Preventive maintenance of an aerodynamic structure

Abstract

An aerodynamic device (200) for mounting on an aerodynamic structure (110) to generate a vortex during rotation of the aerodynamic structure (110), the aerodynamic device (200) comprising: a vibration sensor (201) for monitoring vibration characteristics of the aerodynamic structure (110) to generate vibration data; a battery (203); a solar panel (202) for charging the battery (203); and a controller (210) powered by the battery (203) and comprising a microprocessor (211) for collecting vibration data and a communication module (212) connected to an antenna (205) for transmitting the vibration data.

Description

[0001] PREVENTIVE MAINTENANCE OF AN AERODYNAMIC STRUCTURE

[0002] FIELD OF THE INVENTION

[0003] This invention relates to the field of aerodynamic structures, specifically focusing on preventive maintenance of structures like wind turbines, airplane wings, and industrial fan blades and blower blades. It involves methods for monitoring and controlling flutter-induced vibrations.

[0004] BACKGROUND

[0005] Aerodynamic structures such as wind turbine blades, airplane wings, and industrial fan and blower blades are vulnerable to structural damage from forces such as airflow fluttering.

[0006] All structural members, in general, have a natural frequency, and elongated structural members especially can be made to oscillate to destructive amplitudes by a relatively low impulse that is synchronized with the natural frequency of that structural member.

[0007] One example of destructive vibration from airflow fluttering is the Tacoma Narrows Bridge, which was brought down by a 40 miles / hour crosswind in the fall of 1940. A constant and sustained wind caused an airflow fluttering against the bridge and created a forced mechanical resonance. The amplitude of this resonance grew uncontrollably until the bridge collapsed.

[0008] For example, aerodynamic vortices detaching from a turbine blade at a steady rate is one of the greatest risks of fatigue, damage, or failure in wind turbines. The prior art is silent relative to monitoring vibrations caused by local flow detachments and relating these vibrations to the natural frequency of the blade of a wind turbine. The prior art is also silent relative to monitoring vibrations along the vulnerable segments of a wind turbine blade.

[0009] Aerodynamic vortices detaching from one blade create vibration in that blade and turbulent air near the following blade. Vibration and turbulence reduce torque and efficiency of a wind turbine. Vibration causes fatigue and reduces the life expectancy of a wind turbine.

[0010] Referring to FIGS. 1-5 in the attached drawings, the vulnerability of the blades of wind turbines will be explained. Because air is compressible, the flow detachment of a steady wind may not always occur at a steady frequency. However, this frequency is considered quasi-steady most of the time, and for the convenience of this disclosure, this frequency is illustrated and described as being steady and readable by a vibration sensor.

[0011] FIG. 1 illustrates a typical vortex shedding or detachment phenomenon 20 on a turbine blade 22. This vortex detachment phenomenon is made of a series of vortices 24 separated in space by a distance 26. That distance may remain steady in time (steady vortex shedding frequency) or may change in time (unsteady vortex shedding frequency). Every time one of these vortices 20 detaches from the surface of the turbine blade 22, it produces a small impulse on the blade. During a steady airflow and a steady blade rotational speed, these vortices 24 have substantially a similar impulse and a steady frequency. The radial location of these impulses along the blade, however, has been considered unpredictable in the past.

[0012] FIG. 2 illustrates, for descriptive purposes, a natural frequency of the turbine blade 22. This natural frequency has four nodes 28 and an amplitude "A". The natural frequency of a turbine blade can be mapped on the blade using a well-known "bump-test technique" and measuring vibration amplitudes along the blade using a portable vibration pickup.

[0013] It will be appreciated that when a specific vortex detachment location is stubbornly attached to the blade between the nodes 28 of the natural frequency of the turbine blade 22, this specific vortex detachment can induce destructive vibrations in the blade 22. It will also be appreciated that vibration in a turbine blade reduces the torque-generating efficiency of that blade.

[0014] Wind turbine manufacturers and users have understood the danger of wind-induced vibrations in turbine blades. One solution found in the prior art consists of installing a series of vortex generators on the backside of the blade, to satisfy the need for detachment of the laminar flow present there. This need for detachment is satisfied with a series of vortex generators producing smaller vortices 30 as shown in FIGS. 3 and 4. These vortices 30 produce vibrations of higher frequency and smaller amplitude.

[0015] These vortex generators 32, as illustrated in FIG. 5, are made of rigid material such as plastic, for example, and come in different shapes. Some other aerodynamic devices are referred to as "gurney flaps"; "serrations"; "flow splitters"; "flow spoilers"; "air intake"; "air out", or "cavity" . However, only one shape is illustrated herein for convenience, and to improve the clarity of the information provided.

[0016] These small vortex generators 32 have spaced-apart fins 34 defining a nozzle 36, through which the laminar flow of air on the surface of the turbine blade 22 is broken up into a multitude of small vortices 30. It will be appreciated that the rigid shape of the vortex generators 32 of the prior art has been designed to produce an ideal result for a unique set of conditions, such as wind speed, rotational speed, moisture content, temperature, etc.

[0017] Therefore, there is a recognized need in the industry for a system and method to control airinduced vibrations on turbine and fan blades, as well as airplane wings, across a broader range of air and atmospheric conditions, as well as varying operational blade or rotor speeds. SUMMARY OF THE INVENTION

[0018] In one aspect of the invention, an aerodynamic device for mounting on an aerodynamic structure is provided. This device is designed to generate a vortex during the aerodynamic structure’s rotation and includes a vibration sensor for monitoring aerodynamic structure vibrations, a battery, a solar panel for charging the battery, and a controller powered by the battery. The controller comprises a microprocessor for collecting vibration data and a communication module connected to an antenna for transmitting this data. The technical advantage of this aspect is that it allows for real-time monitoring and data transmission of vibration characteristics, enabling proactive maintenance and optimization of performance of the aerodynamic structure.

[0019] In a preferred embodiment of the invention, the aerodynamic device features a body with at least a portion that is elastic. This elasticity allows the device to adapt to varying wind conditions, providing enhanced control over vortex generation and reducing destructive vibrations. The technical advantage here is the increased adaptability and resilience of the device under different operational conditions, which can lead to improved efficiency and longevity.

[0020] Another preferred embodiment includes the surface of the elastic body portions being covered by a piezoelectric transducer, which charges the battery. This feature provides an additional energy source, enhancing the device's sustainability and reducing dependency on external power sources. The technical advantage is the self-sustaining energy system that ensures continuous operation of the vibration monitoring system.

[0021] In yet another preferred embodiment, the device comprises an energy system to adjust the shape of its body, thereby altering vortex detachment characteristics to reduce aerodynamic structure vibration. This capability allows for dynamic adjustment to changing environmental conditions, optimizing the aerodynamic performance of the aerodynamic structure. The technical advantage is the ability to fine-tune the device's impact on aerodynamic structure vibrations, potentially extending the structure’s operational life and improving energy capture efficiency.

[0022] A further preferred embodiment involves a pneumatic system located within the aerodynamic structure for inflating or deflating the aerodynamic devices to modify their shape. This feature provides a mechanical means to adjust the device's aerodynamic properties, offering precise control over air flow and vibrations. The technical advantage is the enhanced ability to mitigate harmful vibrations through mechanical adjustments, contributing to the structural integrity of the aerodynamic structure.

[0023] Another preferred embodiment involves at least one adjustable element coupled with a current-operated actuator device with metal plates coupled with a piezoelectric material and a power supply, the actuator device being operated by the controller for adjusting the shape or position of the adjustable element.

[0024] In another preferred embodiment, the controller is mounted on a printed circuit board located in a recess at the bottom of the base plate of the aerodynamic device. This configuration increases the rigidity of the device structure, ensuring stable operation under various conditions. The technical advantage is the improved durability and reliability of the device, which is crucial for maintaining consistent performance.

[0025] Additionally, a preferred embodiment includes a flexible base plate that can be adjusted between extended and retracted positions, causing the fins to assume any intermediate position or even flare out or remain parallel to the aerodynamic structure surface. In another preferred embodiment the flexible fins can be adjusted to allow them to maintain any desired position between perpendicular and parallel state to the aerodynamic structure surface. This adjustability provides the ability to tailor the aerodynamic response to specific operational needs. The technical advantage is the customizable aerodynamic profile that can be optimized for different airflow speeds and directions as well as rotational speeds and pitch angles of a wind turbine or a fan blade or an airplane wing.

[0026] In a further preferred embodiment, the device features a first fin with a greater mass than a second fin, allowing it to bend outward under centrifugal force, forming a gap. This design enhances the aerodynamic device's ability to manage airflow and vortex generation. The technical advantage is the improved control over vortex characteristics, which can lead to more effective vibration reduction.

[0027] In another aspect of the invention, an aerodynamic structure monitoring system is provided, comprising at least one aerodynamic device and a gateway device configured to collect vibration data from sensors. This system facilitates comprehensive monitoring , analysis and diagnostics of aerodynamic structure’s vibrations, enabling informed maintenance decisions. The technical advantage is the integrated monitoring capability that supports proactive maintenance strategies, reducing downtime and maintenance costs.

[0028] In a preferred embodiment, the device may further comprise one or more supplementary sensors, such as a strain gauge or a pressure gauge, wherein the controller is further configured to collect and transmit the supplementary data measured by the one or more supplementary sensors.

[0029] In a preferred embodiment, the gateway of a first wind turbine can be configured to, in the event of failure of the gateway of a second wind turbine, receive vibration data from at least one aerodynamic device of the second wind turbine. In a further aspect, a method for preventive maintenance of an aerodynamic structure is described, involving the installation of the monitoring system, monitoring vibrations, and transmitting data to a remote server. This method ensures continuous oversight of structure health and performance, allowing for timely interventions. The technical advantage is the systematic approach to maintenance that enhances structure’s reliability and operational efficiency.

[0030] Despite the detailed description of preferred embodiments that will follow within the context of accompanying drawings, the following are overall comments regarding selected features related to the present invention.

[0031] The wind turbine is the central feature of the invention, serving as the primary mechanism for converting wind energy into electrical power. It consists of multiple components, including the blades, nacelle, and tower, which work together to harness wind energy. The wind turbine's functionality is enhanced by the integration of various sensors and control systems that monitor and optimize its performance. For example, the aerodynamic devices and vibration sensors are specifically designed to address the issue of flutter-induced vibrations in the turbine blades, thereby improving the turbine's efficiency and longevity. The wind turbine's operation can be further optimized by incorporating a gateway device that facilitates communication between the turbine and a remote server for data analysis, diagnostics and preventive maintenance.

[0032] The blade is a critical component of the wind turbine, responsible for capturing wind energy and converting it into rotational motion. The design and material of the blade are crucial for its aerodynamic efficiency and structural integrity. The blade's interaction with aerodynamic devices and vibration sensors is essential for monitoring and controlling vibrations that can lead to fatigue and damage. For instance, the placement of aerodynamic devices along the blade can be adjusted to alter vortex detachment characteristics, thereby reducing destructive vibrations. The blade's natural frequency and vibration characteristics are continuously monitored to ensure optimal performance and prevent structural failures.

[0033] The aerodynamic device is designed to be mounted on the wind turbine blade to generate vortices during rotation. Its primary function is to manage airflow and reduce vibrations by altering vortex detachment characteristics. The device is equipped with a vibration sensor, battery, solar panel, and controller, making it a self-sustaining unit capable of real-time monitoring and data transmission. The elastic nature of the device allows it to adapt to varying wind conditions, enhancing its effectiveness in vibration reduction and airflow optimization. Specific implementations include adjustable fins and a flexible base plate, which can be mechanically or pneumatically adjusted to further optimize aerodynamic performance. The vibration sensor is a crucial feature for monitoring the vibration characteristics of the wind turbine blade. It collects data on the amplitude and frequency of vibrations, which is then used to assess the blade's structural health and performance. The sensor's data is transmitted to a controller and gateway device for further analysis. An example of implementation is the use of accelerometers mounted on the blade to detect vibrations caused by vortex shedding. The sensor's integration with the aerodynamic device allows for real-time adjustments to reduce harmful vibrations and extend the blade's operational life.

[0034] The battery serves as the power source for the aerodynamic device's electronic components, including the vibration sensor, controller, and communication module. It is charged by a solar panel and, in some embodiments, a piezoelectric transducer, making the device self-sustaining and reducing dependency on external power sources. The battery ensures continuous operation of the vibration monitoring system, even in low-light conditions. A specific example of implementation is the use of a rechargeable lithium-ion battery, which provides reliable power storage and discharge capabilities.

[0035] The solar panel is integrated into the aerodynamic device to provide a renewable energy source for charging the battery. It captures solar energy and converts it into electrical power, ensuring the device remains operational even in remote locations. The solar panel's placement on the aerodynamic device is optimized to maximize exposure to sunlight while minimizing aerodynamic drag. An example of implementation is the use of flexible solar panels that can conform to the shape of the device, enhancing its adaptability and efficiency.

[0036] The piezoelectric transducer is an additional energy-harvesting component that converts mechanical vibrations into electrical energy. It is used to supplement the power generated by the solar panel, providing an alternative energy source for charging the battery. The transducer is particularly useful in conditions where solar energy is insufficient, such as during nighttime or cloudy weather. An example of implementation is the integration of piezoelectric materials into the elastic body of the aerodynamic device, allowing it to generate power from the vibrations it is designed to monitor and control.

[0037] The controller is the central processing unit of the aerodynamic device, responsible for collecting and analyzing vibration data from sensors. It comprises a microprocessor and a communication module, enabling it to process data and transmit it to a gateway device or remote server. The controller can also receive control signals to adjust the aerodynamic device's configuration, optimizing its performance in response to changing environmental conditions. An example of implementation is the use of an loT-enabled controller that facilitates seamless communication and data exchange within a wind farm's network. The microprocessor is a key component of the controller, tasked with processing vibration data and executing control algorithms. It performs real-time analysis of the data to identify patterns and anomalies, which can indicate potential issues with the wind turbine blade. The microprocessor's capabilities enable it to make autonomous decisions regarding the adjustment of the aerodynamic device's configuration. An example of implementation is the use of a low- power microcontroller with integrated wireless communication capabilities, ensuring efficient data processing and transmission.

[0038] The communication module is responsible for transmitting vibration data from the aerodynamic device to a gateway device or remote server. It supports wireless communication protocols, allowing for seamless data exchange within a wind farm's network. The module's design prioritizes energy efficiency to extend the battery's operational life. An example of implementation is the use of a short-range wireless standard, such as Bluetooth Low Energy (BLE) or other proprietary protocols designed for efficient communication, to minimize power consumption while maintaining reliable data transmission.

[0039] The gateway device serves as the central hub for collecting and transmitting data from multiple aerodynamic devices within a wind turbine. It aggregates vibration data and other environmental parameters, which are then sent to a remote server for analysis. The gateway device's integration with the wind turbine's network enables comprehensive monitoring and management of the turbine's performance. An example of implementation is the use of a robust communication module that supports long-range wireless protocols, ensuring reliable data transmission even in challenging environmental conditions.

[0040] These and other features, aspects and advantages of the invention will become better understood with reference to the following drawings, descriptions and claims.

[0041] BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Various embodiments are herein described, by way of example only, with reference to the accompanying drawings, wherein:

[0043] FIG. l is a typical illustration of air vortex detachment from a turbine blade as known from the prior art;

[0044] FIG. 2 is a curve-like illustration of a natural frequency of a turbine blade in FIG. 1 as known from the prior art;

[0045] FIG. 3 illustrates a series of aerodynamic devices on a turbine blade and a series of trailing vortices generated by the aerodynamic devices as known from the prior art; FIG. 4 is a partial cross-section of the turbine blade along line 4-4 in FIG. 3 as known from the prior art;

[0046] FIG. 5 is a perspective view of an aerodynamic device of the prior art;

[0047] FIG. 6 is a turbine blade showing a series of vortices detaching from a series of aerodynamic devices mounted on the blade;

[0048] FIG. 7 is a functional schematic of the aerodynamic device;

[0049] FIG. 8 is a first structural embodiment of an elastic adjustable aerodynamic device;

[0050] FIG. 9 is a second structural embodiment of an elastic adjustable aerodynamic device;

[0051] FIGS. 10 and 11 illustrate a third structural embodiment of an elastic adjustable aerodynamic device;

[0052] FIG. 12 illustrates is first variant of a fourth structural embodiment of an elastic adjustable aerodynamic device;

[0053] FIG. 13 is a second variant of the fourth structural embodiment of an elastic adjustable aerodynamic device;

[0054] FIG. 14 is a third variant of the fourth structural embodiment of an elastic adjustable aerodynamic device;

[0055] FIG. 15A shows a first embodiment of a system for adjusting the operational characteristics of the aerodynamic device, relevant to embodiments of the aerodynamic device illustrated in FIGS. 12-14;

[0056] FIG. 15B shows a second embodiment of a system for adjusting the operational characteristics of the aerodynamic device, relevant to any embodiment of the aerodynamic device with adjustable elements;

[0057] FIG. 16 illustrates a turbine blade together with its natural frequency and its regions of vulnerability;

[0058] FIG. 17 illustrates combined impulses of several aerodynamic devices in FIG. 6, adjusted to produce an even force;

[0059] FIG. 18 is an electrical analogy of the adjusted aerodynamic devices in FIG. 6;

[0060] FIG. 19 is a perspective view of a fifth structural embodiment of aerodynamic device;

[0061] FIG. 20 represents two wind turbines in communication with each other;

[0062] FIG. 21 is a functional schematic of the gateway.

[0063] The drawings presented herein contain freehand sketches. These freehand sketches are presented for convenience to better understand the description of the embodiments. Therefore, the drawings should not be considered as at a correct scale. Lines are not always drawn straight, and circles are not always round. Parallel, isometric, or perspective features are not always illustrated as such. These drawings are presented to people skilled in the art with the intent to understand.

[0064] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention.

[0066] The description below will relate to a set of embodiments related to an aerodynamic structure having a form of a blade of a wind turbine. In an equivalent manner it can be employed with other aerodynamic structures, such as wings of an airplane or blades of an industrial fan or blower.

[0067] FIG. 6 shows a wind turbine blade 110 modified in accordance with the principles of the present invention. It comprises a plurality of aerodynamic devices 200 mounted between a base 111 and a tip 112 of the turbine blade 110. In a simple embodiment, a single aerodynamic device 200 is sufficient.

[0068] In FIG. 6, it will be appreciated that each aerodynamic device 200 illustrated therein may have a unique signature. This signature depends on the radial location of an aerodynamic device along the blade. For example, the aerodynamic device at the tip of blade may have a longer displacement per sector 101 of rotation than the aerodynamic device near the base of the blade. Different displacements result in different quantities of vortices being generated, and thus a unique vibration signature for each aerodynamic device.

[0069] Fig. 7 shows a functional schematic of an embodiment of the aerodynamic device 200. It comprises a vibration sensor 201 for monitoring vibration characteristics of the blade 100 to generate vibration data. A battery 203 is charged from electric power generated by a solar panel 202 and optionally a piezoelectric transducer 204. A controller 210 (which can be configured as an Internet of Things (loT) module) is powered by the battery 203 and comprises a microprocessor 211 for collecting vibration data and a communication module 212 connected to an antenna 205 for transmitting the vibration data (in the form as collected from the vibration sensor 201 directly or pre-processed by the microprocessor 211) to a gateway 300 at the nacelle 120 of the wind turbine 100. The aerodynamic device 200 may optionally comprise adjustable elements 206 (such as fins) and in such case the microprocessor 211 can be further configured to receive vortex control data from the communication module 212 that are used to control the adjustable elements 206 . The vibration sensor 201 and the adjustable elements 206 may be also powered from the battery 203 or may have dedicated power sources. The communication module 212 and the antenna 205 may be configured to communicate with a gateway 300 via a relatively short range wireless standard in order to save energy. It may happen that due to harsh environmental conditions, the signal from one of the aerodynamic devices of the blade 110 may not reach the gateway 300, such as the signal from the furthest- distanced device. In order to prevent loss of data, the controller 210 may be further configured as data forwarder, such as to be able to receive vibration data from another aerodynamic device (assuming that its signal is strong enough to be received) and forward the received vibration data by means of its communication module 212.

[0070] The vibration sensor 201 may comprise accelerometers and other elements for registering vibrations in the blade. The vibration sensor 201 can be mounted to the blade using double-sided adhesive tape or glue, for example.

[0071] The aerodynamic device 200 may further comprise one or more supplementary sensors 207, such as a strain gauge (to measure deformation of the blade) or a pressure gauge (which can also act as a microphone to measure noise). In that case the controller 210 is further configured to collect and transmit the supplementary data measured by the supplementary sensors 207.

[0072] Data collected by the gateway 300 from the plurality of aerodynamic devices 200, along with the data collected by the other sensors of the gateway, can be sent wirelessly to a cloud server 400, for use by the windfarm owner, for example, for diagnostic and management purposes.

[0073] The gateway 300, having a functional structure as shown in Fig. 21, comprises an antenna 301 and a communication module 302 compatible with the communication module 212 and antenna 205 of the aerodynamic devices 200, such as to receive vibration data from the aerodynamic devices 200. Data is gathered by a sensors hub module 303, for example a microprocessor running specific software. The sensors hub 303 also collects data from additional sensors 304 for measuring additional parameters, such as atmospheric pressure, temperature, humidity, wind speed, wind direction, lightning strikes, tower vibrations, solar illuminance, etc. The collected data can be locally stored in a data storage 305. The collected data is also transmitted to the cloud server 400 via a wireless communication system, such as via a GSM module 306 connected to a GSM antenna 307.

[0074] A computer system at the windfarm management office, for example, may contain software to analyze vibration data, asses and separate the different frequencies and vibration amplitudes, and associate different frequencies and amplitudes with locations of the aerodynamic devices 200 along the blades 110, and different locations along the curve of the natural frequency of the blade For example, in order to enable better control over the operation of the turbine, the following steps can be taken: defining the natural frequency of a turbine blade and identifying the nodes and periods of this natural frequency;

[0075] - using vibration analysis to catalog the airflow detachment characteristics and vibrations at different circumferential speeds and wind velocities of an assortment of elastic aerodynamic devices;

[0076] - using vibration analysis to define the vibration characteristics of the turbine blade in use; installing a series of elastic aerodynamic devices from the assortment on the turbine blade, wherein the devices are selected to attenuate the vibration of the turbine blade.

[0077] In a further aspect of the present invention, a method for adjusting the shapes and / or locations of these elastic aerodynamic devices can be provided to achieve cooperation between a group of elastic aerodynamic devices, converting multiple vibrations into a monotone force or achieving total dampening of vibration.

[0078] In a method for preventive maintenance on a wind turbine, the vibration captured by the vibration sensors 201 can be analyzed to determine the vibration signature of each aerodynamic device 200 and of the corresponding blade 110. The same vibration signature can further be analyzed to determine whether one or more of the aerodynamic devices 200 correctly mitigate detrimental impulses on the blade, relative to the natural frequency of the corresponding blade 110. The method may also comprise the step of relating the data obtained from the vibration sensor 201 to associate different vibration signatures to different points along the blade 110. A high-frequency signature means a greater distance from the center of rotation. The method may also comprise the "trial-and-error" reconfiguration of the aerodynamic devices 200 along the blade to obtain the least influence on the vibration of the blade 110.

[0079] Vibration data analysis can be also conducted to detect a cracked blade portion, an imbalance in the turbine or its rotor, or a condition requiring blade re-adjustment, blade speed variation, or a complete shutdown of the wind turbine.

[0080] As mentioned before, the aerodynamic devices of the prior art have a rigid form and therefore a constant response to environmental conditions.

[0081] FIGS. 8-19 illustrate, without limitation, several preferable structural embodiments of aerodynamic devices 200 that can be adjusted or calibrated to generate different vibration responses. These adjustable aerodynamic devices can be adjusted in their specific placement along the axis of a blade, like the aerodynamic devices of the prior art, but can additionally be adjusted in their nozzle openings to capture more or less air therein. The aerodynamic devices according to the present invention can also be adjusted in their shapes to release vortices of different sizes at different frequencies and different distances from the surface of the blade. These aerodynamic devices are configurable for shaping flow detachment impulses to achieve desired results across a broader range of environmental and operational conditions.

[0082] The adjustable aerodynamic devices according to the present invention are made of flexible, malleable, or elastic material. The embodiments of the aerodynamic devices illustrated in FIGS. 8-14 are examples only of aerodynamic devices having elastic shapes, i.e. a body of which at least a portion is elastic. Numerous other shapes and configurations can be made using the concepts described herein. Other shapes and configurations are only limited by the choice and imagination of the designer, and the instructions and suggestions presented herein.

[0083] Referring to FIG. 8, the illustration shows a first structural embodiment of flexible aerodynamic device 200 having a flexible base 220. This base 220 is mounted by double-sided tape or otherwise to an embossed substrate 221 to raise the base 220 from the surface of the turbine blade and to cause the base 220 to bend upward and cause the fins 222 to flare out. This adjusted nozzle shape, as illustrated, amplifies or cancels vortex detachments by actively changing the airflow near the surface of the turbine blade. Different vibration amplitudes and frequencies are obtained.

[0084] The second structural embodiment of aerodynamic device 200 has an accordion-like extendable segment 223 along its longitudinal axis, as illustrated in FIG. 9. This aerodynamic device can be widened or made narrower. This aerodynamic device can also be adjusted to change the alignments of its fins 222 relative to each other and mounted on a base 224 to accept more or less airflow and generate different airflow and vibration signatures.

[0085] The aerodynamic device 200 illustrated in FIGS. 10 and 11 has one fin 225 that is made heavier than the other. In use, the heavier fin 225 bends outward due to centrifugal force, as shown in FIG. 11, to open the nozzle effect of the generator. The degree of nozzle opening may vary with the turbine's rotational speed as one potential input parameter.

[0086] In these embodiments, the elastic elements 220, 223, 225 may have surfaces covered by the piezoelectric transducer 204, generating energy to power the battery 203 when these surfaces vibrate or strain (compress or expand) due to wind force.

[0087] In the first and third embodiments, the solar panel 202 can be mounted between the fins 222. In all embodiments, the solar panel 202 can also cover the side areas of the fins 222.

[0088] In another variation of all embodiments, the controller 210 can have its elements 211, 212 (and preferably also the battery 203) mounted on a printed circuit board (PCB) located at a recess 226 at the bottom of the base plate 224 of the aerodynamic device 200, as shown in Fig. 11. This increases the rigidity of the aerodynamic device 200 structure.

[0089] A fourth embodiment of aerodynamic device 200 is illustrated in FIGS. 12, 13, and 14. This type of aerodynamic device is adjustable by controlled inflation. In the first variant, as shown in FIG. 12, a top wall 231 is stiffer than a bottom wall 232, so that air pressure introduced between the two walls via air inlet opening 233 raises the nozzle formation away from the turbine blade surface to facilitate vortex detachment. The fins 234 in this type of aerodynamic device form a quasi-closed nozzle formation.

[0090] In a second variant, as shown in FIG. 13, the top wall 231 is more flexible than the bottom wall 232, so that the nozzle opening is raised and enlarged upon inflation.

[0091] In a third variant, as shown in FIG. 14, a longitudinal inflatable segment 235 joins two halves of the aerodynamic device. This segment 235 can be inflated or deflated to widen or narrow the nozzle opening of this aerodynamic device.

[0092] Having described four structural embodiments of aerodynamic devices capable of being adjusted to different vibration amplitudes and frequencies, it will be appreciated that other shapes and configurations can be designed and used to obtain the desired results as described hereinbelow. However, before describing the advantages and benefits of adjustable aerodynamic devices, the following is a description of an energy supply system for remotely adjusting the shape of a series of aerodynamic devices along a turbine blade.

[0093] Although energy is readily available in the nacelle of a wind turbine, the following system is also proposed. The proposed energy system 250, as illustrated in FIG. 15 A, comprises a common gravity-operated air pump 251, a pressure accumulator 252, a pressure regulator 253, and a hose system 254 connected to a series of aerodynamic devices 200 for inflating or deflating these generators. Pressure regulator 253 is configured to receive and transmit data to and from the vibration sensor 201 or from the controller 210. Inflation of the aerodynamic devices 200 can be done on demand to modify their shape. Other methods can be designed to modify the vibration signatures of elastic aerodynamic devices to obtain the desired result. The hose system 254 may be routed inside the blade or may be made in a tape-like hose mounted on the outside of the blade. The illustration in FIG. 15A is simply one example to demonstrate the feasibility of remote adjustment.

[0094] Another proposed energy system 260, as illustrated in FIG. 15B, acts as a current-operated actuator device 261 and comprises metal plates 262, a piezoelectric material 263 between the metal plates 262, a power supply 264 in a form of a dedicated battery system (or an interface to the battery 203), and a microprocessor-based 211 controller 210 with a wireless communication module 212 as part of any of the aerodynamic devices 200 with adjustable element 206, for adjusting the shape or position of the adjustable element, thereby retracting or expanding the surfaces of aerodynamic devices. Thanks to the controller, the power supply 264 is configured to receive and transmit current to and from the metal plates 262 converting electrical signal into mechanical motion. By applying a voltage to the actuator 261, a strain is induced in the piezoelectric material 263 by the piezoelectric effect, and this strain bends the actuator 261, which in turn causes the adjustable element 206 of the aerodynamic device, for example the fins, to retract or expand. Other methods can be designed to modify the vibration signatures of elastic aerodynamic devices to obtain the desired result. Wires may be routed inside the blade or may be mounted on the outside of the blade to supply voltage to the actuator 261. The illustration in FIG. 15B is simply one example to demonstrate the feasibility of remote adjustment.

[0095] For example, the adjustment of the aerodynamic devices can be done mechanically, by cables and pulleys, by miniature mechanisms, thermally or by bi-metallic materials, shape memory alloys, magneto strictive materials, and other smart materials. Therefore, the present invention is not limited to pneumatics and piezoelectricity.

[0096] Referring now to FIGS. 16-18, the advantages and benefits of adjustable aerodynamic devices will be described. A curve 121 represents the natural frequency of the turbine blade 110. This curve has four nodes 123 and amplitudes between the nodes. A sinusoidal curve is shown for convenience. The natural frequency curve may be more complex than the one illustrated. The curve may have several periods, a single period or part of a period, and non-symmetrical amplitudes. Curve 121 is presented herein to facilitate the description of the method according to the preferred embodiment of the present invention.

[0097] The periods 122 between the nodes 123 constitute vulnerable segments of turbine blade 110. Any vibration induced along these regions 122 with the frequency near or at the natural frequency of the turbine blade has the potential of creating destructive forces. Referring simultaneously to FIGS. 6 and 16, the advantages and benefits of the system and method according to the present invention will be described.

[0098] The first three lines of vortices 124 in FIG. 17 represent the vortices generated by three juxtaposed aerodynamic devices 200 in FIG. 6. Using the preferred method, these aerodynamic devices 200 have been adjusted by position and / or shape so that their phase angle, amplitude, and frequencies can be combined to produce an even force, referred to herein as a monotone force, as illustrated in the fourth line of FIG. 17. When these monotone forces are applied between nodes 123 of the natural frequency curve 121, the impulses produced by vortex detachments along this region 122 cancel adverse effects on the structure of the turbine blade. The system and method according to the preferred embodiment of the present invention provide the instruments and instructions to adjust the effect of aerodynamic devices along sections of or the entire length of a turbine blade so that vibration is substantially reduced. For analogy, the system and method according to the present invention can produce a vibrationreduction effect that is like electric capacitors converting alternating current into direct current, as illustrated in FIG. 18.

[0099] Referring now to FIG. 19, a fifth structural embodiment of an elastic aerodynamic device is illustrated. This aerodynamic device 200 is manufactured using additive manufacturing techniques, such as 3-D printing, to meet specific conditions in a client's wind turbine. The aerodynamic device features several nozzle formations that are aligned and spaced apart by a distance "B". The aerodynamic devices may have varying heights “A” between formations. One nozzle formation is angularly phased backward by a trailing distance "C," while another is angularly phased forward relative to the others. This aerodynamic device, for example, has been 3-D printed for a specific application to reduce vibrations to a monotone force along the central period of the natural frequency of a client's turbine blade. This aerodynamic device demonstrates the versatility of aerodynamic device models that can be produced using the method and system according to the present invention.

[0100] In FIG. 20, another aspect of the present invention is described. Each wind turbine 100 (referred to in the figures as 100 A, 100B) has a nacelle 120 with a gateway device 300 installed therein. These gateway devices 300 are configured to communicate with a remote server and also preferably to communicate data between turbines 100 A, 100B in a wind farm or between different wind farms. Typically, a gateway 300 of each wind turbine 100A, 100B receives vibration data from the aerodynamic devices 200 installed on that particular wind turbine. However, the gateways 300 can be also configured such that in the event of failure of the gateway of a second wind turbine 100B, the gateway of the first wind turbine lOOAis configured to receive vibration data from at least one aerodynamic device 200 of the second wind turbine 100B. This aims to prevent data loss and loss of preventive monitoring and maintenance of the second turbine 100B.

[0101] A change in wind conditions at a distant turbine can be transmitted to a nearby turbine, allowing the nearby turbine to adjust its blades and orientation to benefit from the new conditions in a just-in-time mode, thereby improving efficiency. This adjustment can be performed automatically by the respective gateway device or by wind farm management. Thus, the possibility of damage from a strong gust of wind or a hurricane, for example, can be communicated quickly from one wind turbine to others in a wind farm to initiate a precautionary shutdown. While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications, and other applications of the invention may be made. Therefore, the claimed invention as recited in the claims that follow is not limited to the embodiments described herein.

Claims

CLAIMS1. An aerodynamic device (200) for mounting on an aerodynamic structure (110) to generate a vortex during rotation of the aerodynamic structure (110), the aerodynamic device (200) comprising: a vibration sensor (201) for monitoring vibration characteristics of the aerodynamic structure (110) to generate vibration data; a battery (203); a solar panel (202) for charging the battery (203); and a controller (210) powered by the battery (203) and comprising a microprocessor (211) for collecting vibration data and a communication module (212) connected to an antenna (205) for transmitting the vibration data.

2. The device according to claim 1, having a body of which at least a portion (220, 223, 225) is elastic.

3. The device according to claim 2, wherein the surface of the elastic body portions (220, 223, 225) is covered by a piezoelectric transducer (204) for charging the battery (203).

4. The device according to any of claims 2 to 3, further comprising an energy system (250) to adjust the shape of the body of the device to reduce vibration in the aerodynamic structure (110) by altering the vortex detachment characteristics.

5. The device according to any of claims 2 to 4, further comprising a pneumatic system (251 - 254) located in the aerodynamic structure (110) for inflating or deflating the adjustable aerodynamic devices (200) to modify their shape.

6. The device according to any of previous claims, further comprising at least one adjustable element (206) coupled with a current-operated actuator device (261) with metal plates (262) coupled with a piezoelectric material (263) and a power supply (264), the actuator device (261) being operated by the controller (210) for adjusting the shape or position of the adjustable element (206).

7. The device according to any of the previous claims, wherein the controller (210) is mounted on a printed circuit board located in a recess (226) at the bottom of the base plate (224) of the aerodynamic device (200).

8. The device according to any of the previous claims, wherein the solar panel (202) is located on the top side of the base plate (224) of the aerodynamic device (200).

9. The device according to any of the previous claims, comprising a flexible base plate (220), which is adjustable between the extended position in which the flexible base (220) is bent upwards and the fins (222) are flared out, and the retracted position in which the flexible base plate (220) is parallel to the aerodynamic structure (110) surface.

10. The device according to any of the previous claims, comprising a flexible base plate, in the form of an accordion-like segment (223) extendable along its longitudinal axis, between the widened position in which the fins (222) are located further from each other and the narrowed position in which the fins (222) are located closer to each other.

11. The device according to any of the previous claims, comprising a first fin (225) having a greater mass than a second fin (222), wherein the first fin (225) is configured to bend outward under the effect of the centrifugal force, thereby forming a gap between the bottom of the first fin (225) and the base plate.

12. The device according to any of the previous claims, comprising a bottom wall (232) and a top wall (231) on which the fins (222) are located and an inlet (233) for introducing pressure between the walls (231, 232).

13. The device according to any of the previous claims, further comprising one or more supplementary sensors (207), wherein the controller (210) is further configured to collect and transmit the supplementary data measured by the one or more supplementary sensors (207).

14. The device according to any of the previous claims, wherein the controller (210) is configured to receive vibration data from another aerodynamic device and forward the received vibration data by means of the communication module (212).

15. An aerodynamic structure monitoring system comprising at least one aerodynamic device (200) according to any of the previous claims and a gateway device (300) configured to collect vibration data from the at least one aerodynamic device (200).

16. The aerodynamic structure monitoring system according to claim 15, wherein the gateway (300) of a first wind turbine (100 A) is configured to, in the event of failure of the gateway (300) of a second wind turbine (100B), receive vibration data from at least one aerodynamic device (200) of the second wind turbine (100B).

17. A wind turbine (100) comprising the aerodynamic structure monitoring system according to any of claims 15-16, with at least one aerodynamic device (200) mounted on at least one blade (110) of the wind turbine (100) and the gateway device (300) mounted within a nacelle (120) of the wind turbine (100).

18. A method for preventive maintenance of an aerodynamic structure (100), comprising the steps of: installing the aerodynamic structure monitoring system of any of claims 15-16 on the aerodynamic structure (100); monitoring the vibration characteristics of the aerodynamic structure (100); and- transmitting vibration data from the gateway (300) to a remote server (400).

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