Computational Tribology Introduction

Introduction to Computational Tribology: Contact Pairs Modeling

Xavier BorrasTwente UniversityNovember 2015

The slides are available at my profile page in

3. Collar

2. Fluid

1. Pad

Tribological Contact Pairs

3. Collar

2. Fluid

1. Pad

Thin Film Flow: Reynolds PDE

𝜕𝜕𝑥 ( 𝜌 h

3

12𝜂𝜕𝑝𝜕 𝑥 )=𝑈

2𝜕𝜕 𝑥 (𝜌 h)

gap height velocity

density

viscosity

pressure

1. Fluid Cavitation2. Non-Newtonian Fluid3. Density = f(Temp, Pressure)4. Viscosity = f(Temp, Pressure)5. Homogenization Techniques6. Fluid Starvation7. Time dependent

𝑝𝑝 :𝐻𝑦𝑑𝑟𝑜𝑑𝑦𝑛𝑎𝑚𝑖𝑐 𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒

3. Collar

2. Fluid

1. Pad

Lubrication Regimes

NO CONTACTCONTACT

DRY WET FULL FILM LUBRICATION

3. Collar

2. Fluid

1. Pad

Lubrication Regimes

NO CONTACTCONTACT

DRY WET FULL FILM LUBRICATION

3. Collar

2. Fluid

1. Pad

Lubrication Regimes

NO CONTACTCONTACT

DRY WET FULL FILM LUBRICATION

Gap Height

No Contact ModelContact Model

Asperities

Reynolds PDEModified Reynolds+ Homogenization

+ Starvation

No Reynolds

Fluid Film

3. Collar

2. Fluid

1. Pad

HLHydrodynamic

Lubrication model- Reynolds PDE

Computational Models Coupling

𝑃𝐻𝐷Reynolds PDE

(…)

𝑈

𝑝

h

3. Collar

2. Fluid

1. Pad

HLHydrodynamic

Lubrication model- Reynolds PDE

EHLElastoHydrodynamic

Lubrication model- Reynolds PDE- Linear Elastic

Linear Elastic𝑢  

𝐸 , ν+𝐵𝐶(𝑃𝐻𝐷 ,…)

Computational Models Coupling Degree

𝑝

𝑃𝐻𝐷Reynolds PDE

(…)

𝑈

𝑝

h

3. Collar

2. Fluid

1. Pad

HLHydrodynamic

Lubrication model- Reynolds PDE

EHLElastoHydrodynamic

Lubrication model- Reynolds PDE- Linear Elastic

TEHLThermal

ElastoHydrodynamic Lubrication model- Reynolds PDE- Linear Elastic- Heat Balance

Computational Models Coupling Degree

𝑝

𝑈

𝑃𝐻𝐷Reynolds PDE

(…)

Linear Elastic𝑢  

𝐸 , ν+𝐵𝐶(𝑃𝐻𝐷 ,…)

𝑇Heat Balance

𝑘 ,𝐶𝑝 ,ρ ,𝛼+𝐵𝐶 (𝑃𝐻𝐷 ,…)

h

3. Collar

2. Fluid

1. Pad

Spring-supported Thrust Bearings

THRUST BEARING

3. Collar

2. Fluid

1. Pad COLLAR

PAD SUPPORT

SHAFT WEIGHT

Pressure distribution

p Fluid Velocity Field

U

Gap Height h

Spring-supported Thrust Bearings

𝜕𝜕𝑥 ( 𝜌 h

3

12𝜂𝜕𝑝𝜕 𝑥 )=𝑈

2𝜕𝜕 𝑥 (𝜌 h)

gap heightvelocity

densityviscosity

pressure

3. Collar

2. Fluid

1. Pad

Spring-supported Thrust Bearings

Pressure on the Gap Pad TemperatureFluid Film Thickness

PAD

COLLAR

FLUID

3. Collar

2. Fluid

1. Pad

Stern Tube Seals: Rotary Seals

3. Collar

2. Fluid

Stern Tube Seals: Rotary Seals

Pgas

Pambient

A) No pressure build-up is expected between rod due to the rod rotation.B) Any axial displacement will easily cause a leakage.C) The negative pressure gradient towards ambient will hamper leakage into the

machine.

Introduction to Computational Tribology: Contact Pairs Modeling

Xavier BorrasTwente UniversityNovember 2015

The slides are available at my profile page in