The ensure a good lubrication of hydrodynamic journal

The past few decades a considerable amount of
improvement is made in the design of hydrodynamic journal bearing to increase
the working life of journal bearings. At the same time many experiment were
carried out to see the effect of parameters like speed (rpm), pressure of the
lubricant, lubricant types etc on the bearing performance as well as the life
of bearings.

Journal bearing designed for work where load and
speed is variable and may reach very high values. In this condition bearing may
operate in the stable lubricant region and that operating temperature of the
bearing may not exceed some fixed values. Samuel A. McKee, 1937.Experimental
data obtained in this paper indicates that the minimum point obtained in the
curve f-ZN/p occurs at a values ranging from 1 to 50 and also depending upon
the bearing materials, machining of the bore and the amount of running-in. The
value 30 would be good for bearing having reasonable amount of running-in. Compressive
study of different factors affecting the heat dissipation for different types
of bearings were also studied.

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A journal bearing consist of shaft which rotates
freely in metal sleeve or shell and has no rolling contact. Two different
commercial lubricant oil SAE20W50 and SAE90 were used to study the lubrication,
types of pressure distribution, and the stresses developed in the bearings and
the stresses developed in the bearing under varying loads and speed.Srinivas,
Dr.Mohammed Yunus, Dr.Shadi M.Munshi, Dr.Iftekar Hussain,2015.It was found
that SAE90 is better than SAE20W50 in terms of load carrying capacity.

Different profiles of Journal bearings are also experimentally
studied. Stability analysis of a lemon bore journal bearing Evgeny Kuznetsov,
Glavatskih, ESDA 2008.polymer composite linings hydrodynamic journal bearing
provide improved performance during startup by decreasing the break-away torque.
Lemon bore journal bearing with PTFE surface are compared with the rigid babbitted
lemon bore journal bearing. The result obtained shows that the load carrying
capacity of the bearing is increased at low eccentricities and reduced at high eccentricities;
stability of the journal bearing is also increased at high eccentricities.


Study of pressure profiles in hydrodynamic journal bearings
Chetan Mehra, Amar Singh kokadiya, Neelesh Khandare, 2014.The pressure
condition of the fluid is critical to ensure a good lubrication of hydrodynamic
journal bearings. In this study, an experimental work was carried out to
determine the pressure distribution around the circumference of the
hydrodynamic journal bearing and fluid frictional force of the bearing caused
by shearing actions. The result obtained were experimental pressure data found
to be higher than theoretical data and the point of maximum pressure was not
changed with respect to loads however the position of minimum film thickness
varied with the loads.

Performance characteristic of finite hydrodynamic
journal bearing under micro polar lubrication with turbulent effect Subrata
Das, Sisir Kumar Guha,2013. In this analysis, the turbulent shear stress
coefficients are used based on the Constantinescu’s turbulent model suggested
by Taylor and Dowson with the assumption of parallel and inertia-less flow.
numerical solution of the modified Reynolds equation has yielded the
distribution of film pressure which determines the static performance
characteristics in terms of load capacity, attitude angle, end flow rate and
frictional parameter at various values of eccentricity ratio, non-dimensional
characteristics length, coupling number and Reynolds number. The results
obtained were load carrying capacity reduces with the increase in non
dimensional micro-polar length; with the increase of
average Reynolds number improves the load capacity at any value of non-dimensional
characteristics length.

Analysis of Pressure distribution and friction
coefficient of hydrodynamic journal bearing Akash S.Patel, Prof.N.D Patil,
Pramod R. Mali, Mr.Kaustubh S. Zambre,2017.The aim of this work was to develop
data for better design methods for lubricated journal bearings. The frictional
coefficient increases with the degree of misalignment at lower values of the
eccentricity ratio. Pressure generation is due to fluid being driven from thick
end to thin end of wedge shaped fluid film by the surface movement, the
variation of the surface velocity from place to place and the variation of
surface gap (film thickness).




Journal bearing vibration and ssv hash Scan M.DeCamillo,
Minhue Hi, C.Hunter Cloud, James M.Bryne,2008.Peculiar, low frequency, radial
vibrations are observed in journal bearings. This paper presents data from
various tilt pad journal bearing test. The vibrations characteristics are
defined under the condition of speed, load, oil flow and bearing orientation.

Similarly, Active vibration control by using piezoactuator.
Jaroslav Los,Jaromir Skuta. The actively controlled journal bearing consists
of a movable bushing, which is actuated by two piezoactuators. The journal
vibration is measured by a pair of proximity probes. The control system enables
run-up, coast-down and steady-state rotation.