Online measurement method and apparatus for opening degree of moving blade of fan

Abstract

An online measurement method for the opening degree of moving blades of a fan, which is applied to power station axial-flow fans with adjustable moving blades, and relates to a sensor arrangement solution for online monitoring of the opening degree of blades of power station fans and a test method thereof. On the basis of a blade tip timing method, by arranging blade tip sensors at specific positions corresponding to a housing in a sweeping area of an impeller of a power station fan, and arranging key phase transducers (1) at specific positions of a main shaft of the fan, the method measures signals of different positions of blade tips of fan blades passing through the blade tip sensors, calculates phase information of different axial positions of the fan blades relative to a key phase zero point (5), and obtains pitch angle information of the actual opening degree of the fan blades by means of conversion. The pitch angle information can be used for diagnosing asynchronous opening degree faults of blades of power station fans, thereby solving the problem that it is difficult to monitor the actual opening degree of blades of axial-flow fans with adjustable moving blades. The method involves simple principle, is easy to apply, and has a good application prospect. Also disclosed is an online measurement apparatus for the opening degree of moving blades of a fan.

Description

A method and device for online measurement of the opening degree of wind turbine blades

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510036124.3, filed on January 9, 2025, entitled "A Method and Device for Online Measurement of Moving Blade Opening of Wind Turbine Blades", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of online monitoring of power plant wind turbines, specifically relating to an online measurement method and device for the opening degree of wind turbine blades. Background Technology

[0004] The adjustable-blade axial flow fan is an important type of ventilation equipment. Its key feature is that the blade angle can be changed by adjusting the rotation position of the blades, thus achieving precise control over airflow and pressure. The working principle of the adjustable-blade axial flow fan is relatively complex but highly efficient. When airflow enters the fan from the system duct, it first changes direction through the air box, then flows through the collector to converge and accelerate before flowing to the impeller. The motor provides power to the impeller, enabling it to perform work on the airflow. The blade working angle and blade pitch are steplessly adjustable, allowing for changes in airflow and pressure according to varying operating conditions. After passing through the impeller, the airflow rotates, then flows axially into the diffuser after passing through the rear guide vanes. Inside the diffuser, some of the gas's kinetic energy is converted into static pressure energy, before flowing back to the system to meet operational requirements, thus completing the fan's output process.

[0005] Due to their advantages such as small size, light weight, high efficiency in low-load areas, wide adjustment range, and fast response speed, axial flow fans with adjustable blades have significant economic advantages compared to centrifugal fans and static blade fans. Therefore, they are widely used to replace old-fashioned centrifugal fans in energy-saving technology renovation projects of coal-fired power plants in China.

[0006] The blade adjustment mechanism of a variable-blade axial flow fan is relatively complex. It typically uses a hydraulic cylinder and an actuating disc to drive a slider on a crank at the root of the blade, causing the crank to swing and the blades to rotate around an adjustment shaft, thus changing the blade opening. In actual operation, under the influence of corrosive exhaust gases, alternating vibration loads, and centrifugal loads, variable-blade axial flow fans are prone to mechanical failures such as crank deformation, and corrosion or wear of the slider or actuating disc after a period of operation. This can lead to asynchronous blade openings or deviations between the actual and controlled blade openings during adjustment, affecting fan efficiency and increasing fan vibration.

[0007] Existing axial flow fans with adjustable blades mainly rely on control system feedback values ​​such as the actuation stroke of the actuator or the pumping volume of hydraulic oil to monitor the blade opening. When the end of the actuator, such as the slider, actuator plate, or crank, malfunctions, the control system cannot accurately reflect the actual blade opening. Therefore, it is necessary to set up an online blade opening measurement system independent of the control system.

[0008] Currently, some studies use pressure sensors to attempt to indirectly measure the blade opening of a wind turbine from the flow field characteristics at the impeller outlet, and to diagnose problems such as signal opening asynchrony. This technical approach is difficult to calibrate, easily affected by other flow field factors, and cannot accurately monitor the blade opening; it can only monitor more severe blade opening asynchrony faults. Summary of the Invention

[0009] The purpose of this application is to provide an online measurement method and device for the blade opening of a wind turbine. This application is applied to a power plant blade-adjustable axial flow fan. It can measure the actual opening of each blade of the fan during operation and is used to diagnose faults such as asynchronous blade adjustment and inadequate blade adjustment that occur during the operation of the blade-adjustable axial flow fan.

[0010] To achieve the above objectives, this application adopts the following technical solution:

[0011] This application provides an online measurement device for the moving blade opening degree of a wind turbine blade, including a key phase sensor, an opening degree sensor, a shaft sensor, and a key phase measuring point;

[0012] The key phase sensor is installed in a non-contact manner at the fan coupling or motor output shaft, acquiring a key phase signal once per rotation. The opening sensor and shaft sensor are installed on the casing through openings in the casing. The arrangement of the key phase measuring points ensures that the starting point of the key phase calculation is located within the angle range formed by the leading edge of the blade and the opening adjustment rotation axis of the previous blade when the blade opening is at its minimum.

[0013] An optional improvement in this application is that the key phase sensor and the opening sensor are arranged in phase.

[0014] An optional improvement in this application is that the bond phase is obtained by a photoelectric sensor in conjunction with reflective paper.

[0015] An optional improvement in this application is that the bond phase is obtained by using an eddy current sensor in conjunction with a keyway.

[0016] An optional improvement in this application is that the opening sensor is a blade tip sensor used to record the blade tip passing signal. The sensor type is a fiber optic sensor or an eddy current sensor, which is installed radially on the casing in the blade rotation plane. The center line of the sensor is located in front of or behind the blade opening adjustment rotation axis along the axial position of the fan shaft. If the space allows for the sensor arrangement, it should be arranged in front of the blade opening adjustment rotation axis.

[0017] An optional improvement in this application is that the shaft sensor is a blade tip sensor used to record the blade tip passing signal. The sensor type is a fiber optic sensor or an eddy current sensor, which is installed radially on the casing in the blade rotation plane. The center line of the sensor is at the same axial position along the fan shaft as the axial position of the blade opening adjustment rotation shaft.

[0018] An optional improvement in this application is that the key phase sensor, in conjunction with the key phase measuring point, is used to measure the rotational speed of the fan rotor and to provide key phase information during rotor operation.

[0019] This application also provides a method for online measurement of the moving blade opening of a wind turbine blade, the method using the above-mentioned online measurement device for the moving blade opening of a wind turbine blade, including:

[0020] Step 1: Count the blade tip transmission signals of the blade opening sensor and the blade tip transmission signals of the shaft sensor respectively, and determine whether the blade opening is within the monitoring range by comparing the difference in counts;

[0021] Step 2: When the blade opening is within the monitoring range, record the opening sensor phase data and shaft sensor phase data for each blade in each cycle, and record continuously for 16 full cycles.

[0022] Step 3: Calculate the average phase of the blade opening sensor and the average phase of the shaft sensor within 16 whole cycles, and calculate the difference for each blade separately;

[0023] Step 4: Compare and interpolate the phase difference of the blades with the phase difference and blade opening calibration data under normal operating conditions to obtain the actual opening of each blade.

[0024] An optional improvement in this application is that the phase difference and blade opening calibration data under normal operating conditions are obtained by the following method:

[0025] After installing the sensors and key phase measurement points as required, with the wind turbine blade adjustment mechanism functioning normally, adjust the wind turbine blades to different opening degrees and run at low speeds. Measure the phase difference between the opening degree sensor and the shaft sensor under different blade opening conditions to establish the correspondence between the wind turbine blade opening degree and the phase difference measured by the sensor.

[0026] An optional improvement of this application is that the method identifies the actual opening of the wind turbine blade by measuring the phase difference between the blade tip signal monitored by the opening sensor and the blade tip signal monitored by the shaft sensor.

[0027] Compared with the prior art, this application has at least the following beneficial technical effects:

[0028] The online measurement method and apparatus for wind turbine blade moving blade opening provided in this application directly measures the passing phase of the wind turbine blade tip by arranging two blade tip sensors along the axial direction in the blade rotation area, and calculates the wind turbine blade angle through the phase difference. Compared with methods that diagnose blade opening based on aerodynamic data, the direct measurement method of this application has higher fault diagnosis accuracy and can locate the fault to a specific blade, exhibiting higher stability. Furthermore, this application can pinpoint the fault point to a specific blade when diagnosing asynchronous moving blade opening faults. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 is an overall schematic diagram of an implementation example of this application.

[0031] Figure 2 is a schematic diagram of the blade tip sensor arrangement in an embodiment of this application.

[0032] Figure 3 is a schematic diagram of the sensor arrangement phase in an embodiment of this application.

[0033] Figure 4 shows the relationship between blade opening and the blade tip sensor signal.

[0034] Figure 5 is a flowchart of the blade opening conversion algorithm of this application.

[0035] Explanation of reference numerals in the attached diagram: 1. Key phase sensor; 2. Opening sensor; 3. Rotation shaft sensor; 4. Rotation shaft for blade opening adjustment; 5. Key phase measuring point; 6. Key phase calculation starting point; 7. Arrangement range of key phase calculation starting point. Detailed Implementation

[0036] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0037] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0039] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0040] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0041] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0042] The accompanying drawings illustrate various structural schematics according to embodiments disclosed in this application. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0043] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0044] Example 1

[0045] As shown in Figures 1 to 3, the online measurement device for the moving blade opening of the wind turbine blade provided in this embodiment includes a key phase sensor 1, an opening sensor 2, a shaft sensor 3, and a key phase measuring point 5. The key phase sensor 1 is installed in a non-contact manner at the wind turbine coupling or the motor output shaft, and acquires a key phase signal once per rotation. The opening sensor 2 and the shaft sensor 3 are installed on the casing through openings in the casing. The arrangement of the key phase measuring point 5 ensures that the key phase calculation starting point 6 is located within the angle range 7 formed by the leading edge of the blade and the opening adjustment rotation shaft 4 of the previous blade when the blade opening is at its minimum.

[0046] In this embodiment, as shown in Figure 3, the key phase sensor 1 and the opening sensor 2 are arranged in phase. The arrangement of the key phase measurement point 5 should ensure that the position of the key phase calculation starting point 6 is within the angle range 7 formed by the leading edge of the blade and the previous blade opening adjustment rotation axis 4 when the blade opening is at its minimum. This prevents the blade tip signal from exceeding the phase range during blade opening adjustment, thus avoiding blade coding errors. When the key phase sensor 1 and the opening sensor 2 are arranged in phase, their temporal consistency can be ensured, thereby avoiding confusion caused by phase difference during data processing. By setting the position of the key phase calculation starting point 6 within the angle range 7 formed by the leading edge of the blade and the previous blade opening adjustment rotation axis 4 when the blade opening is at its minimum, it can be ensured that the blade tip signal is always within the expected phase range during blade opening adjustment.

[0047] In this embodiment, the bond phase can be obtained using a photoelectric sensor with reflective paper or an eddy current sensor with a keyway. When using a photoelectric sensor with reflective paper to obtain the bond phase, reflective paper is attached to the rotating component as a marker. As the component rotates, the photoelectric sensor detects the position of the reflective paper by receiving and reflecting light. Each time the sensor passes the reflective paper, a pulse signal is triggered. This method is convenient for phase measurement and improves work efficiency. The photoelectric sensor is highly adaptable to the environment and can operate in various conditions.

[0048] When using an eddy current sensor with a keyway to acquire the key phase, a keyway is machined into the rotating component as a marker. The eddy current sensor generates a pulse signal by measuring the change in distance between the probe and the surface of the rotor being measured. When the rotating component rotates to the keyway position, the distance between the probe and the measured surface changes, thus triggering the pulse signal. This method provides stable and reliable keyway marking, is not easily affected by the environment, and the eddy current sensor exhibits high measurement accuracy and sensitivity.

[0049] The key phase sensor 1, in conjunction with the key phase measuring point 5, is used to measure the rotational speed of the fan rotor and provide key phase information during rotor operation.

[0050] In this embodiment, the opening sensor 2 is a blade tip sensor used to record the blade tip passing signal. The sensor type is an eddy current sensor, which is installed radially on the casing in the blade rotation plane. The center line of the sensor is located in front of the blade opening adjustment rotation axis along the axial position of the fan shaft. The axial distance of the sensor axis is slightly greater than 3 times the diameter of the eddy current sensor to ensure that the eddy current sensor obtains the largest possible blade opening measurement range under the condition that there is no mutual interference.

[0051] One type of sensor is the blade tip sensor, used to detect the gap between the tip of an impeller or blade and surrounding structures (such as a casing or inner wall) in rotating machinery. Eddy current sensors, also known as eddy current measurement sensors, are sensors that utilize the principle of eddy currents for measurement and detection. Their working principle is based on Faraday's law of electromagnetic induction and Lenz's law. When a bulk metal conductor is placed in a changing magnetic field or moves within a magnetic field cutting magnetic lines of force, an induced current in the form of eddy currents is generated within the conductor. This current is called an eddy current, and the phenomenon is known as the eddy current effect. Eddy current sensors use the reverse magnetic field generated by these eddy currents to measure the relative position of the measured metal conductor and the probe end face.

[0052] In this embodiment, the shaft sensor 3 is a blade tip sensor used to record the blade tip passing signal. The sensor type is an eddy current sensor, radially mounted on a casing within the blade's rotation plane. The sensor's centerline is aligned with the axial position of the blade opening adjustment rotation axis along the fan shaft, ensuring that the blade tip phase angles monitored by the shaft sensor are essentially consistent during blade opening adjustment. As shown in Figures 2 and 4, in this embodiment, the opening sensor 2 and the shaft sensor 3 are arranged with the same phase angle. The opening sensor 2 receives the blade passing signal first, and the shaft sensor 3 receives the blade passing signal later.

[0053] Example 2

[0054] As shown in Figure 5, the online measurement method for the moving blade opening of the wind turbine blades provided in this embodiment includes:

[0055] Step 1: Count the blade tip transmission signals of the blade opening sensor and the blade tip transmission signals of the shaft sensor respectively, and determine whether the blade opening is within the monitoring range by comparing the difference in counts;

[0056] Step 2: When the blade opening is within the monitoring range, record the opening sensor phase data and shaft sensor phase data for each blade in each cycle, and record continuously for 16 full cycles.

[0057] Step 3: Calculate the average phase of the blade opening sensor and the average phase of the shaft sensor within 16 whole cycles, and calculate the difference for each blade separately;

[0058] Step 4: Compare and interpolate the phase difference of the blades with the phase difference and blade opening calibration data under normal operating conditions to obtain the actual opening of each blade.

[0059] Example 3

[0060] As shown in Figure 5, the online measurement method for the moving blade opening of the wind turbine blades provided in this embodiment includes:

[0061] Step 1: Count the blade tip transmission signals of the blade opening sensor and the blade tip transmission signals of the shaft sensor respectively, and determine whether the blade opening is within the monitoring range by comparing the difference in counts;

[0062] Step 2: When the blade opening is within the monitoring range, record the opening sensor phase data and shaft sensor phase data for each blade in each cycle, and record continuously for 16 full cycles.

[0063] Step 3: Calculate the average phase of the blade opening sensor and the average phase of the shaft sensor within 16 whole cycles, and calculate the difference for each blade separately;

[0064] Step 4: Compare and calculate the actual blade opening O by comparing the phase difference of the blades with the phase difference ΔΦ under normal operating conditions and the blade opening O calibration data ΔΦ0, as shown in the following formula. r .

[0065] In this embodiment, the phase difference and blade opening calibration data under normal operating conditions involved in step 4 of the blade opening conversion algorithm of this application are obtained as follows:

[0066] After installing the sensors and key phase measurement points as required, with the wind turbine blade adjustment mechanism functioning normally, adjust the wind turbine blades to different opening degrees O and run at low speed. Measure the phase difference ΔΦ0 between the opening degree sensor and the shaft sensor at different blade opening degrees to establish the correspondence between the wind turbine blade opening percentage and the sensor measurement phase difference.

[0067] In this embodiment, as shown in Figure 4, the blade opening conversion algorithm identifies the actual opening of the blade by the phase difference change between the blade tip signal monitored by the opening sensor 2 and the blade tip signal monitored by the shaft sensor 3.

[0068] The foregoing has shown and described the basic principles, main features, and advantages of this application. It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or basic characteristics of this application. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this application. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0069] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of this application and should not be used to limit the scope of protection of this application. Any modifications made to the technical solutions based on the technical concept proposed in this application fall within the scope of protection of the claims of this application.

Claims

1. An online measuring device for the opening degree of a wind turbine blade, characterized in that, It includes a key phase sensor (1), an opening sensor (2), a shaft sensor (3), and a key phase measuring point (5); The key phase sensor (1) is installed in a non-contact manner at the fan coupling or motor output shaft, and acquires a key phase signal once per rotation. The opening sensor (2) and the shaft sensor (3) are installed on the casing through the casing opening. The arrangement of the key phase measuring points (5) ensures that the key phase calculation starting point (6) is located within the angle range (7) formed by the blade leading edge and the previous blade opening adjustment rotation shaft (4) when the blade opening is at its minimum.

2. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The key phase sensor (1) and the opening sensor (2) are arranged in phase.

3. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The bond phase is obtained using a photoelectric sensor in conjunction with reflective paper.

4. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The key phase is obtained using an eddy current sensor in conjunction with a keyway.

5. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The opening sensor (2) is a blade tip sensor used to record the blade tip passing signal. The sensor type is fiber optic sensor or eddy current sensor. It is installed radially on the casing in the blade rotation plane. The center line of the sensor is located in front of or behind the blade opening adjustment rotation shaft along the axial position of the fan shaft. If the space allows, it should be arranged in front of the blade opening adjustment rotation shaft.

6. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The rotating shaft sensor (3) is a blade tip sensor used to record the blade tip passing signal. The sensor type is a fiber optic sensor or an eddy current sensor. It is installed radially on the casing in the blade rotation plane. The center line of the sensor is in the same axial position along the fan shaft as the axial position of the blade opening adjustment rotating shaft.

7. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The key phase sensor (1) is used in conjunction with the key phase measuring point (5) to measure the rotational speed of the fan rotor and provide key phase information during the rotor operation.

8. A method for online measurement of the opening degree of a wind turbine blade, characterized in that, The method uses the online measurement device for the moving blade opening of the wind turbine blade as described in any one of claims 1 to 7, comprising: Step 1: Count the blade tip transmission signals of the blade opening sensor and the blade tip transmission signals of the shaft sensor respectively, and determine whether the blade opening is within the monitoring range by comparing the difference in counts; Step 2: When the blade opening is within the monitoring range, record the opening sensor phase data and shaft sensor phase data for each blade in each cycle, and record continuously for 16 full cycles. Step 3: Calculate the average phase of the blade opening sensor and the average phase of the shaft sensor within 16 whole cycles, and calculate the difference for each blade separately; Step 4: Compare and interpolate the phase difference of the blades with the phase difference and blade opening calibration data under normal operating conditions to obtain the actual opening of each blade.

9. The online measurement method for the moving blade opening of a wind turbine blade according to claim 8, characterized in that, The method for obtaining phase difference and blade opening calibration data under normal operating conditions is as follows: After installing the sensors and key phase measurement points as required, with the wind turbine blade adjustment mechanism functioning normally, adjust the wind turbine blades to different opening degrees and run at low speeds. Measure the phase difference between the opening degree sensor and the shaft sensor under different blade opening conditions to establish the correspondence between the wind turbine blade opening degree and the phase difference measured by the sensor.

10. The online measurement method for the moving blade opening of a wind turbine blade according to claim 8, characterized in that, This method identifies the actual opening of the wind turbine blade by measuring the phase difference between the blade tip signal monitored by the opening sensor (2) and the blade tip signal monitored by the shaft sensor (3).

Images