Concept of a new type of electric machines using ferrofluids

Engelmann, S.; Nethe, A.; Scholz, Hellen

doi:10.1016/j.jmmm.2005.02.044

Cited by 11 publications

(5 citation statements)

References 2 publications

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“…where τ mag F (θ 0 ) is the magnetic fluid torque by its magnetic force. Applying Equations ( 8)-( 10) into (11) gives the following result:…”

Section: Additional Derivations For Stator and Magnetic Fluidmentioning

confidence: 99%

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Torque Analysis for Rotational Devices with Nonmagnetic Rotor Driven by Magnetic Fluid Filled in Air Gap

Kim¹,

Choi²

2021

Energies

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In magnetomechanical applications, it is necessary to calculate the magnetic force or torque of specific objects. If the magnetic fluid is involved, the force and torque also include the effect of pressure caused by the fluid. The standard method is to solve the Navier–Stokes equation. However, obtaining magnetic body force density is still under controversy. To resolve this problem, this paper shows that the calculation of the torque of these applications should not only use the magnetic force calculation method, but also consider the mechanical pressure using an indirect approach, such as the virtual work principle. To illustrate this, we use an experimental motor made of a nonmagnetic rotor immersed in a magnetic fluid. Then, we show that the virtual work principle in appropriate approach can calculate the output torque of the nonmagnetic rotor due to pressure of the magnetic fluid. Numerical analysis and experimental results show the validity of this approach. In addition, we also explain how the magnetic fluid transmits its magnetic force to the stator and rotor, respectively.

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“…where τ mag F (θ 0 ) is the magnetic fluid torque by its magnetic force. Applying Equations ( 8)-( 10) into (11) gives the following result:…”

Section: Additional Derivations For Stator and Magnetic Fluidmentioning

confidence: 99%

“…If the magnetic fluid is filled in an appropriate space, the magnetic field is more concentrated there. Several researchers are using this phenomenon to improve the efficiency and torque of various rotating machines, for example, induction machines [11,12], a linear motor [13], and an interior permanent magnet synchronous motor [14].…”

Section: Introductionmentioning

confidence: 99%

Torque Analysis for Rotational Devices with Nonmagnetic Rotor Driven by Magnetic Fluid Filled in Air Gap

Kim¹,

Choi²

2021

Energies

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“…Based on this definition, the devices that use magnetofluidic composites (magnetizable nanofluids, MR suspension or/and MR suspensions in a mixture with magnetizable nanofluids) are called magnetofluidic devices. In his master's dissertation [134], Montoya carried out an interesting study concerning a modification of the magnetization of nanofluids based on ferrite nanoparticles, showing that the pressure variation D p in a magnetic field with a constant intensity H, is given by the variation DM of magnetization with temperature as follows: [135] and achieve linear motors [136,137]. The models developed in these studies showed that the use of magnetizable nanofluids with low viscosities leads to significant improvement in the electrical properties of steady current electric motors and high-efficiency linear motors.…”

Section: Magnetofluidic Devicementioning

confidence: 99%

Physical characteristics of magnetorheological suspensions and their applications

Bîcă¹,

Liu²,

Choi³

2013

Journal of Industrial and Engineering Chemistry

174

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“…[18], the motor was simplified, and the magnetic field and torque were calculated by applying ferrofluid. In [19,20], the force of the motor was calculated according to the saturation flux density by applying ferrofluid to the airgap of the stepping motor and the induction motor. Similarly, in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…There are disadvantages to applying ferrofluid to the airgap as in Refs. [18][19][20][21]. Since particles of ferrofluid are not all insulated, eddy current loss occurs largely in areas with large changes in magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Improvement in Torque Density by Ferrofluid Injection into Magnet Tolerance of Interior Permanent Magnet Synchronous Motor

et al. 2021

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In an interior permanent magnet synchronous motor, an adhesive such as bond is generally injected into the magnet tolerance to prevent vibration of the permanent magnet within the insertion space. In this case, a disadvantage is that the magnet tolerance does not contribute to the performance. In this paper, ferrofluid is inserted to improve the torque density, utilizing the magnet tolerance. When inserting ferrofluid into the magnet tolerance, it is important to fix the magnet because conventional adhesives are not used, and it is important that the ferrofluid does not act as a leakage path within the insertion space. In this study, a new rotor configuration using a plastic barrier that satisfies these considerations was introduced. The analysis was conducted through finite element analysis (FEA), and this technique was verified by comparing the simulation results and the experimental results through a dynamo test. It was confirmed that the no-load back electromotive force in the final model increased through ferrofluid injection.

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Concept of a new type of electric machines using ferrofluids

Cited by 11 publications

References 2 publications

Torque Analysis for Rotational Devices with Nonmagnetic Rotor Driven by Magnetic Fluid Filled in Air Gap

Torque Analysis for Rotational Devices with Nonmagnetic Rotor Driven by Magnetic Fluid Filled in Air Gap

Physical characteristics of magnetorheological suspensions and their applications

Improvement in Torque Density by Ferrofluid Injection into Magnet Tolerance of Interior Permanent Magnet Synchronous Motor

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