Frequency Analysis of Semi-Active Tuned Magnetic Fluid Column Damper with Two Electromagnets

2014 ◽  
Vol 792 ◽  
pp. 275-280 ◽  
Author(s):  
Kazuki Ikari ◽  
Hideaki Masuda ◽  
Toshiyuki Oyamada ◽  
Tatsuo Sawada
Keyword(s):  
Magnetic Field ◽  
Numerical Analysis ◽  
Numerical Solution ◽  
Natural Frequency ◽  
Frequency Analysis ◽  
Magnetic Fluid ◽  
Momentum Equation ◽  
Experimental Results ◽  
Working Fluid ◽  
Damping Characteristics

A new semi-active tuned liquid column damper (TLCD) that uses magnetic fluid as its working fluid (MF-TLCD) is presented. An MF-TLCD alters the natural frequency of the magnetic fluid column that forms the resident liquid inside the MF-TLCD by applying a magnetic field. We investigated the damping characteristics of an MF-TLCD equipped with two electromagnets, and also the transition of the natural frequency, which is strongly related to the damping performance. The coupled structure-MF-TLCD system was investigated both experimentally and by numerical analysis. The momentum equation of an MF-TLCD and its numerical solution are presented. The numerical results are validated by comparison with experimental results.

Analysis of Vibration Characteristics of Magnetorheological Elastomer Sandwich Beam under Non-Homogeneous Magnetic Field

2011 ◽  
Vol 101-102 ◽  
pp. 202-206 ◽  
Author(s):  
Guo Liang Hu ◽  
Miao Guo ◽  
Wei Hua Li
Keyword(s):  
Magnetic Field ◽  
Natural Frequency ◽  
Sandwich Beam ◽  
Homogeneous Magnetic Field ◽  
Experimental Results ◽  
Magnetorheological Elastomer ◽  
Test Rig ◽  
Thin Aluminum ◽  
Set Up ◽  
The Magnetic Field

In this study, the MRE was manufactured, and the sandwich beam was also fabricated by treating with MRE between two thin aluminum layers. The experiment test rig was set up to investigate the vibration response of the MRE sandwich beam under non-homogeneous magnetic field. The experimental results show that the MRE sandwich beam had the capabilities of left shifting first natural frequency when the magnetic field was increased in the activated regions. It is also obvious that the first natural frequency of the MRE sandwich beam decreased as the magnetic field that applied on the beam was moved from the clamped end of the beam to the free end of the beam.

scholarly journals Ultrasound Frequency Analysis of a Magnetic Fluid in Low-Intensity External Magnetic Field

2017 ◽  
Vol 131 (4) ◽  
pp. 910-912
Author(s):  
J. Kurimský ◽  
M. Rajňák ◽  
R. Cimbala ◽  
B. Dolník ◽  
J. Tóthová ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Frequency Analysis ◽  
Magnetic Fluid ◽  
Low Intensity ◽  
Ultrasound Frequency

Numerical Prediction of Cavitating MHD Flow of Electrically Conducting Magnetic Fluid in a Converging-Diverging Nozzle

2004 ◽  
Vol 71 (6) ◽  
pp. 825-838 ◽  
Author(s):  
Jun Ishimoto
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Mhd Flow ◽  
Cavitating Flow ◽  
Numerical Results ◽  
Nonuniform Magnetic Field ◽  
Working Fluid ◽  
Two Dimensional ◽  
Two Phase ◽  
Electrically Conducting

The fundamental characteristics of the two-dimensional cavitating MHD flow of an electrically conducting magnetic fluid in a vertical converging-diverging nozzle under a strong nonuniform magnetic field are numerically predicted to realize the further development and high performance of a two-phase liquid-metal MHD power generation system using electrically conducting magnetic fluids. First, the governing equations of the cavitating flow of a mercury-based magnetic fluid based on the unsteady thermal nonequilibrium multifluid model are presented, and several flow characteristics are numerically calculated taking into account the effect of the strong nonuniform magnetic field. Based on the numerical results, the two-dimensional structure of the cavitating flow and cavitation inception phenomena of the mercury-based magnetic fluid through a converging-diverging nozzle are shown in detail. The numerical results demonstrate that effective two-phase magnetic driving force, fluid acceleration, and high power density are obtained by the practical use of the magnetization of the working fluid. Also clarified is the precise control of the cavitating flow of magnetic fluid that is possible by effective use of the magnetic body force that acts on cavitation bubbles.

Characteristics of a magnetic fluid heat transport device Part 1: Numerical simulation of flow and heat transport phenomena

2000 ◽  
Vol 214 (4) ◽  
pp. 549-561 ◽  
Author(s):  
H Yamaguchi ◽  
I Kobori ◽  
N Kobayashi
Keyword(s):  
Magnetic Field ◽  
Numerical Analysis ◽  
Heat Transport ◽  
Magnetic Fluid ◽  
Numerical Study ◽  
Thermal Characteristics ◽  
Geometrical Model ◽  
Flow State ◽  
Vortex Zone ◽  
Transport Device

A numerical analysis is conducted in order to study the flow state and thermal characteristics of a magnetic fluid heat transport device. A simple geometrical model of the device is considered in the present numerical study. The highly simplified marker-and-cell (HSMAC) method is adopted for the numerical analysis, where the transient solutions are obtained in the two-dimensional axisymmetric computational plane. From results of the numerical calculation it can be shown that the vortex zone appears when a magnetic field is applied and the configuration of flow associated with the vortex zone changes for variation in the magnetic field, increasing or decreasing the heat transport capability dependent upon the conditions of the device.

Characteristics of Hydrodynamic Pressure of a Magnetic Fluid in a Tuned Magnetic Fluid Damper

2010 ◽  
Vol 670 ◽  
pp. 181-190 ◽  
Author(s):  
Ken Ichi Ohno ◽  
Tatsuo Sawada
Keyword(s):  
Magnetic Field ◽  
Natural Frequency ◽  
Magnetic Fluid ◽  
Hydrodynamic Pressure ◽  
Pressure Measurements ◽  
Fluid Damper ◽  
Sloshing Frequency ◽  
Dynamic Absorber

A tuned magnetic fluid damper (TMFD) is a semi-active dynamic absorber using a magnetic fluid as a damping mass. A characteristic of the TMFD is to change a natural frequency of a sloshing. When a magnetic field is applied to a container filled with a magnetic fluid from below, the natural sloshing frequency increases and a range of a damping frequency is spread. In this paper, pressure measurements were used to control the appropriate magnetic field.

Numerical analysis and experimental verification of magnetic fluid sealing for air cylinder in Aerospace Engineering

2021 ◽  
pp. 1-17
Author(s):  
Chen Fan ◽  
Zhang Chongfeng ◽  
Yang Xiaolong
Keyword(s):  
Magnetic Field ◽  
Numerical Analysis ◽  
Service Life ◽  
Permanent Magnet ◽  
Magnetic Fluid ◽  
Slot Width ◽  
Aerospace Engineering ◽  
Pole Piece ◽  
The Magnetic Field ◽  
Sealing Gap

In order to solve the problem of short service life (2 months) and zero leakage of air cylinder in aerospace engineering, this paper innovatively designs a magnetic fluid sealing device of air cylinder in aerospace engineering through magnetic circuit analysis and magnetic fluid sealing theory. The magnetic field finite element method is used to calculate the magnetic field distribution in the sealing gap under different key parameters such as the number of pole teeth, the height of the radial sealing gap, the thickness of the permanent magnet, the slot width, the ratio of pole piece height to shaft. And numerical analysis of the number of pole teeth, the radial sealing gap height, permanent magnet thickness, slot width, the ratio of pole piece height to shaft and other key parameters on the magnetic fluid sealing performance. Finally, the reliability of the reciprocating magnetic fluid sealing withstand voltage is verified by experimental methods. Research indicates. The pressure capabilities of magnetic fluid sealing is increasing with the increase of the number of pole teeth. The pressure capabilities of magnetic fluid sealing is decreasing with the increase of the radial sealing gap. The sealing withstand voltage increases first and then decreases with the increase of the thickness of the permanent magnet, and finally increases, and the value of the withstand voltage is the largest when the thickness of the permanent magnet is 7.8 mm. The sealing pressure capabilities increases as the slot width increases. The sealing withstand voltage increases first and then decreases as the ratio of pole piece height to shaft increases, and when the ratio of pole piece height to shaft is 0.8, the sealing withstand voltage reaches a maximum value. The pressure test finally reaches the pressure value of 6 MPa, which can meet the pressure value demand of medium pressure cylinder, indicating that the magnetic fluid sealing technology can effectively solve the leakage problem existing in the air cylinder technology of Aerospace Engineering, and improve the reliability and service life of the air cylinder.

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