Numerical and experimental analysis of terminal settling velocity in the presence of magnetic field aligned with gravity for ferro-magnetite particles using coupled CFD+DPM method

Abstract

Based on the previous investigations, in the presence of a magnetic field aligned with the gravity, the terminal settling velocity (TSV) of magnetic particles is improved compared to that of nonmagnetic particles. In this paper, the effects of magnetic fields with intensities of 0.03 and 0.05 T on the TSVs of spherical magnetite particles and steel balls of different sizes were simulated using combined computational fluid dynamics and discrete phase methods (CFD + DPM). Simulations showed that the application of a magnetic field with the mentioned intensities increased the TSVs of the steel balls and the magnetite spherical particles up to 16.16% and 13.88%, respectively. To validate simulation outputs, using synthetic samples and a Magneto-Gravity Settling Device (MGSD) designed and fabricated by the authors, a series of lab settling tests were performed under the same operational conditions as those of simulations. The results of the test work concluded that in the presence of magnetic fields of 0.03 and 0.05 T intensities, steel balls and spherical magnetite particles settled faster by 8.84% and 7.41%, respectively. This shows that, with an acceptable error, CFD + DPM simulation methods can well predict the influence of the magnetic field on the settling behaviour of magnetic particles.Based on the previous investigations, in the presence of a magnetic field aligned with the gravity, the terminal settling velocity (TSV) of magnetic particles is improved compared to that of nonmagnetic particles. In this paper, the effects of magnetic fields with intensities of 0.03 and 0.05 T on the TSVs of spherical magnetite particles and steel balls of different sizes were simulated using combined computational fluid dynamics and discrete phase methods (CFD + DPM). Simulations showed that the application of a magnetic field with the mentioned intensities increased the TSVs of the steel balls and the magnetite spherical particles up to 16.16% and 13.88%, respectively. To validate simulation outputs, using synthetic samples and a Magneto-Gravity Settling Device (MGSD) designed and fabricated by the authors, a series of lab settling tests were performed under the same operational conditions as those of simulations. The results of the test work concluded that in the presence of magnetic fields of 0.03 and 0.05 T intensities, steel balls and spherical magnetite particles settled faster by 8.84% and 7.41%, respectively. This shows that, with an acceptable error, CFD + DPM simulation methods can well predict the influence of the magnetic field on the settling behaviour of magnetic particles.