A project on“Experimental Comparison for Performance Analysis of

Hydrodynamic Journal Bearing with Various Viscous Fluids”

Presented by, Mr. Bhoir Pushkaraj Umesh

Mr. Singh Ankit Narendra Mr. Rakhonde Bapurao Narayanrao

Mr. Wavhal Nikhil Sharad

Under the guidance by, Prof. S. R. Suryawanshi

Mechanical Engineering Department,MET’S Institute of Engineering,

Bhujbal Knowledge City,Adgaon, Nashik-422003

INTRODUCTION:-• Hydrostatic Lubrication:• In Hydrostatic Lubrication, The Load supporting high pressure fluid film created by an external

source like pump.• Hydrodynamic Lubrication:

Figure Hydrodynamic Lubrication• In Hydrodynamic Lubrication, the two surfaces in relative motion are separated by a relatively

thick film of fluid, so as to prevent the metal to metal contact.• The Hydrodynamic lubrication also called full film or thick film lubrication.

Pressure Distribution Along Circumference:

LITERATURE REVIEW:

Sr. No.

Name Of Author Title of Paper Year Outcomes

1 Mobolaji H. Oladeinde and Jhon A. Akpobi

A comparative study of load capacity and pressure distribution of infinitely wide parabolic and inclines slider bearings

2010 A comparative study of the pressure distribution and loadcapacity of infinitely wide parabolic and inclined sliderbearings has been presented.He had focused on the change in property of parabolic bearing using FEA.

2 Nacer Talaighil, Patrick Maspeyrot

Hydrodynamic effects of texture geometries on journal bearing surfaces

2008 Different configurations have been analyzed, assuming the shaft is smooth and rigid and the bearing surface is numerically textured.

Sr. No. Name Of Author Title of Paper Year Outcomes

3 H. Y. Lau, K. P. Liu, Member, IAENG, W. Wang, and P. L. Wong

Feasibility of Using GMM Based Actuators inActive Control of Journal Bearing System

2001 An idea of active control of journal bearing systems usingGMM actuators has been proposed.

4 Ravindra R. NavtharDr. N.V. Halegowda

Stability Analysis of HydrodynamicJournal Bearing using StiffnessCoefficients

2010 Theoretical synchronous whirl occurs at 1666 cycles/min when the bearing is operating at 800 rpm and 150N load. i.e. the bearing is stable up to 1666 rpm.

OBJECTIVES:

• To study the design of hydrodynamic journal bearing to obtain mathematical modeling for selected

parameters.

• To study the geometry of hydrodynamic journal bearing.

• To analyze the performance of hydrodynamic journal bearing theoretically for identifying

parameters using various grades of an oil.

• To prepare experimental test rig and trials on the set up.

LubricantsLubricant is a substance inserted or introduce between the two contacting surfaces

having relative motion, so as to reduce the friction and wear.

Any fluid having some amount of viscosity can be regard as lubricant.

Functions of lubricants:

• To reduce the friction between two contacting surface.

• To reduces the wear.

• To carries away the frictional heat.

• To protects the surface against the corrosion

Types of Lubricant• SAE Grade Oil• ISO Grade Oil

Block Diagram of Hydrodynamic Journal Bearing Test Rig

Selection of lubricant

Sr. No. ISO Grade Equivalent SAE Grade

Viscosity at 40° C(Centistokes)

Density( Kg/ m³)

1 32 10W 32 857

2 46 20 46 861

3 68 20W 68 865

In this project work, the lubricant selected are ISO VG 32, ISO VG 46, ISO VG 68 due to their following specification:• Sufficient anti-wear protection.• Anti-rust and anti-corrosion.• Good dispersant properties.• Natural high viscosity index.• No negative influence due to temperature fluctuation.

Determination of viscosity using Redwood Viscometer

Determination of viscosityObservations:• Type of oil = ISO VG 46• Area of orifice (A) = 0.0026 sq. m.• Viscometer constant (B) = 1.79• t = time in seconds for collecting 50 ml oil• µ = dynamic viscosity in Mpa-s• = kinematic viscosity in centistokes

Observation Table:Sr. No. Temperature

(°C)Time

(minute)Time

(second)

1 40 3:02 182

Calculations:

• Kinematic Viscosity (), = 0.0026 182 = 0.46336 stokes = 46.36 Cst.

• Absolute Viscosity (µ), = 861×4.6336× = 0.03989 pa-s = 39.895 Mpa-s

Result table:

Sr. No. Temperature(°C)

Time(second)

Kinematic viscosity(Cst)

Absolute Viscosity(Mpa-sec.)

1 40 182 46.33 39.895

Components of test rig

• Hydrodynamic journal bearing• Shaft• Motor• Coupling• Hydraulic unit• Electronic unit• Frequency drive

Design of shaft:

Input:• Density of Mild Steel () = 7850 kg/• Speed of motor (n) = 2880 rpm• Power (p) = 1HP = 746 watt• Weight of shaft = 15.41 kg = 151.20 N• Combined shock and fatigue factor applied to bending moment (Kb) = 1.5

• Combined shock and fatigue factor applied to torsional moment (Kt) = 1• Maximum allowable shear stress () = 66.67 N/

Calculation:• Maximum bending moment (M)

The maximum bending moment at point P = 76 × = 28918 N-mmTherefore M = 28918 N-mm

• Maximum torque (T) P = T =

= 2.4736 N-mT = 2473.533 N-mm

• Equivalent Torque () =M)² + )² = = 43447.46 N-mm

 

• Shaft diameter (d) = 66.67=

d = 14.91 mmTaking approximate value for practical purpose (d) = 50 mm

MATHEMATICAL MODELING:

Reynolds Equation

Reynolds equation for hydrodynamic Journal Bearing equation for 2D flow :• Lubricant pressure distribution as a function of journal speed, bearing geometry, oil clearance and

lubricant viscosity is described by Reynolds equation:

• Where:h – local oil film thickness,η – dynamic viscosity of oil,p – local oil film pressure,U – linear velocity of journal,x - circumferential direction.z - longitudinal direction.

Also Reynolds equation given by to find pressure at each angular position of bearing,

222 )cos1()2()cos2(sin6

cUrp

Using Reynolds equation the pressure distribution at various angle of bearing determine as follows :

Sample calculation,Given:

Radius of shaft (r) = 25 mmAbsolute Viscosity (µ) = 39.895 Mpa-sSpeed of shaft (U) = 1308.997 mm/sClearance (c), = 0.001c = 0.025 mmeccentricity (ɛ) = 0.169 ……………….. From Raimondi- Boyd chart.

Putting given value in above equation,

P = P = -2.0883 N/mm²

222 )cos1()2()cos2(sin6

cUrp

The pressure distribution:

Sr. No. Angle (θ) Pressure (Mpa)1 0 0.000

2 30 0.852

3 60 1.602

4 90 2.088

5 120 2.066

6 150 1.328

7 180 0.000

Specification of components:

• Hydrodynamic journal bearinginternal diameter (d) = 50 mmlength (l) = 50 mm = 1Clearance ratio, = 0.001

Where r = radius of bearing = 25 mmC = radial clearanceMaterial: Bronze

Shaft

Diameter = 50 mmLength = 1000 mmMaterial used Mild steelMachining process done,Turning, Step-Turning.

Supporting bearing:

Type of bearing: Deep-groove ball BearingUC210

Frame

Height = 880 mmLength = 1550 mmBreadth = 460 mmMaterial: GCI15Machining process done,Welding, Grinding.

Motor and coupling :

Single phase AC motorSpeed = 2880 rpmPower = 1 HPCurrent = 4.3 ampVoltage = 220/230 voltCoupling: Love-Jack

Assembly

THANK YOU