Effect of Stator Surface Area on Braking Torque and Wall Heat Dissipation of Magnetorheological Fluid Retarder

2020 ◽  
Author(s):  
ZhiQiang Liu ◽  
Gangfeng Tan ◽  
Zhongpeng Tian ◽  
Mi Zhou ◽  
Philip Agyeman ◽  
...  
Keyword(s):  
Surface Area ◽  
Heat Dissipation ◽  
Magnetorheological Fluid ◽  
Braking Torque

Simulation and experimentation of a magnetorheological brake with adjustable gap

2016 ◽  
Vol 28 (12) ◽  
pp. 1614-1626 ◽  
Author(s):  
Wan-Li Song ◽  
Dong-Heng Li ◽  
Yan Tao ◽  
Na Wang ◽  
Shi-Chao Xiu
Keyword(s):  
Magnetorheological Fluid ◽  
Structure Design ◽  
Experimental Results ◽  
Wear Property ◽  
Braking Performance ◽  
Braking Torque ◽  
The Difference ◽  
The Impact ◽  
Theoretical Analyses ◽  
Magnetostatic Simulation

The aim of this work is to investigate the effect of the small magnetorheological fluid gap on the braking performance of the magnetorheological brake. In this article, theoretical analyses of the output torque are given first, and then the operating principle and design details of the magnetorheological brake whose magnetorheological fluid gap can be altered are presented and discussed. Next, the magnetic circuit of the proposed magnetorheological brake is conducted and further followed by a magnetostatic simulation of the magnetorheological brakes with different sizes of fluid gap. A prototype of the magnetorheological brake is fabricated and a series of tests are carried out to evaluate the braking performance and torque stability, as well as the verification of the simulation results. Experimental results show that the braking torque increases with the increase in the current, and the difference for the impact of the fluid gap on braking performance is huge under different currents. The rules, which the experimental results show, have an important significance on both the improvement of structure design for magnetorheological brake and the investigation of the wear property under different fluid gaps.

A new high-torque retarder based on combined effects of magnetorheological fluid and eddy current

2018 ◽  
Vol 30 (2) ◽  
pp. 256-271 ◽  
Author(s):  
Hui Huang ◽  
Shumei Chen ◽  
Cheng Wang
Keyword(s):  
Eddy Current ◽  
Material Selection ◽  
Magnetorheological Fluid ◽  
Experimental Result ◽  
Element Analysis ◽  
Operating Concept ◽  
Braking Torque ◽  
High Torque ◽  
The Magnetic Field ◽  
Excitation Circuit

In this article, a new high-torque retarder combining the effects of magnetorheological fluid and eddy current is researched. The new retarder provides a part of the braking torque generated by the shear stress of the magnetorheological fluid and an additional braking torque generated by the effect of the eddy current on the rotors. This operating concept is realized by a common magnetic excitation circuit generated by a new structure with several separated coils. The configurations and design details of the new retarder, including the structure, material selection, and magnetic circuit, are discussed. The mathematical models of braking torque caused by the magnetorheological fluid and eddy current are also derived. Then, a finite element analysis is performed to verify the magnetic field design of the new retarder. Finally, a prototype is fabricated, and the relevant parameters are tested. The experimental result shows that the new retarder provides not only a stable braking torque at low speed but also a great increment of braking torque varied with rotation speed, which effectively improves the total braking torque compared with conventional magnetorheological retarders.

Influence of Permanent Magnets Installation Approach on the Torque of а Magneto-Rheological Disk Brake

2021 ◽  
Vol 105 ◽  
pp. 184-193
Author(s):  
Ilya Aleksandrovich Frolov ◽  
Andrei Aleksandrovich Vorotnikov ◽  
Semyon Viktorovich Bushuev ◽  
Elena Alekseevna Melnichenko ◽  
Yuri Viktorovich Poduraev
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Magnetorheological Fluid ◽  
Simulation Modelling ◽  
Disc Brake ◽  
Large Area ◽  
Braking Torque ◽  
The Magnetic Field

Magnetorheological braking devices function due to the organization of domain structures between liquid and solid magnetic materials under the action of an electromagnetic or magnetic field. The disc is most widely used as a rotating braking element that made of a solid magnetic material due to the large area of contact with a magnetorheological fluid. Many factors affect the braking characteristics of the magnetorheological disc brake. Specifically, the value of the magnetic field and how the field is distributed across the work element is significantly affected at the braking torque. There are different ways to generate a magnetic field. In this study, the method of installation of permanent magnets into the construction, allowing to increase the braking torque of the magnetorheological disc brake is proposed. Simulation modelling showing the distribution of the magnetic field across the disk depending on the installation of permanent magnets with different pole orientations were carried out. The model takes into account the possibility of increasing the gap between solid magnetic materials of the structure, inside them which the magnetorheological fluid is placed. Comparative estimation of the distribution of the magnetic fields depending on the chosen method of installation of permanent magnets with different orientations of their poles is carried out. Further research is planned to focus on a comparative assessment of the distribution of magnetic fields depending on the selected material of the braking chamber.

Thermal and tribological characteristics of a disc-type magnetorheological brake operated by the shear mode

2018 ◽  
Vol 30 (5) ◽  
pp. 722-733 ◽  
Author(s):  
Wanli Song ◽  
Siyuan Wang ◽  
Seung-Bok Choi ◽  
Na Wang ◽  
Shichao Xiu
Keyword(s):  
Heat Dissipation ◽  
Operating Time ◽  
Wear Test ◽  
Magnetorheological Fluid ◽  
Operating Conditions ◽  
Tribological Characteristics ◽  
Transient Temperature ◽  
Shear Mode ◽  
Experimental Apparatus ◽  
Worn Surfaces

In this article, thermal characteristics and tribological properties of a disk-type magnetorheological fluid–based brake are investigated under various brake operating conditions such as different working gaps. In order to achieve this goal, a theoretical analysis of the heating and heat dissipation of the magnetorheological brake is first performed and then the transient temperature behaviors of the magnetorheological brake are investigated through simulation works associated with the finite element method. Subsequently, an experimental apparatus is established to measure temperature distributions of the magnetorheological brake as a function of the operating time. Thereafter, several heating and wear tests are conducted on the magnetorheological brake, and worn surfaces of the friction plates are observed using a scanning electron microscope to understand tribological characteristics of the magnetorheological brake. It is shown that the smaller working gap causes the higher temperature compared with the larger gap under the same magnitude of the input current applied to the magnetorheological fluid domain. This thermal behavior consequently results in the reduction of the braking torque. It is also demonstrated from the wear test that the small working gap significantly affects both wear and tribological characteristics showing the large ridges and deep grooves on the worn surfaces of the friction plate.

scholarly journals Numerical and experimental studies on a novel magneto-rheological fluid brake based on fluid–solid coupling

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041987900 ◽  
Author(s):  
Shujun Li ◽  
Wenjun Meng ◽  
Yao Wang
Keyword(s):  
Heat Dissipation ◽  
Coupling Effect ◽  
Experimental Studies ◽  
Test System ◽  
Structure Design ◽  
Brake Disc ◽  
Braking Torque ◽  
Braking Process ◽  
Magneto Rheological ◽  
The Impact

The previous work of the authors indicated that the fluid–solid coupling effect of the magneto-rheological fluid and the brake disc is a necessary focus during braking process. In this study, a novel design of magneto-rheological fluid brake was proposed and studied theoretically and numerically, aiming to solve the prominent problem of heat dissipation, especially in the case of single emergency braking. First, based on the modified Bingham model, a parameter defined as the apparent equivalent viscosity was utilized to represent the relationship of magnetic field, flow field, and temperature field. The braking torque and the formula for calculating the impact factor of fluid–solid coupling employed for characterizing the associations among the thermal field and the stress field were established based on fluid–solid coupling. With a detailed explanation of simulation method, the distribution disciplinarian’s numerical simulation of each field was analyzed using COMSOL software. To validate the accuracy of the established model on the designed magneto-rheological fluid brake, the prototype was also manufactured, and results achieved experimentally which were measured on inertia test system of brake, for braking torque, motion parameters, and surface temperature in braking process, were compared with simulations. Simulation results manifested that the designed magneto-rheological fluid brake’s magnetic circuit structure is feasible based on magnetic induction intensity distribution. Finally, it has been shown that the simulations appear to be basically consistent with the experimental results, and the heat dissipation of the designed magneto-rheological fluid brake is partially improved. These results might contribute to the structure design, optimization, and improvement of magneto-rheological fluid products, extending the previous work on fluid–solid coupling analyses.

Design of a safety escape device based on magnetorheological fluid and permanent magnet

2012 ◽  
Vol 24 (1) ◽  
pp. 49-60 ◽  
Author(s):  
Bintang Yang ◽  
Tianxiang Chen ◽  
Guang Meng ◽  
Zhiqiang Feng ◽  
Jie Jiang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Permanent Magnet ◽  
Dynamic Model ◽  
Magnetic Field Intensity ◽  
Magnetorheological Fluid ◽  
Test Results ◽  
Element Analysis ◽  
Braking Torque ◽  
The Magnetic Field

In this research, a novel safety escape device based on magnetorheological fluid and permanent magnet is designed, manufactured, and tested. The safety escape device with magnetorheological fluid and permanent magnet can provide an increasing braking torque for a falling object by increasing the magnetic field intensity at the magnetorheological fluid. Such increase is realized by mechanically altering the magnetic circuit of the device when the object is falling. As a result, the falling object accelerates first and then decelerates to stop in the end. Finite element analysis is used to determine some of the specifications of the safety escape device for larger braking torque and smaller size. Finite element analysis results are also used for theoretical study and establishment of the dynamic model of the safety escape device. A prototype is realized and tested finally. The experimental test results show that the operation of the prototype conforms to the prediction by the dynamic model and validates the feasible application of magnetorheological fluids in developing falling devices.

Next Generation Insert for Forced Coolant Application in Machining of Inconel 718

2016 ◽  
Vol 836-837 ◽  
pp. 340-347 ◽  
Author(s):  
Nageswaran Tamil Alagan ◽  
Tomas Beno ◽  
Anders Wretland
Keyword(s):  
Tool Wear ◽  
Surface Area ◽  
Inconel 718 ◽  
Material Removal ◽  
Metal Cutting ◽  
Heat Dissipation ◽  
Catastrophic Failure ◽  
Mass Ratio ◽  
Next Generation ◽  
Primary Focus

Machining technology has undergone an extensive evolution throughout the last decades in its capability to machine hard-to-cut material. This paper will discuss about the next generation insert with cooling feature coupled with forced coolant in machining Inconel 718. The geometry of the insert was changed in a way which has enlarged the surface area approximately 12% compared to regular insert named as nusselt insert. The idea applied in “nusselt insert” was the relation of increase in surface area to heat dissipation. Forced coolant application has become a way to improve existing metal cutting concepts and improve their current material removal rates without any need for a reengineered machining process.Experiments conducted on the inserts is that the first experiment of its kind in machining technology together with forced coolant and tested in four different inserts. The primary focus of the work was the investigation of the relation between the heat dissipation with an increase in surface area/mass ratio in the cutting interface based on its influence on tool wear. The experimental results showed the nusselt insert have better ability for heat dissipation which has led to significant reduce in tool wear and successfully facing Inconel 718 at vc 105 m/min, f 0.3 mm/rev and ap 1 mm where the regular insert had a catastrophic failure at vc 90 m/min, f 0.1 mm/rev and ap 1 mm. Nusselt insert has shown to increase MRR significantly compared to regular insert.

scholarly journals Environmental correlates and functional consequences of bill divergence in island song sparrows

2021 ◽  
Author(s):  
Maybellene P Gamboa ◽  
Cameron K Ghalambor ◽  
T Scott Sillett ◽  
W Chris Funk ◽  
Ross A Furbush ◽  
...  
Keyword(s):  
Surface Area ◽  
Heat Dissipation ◽  
Song Sparrow ◽  
Maximum Temperature ◽  
Foraging Efficiency ◽  
Channel Islands ◽  
Environmental Selection ◽  
Song Sparrows ◽  
Functional Consequences ◽  
Bill Morphology

Inferring the environmental selection pressures responsible for phenotypic variation is a challenge in adaptation studies as traits often have multiple functions and are shaped by complex selection regimes. We provide experimental evidence that morphology of the multifunctional avian bill is related to climate, not foraging efficiency, in song sparrows (Melospiza melodia) on the California Channel Islands. Our research builds on a study in song sparrow museum specimens that demonstrated a positive correlation between bill surface area and maximum temperature, suggesting a greater demand for dry heat dissipation in hotter, xeric environments. We sampled contemporary sparrow populations across three climatically distinct islands to test the alternate hypotheses that song sparrow bill morphology is either a product of vegetative differences with functional consequences for foraging efficiency or related to maximum temperature and, consequently, important for thermoregulation. Measurements of >500 live individuals indicated a significant, positive relationship between maximum temperature and bill surface area when correcting for body size. In contrast, maximum bite force, seed extraction time, and vegetation on breeding territories (a proxy for food resources) were not significantly associated with bill dimensions. While we cannot exclude the influence of foraging ability and diet on bill morphology, our results are consistent with the hypothesis that variation in song sparrows' need for thermoregulatory capacity across the northern Channel Islands selects for divergence in bill surface area.

Design Technologies of Eddy Current Retarder Used in an Automobile

2012 ◽  
Vol 251 ◽  
pp. 134-138 ◽  
Author(s):  
Cheng Ye Liu ◽  
Jian Ming Shen
Keyword(s):  
Eddy Current ◽  
Heat Dissipation ◽  
Magnetic Circuit ◽  
Effect Of Temperature ◽  
Heavy Duty ◽  
Braking Performance ◽  
Split Flow ◽  
Braking Torque ◽  
Eddy Current Retarder

Auxiliary brake sets had been widely used for heavy duty trucks and advanced buses. They played a role of split-flow braking load of main brake system. As one of auxiliary brake sets eddy current retarder had good braking performance and braking stability, and it is automotive and maintain constant speed by its continual braking. In this paper, key technologies of eddy current retarder, such as braking torque, working volt and current, magnetic circuit, material of rotor plate and iron, heat dissipation performance of rotor plate, match between eddy current retarded and automobile, and effect of temperature rise on its braking performance were presented and discussed in detail. Meanwhile, advantage and disadvantage of eddy current retarder were analyzed.

scholarly journals Heat Dissipation Characteristics of a FSAE Racecar Radiator

2021 ◽  
Vol 39 (5) ◽  
pp. 1667-1672
Author(s):  
Shreyas Padmaraman ◽  
Nagarathnam Rajesh Mathivanan ◽  
Babu Rao Ponangi
Keyword(s):  
Surface Area ◽  
Internal Combustion Engines ◽  
Heat Dissipation ◽  
Cooling System ◽  
Operating Temperature ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Combustion Engines ◽  
Significant Drop ◽  
Race Car

In recent times, the rise in performance and power of internal combustion engines has resulted in an increased demand for more efficient cooling systems. Customized engineered coolants, additives, radiator materials, redesigned coolant pumps and radiators help to meet these increased demands. In case of FSAE racecar, designing a radiator is an important part for controlling the engine operating temperature and increasing the effectiveness of the cooling system. In this work, an attempt is made to develop a simple yet reasonably accurate analytical model to calculate the effectiveness of a radiator. The model is then applied to predict the operating temperature of the engine at varying load conditions. Experimental investigations were performed using a customized radiator test rig to replicate the field test conditions. The rate of heat dissipation through the radiator with respect to the inlet temperature is analyzed by changing the surface area of the radiator. The developed model is able to predict the engine operating temperature in close agreement with the experimentation conducted. A marginal increase in surface area of the radiator resulted in significant drop in engine operating temperature. Thereby reduction in engine operating temperature will boost the performance of FSAE race car.

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