F. Xavier Borràs*1, Jan Ukonsaari2 and Andreas Almqvist1

1Luleå University of Technology, Division of Machine Elements, Luleå, Sweden; 2Vattenfall, Vattenfall Research and Development AB, Luleå, Sweden.*Corresponding author: Luleå University of Technology, 97 187 Luleå (Sweden), borrasfx@gmail.com

Multiphysics Modelling of Spring-Supported Thrust Bearings for

Hydropower Applications

Thrust bearings are commonly used in hydroelectric power plants. These bearings are required to support the shafts of the turbines.

1.1) Thrust Bearings

THRUST BEARING

1

2

3

3. Collar

2. Fluid

1. Pad

The relative motion between the collar and the pads generates a pressure distribution.

COLLAR

PAD SUPPORT

External Load

Pressure distribution

p

1.2) HOW does it work

Fluid Velocity Field

U

GAP GEOMETRY • Elastic Deformation• Thermal Expansion

• Tilting

1

2

3

Gap Height h

• The pad is supported by a spring mattress.

• There is not a defined pivot point.

1.3) Spring-Supported

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2

3

A.) PAD

B.) COLLAR

C.) FLUID

2) Model

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2

3

2.1) Physics AppliedCOLLAR

FLUID

PAD

MM

HTf

HTs

SM

LS

Heat Transfer in Solids

Solid Mechanics

Moving Mesh

(mesh deformation)

Lubricant Shell

Heat Transfer in Fluids

SM

HTs

HTf

MM

LS

SM

HTs

1

2

3

2.2) Model CouplingCOLLAR

FLUID

PAD

pf

pf

pf

u,v,z

hwall

u,v,z

T

T

T

X,Y,Z

hchannel

u,v,z

T

u,v,zSM

HTs

HTf

MM

LS

SM

HTs

1

2

3

OUTPUTS

Pressure on the Gap

PADDeformation

Temperature

COLLARDeformation

Temperature

FLUIDFilm Thickness

Temperature

Power Losses

INPUTSShaft Angular Velocity

External Load Applied

Bath Temperature

Geometry Parameters

Material ProprietiesSprings Pattern Characteristics

Spring-Supported Thrust Bearing Model

3) RESULTS: Global Scheme

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2

3

HOW does it work? Springs

3.1) ResultsPressure on the Gap

Fluid Velocity Field

Pad Temperature

Fluid Film Thickness

Collar Displacement

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2

3

3.2) Applications of the Model

• Varying operating conditions:a) Loadb) Angular Velocityc) Bath Temperatured) Springs Patterns

• Test different kinds of lubricants.• Test different compounds materials.• Test shape improvements.

1

2

3

F. Xavier Borràs*1, Jan Ukonsaari2 and Andreas Almqvist1

1Luleå University of Technology, Division of Machine Elements, Luleå, Sweden; 2Vattenfall, Vattenfall Research and Development AB, Luleå, Sweden.*Corresponding author: Luleå University of Technology, 97 187 Luleå (Sweden), borrasfx@gmail.com

Multiphysics Modelling of Spring-Supported Thrust Bearings for

Hydropower Applications