Scaling between viscosity and hydrodynamic/magnetic forces in magnetic fluids
Metadatos
Mostrar el registro completo del ítemAutor
López López, Modesto Torcuato; García López-Durán, Juan De Dios; Delgado Mora, Ángel Vicente; González Caballero, FernandoEditorial
Croatian Chemical Society
Materia
Magnetic colloids Viscosity Magnetorheology
Fecha
2007Referencia bibliográfica
López-López, M.T.; et al. Scaling between viscosity and hydrodynamic/magnetic forces in magnetic fluids. Croatica Chemica Acta, 80(3-4): 445-451 (2007). [http://hdl.handle.net/10481/29096]
Patrocinador
Financial support from MEC (Spain) and FEDER funds (EU) (Project MAT2005-07746-C02-01) and Junta de Andalucía, Spain (PE-FQM-410) are gratefully acknowledged.Resumen
The aim of this work is the investigation of the magnetorheological behavior, under both simple steady- and oscillatory-shear flow regimes, of fluids composed by micron-sized iron particles (average diameter 930 ± 330 nm) dispersed in silicone oil. Magnetic fields ranging from 279 A/m (0.35 mT) to 1727 A/m (2.17 mT) were applied to the suspensions. The effect of silica
nanoparticles as stabilizer of the suspensions has also been considered. The study has been made by the scaling between the viscosity of the suspension and the ratio of hydrodynamic to magnetic forces acting on the dispersed particles, given by the dimensionless Mason number (Mn), and interpreted in terms of the chainlike model taken from the theory of Martin and Anderson
(J. Chem. Phys. 104 (1996) 4814-4827). The model is quite well accomplished for iron
suspensions of different (20 % and 30 %) volume fraction without any stabilizing agent. The presence of added silica nanoparticles in the suspension hinders the formation of regular iron structures induced by the magnetic field, especially at the lowest applied magnetic fields. Thus
the model becomes not applicable to these cases. Viscometry has been shown to be more adequate than oscillometry for scaling the viscous properties of magnetorheological suspensions with microscopic interparticle forces in terms of Mn number.