A discrete element model for the influence of surfactants on sedimentation characteristics of magnetorheological fluids

• Published in: Korea-Australia rheology journal Vol. 30; no. 1; pp. 29 - 39
• Main Author: Son, Kwon Joong
• Format: Journal Article
• Language: English
• Published: Seoul / Melbourne Korean Society of Rheology, Australian Society of Rheology 01.02.2018; Springer Nature B.V; 한국유변학회
• Subjects: Additives; Characterization and Evaluation of Materials; Chemistry and Materials Science; Complex Fluids and Microfluidics; Computational fluid dynamics; Computer simulation; Controllability; Discrete element method; Fluids; Food Science; Gravitation; Interaction models; Magnetorheological fluids; Materials Science; Mechanical Engineering; Particle interactions; Polymer Sciences; Sedimentation; Sedimentation & deposition; Soft and Granular Matter; Stokes law (fluid mechanics); Surfactants; 공학일반; surfactants; sedimentation simulation; discrete element method; magnetorheological fluids
• ISSN: 1226-119X; 2093-7660
• DOI: 10.1007/s13367-018-0004-z

Hindering particle agglomeration and re-dispersion processes, gravitational sedimentation of suspended particles in magnetorheological (MR) fluids causes inferior performance and controllability of MR fluids in response to a user-specified magnetic field. Thus, suspension stability is one of the principal factors to be considered in synthesizing MR fluids. However, only a few computational studies have been reported so far on the sedimentation characteristics of suspended particles under gravity. In this paper, the settling dynamics of paramagnetic particles suspended in MR fluids was investigated via discrete element method (DEM) simulations. This work focuses particularly on developing accurate fluid-particle and particle-particle interaction models which can account for the influence of stabilizing surfactants on the MR fluid sedimentation. Effect of the stabilizing surfactants on interparticle interactions was incorporated into the derivation of a reliable contact-impact model for DEM computation. Also, the influence of the stabilizing additives on fluid-particle interactions was considered by incorporating Stokes drag with shape and wall correction factors into DEM formulation. The results of simulations performed for model validation purposes showed a good agreement with the published sedimentation measurement data in terms of an initial sedimentation velocity and a final sedimentation ratio.