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In the present theoretical investigation, the effect of ferrofluid on the dynamic characteristics of curved slider bearings is presented using Shliomis model which accounts for the rotation of magnetic particles, their magnetic moments, and the volume concentration in the fluid. The modified Reynolds equation for the dynamic state of the bearing is obtained. The results of dynamic stiffness and damping characteristics are presented. It is observed that the effect of rotation of magnetic particles improves the stiffness and damping capacities of the bearings.

In the field of engineering and technology, slider bearings are often designed to bear the transverse loads. The study of performance characteristics of slider bearings with different shape and different lubricants has been done from time to time by the researchers. Gupta and Kavita [

In last few decades, the researches shown that the performances of the bearings can be improved, and enhanced pressure and load carrying capacity can be obtained by use of the magnetic lubricants and magnetic fields [

All these researchers have analyzed the steady-state characteristics of the bearings lubricated with magnetic fluids. However, the study of the dynamic (damping and stiffness) characteristics of the bearings lubricated with magnetic fluids is yet to be investigated for its importance in the bearing design.

In the present theoretical analysis, an attempt has been made to investigate the effects of the particle rotation and volume concentration of magnetic particles on the dynamic characteristics of curved slider bearings lubricated with magnetic fluids in the presence of transversely uniform magnetic fields.

The physical configuration of a curved slider bearing lubricated with a magnetic fluid in the presence of a transverse magnetic field is described in Figure

Schematic diagram of a curved slider bearing under applied magnetic field with a pivot at the centre of pressure (C.P.) and

After the ferrohydrodynamic flow model by Shliomis [

Constitutive equations for incompressible magnetic fluid with internal rotation of magnetic particles [

Assuming the slider to be infinitely wide, (

Substituting (

For the one-dimensional curved slider bearings (Figure

Introducing the dimensionless quantities:

The steady state load capacity (

The dynamic damping coefficient

To study the ferrohydrodynamic effects on the dynamic characteristics of curved slider bearings, the numerical results for the coefficients of dynamic damping (

Variation of steady-state load capacity of plane inclined slider with respect to film thickness ratio

The values of the parameters taken in the present analysis are as follows:

(i)

Figure

Figure

Variation of dynamic damping coefficient with respect to volume concentration parameter

Figure

Variation of dynamic stiffness coefficient with respect to Langevin parameter

In the present theoretical investigation, the dynamic characteristics of curved slider bearings are studied in the presence of transverse magnetic field. The ferrofluid model given by Shliomis is adopted to obtain modified Reynolds equation. Based on the results, so obtained, the following conclusions have been drawn.

Magnetic fluid under the transverse magnetic field provides an improvement in the dynamic stiffness and damping characteristics of slider bearings.

On comparing with the conventional lubricants, both the dynamic stiffness and the dynamic damping coefficients are higher for ferrofluids even if the magnetic field is absent.

Under the applied magnetic field, both the stiffness and the damping increase with the increase of volume concentration of magnetic particles.

Length of the bearing

Dynamic damping coefficients,

Film force,

Dimensionless steady state load capacity

Film thickness,

Time dependent minimum film thickness,

Steady state film thickness,

Applied magnetic field

Sum of moments of inertia of the particles per unit volume

Boltzmann constant

Width of the bearing

Magnetic moment of a particle

Magnetization vector

Number of magnetic particles per unit volume

Film pressure,

Internal angular moment

Dynamic stiffness coefficients,

Time,

Temperature

Velocity vector

Coordinate distance,

Centre of pressure

Langevin parameter

Effective viscosity (Shliomis model),

Additional viscosity due magnetization,

Viscosity of the carrier fluid

Free space permeability

Local angular velocity

Volume fraction of the dispersed solid phase

Fluid density

Spin relaxation time

Brownian relaxation time of magnetic particles.

The authors, hereby, thank Dr. V. K. Kapur (Former Professor and Chairman, K. N. Institute of Technology, Sultanpur, India) for providing useful materials and the valuable guideline to enhance the content of this paper.