresis processes,and it becomes a promising method for label-free manipulation,which has derived a variety of manipulation techniques and related applications.Among them,magnetic levitation(MagLev)via negative magnetophoresis has been widely concerned because of its application potential in fields like density measurement,separation,assembly and quality detection.In particular,the newly developed axial MagLev configuration with single/dual ring magnets has more advantages in operation and visualization,and the research on the performance of MagLev and its application have become a hot topic in this field.However,on the one hand,the existing MagLev systems are not sensitive enough to perform separation and detection for materials of similar density.On the other hand,the small working range,especially in the case of magnets of small radius,makes it difficult for such devices to be used in materials measurement and manipulation in a wide density range.In order to solve the above problems,based on the axial MagLev configuration,this work systematically explores the influence of magnetic field distribution and structural parameters on the suspension characteristics of the samples combined with numerical analysis and experimental research.On this basis,the new functional region is developed in the conventional system and a new MagLev system with dual-ring magnets is proposed.The relevant research and expected results provide a feasible way and key technical support for significantly improving the sensitivity and working range of the existing MagLev system,which have great theoretical value and practical significance.In terms of numerical simulation,on the one hand,based on the finite element simulation software COMSOL Multiphysics,the 2-D axisymmetric numerical model for axial MagLev system is established and solved in this work,which provides an effective method for the levitation analysis of samples under different magnetic field and solution parameters.On the other hand,from the view of system energy,the rapid prediction and analysis on deviation characteristics of particles and levitation characteristics of samples is performed based on MATLAB and Monte Carlo simulation method.At the same time,a set of MagLev experimental platform is built,and the effectiveness and accuracy of the numerical model are systematically demonstrated with the standard density floats.In terms of performance improvement in MagLev,the influence of separation distance of axial MagLev system on the levitation and deviation of samples is illustrated in this work.It is found for the first time that the levitation system has a new high-sensitivity measurement functional region,which can realize the linear and nonlinear analysis based on the density.The research shows that the sensitivity of linear measurement is more than 100 times higher than that of the conventional functional region in the same device.Based on the new functional region,the samples with density difference of about 0.0013g/cm~3 are separated effectively and the density measurements with error rate of about 0.07%are completed,which fully proved the effectiveness and superiority of the new functional region in high-sensitivity separation and measurement.In addition,in order to solve the problem of small working range in the conventional axial MagLev system,the MagLev system based on radial ring magnets is proposed in this work.Numerical analysis shows that the new MagLev system can significantly improve the working range without changing the measuring range,which provides a better technical support and platform for the experimental research on measurement.On this basis,the levitation characteristics of the new MagLev system are further explored,and the multi-tile configuration of the radial magnetized magnet is designed.