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Article
Publication date: 2 October 2007

W. Ochoński

This paper seeks to present some new designs of sliding bearings lubricated with magnetic fluids (ferrofluids) and the possibility of using them in modern bearing…

Abstract

Purpose

This paper seeks to present some new designs of sliding bearings lubricated with magnetic fluids (ferrofluids) and the possibility of using them in modern bearing technology, in new computer and audiovisual equipment among others.

Design/methodology/approach

The paper presents new designs of journal, thrust and journal‐thrust sliding bearings lubricated and sealed with magnetic fluids such as: magnetic fluid bearing bushing made of magnetizable material, pivot bearings with porous sleeve impregnated with ferrofluid, self‐aligning bearings, hydrodynamic ferrofluid bearings with spiral and herringbone grooves structure are presented. Moreover, examples are shown of applications in modern bearing technology.

Findings

The paper provides information about new designs of magnetic fluid sliding bearings assemblies and gives the main advantages of these bearings over conventional ball bearings, such as extremely low non‐repetitive run‐out (high‐accuracy of rotation), good damping and quietness of operation, maintenance free service and high reliability.

Originality/value

This paper offers some new designs of compact, low friction and self‐contained magnetic fluid sliding bearings and points up their practical applications.

Details

Industrial Lubrication and Tribology, vol. 59 no. 6
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 October 2018

Penggao Zhang, Boqin Gu, Jianfeng Zhou and Long Wei

The purpose of this study is to investigate the hydrodynamic lubrication characteristics of ferrofluid film for spiral groove mechanical seal in external electromagnetic…

Abstract

Purpose

The purpose of this study is to investigate the hydrodynamic lubrication characteristics of ferrofluid film for spiral groove mechanical seal in external electromagnetic field and to analyze the effects of the volume fraction of ferrofluid, parameters of the electromagnetic field, operating parameters and geometrical parameters of mechanical seal on the characteristics of ferrofluid film.

Design/methodology/approach

The relationship between the ferrofluid viscosity and the intensity of external electromagnetic field was established. Based on the Muijderman narrow groove theory, the pressure distribution was calculated with the trial method by trapezoid formula.

Findings

It was found that pressure, average viscosity, average density and opening force of ferrofluid between end faces increase with the increase in intensity of current, volume fraction of ferrofluid, rotating speed, pressure differential and spiral angle; decrease with the increase in temperature; and increase at first and then decrease with the increase in the ratio of groove width to weir and the groove length. All of them reach the maximum value when the ratio of width of groove to weir is 0.7 and the ratio of groove length is 0.6. Leakage of ferrofluid increases with an increase in intensity of current, volume fraction of ferrofluid, rotating speed, pressure differential, spiral angle and ratio of groove length; decreases with an increase in temperature; and increases at first and then decreases with the increase in the ratio of groove width to weir. The tendencies of characteristics of silicone oil are consistent with those of ferrofluid, and the characteristics of silicone oil are smaller than those of ferrofluid under the same condition.

Originality/value

The volume fraction of ferrofluid, rotating speed, spiral angle, ratio of groove width to weir, groove length and temperature have a significant influence on the characteristics of ferrofluid film; however, intensity of current and the pressure differential have slight influence on the characteristics of ferrofluid film. An analytical method for analyzing hydrodynamic lubrication characteristics of ferrofluid film in a spiral groove mechanical seal was proposed based on the Muijderman narrow groove theory.

Details

Industrial Lubrication and Tribology, vol. 70 no. 9
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 4 September 2017

Nimeshchandra S. Patel, Dipak Vakharia and Gunamani Deheri

This paper aims to investigate the performance of a ferrofluid-based hydrodynamic journal bearing system.

Abstract

Purpose

This paper aims to investigate the performance of a ferrofluid-based hydrodynamic journal bearing system.

Design/methodology/approach

This paper presents a new design of ferrofluid-based hydrodynamic journal bearing. An experimental set-up consisting of a magnetic shaft along with a brass bearing was modified and developed. A permanent magnet was used to make the selected shaft material magnetic. The load and speed were varied to conduct the analyses for different test conditions.

Findings

The paper provides information about a design of ferrofluid-based journal bearing and its improved performances. For moderate to higher loads at different shaft speeds, it was found that because of the magnetization effect, the maximum film pressure in case of a ferrofluid lubricant increased up to approximately 60 per cent, compared with that of the conventional lubricant-based journal bearing system. Besides, the temperature rise was found smaller for ferrofluid lubricants, thus making the system cooler while running.

Originality/value

This paper offers a new design of magnetic bearing system for the experimental analysis by utilizing a magnetic shaft with a non-magnetic bearing. The present ferrofluid-based bearing design is less complicated from manufacturing point of view.

Details

Industrial Lubrication and Tribology, vol. 69 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 8 May 2018

Jaw-Ren Lin and Li-Ming Chu

The purpose of this paper is to investigate the dynamic characteristics of exponential slider bearings lubricated with a ferrofluid. Because of the development of modern…

Abstract

Purpose

The purpose of this paper is to investigate the dynamic characteristics of exponential slider bearings lubricated with a ferrofluid. Because of the development of modern engineering, the increasing use of ferrofluids in lubrication fields has shown great importance. Understanding the dynamic characteristics of exponential film bearings is helpful for engineers in bearing selection.

Design/methodology/approach

Applying the Shliomis ferrohydrodynamic flow model and considering the squeezing action of bearing pads, a dynamic Reynolds equation is obtained for an exponential film slider bearing lubricated with a ferrofluid in the presence of a transverse magnetic field. Analytical solutions of dynamic characteristics are obtained.

Findings

According to the results, the ferrofluid-lubricated exponential film bearing provides better dynamic stiffness and damping characteristics than the non-ferrofluid ones, especially the bearing operating at higher values of the volume concentration parameter and the magnetic Langevin parameter.

Originality/value

Numerical tables of stiffness and damping coefficients for different values of the volume concentration parameter and the Langevin parameter are also included for engineering references.

Details

Industrial Lubrication and Tribology, vol. 70 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 12 September 2016

Jaw-Ren Lin, Tzu-Chen Hung and Shu-Ting Hu

This paper aims to study the inertia squeeze film characteristics between ferrofluid-lubricated circular stepped disks. Owing to the development of modern machine systems…

Abstract

Purpose

This paper aims to study the inertia squeeze film characteristics between ferrofluid-lubricated circular stepped disks. Owing to the development of modern machine systems, the application of ferrofluids has received great attention. Because the circular disks are a special situation of circular stepped squeeze films, a further study of fluid inertia force effects on the ferrofluid-lubricated circular stepped squeezing mechanism is motivated.

Design/methodology/approach

On the basis of the ferrohydrodynamic flow model of Shliomis incorporating the momentum integral method, the effects of fluid inertia forces in ferrofluid-lubricated circular stepped squeeze films in the presence of external magnetic fields are investigated in this study. Analytical solutions of squeeze film performances are derived.

Findings

The fluid inertia force effects provide an increased load capacity and a longer squeeze film time for the ferrofluid-lubricated circular stepped squeeze film, especially for a larger value of the inertia parameter, the Langevin parameter and the volume concentration and a smaller value of the radius ratio and the step height ratio.

Originality/value

For engineering applications, numerical tables for squeeze film loads of circular stepped disks are also provided in this paper.

Details

Industrial Lubrication and Tribology, vol. 68 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 1 December 2003

Rajesh C. Shah

A study of step bearing lubricated with a ferrofluid was made in this paper. Shah and Bhat considered the term μ0M(∂H/∂x) of ferrofluid as lubricant. The present paper…

Abstract

A study of step bearing lubricated with a ferrofluid was made in this paper. Shah and Bhat considered the term μ0M(∂H/∂x) of ferrofluid as lubricant. The present paper discusses the problem with the modified term as μ0M (∂H/∂x)+(16πμ0r3χM)/(9(l+2)3)(∂H/∂x) of ferrofluid which incorporates more properties of ferrofluids. Expressions for pressure under the two steps and load carrying capacity were obtained. It was observed that the use of ferrofluid increases the load capacity of the bearing. Also load capacity become more when the length of the first step was taken less.

Details

Industrial Lubrication and Tribology, vol. 55 no. 6
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 April 1993

W. Ochonski

The ferromagnetic rotary shaft seals are for the present the most important industrial applications of magnetic fluid (ferrofluid) technology developed mainly in the last decade.

Abstract

The ferromagnetic rotary shaft seals are for the present the most important industrial applications of magnetic fluid (ferrofluid) technology developed mainly in the last decade.

Details

Industrial Lubrication and Tribology, vol. 45 no. 4
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 4 March 2021

Harun Zontul, Hudhaifa Hamzah and Besir Sahin

This paper aims to exhibit a numerical study to analyze the influence of a periodic magnetic source on free convection flow and entropy generation of a ferrofluid in a…

Abstract

Purpose

This paper aims to exhibit a numerical study to analyze the influence of a periodic magnetic source on free convection flow and entropy generation of a ferrofluid in a baffled cavity. In this study, ferrofluid nanofluid was selected due to its ability to image magnetic domain structures within the cavity. The non-uniform magnetic source is considered as a sinusoidal distribution in the vertical direction.

Design/methodology/approach

The finite volume technique is used to evaluate the steady two-dimensional partial differential equations that govern the flow with its corresponding boundary conditions.

Findings

The obtained results indicate that a significant increase in the average Nusselt number can be achieved with the use of the periodic magnetic source instead of a uniform case. In addition, the effectiveness of the adiabatic baffle notably depends on its position and Rayleigh number. Regardless of the values of period and Hartmann numbers, the periodic magnetic source has a higher entropy generation and lower Bejan number than the uniform magnetic source.

Originality/value

The novelty of this research lies in applying a periodic magnetic source on the natural convection of ferrofluids in a baffled cavity.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 10 August 2015

Marcin Szczech and Wojciech Horak

The purpose of this publication is to determine the influence of selected factors on the durability and the tightness of ferrofluid seals working in water environments…

Abstract

Purpose

The purpose of this publication is to determine the influence of selected factors on the durability and the tightness of ferrofluid seals working in water environments. Ferromagnetic fluid (FF) seals are one of the most common applications of magnetic fluid. New applications can be developed by extending the capabilities of these seals in fluid environments, especially in water.

Design/methodology/approach

Tests were performed using ferrofluids with differing physical properties like density, dynamic viscosity and saturation magnetization. Working conditions, such as water pressure and peripheral speed, were taken into account.

Findings

A mathematical description which allows the selection of an appropriate ferrofluid and the determination of the operating parameters of an FF seal was developed.

Originality/value

This study concerns the influence of peripheral speed, water pressure and magnetic fluid properties on seal tightness.

Details

Industrial Lubrication and Tribology, vol. 67 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 23 November 2020

Muhammad Usman, Muhammad Hamid, Zafar Hayat Khan, Rizwan Ul Haq and Waqar Ahmed Khan

This study aims to deal with the numerical investigation of ferrofluid flow and heat transfer inside a right-angle triangular cavity in the presence of a magnetic field…

Abstract

Purpose

This study aims to deal with the numerical investigation of ferrofluid flow and heat transfer inside a right-angle triangular cavity in the presence of a magnetic field. The vertical wall is partially heated, whereas other walls are kept cold. The effects of thermal radiation are included in the analysis. The governing equations including continuity, momentum and energy equations are converted to nondimensional form using viable variables.

Design/methodology/approach

Finite element method (FEM)-based simulations are performed using finite element approach to investigate the effects of the volume fraction of ferroparticles (Fe3O4), the length of the heating element and the dimensionless numbers including Rayleigh and Hartmann numbers on the streamlines, isotherms and Nusselt number.

Findings

It is demonstrated that both horizontal and vertical velocity components increase with the length of the heating element, whereas the dimensionless temperature decreases the heating domain. It is observed that an increase of 10% in the volume fraction of ferroparticles increases Nusselt number more than 12%, and 20% increase in the volume fraction of ferroparticles increases more than 30%, depending upon the length of the heating element.

Originality/value

This is a new study showing the significance of the magnetic nanoparticles for the enhancement of heat transfer rate in a triangular cavity.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

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