Effect of the number of magnetic matrices on particle capture in high gradient magnetic separation

A comprehensive understanding of the capture process involving matrices in high gradient magnetic separation (HGMS) is crucial for the design and improvement of matrix performance. However, few existing studies have paid attention to the influence of the number of magnetic matrices on the capture process. In this work, we numerically investigate this issue in both longitudinal and transversal HGMS systems, where multiple scenarios with different particle sizes, flow rates and matrix spacing are considered. Interestingly, we show that in most cases, increasing the number of magnetic matrices along the flow direction has little to no influence on the capture radius. It has a certain effect on improving the capture radius only in a few specific cases, such as when dealing with large particles at low flow rates with closely spaced matrices or when working with small particles at high flow rates with widely spaced matrices. These phenomena are related to the appearance of repulsive magnetic forces around matrices and the distribution characteristics of magnetic forces. The obtained results indicate that, in the design of the practical HGMS system, simply increasing the number of matrices along the flow direction may not be a reasonable or effective strategy for enhancing capture performance.