JP2020079746A - Erosion detection system and method of hydraulic machine - Google Patents

Abstract

To provide an erosion detection system of a hydraulic machine capable of precisely detecting erosion that can occur in a runner of the hydraulic machine.SOLUTION: An erosion detection system 20 of a hydraulic machine according to an embodiment includes: at least two AE sensors 21 that are provided in a runner 5 and detects shock waves generated following erosion of the runner 5; and a data processor 22 for locating an occurrence position of erosion in the runner 5 based on a propagation time difference of shock waves detected by at least the two AE sensors 21.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to fluid machine erosion detection systems and methods.

  For example, in a runner of a fluid machine such as a Francis turbine, erosion may occur due to a shock wave accompanying the collapse of cavitation in running water or collision of sediment in running water. When such erosion progresses, the fluid performance and strength of the runner may deteriorate, and normal operation may be hindered. Therefore, in such a fluid machine, work for repairing erosion may be performed.

  Repair work for erosion involves a long-term operation outage, so it is desirable to carry out systematically after grasping the extent of erosion. In connection with such demands, many techniques related to cavitation detection and runner erosion detection have been proposed.

Japanese Patent No. 4812100 Japanese Patent No. 4580601

  By the way, there is already known a technique of detecting a cavitation occurrence position and the number of occurrences of cavitation in a fluid machine and identifying a portion on the runner where erosion is likely to occur based on the information. In this technique, the position where cavitation occurs can be accurately determined by comparing the feature amount of the cavitation detection signal with the information stored in the database.

  However, since the state of erosion on the runner is not directly estimated, there is room for improvement regarding the detection of the erosion occurrence position or its size.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an erosion detection system and method for a fluid machine that can detect erosion that may occur in a runner of the fluid machine with high accuracy.

  An erosion detection system for a fluid machine according to one embodiment is provided in a runner of the fluid machine, and at least two AE sensors for detecting a shock wave generated due to erosion of the runner, and at least two AE sensors. A data processing device that specifies the position where erosion occurs in the runner based on the propagation time difference of the shock wave detected by.

  An erosion detection system for a fluid machine according to an embodiment is provided in a runner of the fluid machine, and detects at least one AE sensor for detecting a shock wave generated due to erosion of the runner, and the AE sensor. A data processing device that specifies the size of erosion in the runner based on the size of the shock wave.

  A method for detecting erosion of a fluid machine according to an embodiment includes a step of detecting a shock wave generated by the erosion of the runner by at least two AE sensors provided in a runner of the fluid machine, and at least two. Locating the erosion occurrence position in the runner based on the propagation time difference of the shock wave detected by the AE sensor.

  A method for detecting erosion of a fluid machine according to one embodiment, a step of detecting a shock wave generated by erosion of the runner by at least one AE sensor provided in a runner of the fluid machine, and the AE sensor. Determining the magnitude of erosion in the runner based on the magnitude of the shock wave detected by.

  According to the present invention, erosion that can occur in a runner of a fluid machine can be detected with high accuracy.

FIG. 1 is a diagram showing a erosion detection system for a fluid machine according to an embodiment and a Francis turbine as a fluid machine to which the system is applied. It is a block diagram which shows the system configuration of the erosion detection system of the fluid machine which concerns on one Embodiment. It is a figure which shows the installation position of the AE sensor which comprises the erosion detection system of the fluid machine which concerns on one Embodiment.

  Hereinafter, one embodiment will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing an erosion detection system 20 for a fluid machine and a Francis turbine 1 to which the system is applied according to an embodiment. In addition, although the Francis type turbine 1 is illustrated and demonstrated as an example of the fluid machine to which the erosion detection system 20 is applied here, the fluid machine is not limited to the turbine.

  First, the configuration of the Francis turbine 1 will be described with reference to FIG. In the Francis turbine 1 shown in FIG. 1, when the turbine is in operation, the water flow from the casing 2 flows into the runner 5, which is the rotating part, via the stay vanes 3 and the guide vanes 4, and the runner 5 rotates due to the pressure of the inflow water. Rotate around the axis C1.

  The runner 5 includes a plurality of runner blades 6 arranged side by side in the circumferential direction, a crown 7 that is an annular member that fixes the plurality of runner blades 6 from one side in the blade height direction, and a fixed from the other side. And a band 8 which is an annular member. The runner 5 is connected to the main shaft portion 9 via the crown 7, and the main shaft portion 9 rotates integrally with the runner 5.

  Hereinafter, the erosion detection system 20 will be described with reference to FIGS. 1 to 3.

  As shown in FIGS. 1 and 2, the erosion detection system 20 according to the present embodiment includes rotation-side data including a plurality of AE sensors 21, a data processing device 22, and a data transfer device 23, which are provided on the rotation unit side. A processing unit 20A and a stationary side data processing unit 20B having a data receiving device 24 and an integrating device 25, which are provided on the stationary part outside the turbine, are provided.

  In the rotation-side data processing unit 20A, the plurality of AE sensors 21 and the data processing device 22 are provided in the runner 5, the AE sensor 21 detects a shock wave generated due to the erosion of the runner 5, and the data processing device 22 uses the AE. Based on the information of the shock wave detected by the sensor 21, the erosion occurrence position and the size of the erosion in the runner 5 are specified. The data transfer device 23 is provided on the main shaft unit 9 and transfers information on the erosion occurrence position and the erosion size specified by the data processing device 22. In the stationary data processing unit 20B, the data receiving device 24 receives the information from the data transfer device 23, and the accumulating device 25 accumulates the received information.

  In the Francis type water turbine 1, erosion may occur especially in the runner blades 6 of the runner 5 due to a shock wave generated by the collapse of cavitation generated inside thereof or a collision of hard foreign matter such as earth and sand contained in running water. The AE (Acoustic Emission) sensor 21 is provided to detect a shock wave (AE wave) generated due to the erosion generated on the runner blade 6.

  In the present embodiment, four AE sensors 21 are provided corresponding to each runner blade 6, and the four AE sensors 21 are arranged at positions separated from each other. Thus, the shock wave associated with erosion in one runner blade 6 is detected by the four AE sensors 21, and the data processing device 22 identifies the erosion occurrence position and the size of erosion in each runner blade 6. It is like this.

  The installation position of the AE sensor 21 will be described in detail with reference to FIG.

  The four AE sensors 21 provided corresponding to one runner blade 6 include front edge side and rear edge side in the vicinity of the connection portion of the crown 7 with the runner blade 6, and the vicinity of the connection portion of the band 8 with the runner blade 6. Are arranged on the leading edge side and the trailing edge side. The leading edge side of the runner blades 6 means here the upstream side in the direction of the water flow during turbine operation, and the trailing edge side means the downstream side.

  On the front edge side and the trailing edge side in the vicinity of the connection portion of the crown 7 with the runner blade 6, a bottomed sensor installation hole that is recessed from the surface of the crown 7 opposite to the runner blade 6 side toward the runner blade 6 side. 7A is provided, and the AE sensor 21 is provided in each sensor installation hole 7A. The detection surface of the AE sensor 21 is in contact with the bottom surface of the sensor installation hole 7A and faces the runner blade 6 side.

  Further, on the front edge side and the trailing edge side in the vicinity of the connection portion of the band 8 with the runner blade 6, the bottomed sensor is recessed from the surface on the side opposite to the runner blade 6 side of the band 8 toward the runner blade 6 side. The installation hole 8A is provided, and the AE sensor 21 is provided in each sensor installation hole 8A. The detection surface of the AE sensor 21 is in contact with the bottom surface of the sensor installation hole 8A and faces the runner blade 6 side.

  A sensor cable 26 for electrical connection with the data processing device 22 is connected to each AE sensor 21. Among these, the sensor cable 26 of the AE sensor 21 on the trailing edge side of the crown 7 extends out from the sensor installation hole 7A on the trailing edge side of the crown 7 and is connected to the data processing device 22.

  On the other hand, the sensor cables 26 of the AE sensor 21 on the front edge side of the crown 7, the front edge side of the band 8 and the rear edge side of the band 8 are passed through a tunnel-shaped cable passage 27 provided inside the runner 5 and then on the rear edge side of the crown 7. To the sensor installation hole 7A, and then extends outside from the sensor installation hole 7A to be connected to the data processing device 22.

  The sensor cable 26 transmits the shock wave signal detected by the AE sensor 21 to the data processing device 22, but the AE sensor 21 may wirelessly transmit the signal to the data processing device 22. The cable passage 27 is configured by connecting a plurality of passage elements 28 extending linearly or curvedly, and the cable passage 27 in the present embodiment has five passage elements 28A to 28E.

  Specifically, of the five passage elements 28A to 28E, the passage element 28A is provided in the band 8, one end of which is connected to the sensor installation hole 8A on the front edge side of the band 8 and extends to the rear edge side. The passage element 28B is provided on the band 8 and has one end connected to the sensor installation hole 8A on the trailing edge side of the band 8 and extends to the leading edge side. The passage element 28C is provided on the runner blade 6, has one end connected to the other end of the passage element 28A and the other end of the passage element 28B, and extends from the band 8 to the crown 7.

  The passage element 28D is provided in the crown 7, one end thereof is connected to the sensor installation hole 7A on the front edge side of the crown 7 and extends toward the trailing edge side, and the other end thereof is connected to the other end of the passage element 28C. The passage element 28E is provided in the crown 7, has one end connected to the other end of the passage element 28C and the other end of the passage element 28D, extends to the trailing edge side, and is connected to the sensor installation hole 7A on the trailing edge side of the crown 7. ..

  One end of the passage element 28C and the other end of the passage element 28A or the other end of the passage element 28B are connected so as to be bent, and the connecting portion 29A is opened from the surface of the band 8 opposite to the runner blade 6 side. There is. On the other hand, the other end of the passage element 28C and the other end of the passage element 28D or one end of the passage element 28E are also connected so as to be bent, and the connecting portion 29B is also opened from the surface of the crown 7 opposite to the runner blade 6 side. is doing.

  The passage element 28C bends and guides the sensor cable 26 passed through the passage element 28A or the passage element 28B into the sensor cable 26. However, as described above, the connection portion 29A is open, so that the sensor cable is released from the open portion. It becomes possible to access to 26, and piping work becomes easy. Similarly, the piping work is facilitated at the connecting portion 29B.

  The open portion of the connection portion 29A and the open portion of the connection portion 29B are covered with the lid 30, and the open portions of the sensor installation hole 7A and the sensor installation hole 8A are also covered with the lid 30. A through hole for passing a plurality of sensor cables 26 is formed in the sensor installation hole 7A on the trailing edge side of the crown 7.

  The installation configuration of the AE sensor 21 provided corresponding to the other runner blades 6 is the same as that described above.

  Returning to FIG. 1 and FIG. 2, the data processing device 22 is provided in the runner 5, and more specifically, is arranged on the inner peripheral side of the crown 7 on the rotation axis C1 and is fixed to the crown 7. Further, the data processing device 22 is close to the end of the main shaft portion 9 on the coupling side with the runner 5, and is located immediately below the main shaft portion 9. However, the installation position of the data processing device 22 is not particularly limited, and the data processing device 22 may be provided on the main shaft portion 9 that rotates integrally with the runner 5, or may rotate other than the main shaft portion 9 that rotates integrally with the runner 5. It may be provided on the body or outside the turbine. More specifically, the data processing device 22 may be provided, for example, inside the main shaft portion 9, or may be provided outside the main shaft portion 9, for example, in the vicinity of the outer peripheral surface, or in the crown 7. It may be embedded inside, or may be embedded inside a rotating body other than the main shaft portion 9 that rotates integrally with the runner 5.

  The signal detected by the AE sensor 21 includes many signals spanning a very wide frequency band (for example, 10 KHz to 1 MHz), and the AE sensor 21 detects a signal corresponding to a shock wave due to collapse of cavitation, for example. You can Here, the shock wave due to the collapse of cavitation and the shock wave generated due to the erosion generated on the runner blade 6 are greatly different in magnitude and frequency. In consideration of this point, the data processing device 22 according to the present embodiment filters the other vibration wave different from the shock wave generated due to the erosion generated on the runner blade 6 with the bandpass filter to obtain the runner blade 6 It is configured to extract only the signal corresponding to the shock wave generated due to the above-mentioned erosion.

  Then, the data processing device 22 according to the present embodiment is based on the difference in the propagation time of the shock wave due to erosion detected by the four AE sensors 21 provided for one runner blade 6, and the destruction of one runner blade 6 is performed. The position where the erosion occurs is specified, and the size of the erosion in the runner blade 6 is specified based on the size of the shock wave due to the erosion detected by each AE sensor 21.

  When erosion occurs in the region 7 on the crown 7 side and the trailing edge side of the runner blade 6 shown in FIG. 3, the shock wave due to the erosion is, for example, the AE sensor 21 on the trailing edge side of the crown 7 and the AE on the leading edge side of the crown 7. The sensor 21, the AE sensor 21 on the trailing edge side of the band 8 and the AE sensor 21 on the trailing edge side of the band 8 are detected in this order, and in this case, a difference occurs in the propagation time of the shock wave propagated to each AE sensor 21. . That is, a difference occurs in the timing at which each AE sensor 21 detects a shock wave, and a propagation time difference occurs between the propagation times from the erosion occurrence position to the shock wave propagating to each AE sensor 21 (see four arrows). ). In the present embodiment, for example, the distance from the region 40 to the AE sensor 21 on the trailing edge side of the crown 7 closest to the region 40 and the other AE sensor 21 depending on the propagation time difference in each AE sensor 21. The position where erosion occurs is specified by calculating the ratio with each distance up to.

  If three AE sensors 21 are arranged in a triangular shape, it is possible to identify the erosion occurrence position in the biaxial directions intersecting each other only with the information on the shock waves from the AE sensor 21. On the other hand, even when only two AE sensors 21 are arranged, if there is other information such as information indicating that cavitation has occurred on either side in the direction intersecting the direction in which the AE sensors 21 are arranged, It is possible to specify the erosion occurrence position in the biaxial directions intersecting with each other.

  Further, in the present embodiment, the erosion occurrence position is specified, the distance from each AE sensor 21 to the erosion occurrence position, and the strength of the shock wave propagated to and detected by each AE sensor 21, that is, the amplitude. From this, the magnitude (pressure) of the shock wave generated at the erosion occurrence position is specified. Here, the data processing device 22 correlates the distance from the AE sensor 21 to the erosion generation position, the strength of the shock wave detected by the AE sensor 21, and the magnitude of the shock wave generated at the erosion generation position. Is stored in the database, and the magnitude of the shock wave generated at the erosion occurrence position is specified using the map.

  Then, in the present embodiment, the magnitude (pressure) of the shock wave at the erosion occurrence position specified as described above is determined by the magnitude of the shock wave and the magnitude of the erosion stored in the database of the data processing device 22. The size of the erosion at the position where the erosion occurs is specified by comparing with the map showing the correlation.

  If the position where erosion occurs can be specified using information other than the information from the AE sensor 21, it is also possible to detect only the intensity of the shock wave with the AE sensor 21 and specify the size of the erosion. Further, in the present embodiment, the size of erosion is specified using the map stored in the database, but the size of erosion may be specified by another method, for example, using a predetermined mathematical formula. A configuration may be adopted that specifies the size of erosion.

  The data processing device 22 in the present embodiment is adapted to generate digital data indicating the erosion occurrence position or the size of the erosion specified as described above and output it to the data transfer device 23. .. The data processing device 22 and the data transfer device 23 are electrically connected by a transmission cable 31, and the transmission cable 31 passes through the rotation axis C1 at the center of the main shaft portion 9. Further, the data transfer device 23 is fixed to the outer peripheral surface of the main shaft portion 9, but its installation position is not particularly limited.

  The data processing device 22 filters the signal detected by the AE sensor 21 with a bandpass filter to extract only the signal corresponding to the shock wave, and then performs AD conversion before determining the erosion occurrence position or the erosion magnitude. Specific processing may be performed to generate these digital data. Alternatively, the data processing device 22 filters the signal detected by the AE sensor 21 with a bandpass filter to extract only the signal corresponding to the shock wave, and then uses the analog signal as it is to determine the erosion occurrence position or destruction. The size of the food may be generated as analog data, and then AD conversion may be performed.

  The data transfer device 23 transfers the erosion occurrence position and the size of the erosion generated by the data processing device 22 as digital data to the data receiving device 24 of the stationary side data processing unit 20B in a non-contact manner. A transfer method of formula may be adopted. The non-contact type transfer may be performed by transmitting and receiving radio waves or by transmitting and receiving light.

  In the stationary data processing unit 20B, the data receiving device 24 outputs the information on the erosion generation position and the erosion size generated by the data processing device 22 as digital data to the integrating device 25. The integrating device 25 sequentially integrates the size of the erosion corresponding to the erosion occurrence position each time the information is received. Here, the stationary data processing unit 20B may be configured to give a warning when the integrated value of erosion becomes equal to or larger than a predetermined threshold value.

  In the erosion detection system 20 according to the present embodiment described above, the plurality of AE sensors 21 provided in the runner 5 detect the shock wave generated due to the erosion of the runner 5, and the plurality of AE sensors 21. On the basis of the propagation time difference of the shock wave detected by, the erosion occurrence position in the runner 5 is specified, and the size of the erosion in the runner 5 is specified.

  As described above, the shock wave due to erosion is directly detected by the AE sensor 21, and the erosion occurrence position and the erosion size are specified based on the shock wave. The size can be detected with high accuracy.

  Further, the data processing device 22 according to the present embodiment is provided in the runner 5, generates digital data indicating the erosion occurrence position or the size of the erosion in the runner 5, sends the digital data to the data transfer device 23, and transfers the data. The device 23 transfers the digital data generated by the data processing device 22 to the data receiving device 24 of the stationary side data processing unit 20B in a contactless manner.

  According to this configuration, the data transfer device 23 transfers the erosion occurrence position or the size of the erosion as digital data to the data receiving device 24 outside the water turbine, so that the information is transmitted from the runner 5 side rotating at high speed to the outside. Can be stably transferred to. That is, when the analog signal is transferred to the outside from the runner 5 side that rotates at high speed, the transfer state may become unstable.

  Further, the runner 5 has a tunnel-shaped cable passage 27 for passing the sensor cable 26 connected to the AE sensor 21, and the cable passage 27 connects a plurality of passage elements 28A to 28E extending linearly or curvedly. It is composed of The connecting portions 29A and 29B of the passage elements 28A to 28E that are connected so as to be bent are open to the outside, and the open portions are covered by the lid 30.

  According to this configuration, the sensor cable 26 can be accessed from the open portions of the connection portions 29A and 29B, which facilitates the piping work of the sensor cable 26.

  Although one embodiment has been described above, the above embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

  In the present embodiment, a plurality of AE sensors 21 are provided around the runner blade 6 to detect erosion that may occur in the runner blade 6. However, based on the information from the AE sensor 21, the running water surface of the crown 7 and the band. Erosion that occurs on the surface of running water 8 may be detected. Further, the number of AE sensors 21 installed is not particularly limited as long as it is possible to specify the erosion occurrence position or the erosion size.

1... Francis type turbine, 2... Casing, 3... Stay vane, 4... Guide vane, 5... Runner, 6... Runner blade, 7... Crown, 7A... Sensor installation hole, 8... Band, 8A... Sensor installation hole, 9... Main shaft part, 20... Erosion detection system, 20A... Rotation side data processing unit, 20B... Stationary side data processing unit, 21... AE sensor, 22... Data processing device, 23... Data transfer device, 24... Data receiving device, 25 ... integrating device, 26... sensor cable, 27... cable passage, 28A-E... passage element, 29A, 29B... connecting portion, 30... lid

Claims (7)

At least two AE sensors provided on a runner of a fluid machine for detecting a shock wave generated due to erosion of the runner;
An erosion detection system for a fluid machine, comprising: a data processing device that identifies an erosion occurrence position in the runner based on a propagation time difference between the shock waves detected by at least two AE sensors. At least one AE sensor provided in a runner of a fluid machine for detecting a shock wave generated due to erosion of the runner;
An erosion detection system for a fluid machine, comprising: a data processing device that specifies the size of erosion in the runner based on the size of the shock wave detected by the AE sensor. The data processing device is provided in any of the runner and a rotating body that rotates integrally with the runner,
The data processing device generates digital data indicating an erosion occurrence position or an erosion size in the runner,
The erosion detection system for a fluid machine according to claim 1 or 2, further comprising a data transfer device that transfers the digital data generated by the data processing device to the outside in a non-contact type or a contact type. The AE sensor is provided corresponding to each of the plurality of runner blades of the runner,
The erosion detection system for a fluid machine according to claim 1, wherein the erosion generation position or the size of erosion is detected in each of the plurality of runner blades. The runner has a tunnel-shaped cable passage for passing a sensor cable connected to the AE sensor,
The cable passage is configured by connecting a plurality of passage elements extending linearly or curvedly,
The erosion detection system for a fluid machine according to any one of claims 1 to 4, wherein at least one of connection portions of the passage elements connected to be bent is open to the outside, and the open portion is covered by a lid. Detecting a shock wave generated by erosion of the runner by at least two AE sensors provided on the runner of the fluid machine;
And a step of identifying an erosion occurrence position in the runner based on a propagation time difference between the shock waves detected by at least two AE sensors. Detecting a shock wave generated by erosion of the runner by at least one AE sensor provided in the runner of the fluid machine;
Erosion detection method for a fluid machine, comprising: determining the size of erosion in the runner based on the size of the shock wave detected by the AE sensor.

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