GB2469516A - Rotor blade with optical strain sensors covered by erosion shield - Google Patents

Rotor blade with optical strain sensors covered by erosion shield Download PDF

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Publication number
GB2469516A
GB2469516A GB0906625A GB0906625A GB2469516A GB 2469516 A GB2469516 A GB 2469516A GB 0906625 A GB0906625 A GB 0906625A GB 0906625 A GB0906625 A GB 0906625A GB 2469516 A GB2469516 A GB 2469516A
Authority
GB
United Kingdom
Prior art keywords
rotor blade
optical fibre
blade
rotor
sensor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB0906625A
Other versions
GB0906625D0 (en
Inventor
Roger Caesley
Mark Volanthen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Insensys Ltd
Original Assignee
Insensys Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Insensys Ltd filed Critical Insensys Ltd
Priority to GB0906625A priority Critical patent/GB2469516A/en
Publication of GB0906625D0 publication Critical patent/GB0906625D0/en
Priority to PCT/GB2010/050638 priority patent/WO2010119298A1/en
Publication of GB2469516A publication Critical patent/GB2469516A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/32—Rotors
    • B64C27/46—Blades
    • B64C27/473—Constructional features
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/16—Blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/16—Blades
    • B64C11/20—Constructional features
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/006—Safety devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/32—Rotors
    • B64C27/46—Blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D45/00—Aircraft indicators or protectors not otherwise provided for
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06—Rotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06—Rotors
    • F03D1/065—Rotors characterised by their construction elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D3/00—Wind motors with rotation axis substantially perpendicular to the air flow entering the rotor 
    • F03D3/06—Rotors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D3/00—Wind motors with rotation axis substantially perpendicular to the air flow entering the rotor 
    • F03D3/06—Rotors
    • F03D3/062—Rotors characterised by their construction elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/74—Wind turbines with rotation axis perpendicular to the wind direction

Abstract

A method of manufacturing a rotor blade 10 comprising the steps of applying at least one optical fibre strain sensor 14 to the leading edge of the rotor blade body 12 and fitting an erosion shield 16 to the leading edge of the rotor blade body 12, over the optical fibre sensor 14. The optical strain sensors 14 may measure the strain in the axial direction of the blade 10, and may be placed at an angle between 30 and 60 degrees to the rotor blade axis, with 45 degrees being the preferred angle. The sensors may comprise Bragg gratings 18 spaced along the length of the fibre 14, and may be positioned at a location which is not a node of oscillation. The blade 10 may be a helicopter rotor blade.

Description

Improved Rotor Blade
Field of the Invention
This invention relates to rotor blades and is application with particular advantage to helicopter rotor blades.
Background to the Invention
Optical fibre strain sensors are known and patent publication WO 2004/0560 17 discloses a method of interrogating multiple fibre Bragg grating strain sensors along a single fibre.
In the system of WO 2004/056017, Bragg gratings are defined in the optical fibre at spaced locations along the optical fibre. When the optical fibre is put under strain, the relative spacing of the planes of each Bragg grating changes and thus the resonant optical wavelength of the grating changes. By determining the resonant wavelength of each grating, a strain measurement can be derived for the location of each grating along the fibre. Optical strain sensors operating on the principle of back scattering which do not require discrete gratings along the fibre are also known.
It is desirable to monitor the loads on rotor blades, especially helicopter rotor blades, for safety reasons and also to monitor the performance of the blade. Advantageously, the loads on rotor blades due to impacts can be monitored and quantified. However, applying sensors to monitor loads to the outside of the rotor blade may affect the aerodynamic properties of the blade and the sensors themselves are exposed to damage from impacts with foreign bodies. Furthermore, the sensors cannot be contained within the blade, as with hollow wind turbine rotor blades, because helicopter blades are of closed section and getting the sensor out is difficult. Whilst it is possible to embed the sensor within the blade, this may change the structural properties of the blade and a blade with an embedded sensor would significanfly increase the recertification cost for the blade.
Furthermore, should the sensor become damaged, the whole blade would need replacing.
Summary of the Invention
Accordingly, the present invention comprises a method of manufacturing a helicopter rotor blade comprising the steps of; applying at least one optical fibre strain sensor to the leading edge of the rotor blade body; and fitting an erosion shield to the leading edge of the rotor blade body, over the optical fibre sensor.
Helicopter rotor blades have sacrificial erosion shields that are externally bonded around the leading edge. The erosion shields extend the life of the blade and are routinely replaced once they have experienced a significant amount of wear. Positioning an optical fibre strain sensor between the blade body and the erosion shield does not interfere with the structural or aerodynamic properties of the blade and also allows easy access to the sensor for maintenance purposes. Should the optical fibre break in two or more places, a new fibre can be fitted by removing the erosion shield and bonding a new fibre to the blade body. Should the optical fibre strain sensor break in just a single position, this can be catered for by terminating both ends of the fibre.
Advantageously, a plurality of optical fibre strain sensors is applied to the length of the blade body. This allows the detection of impact forces and for profiling of the aerodynamic forces along the blade.
Preferably, optical strain sensors are positioned to measure strains in the axial direction of the blade. By positioning a plurality of sensors around the leading edge at a single cross-section, measurements of the axial strain can be made to determine the lift and drag forces on the rotor blade.
Advantageously, one or more optical fibre strain sensors are positioned at an angle of the order of 45 degrees, for example substantially 45 degrees to the rotor blade axis. By positioning a sensor at this angie, the torsion in the blade caii be measured. Other angles for example, 30 degrees to 60 degrees to the rotor blade axis could also be used.
As the rotor blade is impacted, a variety of the natural nodes of oscillation are excited. In a preferred configuration, the optical fibre strain sensors are positioned at locations other than at the nodes of oscillation. By arranging the optical fibre strain sensors away from the nodes of oscillation, it is possible to identify the impact location from analysis of the signals from the sensors. Furthermore, the magnitude of the impact can be identified from the amplitude of the sensor signals.
The invention includes within its scope a helicopter rotor blade comprising a rotor blade body and an erosion shield, wherein at least one optical fibre strain sensor is provided between the rotor body and the erosion shield.
Brief Description of the Drawings
An embodiment of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is an axial cross-sectional view of a helicopter rotor blade in accordance with the present invention; and Figure 2 is a plan view of the helicopter rotor of Figure 1, wherein the erosion shield has been removed.
Detailed Description of Exemplary Embodiments
Figures 1 and 2 show a helicopter rotor blade 10, comprising a rotor blade body 12 and an optical fibre strain sensor 14 attached to the rotor blade body. An erosion shield 16 is bonded to the leading edge of the rotor blade body 12, which protects the optical fibre strain sensor 14 and rotor blade body 12 from damage from impacts with foreign bodies.
The erosion shield 16 can detached from the rotor blade body 12 replaced if necessary.
As shown in Figure 2, the optical fibre strain sensors comprise Bragg gratings 18 spaced along the length of the fibre 14. The optical fibre 14 extends the length of the rotor blade body 12 and a plurality of optical fibres 14 are positioned longitudinally about the leading edge of the rotor blade body 12 to allow measurements of the life, drag and torsion of the rotor Made 10.
Whilst the present invention has been described in relation to helicopter rotor blades, it may also be used in other applications, such as in aircraft propellers.
In summary, a method of manufacturing a helicopter rotor blade comprising the steps of applying at least one optical fibre strain sensor to the leading edge of the rotor blade body and fitting an erosion shield to the leading edge of the rotor blade body, over the optical fibre sensor.

Claims (10)

  1. Claims 1. A method of manufacturing a rotor blade comprising the steps of; applying at least one optical fibre strain sensor to the leading edge of the rotor blade body; and fitting an erosion shieki to the leading edge of the rotor Made body, over the optical fibre sensor.
  2. 2. A method according to claim 1, wherein the, or each, optical strain sensor is positioned to measure strain in the axial direction of the blade.
  3. 3. A method according to claim 1 or claim 2, wherein one or more of the optical fibre strain sensors is or are positioned at an angle of the order of 45 degrees to the rotor blade axis.
  4. 4. A method according to any preceding claim, wherein the, or each, optical fibre strain sensor is positioned at a location other than at a node of oscillation.
  5. 5. A method according to any preceding claim, wherein a plurality of optical fibre strain sensors is applied to the length of the blade body.
  6. 6. A rotor blade body and an erosion shield, wherein at least one optical fibre strain sensor is provided between the rotor body and the erosion shield.
  7. 7. A method of manufacturing a rotor blade substantially as described herein with reference to and as illustrated in any appropriate combination of the accompanying text and/or drawings.
  8. 8. A rotor blade substantially as described herein with reference to and as illustrated in any appropriate combination of the accompanying text and/or drawings.
  9. 9. A method of manufacturing a rotor blade according to any of claims 1 to 6 or claim 8, wherein the blade is a helicopter rotor blade.
  10. 10. A rotor blade according to claim 6 or claim 8, wherein the rotor blade is a helicopter rotor blade.
GB0906625A 2009-04-17 2009-04-17 Rotor blade with optical strain sensors covered by erosion shield Withdrawn GB2469516A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB0906625A GB2469516A (en) 2009-04-17 2009-04-17 Rotor blade with optical strain sensors covered by erosion shield
PCT/GB2010/050638 WO2010119298A1 (en) 2009-04-17 2010-04-19 Rotor blade

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0906625A GB2469516A (en) 2009-04-17 2009-04-17 Rotor blade with optical strain sensors covered by erosion shield

Publications (2)

Publication Number Publication Date
GB0906625D0 GB0906625D0 (en) 2009-05-27
GB2469516A true GB2469516A (en) 2010-10-20

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB0906625A Withdrawn GB2469516A (en) 2009-04-17 2009-04-17 Rotor blade with optical strain sensors covered by erosion shield

Country Status (2)

Country Link
GB (1) GB2469516A (en)
WO (1) WO2010119298A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2505736A (en) * 2013-03-15 2014-03-12 Epsilon Optics Aerospace Ltd Method of incorporating a coil of optical fibre into a composite structure
EP2778059A1 (en) * 2013-03-14 2014-09-17 Bell Helicopter Textron Inc. Amorphous metal rotor blade abrasion strip
EP3068994A4 (en) * 2013-11-15 2017-07-19 United Technologies Corporation Component with embedded sensor
EP3485161A4 (en) * 2016-07-15 2020-04-08 Sikorsky Aircraft Corporation Rotor blade deflection sensing system
WO2021234227A1 (en) * 2020-05-20 2021-11-25 Teknologian Tutkimuskeskus Vtt Oy Sensor, arrangement, method of estimating an angle of attack, and computer readable memory
EP3768969A4 (en) * 2018-03-18 2021-12-08 Udesen Trade The present invention relates to a device for remedying erosion problems on wind turbine blades

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014081355A1 (en) * 2012-11-20 2014-05-30 Saab Ab An erosion protection strip for a leading edge of an airfoil article
JP6421078B2 (en) 2015-05-28 2018-11-07 エムエイチアイ ヴェスタス オフショア ウィンド エー／エス Wind turbine blade and wind power generator, and method for manufacturing or modifying wind turbine blade
CN113404652A (en) * 2021-06-09 2021-09-17 东方电气集团科学技术研究院有限公司 Method for monitoring state of blade of wind generating set in severe environment

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2440953A (en) * 2006-08-18 2008-02-20 Insensys Ltd Monitoring wind turbine blades
WO2009068918A1 (en) * 2007-11-30 2009-06-04 Bae Systems Plc Improvements relating to temperature monitoring

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1270802A (en) * 1985-02-07 1990-06-26 Edward A. Rothman Prop-fan with improved stability
US6447254B1 (en) * 2001-05-18 2002-09-10 Sikorsky Aircraft Corporation Low dieletric constant erosion resistant material
CN1294353C (en) * 2001-07-19 2007-01-10 Neg麦康公司 Wnd turbine blade
US20060049302A1 (en) * 2004-08-31 2006-03-09 Kennedy Dennis K Apparatus and methods for structurally-integrated conductive conduits for rotor blades
GB2440954B (en) * 2006-08-18 2008-12-17 Insensys Ltd Structural monitoring

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2440953A (en) * 2006-08-18 2008-02-20 Insensys Ltd Monitoring wind turbine blades
WO2009068918A1 (en) * 2007-11-30 2009-06-04 Bae Systems Plc Improvements relating to temperature monitoring

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2778059A1 (en) * 2013-03-14 2014-09-17 Bell Helicopter Textron Inc. Amorphous metal rotor blade abrasion strip
GB2505736A (en) * 2013-03-15 2014-03-12 Epsilon Optics Aerospace Ltd Method of incorporating a coil of optical fibre into a composite structure
GB2505736B (en) * 2013-03-15 2015-06-10 Epsilon Optics Aerospace Ltd A method of incorporating a coil of optical fibre into a composite structure
EP3068994A4 (en) * 2013-11-15 2017-07-19 United Technologies Corporation Component with embedded sensor
US10006304B2 (en) 2013-11-15 2018-06-26 United Technologies Corporation Component with embedded sensor
EP3485161A4 (en) * 2016-07-15 2020-04-08 Sikorsky Aircraft Corporation Rotor blade deflection sensing system
EP3768969A4 (en) * 2018-03-18 2021-12-08 Udesen Trade The present invention relates to a device for remedying erosion problems on wind turbine blades
WO2021234227A1 (en) * 2020-05-20 2021-11-25 Teknologian Tutkimuskeskus Vtt Oy Sensor, arrangement, method of estimating an angle of attack, and computer readable memory

Also Published As

Publication number Publication date
GB0906625D0 (en) 2009-05-27
WO2010119298A1 (en) 2010-10-21

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)