FRICTION FACTOR OF MAGNETO-RHEOLOGICAL FLUID FLOW IN GROOVED CHANNELS

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1297-1303 ◽  
Author(s):  
F. GORDANINEJAD ◽  
B. M. KAVLICOGLU ◽  
X. WANG
Keyword(s):  
Fluid Flow ◽  
Friction Factor ◽  
Shear Yield Stress ◽  
Mr Fluid ◽  
Flow Rates ◽  
Mr Fluids ◽  
Mason Number ◽  
Shear Yield ◽  
Grooved Surface ◽  
Magneto Rheological

The focus of this work is to study surface effects on the friction factor a magneto-rheological (MR) fluid flowing through a grooved channel under various magnetic fields and volumetric flow rates. Based on the experimental data, a relation is developed for the friction factor of MR fluid in channel flow in terms of Mason number evaluated at the surface, and the depth of the grooves. Using this relation, the pressure loss of a MR fluid flowing through a channel with grooved walls can be determined without implementing a constitutive model for MR fluids or utilizing the concept of shear yield stress. Several grooves with different configurations in channel walls have been considered. From the experimental results it has been demonstrated that under an applied magnetic field, the grooved surface would increase the friction factor of MR fluid flow significantly when comparing to the surface without grooving. The depth of grooves plays an important role in this increment.

A New Unified Approach for Flow Analysis of Magneto-Rheological Fluids

Aerospace ◽  
2004 ◽  
Author(s):  
Barkan M. Kavlicoglu ◽  
Faramarz Gordaninejad ◽  
Xiaojie Wang ◽  
Gregory Hitchcock
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Pressure Loss ◽  
Flow Analysis ◽  
Volumetric Flow Rate ◽  
Mr Fluid ◽  
Mason Number ◽  
Universal Approach ◽  
Shear Yield ◽  
Magneto Rheological

The focus of this study is to develop a new universal approach for the flow analysis of magneto-rheological (MR) fluids through channels. An experimental study is conducted to investigate the relationship between the pressure loss of a MR fluid as a function of the applied magnetic field strength, volumetric flow rate, and surface roughness without utilizing the assumption of shear yield stress. A relation for nondimensional friction factor is developed in terms of Mason number and dimensionless surface roughness. It is demonstrated that the pressure loss across the MR fluid flow channel is significantly affected by the magnetic field and the surface roughness.

A Unified Approach for Flow Analysis of Magnetorheological Fluids

2011 ◽  
Vol 78 (4) ◽  
Author(s):  
Barkan Kavlicoglu ◽  
Faramarz Gordaninejad ◽  
Xiaojie Wang
Keyword(s):  
Experimental Study ◽  
Channel Flow ◽  
Pressure Loss ◽  
Flow Analysis ◽  
Surface Topology ◽  
Shear Yield Stress ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Channel Surface ◽  
Shear Yield

This study presents a new approach for flow analysis of magnetorheological (MR) fluids through channels with various surface topologies. Based on an experimental study an analytical method is developed to predict the pressure loss of a MR fluid as a function of the applied magnetic field strength, volumetric flow rate, and surface topology, without utilizing the concept of shear yield stress. A channel flow rheometer with interchangeable channel walls is built to demonstrate that the pressure loss across the MR fluid flow channel is significantly affected by the channel surface properties. Based on the experimental study it is concluded that a unique shear yield stress cannot be defined for a given MR fluid, since its pressure drop depends on the surface topology of the device. Therefore, a relation for nondimensional friction factor associated with MR fluid channel flow is developed in terms of a modified Mason number and dimensionless surface topology parameters. Using the nondimensional model, the pressure loss for various magnetic fields and volumetric flow rates can be represented by a single master curve for a given channel surface topology without the assumption of a constitutive model for MR fluids.

Shear and Squeeze Rheometry of Magnetorheological Fluids

2011 ◽  
Vol 305 ◽  
pp. 344-347 ◽  
Author(s):  
Hong Yun Wang ◽  
Hui Qiang Zheng
Keyword(s):  
Magnetic Field ◽  
Yield Stress ◽  
Electrical Current ◽  
Test System ◽  
Compression Stress ◽  
Shear Yield Stress ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Shear Yield ◽  
The Magnetic Field

The mechanical properties of a magnetorheological (MR) fluid in shearing, compression and shearing after compression have been studied in the magnetic field which is generated by a coil carrying different magnitudes of DC electrical current on a self-constructed test system. The relations of compression stress versus compression strain, yield stress versus compression stress were studied under different magnetic fields. The compressing tests showed that the MR fluid is very stiff at small compressive strains lower than 0.13. The shear yield stress of MR fluids after compression was much stronger than that of uncompressed MR fluids under the same magnetic field. The enhanced shear yield stress of MR fluids can be utilized to design the MR clutch and brake for new structure and will make MR fluids technology attractive for many applications.

Field-On Versus Field-Off Characteristics of Magnetorheological Fluids With an Application in Prosthetic Devices

2011 ◽  
Author(s):  
Ketill H. Gudmundsson ◽  
Fjola Jonsdottir ◽  
Freygardur Thorsteinsson
Keyword(s):  
Knee Joint ◽  
Yield Stress ◽  
Solid Loading ◽  
Fluid Composition ◽  
Shear Yield Stress ◽  
Mr Fluid ◽  
Prosthetic Devices ◽  
Prosthetic Knee ◽  
Mr Fluids ◽  
Shear Yield

The study presents an experimental investigation into the trade-offs between field-on versus field-off rheological characteristics of magnetorheological (MR) fluids. This is relevant in a particular application in prosthetic devices where field-off characteristics are of equal importance to the field-on rheological characteristics. The paper introduces a biomechanical prosthetic knee joint that uses an MR fluid to actively control its rotary stiffness while an amputee walks. The knee is a synergy of artificial intelligence, advanced sensors and MR actuator technology. The knee joint is equipped with an MR rotary brake, utilizing the fluid in direct-shear mode. The MR fluid has response time in the order of milliseconds, making it possible to vary the knee’s stiffness in real-time, depending on sensors data. The field-on characteristics of the employed MR fluid define the rigidness of the knee joint while the field-off characteristics define its flexibility in the absence of a magnetic field. Five MR fluid compositions are prepared, each with a different solid loading ranging from 0.25 to 0.35, by volume. All fluids employ a commercially available carbonyl iron powder and a base fluid. The MR fluids are experimentally evaluated in a rheometer, where both field-off and field-on characteristics are measured. An MR fluid figure of merit function is introduced which is used to rate the selected MR fluids for a potential application in the MR prosthetic knee. An MR fluid composition is sought with the highest ratio between the field-on shear yield stress and the off-state viscosity. The research shows the off-state viscosity to decrease faster than the field-on shear yield stress when reducing the solid loading from 0.35 to 0.25. This suggests that an optimum solid loading exists with regards to the defined merit function. The off-state viscosity of suspensions is known to be exponentially dependent on solid loading while the field-on shear-yield stress is known to sub-quadratically dependent on solid loading. Field-on and field-off models are presented from literature. The models compared to the experimental data and used to theoretically predict the optimum solid loading with regards to field-on shear yield stress and off-state viscosity. As a result of the experimental and the theoretical analysis, a prominent MR fluid composition is selected for a potential application in the MR prosthetic knee. This has been shown to help in the development of prosthetic devices and furthering the success of an MR prosthetic knee joint.

Experimental analysis on thermal and friction factor characteristics of fluid flow in tube with novel double strip helical screw tape

2019 ◽  
Vol 234 (6) ◽  
pp. 874-886
Author(s):  
Shashank R Chaurasia ◽  
RM Sarviya
Keyword(s):  
Nusselt Number ◽  
Fluid Flow ◽  
Friction Factor ◽  
Experimental Analysis ◽  
Flow Characteristics ◽  
Performance Ratio ◽  
Working Fluid ◽  
Flow Rates ◽  
Twist Ratio ◽  
Single Strip

An experimental analysis has been carried out to investigate the thermal and friction factor characteristics of fluid flow in a tube with double strip helical screw tape (DS-HST) inserts with different values of twist ratio and compared with single strip helical screw tape inserts and plain tube. Water is used as a working fluid at different flow rates with constant heat flux conditions. CFD analysis is also carried out to visualize thermal and fluid flow characteristics of fluid flow in tube with inserts. Experimental results have showed that Nusselt number and friction factor have attained excellent enhancement with double strip helical screw tape inserts in the range of flow rates than single strip helical screw tape inserts at the value of twist ratio 1.5. Correlation is also developed for Nusselt number with a range of Reynolds number, twist ratio and number of strips. Moreover, the performance ratio has attained maximum value at twist ratio of 2.5 with high values of flow rate. It is concluded that DS-HST is able to attain enhancement in the efficiency of heat exchanger, causing a reduction in size for thermal applications.

PREPARATION AND ABRASION PROPERTIES OF MAGNETO-RHEOLOGICAL FLUID OF DISPERSED SILICA-COATED IRON

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1121-1127 ◽  
Author(s):  
A. SHIBAYAMA ◽  
T. OTOMO ◽  
Y. AKAGAMI ◽  
K. SHIMADA ◽  
T. FUJITA
Keyword(s):  
Carbonyl Iron ◽  
Spherical Particles ◽  
Fluid Viscosity ◽  
Iron Particles ◽  
Mr Fluid ◽  
Abrasion Test ◽  
Silicon Oil ◽  
Mr Fluids ◽  
Transmission Oil ◽  
Magneto Rheological

In this study, a magneto-rheological fluid dispersed by silica-coated iron was developed and its properties such as fluid viscosity (shear stress or shear rate) and abrasion were investigated. The metallic iron coated by silica dispersed in magneto-rheological fluid was prepared by H 2 reducing of precipitated magnetite ( Fe 3 O 4). Then, the magneto-rheological fluid (MR fluid) for the seal was prepared with silica-coated iron or carbonyl iron (HQ type; diameter of 1.6-1.9 10-6m) and two solvent oils i.e. silicon oil (SH200cv, 10000cSt) and CVT oil (T-CVTF, automobile transmission oil). It was observed that the MR fluid viscosity of CVT oil with HQ particles is lower in every fluid condition. Furthermore, the surface roughness of polyvinyl plate after abrasion test for MR fluid with silica coated iron and CVT oil as solvent was higher compared to the other types of MR fluids. The results indicated that carbonyl iron (spherical particles) and silica-coated iron particles dispersed in silicon oil are feasible to be used where the low abrasion in mechanics is required.

Demonstration of Combined Shear and Squeeze Strengthening Modes in a Searle-Type Magnetorheometer

2013 ◽  
Author(s):  
Andrew C. Becnel ◽  
Norman M. Wereley
Keyword(s):  
Yield Stress ◽  
Energy Absorption ◽  
Shear Yield Stress ◽  
Particle Chain ◽  
Solids Loading ◽  
Mr Fluids ◽  
Shear Yield ◽  
Microstructure Model ◽  
Novel Method ◽  
A Chain

This research details a novel method of increasing the shear yield stress of magnetorheological (MR) fluids by combining shear and squeeze modes of operation to manipulate particle chain structures, to achieve so-called compression-assisted aggregation. The contribution of both active gap separation and particle concentration are experimentally measured using a custom-built Searle cell magnetorheometer, which is a model device emulating a rotary Magnetorheological Energy Absorber (MREA). Characterization data from large (1 mm) and small (250 μm) gap geometries are compared to investigate the effect of the gap on yield stress by compression enhancement. Two MR fluids having different particle concentrations (32 vol% and 40 vol%) are also characterized to demonstrate the effect of solids loading on compression-assisted chain aggregation. Details of the experimental setup and method are presented, and a chain microstructure model is used to explain experimental trends. The torque resisted by practical rotary MREAs is directly related to the strength of the MR fluid used, as measured by the shear yield stress. This study demonstrates that it is feasible, utilizing the compression-enhanced shear yield stress, to either (1) design a rotary MREA of a given volume to achieve higher energy absorption density (energy absorbed normalize by device volume), or (2) reduce the volume of a given rotary MREA to achieve the same energy absorption density.

Study on Design Method of Magneto-Rheological Fluid Shock Absorber Employing Shear Rate Profiles and Experimental Tests

2011 ◽  
Vol 121-126 ◽  
pp. 1095-1099
Author(s):  
Chang Rong Liao ◽  
J.H. Hao ◽  
D.X. Zhao ◽  
K.L. Wang
Keyword(s):  
Differential Equation ◽  
Shear Stress ◽  
Analytical Study ◽  
Shock Absorber ◽  
Damping Force ◽  
Mr Fluid ◽  
Annular Channels ◽  
Mr Fluids ◽  
Stress Profiles ◽  
Magneto Rheological

The flow differential equation for Magneto-rheological (MR) fluids in annular channels of MR fluid shock absorber is set up and several rational simplifications are made. Analytical shear stress profiles of MR fluids through annular channels are obtained via solution of the flow differential equation. An analytical study on MR fluid shock absorber is present employing shear stress profiles. Both boundary conditions and compatible conditions are established. Both flow velocity profiles and total volumetric flow rate are developed by integration by parts and numerical integration. The prediction method for damping force of MR fluid shock absorber is developed via simultaneous equations. The analytical study on MR fluid shock absorber is validated by means of reformative Herschel–Bulkley constitutive model, in which flow velocity profiles and flow regions boundary radii are drawed. A MR fluid shock absorber, which is designed and fabricated in Chongqing University, is tested by electro-hydraulic servo vibrator in National Center for Test and Supervision of Coach Quality. The experimental results reveal that the methodology is able to predict damping force of MR fluid shock absorber via shear rate profiles and experimental damping forces are in good agreement with analytical those.

Developing of the Experimental Device that Test Magneto Rheological Fluid(MRF) Shear Yield Stress Nnder Non Uniform Composite Field

2015 ◽  
Vol 667 ◽  
pp. 385-390
Author(s):  
Wei Zeng Chen ◽  
Guang Zhang ◽  
Xin Sheng He ◽  
Shao Qing Ren ◽  
Peng Huang
Keyword(s):  
Magnetic Field ◽  
Yield Stress ◽  
Experimental Device ◽  
Actual Condition ◽  
Shear Yield Stress ◽  
Fluid Shear ◽  
Composite Field ◽  
Shear Yield ◽  
Magneto Rheological ◽  
The Magnetic Field

In order to study magneto rheological fluid shear characteristics developing of magnetic field and temperature field under the actual condition (non-uniform composite field), Experimental device that test magneto rheological fluid (MRF) Shear yield stress under Non uniform composite field was developed. The device of the magnetic field distribution, temperature conductivity, shear yield stress are studied in theory and prototype production, and then testing the Shear yield stress of magneto rheological fluids of different magnetic field, temperature yield . The adjusting range of temperature of the experimental device is for 0-200, the magnetic field adjusting range by adjusting the current of the electromagnetic coil in the 0mt-300mt. Makes the air gap magnetic field intensity is 20mt, magneto rheological fluid in the shear rate at , the research of magneto rheological fluid shear yield stress with the magnetic field variation different temperatures (T=10, T=50, T=100,T=130, T=150, T=170) . The experimental results show that: in the 10-170, the temperature value basically does not affect the shear yield stress of the MR fluid, but the temperature is less than 10 and the temperature is greater than 170, the effects that temperature size on MRF Shear yield stress is relatively large.

Changes in the Resistance Force of a Magneto-Rheological Shock Absorber Induced by a Magnetic Field

2018 ◽  
Vol 915 ◽  
pp. 39-44
Author(s):  
Tatsuo Sawada ◽  
Takuma Endo ◽  
Yuzo Shimizu ◽  
Hitoshi Nishida
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Shear Flow ◽  
Applied Magnetic Field ◽  
Shock Absorber ◽  
Plug Flow ◽  
Resistance Force ◽  
Mr Fluid ◽  
Bingham Plastic ◽  
Magneto Rheological

In this study, we report the theoretical resistance force of a magneto-rheological (MR) shock absorber. We use the Bingham plastic model to theoretically represent the dynamic behavior of MR fluid flow in a circular pipe under the effect of a magnetic field. Because an MR fluid has yield stresses, the flow is divided into two regions: shear flow and plug flow. We reveal the relation between the resistance force of the MR shock absorber and the applied magnetic field. We conduct experiments and compare the experimental and analytical results to verify the theoretical approach.

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