Effect of non-Newtonian
magneto-elastohydrodynamic on
performance characteristics of slider-bearings
Mouhcine Mouda, Mohamed Nabhani and Mohamed El Khlifi
Faculty of Sciences and Techniques, University of Hassan II Casablanca, Mohammedia, Morocco
Abstract
Purpose – This study aims to examine the magneto-elastohydrodynamic effect on finite-width slider-bearings lubrication using a non-
Newtonian lubricant.
Design/methodology/approach – Based on the magneto-hydrodynamic (MHD) theory and Stokes micro-continuum mechanics, the modified two-
dimensional Reynolds equation including bearing deformation was derived.
Findings – It is found that the bearing deformation diminishes the load-capacity and increases the friction coefficient in comparison with the rigid
case. However, the non-Newtonian effect increases load-capacity but decreases the friction coefficient. Moreover, the use of a transverse magnetic
field increases both the friction coefficient and load capacity.
Originality/value – This study combines for the first time MHD and elastic deformation effects on finite-width slider-bearings using a non-
Newtonian lubricant.
Keywords Load-carrying capacity, Lubricant additives, Couple stress fluid, Elastohydrodynamic lubrication, Friction coefficient,
Magneto-hydrodynamic lubrication, Non-Newtonian lubricants, Slider-bearings
Paper type Research paper
Nomenclature
B = bearing width (m);
B
!
0
= applied magnetic field, B
!
0
¼ B
0
e
!
z
;
C
f
= friction coefficient;
C
s
= dimensionless compliance coefficient;
d = thin layer thickness (m);
E = Young’s modulus (Pa);
E
y
= induced electric field in the y-direction;
F
m
= friction force (N);
F
m1
,F
m2
= friction force components following the
directions x and y (N);
h = film thickness (m);
h
Ã
= dimensionless film thickness;
h
m
= undeformed film thickness (m);
h
Ã
m
= dimensionless undeformed film thickness;
hi = maximum film thickness (m);
h
o
= minimum film thickness (m);
L = bearing length (m);
l = couple stress parameter (m), l ¼
ffiffiffi
h
m
q
;
l
Ã
= dimensionless couple stress parameter, l
Ã
¼
l
ho
;
M = Hartmann number, M ¼ B
0
h
o
ffiffiffi
s
m
q
;
p
Ã
= dimensionless pressure, p
Ã
¼
h
2
o
m LU
p;
U = slider speed (m.s
À1
);
u, v, w = vector velocity components following the
directions x, y and z;
W = load capacity (N);
W
Ã
= dimensionless load capacity;
x, y, z = Cartesian coordinates;
x
Ã
,y
Ã
= dimensionless Cartesian coordinates;
a = profile parameter a ¼
hi
ho
;
d = deformation (m);
d
Ã
= dimensionless deformation;
s = fluid electrical conductivity (mho.m
À1
);
h = material constant of couple stress (N.s);
m = lubricant dynamic viscosity (Pa.s); and
= Poisson’s ratio.
1. Introduction
Recently, the increasing use of electrically conducting fluids as
lubricants has received more attention because it restricts the
unexpected lubricant viscosity variation with temperature
under hard functioning conditions. In addition, the
hydrodynamic bearings performance can be improved by
applying a magnetic field on conducting lubricants. As the
situation is primarily related to the interaction between the
movements of electrically conducting lubricant across a
magnetic field, it results in an induced current density, which
interacts with this magnetic field to produce a Lorentz force,
which acts on the lubricant. Using this magneto-hydrodynamic
(MHD) principle has a great interest in several areas of
industrial engineering and technology. Therefore, a detailed
The current issue and full text archive of this journal is available on
Emerald Insight at: www.emeraldinsight.com/0036-8792.htm
Industrial Lubrication and Tribology
71/10 (2019) 1158–1165
© Emerald Publishing Limited [ISSN 0036-8792]
[DOI 10.1108/ILT-11-2018-0416]
Received 15 November 2018
Revised 6 May 2019
Accepted 31 May 2019
1158