Artículo
Magnetic stabilization of fluidized beds: Effect of magnetic field orientation
Autor/es | Espín Milla, Manuel Jesús
Sánchez Quintanilla, Miguel Angel Valverde Millán, José Manuel |
Departamento | Universidad de Sevilla. Departamento de Electrónica y Electromagnetismo Universidad de Sevilla. Departamento de Física Aplicada II |
Fecha de publicación | 2017 |
Fecha de depósito | 2018-01-31 |
Publicado en |
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Resumen | Fluidized beds of granular materials can be stabilized by interparticle attractive forces which confer the expanded bed an elastic modulus that stabilizes it against flow perturbations. Stabilization in a structure of ... Fluidized beds of granular materials can be stabilized by interparticle attractive forces which confer the expanded bed an elastic modulus that stabilizes it against flow perturbations. Stabilization in a structure of enduring contacts is seen to occur naturally due to the universal van der Waals forces for ∼50 μm particle size beds albeit in a quite reduced interval of gas velocities over the minimum fluidization velocity vmf. As shown in this work, a magnetic field may induce attractive forces between magnetizable particles thus extending the stable fluidization interval well beyond vmf. The structure of the magnetically stabilized bed is however markedly anisotropic since attractive magnetic forces are maximum along the direction of the externally imposed field which leads to the formation of chain particle aggregates. This paper shows experimental measurements on the magnetic yield stress, gas velocity at the transition to marginal stability and microstructure of magnetostabilized beds as affected by the direction of the magnetic field. Data shows that magnetic stabilization is optimized for co-flow fields as chain aggregates are preferentially orientated parallel to the magnetic field and along the direction of minimum drag. As the magnetic field is tilted, particle chains become tilted according to a balance between the magnetic attractive force between the particles and the vertical drag force, which reduces the magnetic yield stress and therefore shortens the interval of magnetic stabilization. |
Agencias financiadoras | Junta de Andalucía Ministerio de Economía y Competitividad (MINECO). España |
Identificador del proyecto | FQM-5735
CTQ2014-52763-C2-2-R FIS2014-54539-P |
Cita | Espín Milla, M.J., Sánchez Quintanilla, M.A. y Valverde Millán, J.M. (2017). Magnetic stabilization of fluidized beds: Effect of magnetic field orientation. Chemical Engineering Journal, 313, 1335-1345. |
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