3 lobe bearing pps

7/28/2019 3 Lobe Bearing PPS

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multi-loBE BEARinG

SUBMITTED BY

KRISHANU DAS

GOURAB SARKAR

KOUSHIK DEBNATH

MD. SAMI M AKHTAR

DEPARTMENT OF MECHANICAL ENGINEERING

GLOBAL INSTITUTE OF MANAGEMENT AND TECHNOLOGY

KRISHNAGAR, NADIA-741102

WEST BENGAL


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ABSTRACT

In this project the various parameters of the oil flow in a multi

lobe bearing are studied using unsteady k-epsilon turbulence model.

For realizing the problem a 3 lobe bearing was selected which had the

lobes placed at a distance of 120 degrees. The rotation speed of the

shaft was considered to be 20000 rpm. The results show a strong affinityof the oil property to segregate to critical values at elevated rotational

speeds. Thus the present study could lead towards the formulation of

new bearing oil which corresponds to higher performance indices. The

results show the presence of lobes highly effect the performance of the

multi lobe bearing as the critical quantities developed here are

comparatively lesser to the other zones in the bearing.


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INTRODUCTION

OBJECTIVE

MULTI-LOBE BEARING

METHODOLOGY

DEFINING THE PHYSICAL MODEL

GENERATION OF COMPUTATIONAL DOMAIN

ADVANTAGES

DISADVANTAGES

APPLICATIONSCONCLUSION

CONTENTS


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Various parameters of the oil flow in a multi lobe bearing.

For realizing the problem a 3 lobe bearing was selected which

had the lobes placed at a distance of 120 degrees.

The rotation speed of the shaft was considered to be 20000

rpm.

Fixed-geometry bearings differ from tilting pad bearings in

that the fixed-geometry bearing has no moving parts, making the

lobes or arcs stationary around the shaft.

INTRODUCTION


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The objective of the present work is to design 3 lobe

bearing.

Analyze the various flow parameters arising due to the

motion of the shaft at rpm of 20000.

The design of the 3 lobe model and its subsequent

analysis and simulation was carried out using CATIA.

OBJECTIVE


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A bearing is a machine element that constrains relative

motion between moving parts to only the desired motion.

The design of the bearing may provide for free linear

movement of the moving part or for free rotation around a

fixed axis.

Fluid film bearings support the shaft weight and control

motions caused by unbalance forces, aerodynamic forces,

and external excitations from couplings.

Fixed-geometry bearings differ from tilting pad

bearings in that the fixed-geometry bearing has no movingparts, making the lobes or arcs stationary around the shaft.

Superior ability to absorb energy to dampen vibrations,

and their longevity due to the absence of rolling contact

stresses.

MULTI-LOBE BEARING


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The main objectives in this stage were:

To find the pressure distribution across the various parts of the

oil media as well as the shaft in an unsteady condition.

To find the temperature distribution across the oil media and

the shaft body in an unsteady condition.

To find the various other quantities across the oil media and

the shaft body in an unsteady condition.

METHODOLOGY


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For purpose of defining the physical model we used

the following values for the shaft and the bearing

surface.

The bearing of .08 m was selected and the

diameter was selected to be .06 m.

The 3 lobes were placed 120 degrees apart whose

diameter was 0.004 m.

The surface which holds the oil was assumed to be

present between the shaft and the bearing surface

area.

The walls were defined and the continuum was

supposed to exist in the fluent state.

The rest of the model continuum was supposed to

be solid walls.

DEFINING THE PHYSICAL MODEL


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It involved transforming the

generated physical domain into a mesh

(structured/ unstructured) with number

of node points depending on the fineness

of the mesh.

The various flow properties were

evaluated at these points.

The extent of accuracy of the result

depended to a great extent on the fact

that how fine the physical domain was

meshed.

GENERATION OF COMPUTATIONAL DOMAIN


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Virtually no metal to metal contact between shaft and bearing while the

machine is operating.

Dampened, low-oscillation, noise and wear-free shaft operation. If the oil

supply is operating properly, virtually unlimited bearing service life.

Several supportive lubrication films distributed around the shaftcircumference guarantee that the shaft is generally centered, thus

significantly improving concentricity.

Permits high continuous loading.

Shock loads of several times the level of the continuous load are

acceptable.

Low friction losses.

Good lubricant flushing and cooling effects.

Structural adaptability to every existing machine construction.

Advantages


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Some types can be expensive to make properly.

Subject to whirl at high speeds.

High cost.

Required careful design.

Complex bearing requiring detailed analysis.

disadvantages


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Mul ti-lobe bearings are being

successful ly used in:

Turbochargers

Boiler feed pumps

Large electric motors

Refrigeration turbines

Water turbines

Centrifugal test rigs

Turbine test rigs

Noise test rigs

Precision drills and lathes

Transfer machines

Precision borers

Grinders

Applications


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We gained our practical knowledge which we can apply infuture in the industries.

Preference of one bearing type over another bearing, should

not be overly generalized.

The values are comparatively on the higher side, it could be

easily explained.

The analysis were carried out at particularly very high speed.

CONCLUSION


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3 lobe bearing pps

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