Magnetic Fluid Jet Research Articles

Design of Alternating Current Abrasive Magnetic Fluid Jet Generator Based on Permanent Magnet

During the test of DC(direct current) abrasive magnetic fluid technology,many bubbles and noises were generated near the graphite electrode , and the yellow green liquid was produced, which affected the further test.Through the study of graphite electrode, it was found that NaCl solution magnetic fluid produced hydrogen and chlorine gas after electrolysis. At the same time, chlorine gas dissolved in water to form yellow green liquid.The magnetic field of neodymium boron permanent magnet was equivalent to a mechanical stirring, which inhibited the production of chlorine gas.According to the difference of impressed current system, the abrasive magnetic fluid jet technology was divided into DC and AC(alternating current) .There was no electrode in AC abrasive magnetic fluid jet technology, so no gas or noise would be produced.The rotating magic ring permanent magnet produced alternating magnetic field, acting on the abrasive magnetic fluid to form an induced current.Under the action of the magnetic field, the electromagnetic force was applied to move along the circumferential direction to promote the motion of the abrasive magnetic fluid.

Research of Abrasive Suspension Magnetic Fluid Jet Technology

Through analyzing the existing abrasive jet technology, and discussing the MHD technology principle and its advantages, this paper proposes a new method of abrasive suspension magnetic fluid jet technology. The experimental device validates that conductive fluid can produce a boost effect Conductive fluid can produce a boost effect. This paper points out the key technologies involved in the new technology of the magnetic fluid jet of the suspended abrasive, and expounds the research status of the key technology and the main technical problems, and provides a new research direction for the development of abrasive jet.

Instability of a Magnetic Fluid Jet in a Transverse Magnetic Field

The instability behavior of moving magnetic fluid jet in the presence of a constant uniform transverse magnetic field is investigated theoretically within the framework of linear stability analysis. The corresponding dispersion relation between the wave growth rate of instability and the magnitude of its wavenumber is obtained. The dependence of the wave growth rate on the polar angle in the presence of magnetic field is found. The influence of the magnetic field on the length of undisturbed jet section and the instability wavelength is studied. The correlation with the experimental results is demonstrated.

Surface density of the polarization charge of a magnetic fluid jet in a uniform electric field

The behavior of magnetic fluid jets in electric and magnetic fields is investigated. A way of calculating the density of a charge forming on the jet’s surface is suggested, and a charge formation mechanism is put forward.

Alternating Magnetic Field Responses of Magnetic Fluid Drop Adsorbed to a Small Permanent Magnet

Experimental studies of the behavior of magnetic fluid drop under the effect of an external alternating magnetic field were performed using a high speed digital video camera system. A small permanent magnet was immersed in magnetic fluid drop, and it was fixed with an aluminum bar. The surface of magnetic fluid responded to the external magnetic field sensitively. The free surface of the magnetic fluid drop responded to the external alternating field in elongation and contraction along the direction of the field. The capillary magnetic fluid jet was produced at the certain external magnetic field condition.

Experimental analysis on MR fluid channel flow dynamics with complex fluid–wall interactions

MR fluid plugging performance by aggregation of magnetized particles in MR fluid is recently expected to be one of the most promising applications in medical or safety devices, such as blood flow control, steam issuing shut-down valve and fuel supply control for automobile. In this study, dynamic response of MR fluid plugging and its breakdown in a pressure mode with complex fluid–wall interactions was experimentally investigated, considering the effects of magnetic flux density, wall surface structure, wall permeability and wall elasticity of tube. Higher endurance pressure is obtained for wall surface groove structure and for steel wall due to a strong anchoring effect by rigid cluster formation in a concave region and strong MR fluid column formation in a channel core region, respectively. Furthermore, MR fluid plugging performance and the fluid storage characteristic of PVA tube as a bio-material was clarified. Because of the large radial expansion of the tube at the applied magnetic region in a pressure mode, PVA tube shows unique characteristics, such as storing MR fluid under magnetic field and MR fluid jet issuing under releasing magnetic field.

The dynamic behavior of magnetic fluid adsorbed to small permanent magnet in alternating magnetic field

The dynamic behavior of a magnetic fluid adsorbed to a small NdFeB permanent magnet subjected to an alternating magnetic field was studied with a high speed video camera system. The directions of alternating magnetic field are parallel and opposite to that of the permanent magnet. It was found that the surface of magnetic fluid responds to the external alternating magnetic field in elongation and contraction with a lot of spikes. Generation of a capillary magnetic fluid jet was observed in the neighbourhood of a specific frequency of alternating field. The effect of gravitational force on surface phenomena of magnetic fluid adsorbed to the permanent magnet was revealed.

Capillary jet production of magnetic fluid by electromagnetic vibration

The purpose of the present paper is to develop the generator of the capillary magnetic fluid jet. The experiments on magnetic fluid sloshing were conducted at first. Based on th e results of experimental study on the fluid motions in a longitudinally vibrated tank with a permanent magnet, a magnetic fluid jet generator was developed. The generator is com posed of NdFeB magnets, magnetic fluid, small circular cylindrica l tank, and a coil. It is found experimentally that the magnet ic fluid droplets and capillary jet are formed by the generator.

Experimental and numerical investigations on magnetic fluid jet

The rheological properties of water-based magnetic fluids (MFs) were measured using rotating and capillary rheometers. It is found that the theological behaviors of MFs with high solid content under an applied magnetic field can be described using the Herschel-Bulkley (H-B) model. Two-dimensional numerical simulation was performed to investigate ejection phenomena of the MF from a capillary with the H-B model. Experiments was conducted to observe drop formations. The measured numerical results are validated by the experimental findings.

Droplet production from a capillary jet of magnetic fluid under a magnetic field

This paper is concerned with the development of the vibration system for the drop formation of magnetic fluid. The breakup of magnetic fluid jet generated by the longitudinal vibration of the permanent magnet-magnetic fluid system is studied experimentally with the three-dimensional motion analysis system. The detailed processes of the droplet production, capillary jet breakup, and jet formation are revealed.

Nonlinear waves on the surface of a magnetic fluid jet in porous media

Abstract A weakly nonlinear theory of capillary waves on the surface of a magnetic fluid jet is investigated. The magnetic fluids are uniformly streaming through porous media. The linear forms of the equations of motion are solved in the light of the nonlinear boundary conditions. The boundary-value problem leads to a nonlinear characteristic equation governing the interfacial displacement and having complex coefficients, where the nonlinearity is kept up to the third order. Taylor theory is adopted to expand the governing nonlinear equation through the multiple scales, in both space and time, to yield the well-known Schrodinger equation with complex coefficients. This equation describes the evolution of the wave train, it may be regarded as the counter parts of the single nonlinear Schrodinger equation that occurs in the non-resonance case. The stability criteria are discussed theoretically and illustrated graphically in which stability diagrams are obtained. Regions of stability and instability are identified for the stratified magnetic fields versus the wave number for the wave train of the disturbance. It is found that the porous media have a destabilizing influence. This influenced is enhanced when the Darcy's coefficients are different. New instability regions in the parameter space, which appear due to the nonlinear effects, are shown.

Jet formation of magnetic fluid with vibration of an annular magnet

This paper describes the novel method for generating the narrow vertical jet of magnetic fluid. This jet is formed by the vibration of magnetic fluid-permanent annular magnet system. The dynamic behavior of narrow magnetic fluid jet is analyzed by a three-dimensional motion analysis system. Effect of the excitation amplitude on the jet formation of magnetic fluid and the atomization characteristics is revealed experimentally.

1113 磁石-磁性流体系の縦振動によって生成する磁性流体噴流の流動特性

The magnetic fluid jet generated by the vibration of an annular permanet magnet-magnetic fluid system was investigated experimentally making use the vibration-testing system. The dynamic behavior of narrow magnetic fluid jet and magnetic fluid surface were analyzed by a three-dimensional motion analysis system composed of two high speed digital cameras. It was found that narrow magnetic fluid jet and homogeneous size drops can be produced by combination of certain excitation frequency and amplitude. Effect of the excitation amplitude on the jet formation of magnetic fluid and the atomization characteristics was revealed in detail.

Magnetic fluid systems of finite geometry with surface adsorption

The surface instability of magnetic fluid systems with finite geometry in the presence of an external magnetic field is discussed, taking into consideration the phenomenon of surface adsorption in the fluid, using energy method. The dispersion relations are derived for normal field instability and magnetic fluid jet, taking azimuthal and axial magnetic fields separately. We find that the phenomenon of surface adsorption of magnetic particles stabilizes the magnetic fluid systems under certain conditions.

Dynamic behavior of a magnetic fluid jet injected from a vibrating nozzle

This paper describes an experimental study of the dynamic behavior of magnetic fluid jets which are injected from a vibrating nozzle into the atmosphere. It was found that an intact liquid jet can be made to bifurcate continuously into a pronged jet by vibrating the nozzle with certain combinations of frequency and acceleration. The effects of the magnetic fields on the drops produced by the jet breakup are also revealed.

Stability of a magnetic fluid jet

The stability of a magnetic fluid jet in the presence of a magnetic field when the field is either azimuthal or axial is investigated by using the energy principle. By constructing the respective Lagrangian functions and solving the associated Euler-Lagrange equations of motion, the dispersion relations are derived.

Nonlinear waves on the surface of a magnetic fluid jet

A weakly nonlinear theory of capillary waves on the surface of a magnetic fluid jet is investigated. It is found that the wavetrain of constant amplitude is unstable against modulations. The wave number k m at which the modulational instability sets in decreases with the increase in the strength of the applied magnetic field.