Mason numbers for magnetorheology

Abstract:In this paper we performed steady shear and oscillatory magnetorheological (MR) studies in magnetic fluids containing CoNi nanoclusters of 450 nm in diameter. Co-rich nanoclusters were synthesized by conventional homogeneous nucleation without any external surfactant or reducing agent in liquid polyol at elevated temperature. The x-ray diffraction, energy dispersive X-Ray analysis, scanning and transmission electron microscopy studies were done for analyzing the sample composition and morphology. Two variants of fluid samples were prepared by dispersing 15 vol% and 20 Vol% of CoNi powders in castor oil. Room temperature steady magnetoshear studies indicate viscoplastic behavior with stronger dependence of static yield stress on magnetization than a dipolar coupling that was operational in the dynamic yield stress. Magnetosweep measurements at constant shear rate showed interesting relaxation at high magnetic fields. We also explored dynamical elastic behavior through oscillatory magnetorheological studies under both strain sweep and frequency sweep modes, and showed glass transition like phenomenon occurring in them above critical shear amplitudes.

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“…This was the basic assumption in that paper [20]. However, for the static case the interaction was stronger.…”

Section: Static and Dynamic Yield Stressmentioning

confidence: 98%

“…There is an alternative relation to the fit. According to Klingenberg et al [20], a better fit can be observed when H is replaced by M and it is applicable to wide range of M. This is plotted in Fig. 9, with both types of τ and M values calculated from powder magnetization data (M-H curves, vide Fig.…”

Section: Static and Dynamic Yield Stressmentioning

confidence: 99%

Dynamic and rate-dependent yielding behavior of Co0.9Ni0.1 microcluster based magnetorheological fluids

Arief

Mukhopadhyay

2016

Journal of Magnetism and Magnetic Materials

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“…In a simple shear flow, the local velocity in this relation is where is the shear rate. The dimensionless ratio of the magnetic force to the hydrodynamic force results in the Mason number (Marshall et al, 1989 (for equivalent problem in ER fluids), Klingenberg et al, 2007) .…”

Section: Submitted To the Journal Of Intelligent Materials Systems Andmentioning

confidence: 99%

“…The magnetic force generated between two particles placed in a homogeneous field can be viewed as arising from the distorted field lines of each magnetically susceptible particle. This interparticle force for the case of two spherical particles in contact is (Klingenberg et al, 2007)…”

Section: Introductionmentioning

confidence: 99%

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Rheology and microstructural evolution in pressure-driven flow of a magnetorheological fluid with strong particle–wall interactions

Ocalan

McKinley

2012

Journal of Intelligent Material Systems and Structures

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The interaction between magnetorheological (MR) fluid particles and the walls of the device that retain the fluid is critical as this interaction provides the means for coupling the physical device to the field-controllable properties of the fluid. This interaction is often enhanced in actuators by the use of ferromagnetic walls which generate an attractive force on the particles in the field-on state. In this paper, the aggregation dynamics of MR fluid particles and the evolution of the microstructure in pressure-driven flow through ferromagnetic channels are studied using customfabricated microfluidic devices with ferromagnetic side walls. The aggregation of the particles and the time-dependent evolution in the microstructure is studied in rectilinear, expansion and contraction channel geometries. These observations help identify methods for improving MR actuator design and performance.

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Aggregation Volume Estimator–Based Offline Programming Guidance of Magnetic Nanoparticles in the Realistic Rat‐Brain Vasculature Model

Park

et al. 2023

Advanced Intelligent Systems

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Targeted delivery of magnetic nanoparticles (MNPs) to an area of a blood vessel with fluidic flow is hampered by the lack of a suitable real‐time imaging modality for MNPs, the control system complexity, and low targeting performance. Herein, an offline programming guidance (OLPG) scheme for aggregated MNPs is proposed based on a real‐time aggregation volume estimator. The proposed aggregation volume estimator based on a magnetic drug‐targeting simulator reflects volume changes of aggregated MNPs; hence, it can model a magnetic force acting on aggregated MNPs in real time while enhancing targeting performance. The proposed guidance system is evaluated using a simulation testbed and in vitro model of the rat brain, which yields comparable results at different fluid viscosities, flow velocities, target areas, and flow types. The OLPG with the aggregation volume estimator improves targeting performance by 116%–409% compared with the default mode, and by 111%–180% compared to the performance without the aggregation volume estimator. Furthermore, a guidance margin predicts enhanced targeting performance (root‐mean‐square error < 5%) irrespective of the flow environment. The proposed guidance strategy has the potential to overcome the problems caused by the lack of an imaging modality, control‐system complexity, and low targeting performance.

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Mason numbers for magnetorheology

Cited by 140 publications

References 14 publications

Dynamic and rate-dependent yielding behavior of Co0.9Ni0.1 microcluster based magnetorheological fluids

Dynamic and rate-dependent yielding behavior of Co0.9Ni0.1 microcluster based magnetorheological fluids

Rheology and microstructural evolution in pressure-driven flow of a magnetorheological fluid with strong particle–wall interactions

Aggregation Volume Estimator–Based Offline Programming Guidance of Magnetic Nanoparticles in the Realistic Rat‐Brain Vasculature Model

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