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By

SECURE ANNUAL ENERGY

PRODUCTION BY A LEAP IN

LEADING EDGE PROTECTION OF

WIND TURBINE BLADES

SANDIA BLADE WORKSHOP 2014

Albuquerque, NM

Michael Drachmann Haag

All rights reserved, February 2013

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SECURE ANNUAL ENERGY PRODUCTION BY A

LEAP IN LEADING EDGE PROTECTION OF WIND

TURBINE BLADES

1. Introducing LM Wind Power

2. Leading Edge Erosion is Affecting the Cost of Energy

3. Aerodynamic Testing and Results

4. Understanding Water Droplet Erosion (WDE)

5. Rain Erosion Testing and Results

6. The Journey towards Excellence

7. Conclusions and Outlook

2013

... the longest track record of supply and

innovation in the industry…

From technology pioneering

to global industrial excellence

1st generation

Lightning-

Protection;

Vortex

generators

VARTM

vacuum

infusion

technology

Pre-bending The world’s

longest

rotor blade

introduced;

LM Blade

Monitoring

FutureBlade

technology

(carbon/glass

hybrid

LM the world’s

largest

manufacturer of

rotor blades

Rotor blade

production

starts in

Denmark

Wind tunnel

inaugurated

Tailor-made

aerodynamics

with LM profiles

Establishing a leading position through technology excellence and industrialization

1989 1996 1999 2002 2003 2004 2005 2006 2010

LM Drain-Receptor;

LM Diverter-Strips;

Multi-Receptor

lightning protection;

LM SuperRoot

1978

2008

GloBlade

Introduction

2011

Newer

longest

blade record

(LM 73.5)

2012

Launch of

GloBlade 3

2013 Manufacturing 2.0

New Offshore

blades for China

(73+, 66)

>160,000 blades delivered

~23% of global installed base

1978

ProBlade

Collision

Barrier for

improved

leading

edge

protection

Introducing ProBladeTM Collision Barrier

ProBladeTM Collision Barrier is a new

leading edge protective material system

with outstanding erosion properties.

Highly flexible 2-component solvent-free

UV-resistant polyurethane based paint

system.

Proprietary application procedure

developed and solely owned by LM Wind

Power.

It is applied where it is needed – directly at

the leading edge.

……taking advantage of our reliable and

cost efficient polyester gel coat surface on

the rest of the blade surface.

Offering minimum aerodynamic influence

and less noise generation than tape.

…..leading edge erosion is affecting the Cost of

Energy…..

Resulting in increased O&M cost and signifcant loss in AEP

Airline layout: Top view: 37 m x 14 m

LM Wind Power LSWT wind tunnel tests:

Objective:

Minimize aerodynamic impact of the

leading edge protection system

Test:

LM airfoil (24% relative thickness) with:

Clean LE

ProBlade

PPT

Zigzag tape (5%c suction and 10%c pressure side)

Aerodynamic Testing at LM Wind Power

• Max wind speed: 105 m/s

• Reynolds number: up to 6 million

• Turbulence intensity: 0.1%

Aerodynamic Results

• Adding leading edge protection has an impact on aerodynamic performance

compared to a clean airfoil.

• PPT may result in drag increase up to 100% (loses in AEP of around 1.5%

compared to the clean blade).

• ProBlade application has been optimized to minimize any aerodynamic effects,

resulting in loses in AEP of less than 0.7%.

• Aerodynamic impact of leading edge protection systems will in general be much

lower than an eroded LE (worse than zigzag tape).

Maximum lift

decreases

Drag

increases

WDE affecting parameters

Blade Tip Speed

Material Properties

Turbine location (on/off-shore)

Droplet size distribution at site

Annual rainfall

Capacity factor of turbine

Configuration and build-up of base

material

What is affecting Water Droplet Erosion (WDE)?

Droplet properties

Diameter: d

Density: ρL

Angle of attack: θ

Speed of impact: v

θ

Material properties

Density: ρS

Strain at Failure

Toughness

Tear strength

Modulus of Elasticity: ES

Increasing Tip Speeds….

Alstom Haliade 150-6MW

XEMC Darwind XD115-4.5 MW

New markets are evolving….

Figure shows the mean annual rainfall (mm) all over the world

Source: Defence Standard 00-35 Part 4 Section 6 p. 190

NASA, “Precipitation, Fog And Icing”

Data driven learning experience…..

Site Kirkby Moor, UK

Region Europe

Location On-shore

Blade Length [m] 17

Tip Speed [m/s] 62

Rainfall [mm/year] See graph

Average wind speed [m/s] 6,75

Mean Daily Sun Irradiation [J/m2] 65

Annual Average Temperature [°C] 9,83

Leading Edge Material Polyester Gel Coat

Operating Time [Years] 18

Average Tip Categorization at site 3,14

Init

ial

turb

ine

de

sig

n –

19

80

-199

0’s

Cu

rre

nt

turb

ine

de

sig

n –

20

00’s

New

tu

rbin

e d

es

ign

– 2

01

0’s

Cu

rre

nt

RE

T T

es

tin

g

Instantenous impact force is increasing

Principle: Whirling Arm

Duration: Variable

Vroot: 123 m/s

Vcenter: 140 m/s

Vtip: 157 m/s

Rain: 30-35 mm/h

Droplet size: 1-2 mm

Temperature: 20-25°C

ASTM G73

ISO (under development)

Rain Erosion Testing at LM Wind Power

ProBlade® performance Gel-coat vs. PPT vs. ProBlade®

ProBlade 5,4x vs PPT

54x vs Gel Coat

Gel-coat 1x

PPT 10x vs Gel Coat

LM developed application method

shows a 5,4 times increase in

performance compared to PPT in

accelerated rain erosion testing

Polyurethane Protective Tape - Failure Mechanism

Mass removal

Film Rupture

Droplet Impact

The journey towards excellence….

Building the Foundation

Using field data and analyzing extreme sites and operating

conditions

Fully correlated and validated leading

edge erosion reliability models

Securing AEP is becoming harder with increasing tip speeds and markets

evolving in harsher climates.

Selecting the right leading edge protection is now more essential than ever

before.

Through field studies and theoretical understanding we now know what

happens when water droplets collide with our blades.

A new approach to experimental validation has assisted us in defining the

correct Critical-to-Quality parameters for developing a reliable leading

edge protection system.

ProBlade offers a significant improvement in leading edge protection over

known products when applied with LM’s proprietary application procedure.

Furthermore, ProBlade has a clear aerodynamic advantage over PPT.

ProBlade is running on selected prototype turbines to enable

understanding of its life-time expectancy.

Conclusions

3D scanning is employed to get an exact

replicate of the surface after leading edge

erosion.

This methodology is an enabling

technology for improved understanding

of the failure mechanisms behind water

droplet erosion.

Drone inspections are beginning to offer

easier access to high quality field

inspection of blades at lower cost.

This technology is a key enabler in

establishing prevententive maintenance

schemes .

LM Wind Power have already

encountered this technology and

received impressive data.

Outlook

Erosion System

Impact Energy Droplet size, Impact velocity,

Impact angle

Damping Behaviour Water film, Surface

characteristics, Elasticity of

base materiale

Erosion Resistance

of Material Hardness, Elasticity, Fatigue

resistance, Ductility

Secure Annual Energy Production by a leap in leading edge protection of wind turbine

blades, by controlling and understanding the complete erosion system

Thank you for your time

Contact details: Head quarters:

Michael Drachmann Haag LM Wind Power Group

Lead Engineer Jupitervej 6

Materials & Processes 6000 Kolding

Denmark

Tel +45 7984 0384 Tel + 45 79 84 00 00

Mob +45 51388384 Fax +45 79 80 00 01

E mdh@windpower.com E info@lmwindpower.com

W lmwindpower.com

Note:

The contents of this presentation are confidential and may not be copied,

distributed, published or reproduced in whole or in part, or disclosed or

distributed by recipients to any other person.