Magnetic Levitation With Cylindrical Magnets for Density-Based Measurement

Magnetic levitation (MagLev) based on the magneto-Archimedes effect is an emerging technology for density measurement and analysis. However, the most commonly used standard MagLev faces the problem of cumbersome and time-consuming calculation procedures when analyzing the levitation behavior of samples in the whole working region. This work explores a new MagLev configuration using two cylindrical permanent magnets called “cylindrical MagLev” to solve the above issue. A theoretical model is developed to rapidly determine the relationship between the density of samples and their levitation height when they are stably levitated along the centerline of the MagLev system. Meanwhile, numerical simulations with a simple two-dimensional (2-D) symmetrical model are performed to reveal the levitation characteristics of samples in the whole working region with regard to measurement linearity, sensitivity, and magnetic force distribution, which are well-verified by experiments. On this basis, the performance of the developed cylindrical MagLev for density measurement is investigated using both linear and nonlinear measurement regions, and measurement uncertainties are evaluated. The proposed cylindrical MagLev exhibits similar performance to the standard MagLev, but its system design and performance analysis become much simpler and more convenient. Therefore, it is expected to replace the latter as a general MagLev configuration in practical applications such as density-based measurement, separation, and detection.