wind turbine optimization

8/8/2019 Wind Turbine Optimization

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WIND TURBINE OPTIMIZATIONTesting, Inspection and Maintenance


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Inspection of a wind turbine.Courtesy of Rope Partner, USA.


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As environmental concerns escalate and the limits of fossilfuel are approached, wind power has gained momentum as

a viable and cost-effective renewable energy source for thefuture.

Greater demands on efficiency of wind turbines result in con-tinuous improvement of design, placement and perform-

ance. Given that modern wind turbines produce in excess of2.5MW, the aerodynamic loads and structural demands on

the blades are increasing, being driven by the necessity forlonger and lighter blades. Consequently, there is a growing

need to incorporate new composite materials, making thedesign, manufacture and maintenance of modern wind tur-bines an ever increasing challenge. In addition, placing the

wind turbine farms at locations with optimal wind conditionsis important when optimizing the efficiency of each wind

turbine.

Your key to overcome these challenges is state-of-the-artinstrumentation for testing, inspecting and maintaining your

wind turbines.

Dantec Dynamics is a leading manufacturer of solutions for

Deformation and strain measurements Non-destructive testing

Air flow measurements Validation of computational models

Our instrumentation assists you in alleviating some of the

challenges associated with wind turbine design, manufactureand maintenance to protect your investment.

As environmental concerns escalate and the limits of fossil fuel

are approached, wind power has gained momentum as a viable

and cost-effective renewable energy source for the future.

Maximizing Performance and Minimizing

Maintenance Cost of Wind Turbines

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Over the course of its lifetime, a blade is exposed to manyfactors that can lead to damage and fatigue. These include

cyclic operational loads and gust loading, as well as icing anderosion. Ultimately, any of these factors may result in blade

failure.

Defects incurred during the manufacturing process, as well

as damage inflicted during blade transportation, may lead tothe failure or loss of turbine operation, if left undetected.

Non-contact measurement systems are employed in thedesign, manufacture and quality assurance processes to

reduce the risk of blade failure through optimization of theblade design and inspection of the blade for defects. Systems

for field use are also available.

Rapid and economical non-destructive testing for windpower

The quality of a composite material has a strong influence

on the lifetime of a component. With a very complex manu-facturing process, flaws can easily sneak into the process

and, in combination with high cyclical loads, result in failure

of vital components.

Non-destructive testing (NDT) is an important element in thequality process for all composite material manufacturers and

users. For an economical NDT inspection of a wind turbine

blade, with its extreme size, a rapid method that covers alarge surface area per hour is needed. Shearography is the

fastest existing NDT method for composite materials and alsohas a unique capability to detect wrinkles.

Ensuring Wind Turbine Blade Longevity

The image shows a typical result of a lighting strike at the blade tip.The test result shows that the real defect is much larger than thestrike indications.

In-field NDT test on rotorblades after a thunder storm accident.

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In-field inspection can be carried out using a portableshearography system with an integrated vacuum hood for

attachment to the blade. Each measurement takes 15seconds.

Materials that shearography can inspect include glass-fiber-

reinforced plastic (GFRP) and carbon-fiber-reinforced plastic(CFRP). Defects including wrinkles, impact damage, delami-

nation, dry-spots, cracks, voids, kissing bonds and much morecan be detected.

Shearography can inspect areas at a rate of 15 m2 per hour(160 sq ft/hr) and requires no surface preparation. An auto-

mated production inspection system can inspect a full bladein just a few hours.

Deformation and strain measurements

Digital Image Correlation (DIC) is a non-contact, full-fieldoptical technique that can measure 3D deformation and sur-

face strain on almost any material.

Typical applications for wind turbine blades include:

Coupon testing

Crack propagation and fracture mechanics Criticality assessment of defects or damage Full-size blade testing on:

- Internal structural components

- External surface of the blade

Bending of a rotorblade for a fatigue test.

In-field NDT test.Courtesy of Rope Partner, USA.

A Q-400 DIC placed on a critical area for strain measurement in abending test (left). A typical strain field in an area with wrinkling(right).

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Air flow measurements around a wind turbine installationcan be important for the following applications:

Blade design and aerodynamic modeling Flow-structure interaction and flow separation

Placement of wind turbines

Impact on and effects of submerged wind turbine towers

Optimizing Blade Design by Aerodynamic Modeling

Blade design is critical for optimizing the aerodynamic effi-

ciency of the turbine during light wind conditions. Thedesign, however, must also be strong enough to withstand

operational loads including gust loads. Dantec Dynamics ishelping you to meet these criteria by offering a range of

instruments for fluid flow investigations.

For aerodynamic modeling in wind tunnels Particle ImageVelocimetry (PIV) may be used. A PIV system provides an

instantaneous snapshot of a flow field which can be ren-dered in a plane or volume providing information on all

three components of velocity.

The investigation of the far wake development is needed in

the case of wind farm design. The near wake structure isrelevant when the flow around the wind turbine is analyzed.

Flow-Structure Interaction and Flow Separation

As the blades of a wind turbine turn they are exposed todifferent levels of pressure loading leading to deflection of

the blade. The flow around the blade and associated defor-

mation of the blade can be measured simultaneously using acombination of optical deformation, strain and PIV measure-

ments.

Maximizing Power Output of Wind Turbine Farms

The near wake flow field behind a model wind turbine measured byPIV. Courtesy of Prof. Massouh, ENSAM, Paris, France.

Array of thin film sensors on a blade for detection of flow separationand re-attachment.

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Flow separation at the blade surface influences not onlyaerodynamic efficiency but blade noise as well. To determine

the location of separation, you deploy a ConstantTemperature Anemometer (CTA), which derives flow infor-

mation from an array of thin film sensors attached to the

blade. As the blade rotates and the wind speed varies, theseparation point can be determined.

Proper Placement of Wind Turbines

The prevailing wind conditions are critical for determiningthe location of wind turbines. Both the mean velocity at dif-

ferent heights as well as turbulence are important factors inpredicting power output and blade fatigue. Laser Doppler

Anemometer (LDA) or CTA is used to accurately measure the

airflow over geographical models in wind tunnels. LDA is anoptical technique to measure 3D velocity information at any

point in the flow.

Minimizing Impact of Submerged Wind TurbineTowers

Placement of off-shore wind turbine farms requires the con-

sideration of several factors in order to mitigate environmen-tal impact. These include the farm's position relative to

ocean currents, ocean floor topography as well as the local

effects on the transportation of sediment and mixing ofocean floor flows.

Many of these impacts can be prevented by proper model

investigation of flows and solid transport prior to installing

off-shore wind turbine farms.

Techniques including PIV, LDA or Phase DopplerAnemometare (PDA) is used to provide information about

global and local flow structures and sediment size distribu-

tion. PDA is an extension to LDA providing velocity and par-ticle size information.

Investigation of prevailing wind conditions over geographical models.Courtesy of Force Technology, Denmark.

Flow distribution around a bottom mounted cylinder.Courtesy of University of Rostock, Germany.

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About Dantec Dynamics

Worldwide representation

Dantec Dynamics is the leading provider of laser optical measurement systems and sensors.

Since 1947 we have provided solutions for customers to optimize their component testing

and products. Our large number of customers benefit from our quality solutions within:

From our six offices and more than 30 representatives worldwide we

approach our customers individually. We examine the specific needs

and find the best solution for you. For us you are a long-term partner

in improving efficiency, safety and quality of life.

A list of representatives is available at our website.

DENMARK (headquarters)

Dantec Dynamics A/S

[email protected]

FRANCE

Dantec Dynamics S.A.S.

[email protected]

GERMANY

Dantec Dynamics GmbH

[email protected]

JAPAN

Dantec Dynamics K.K.

[email protected]

UNITED KINGDOM

Dantec Dynamics Ltd.

[email protected]

USA

Dantec Dynamics Inc.

[email protected]

www.dantecdynamics.com

The specifications in this document are subject to change without notice.

Dantec Dynamics is trademark of Dantec Dynamics A/S

Publication.:270_v3

Fluid Mechanics

Particle Characterization

Combustion Diagnostics

Thermal Comfort

Microfluidics

Process Control

Strain, Stress & Vibration

Non-destructive Testing

Disatac Tachometers

wind turbine optimization

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