International Journal of Applied Electromagnetics and Mechanics 48 (2015) 387–397 387 DOI 10.3233/JAE-140157 IOS Press Optimization of the capture element for an OGMS based on the 3D computation of the magnetic particle behavior A. Belounis ∗ , R. Mehasni, M. Ouili and M.E. Latreche Laboratoire d’Electrotechnique de Constantine (LEC), Université Constantine 1, Route Ain Elbey, Constantine, Algérie Abstract. In this work, we present a 3D approach for the optimization of the capture element for an open-gradient magnetic separation (OGMS) used for the purification of flowing liquids in a channel of small diameter D = 2.5 × 10 -2 m. This op- timization is concerned with the research of the capture element design and the excitation current that allow the separation of ferromagnetic particles of fine size Rp = 3 × 10 -5 m. The proposed approach is based on the minimization of an objective function which is the distance between the particle capture site and the central point of the capture element assumed to be the perfect capture site. To obtain the particle capture site we have computed its behavior where the important magnetic and hydrodynamic applied forces have been taken into account. To perform the minimization of the objective function, we have ap- plied the Tabu search method. To validate the obtained results, experiments have been performed on a flowing water containing particles of iron. Such validation has dealt with the verification of the capture site and the quantification of the volume of the separated particles buildup. Keywords: Interdisciplinary applications of physics, magnetic separation, magnetic device characterization, particle dynamics, optimization. 1. Introduction In magnetic separation, the applied magnetic field acts selectively on the different components of the treated material [1–6]. In the open-gradient magnetic separators (OGMS), the field gradient is generated in several ways: As a result of the natural non-homogeneity of the field caused by the dependence of the field on the distance from its source (overband, suspended, plate and grate magnets) or by special arrangements of permanent magnets or of the windings of electromagnets (magnetic rolls, pulleys and drum separators). Multipolar windings of conventional or superconducting coils with alternating polar- ity are employed in OGMS separators [7]. In this category of magnetic separation no capture matrix is used. The capture element can be the source of the applied magnetic field (permanent magnet or electro- magnet). To extract ferromagnetic particles from nonmagnetic materials, a static magnetic field can be used [8,9]. To realize an efficient separation, a magnetic field of high strength and gradient must be ap- plied. This requires an optimal choice of both the capture element dimensioning and excitation current. ∗ Corresponding author: A. Belounis, Laboratoire d’Electrotechnique de Constantine (LEC), Université Constantine 1, Route Ain Elbey, Constantine 25000, Algérie. Tel./Fax: +213 31 819 013; E-mail: abdallah.belounis@lec-umc.org. 1383-5416/15/$35.00 c  2015 – IOS Press and the authors. All rights reserved