Friction position identification device and method for rotating machinery

Abstract

This invention relates to a friction position identification device for rotating machinery having a fixed part and a rotating part. The device includes an AE sensor, a shaft vibration sensor, and a friction position identification unit. In the friction position identification unit, when friction occurs in the rotating machinery, the AE phase corresponding to the peak value of the envelope determined based on the time variation of the AE signal detected by the AE sensor, and the shaft vibration phase corresponding to the high point position of the rotating part determined based on the time variation of the shaft vibration signal detected by the shaft vibration sensor, are calculated. The circumferential position of the friction-generating part in the rotating machinery is identified based on the phase difference between these phases.

Description

Technical Field

[0001] This invention relates to a friction position identification device and a friction position identification method for rotating machinery.

[0002] This application claims priority based on Japanese Patent Application No. 2021-065608 filed with the Japan Patent Office on April 8, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] Traditionally, friction detection in rotating machinery has been performed by detecting shaft vibration. Due to thermal deformation of the machine chamber, seals and other components rub against the rotating shaft, and the heat generated by this friction causes thermal bending within the shaft, sometimes resulting in shaft vibration. This friction leads to performance degradation caused by shaft vibration or seal deterioration. Furthermore, shaft vibration can be detected at the stage where friction progresses to the point of thermal bending within the rotor. Therefore, when friction is detected through shaft vibration, measures such as emergency shutdown of the rotating machinery may be necessary, significantly impacting its operation. Thus, early friction detection is desirable.

[0004] As a method for addressing such problems, friction detection technology using AE (Acoustic Emission) sensors capable of detecting AE signals is known. AE sensors are easy to install and, by detecting AE signals based on the contact sound of a rotating body, show promise in detecting friction at an earlier stage compared to conventional methods based on shaft vibration. For example, Patent Document 1 discloses a technique in which multiple AE sensors are arranged circumferentially relative to the axis of rotation, and the location of friction generation in the circumferential direction is identified by processing the AE signals detected by these sensors.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-145712 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In the aforementioned Patent Document 1, multiple AE sensors are required for the rotating machinery, thus increasing the number of AE sensors and consequently raising costs. Furthermore, since the friction in the cross-section where the multiple AE sensors are located is the object of detection, it is difficult to detect friction occurring at axial positions different from that cross-section. Moreover, since friction detection is based on the minute phase difference between the multiple friction-based AE sensors, friction may be difficult to detect due to noise contained in the AE signals.

[0010] At least one embodiment of the present invention was made in view of the above circumstances, and its object is to provide a friction position identification device and friction position identification method for rotating machinery that can identify the circumferential position of friction with a simple structure.

[0011] means for solving technical problems

[0012] To address the aforementioned issues, at least one embodiment of the present invention provides a friction position identification device for rotating machinery that includes a fixed portion and a rotating portion. The friction position identification device comprises:

[0013] At least one AE sensor is provided for detecting the AE signal of the rotating machinery;

[0014] At least one shaft vibration sensor is used to detect the shaft vibration signal of the rotating part; and

[0015] The friction position identification unit is used to identify the circumferential position of the friction-generating part in the rotating machinery based on the difference between the AE phase and the shaft vibration phase when friction is generated in the rotating machinery. The AE phase corresponds to the peak value of the envelope determined based on the time change of the AE signal, and the shaft vibration phase corresponds to the high point position of the rotating part determined based on the time change of the shaft vibration signal.

[0016] To address the aforementioned issues, at least one embodiment of the present invention relates to a friction position identification method for a rotating machine having a fixed part and a rotating part, the friction position identification method comprising the following steps:

[0017] Detect the AE signal of the rotating machinery;

[0018] Detect the shaft vibration signal of the rotating part; and

[0019] When friction occurs in the rotating machinery, the circumferential position of the friction-generating part in the rotating machinery is identified based on the difference between the AE phase and the shaft vibration phase. The AE phase corresponds to the peak value of the envelope determined based on the time change of the AE signal, and the shaft vibration phase corresponds to the high point position of the rotating part determined based on the time change of the shaft vibration signal.

[0020] Invention Effects

[0021] According to at least one embodiment of the present invention, a friction position identification device and a friction position identification method for rotating machinery that can identify the circumferential position of friction with a simple structure can be provided. Attached Figure Description

[0022] Figure 1 This is a cross-sectional structural diagram of a rotating machine involved in one embodiment.

[0023] Figure 2 This is a flowchart illustrating a friction position identification method according to one embodiment.

[0024] Figure 3A It is a schematic diagram showing the internal state of rotating machinery.

[0025] Figure 3B It is a schematic diagram showing the internal state of rotating machinery.

[0026] Figure 4 Is Figure 2 An example of the AE signal and shaft vibration signal obtained in step S101.

[0027] Figure 5 This is a schematic diagram showing the mounting position of the shaft vibration sensor in a friction position identification device according to another embodiment, viewed from the axial direction.

[0028] Figure 6 This is a flowchart illustrating a friction position identification method according to another embodiment.

[0029] Figure 7 Is Figure 6 An example of the AE signal detected by the AE sensor and the shaft vibration signal detected by the first shaft vibration sensor and the second shaft vibration sensor obtained in step S201.

[0030] Figure 8A Is Figure 6 An example of the trajectory line diagram created in step S202.

[0031] Figure 8B Based on Figure 8A An example of identifying the circumferential friction position in the normal direction determined by the trajectory diagram.

[0032] Figure 9 This is a diagram showing the structure of a friction position identification device according to another embodiment.

[0033] Figure 10 It means that it can be generated by Figure 9 The flowchart illustrates the friction position identification method implemented by the friction position identification device.

[0034] Figure 11 This is an explanatory diagram of the linear interpolation of the shaft vibration vector corresponding to the shaft vibration signal detected by the third shaft vibration sensor and the shaft vibration vector corresponding to the shaft vibration signal detected by the fourth shaft vibration sensor.

[0035] Figure 12 It means that it can be generated by Figure 9 The flowchart shows another friction position identification method implemented by the friction position identification device. Detailed Implementation

[0036] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the constituent components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0037] Figure 1 This is a cross-sectional structural diagram of a rotating machine 1 according to one embodiment. The rotating machine 1 includes a stationary part 2 and a rotating part 4 that is rotatable relative to the stationary part 2. The stationary part 2 is the housing of the rotating machine 1 and is stationary relative to the outside. The rotating part 4 is supported by a pair of bearings 6a and 6b and is rotatable relative to the stationary part 2.

[0038] A gap D is provided between the stationary part 2 and the rotating part 4. Working fluid W is supplied to the gap D from the supply part 3 provided in the stationary part 2, thereby driving the rotating part 4. The working fluid W driving the rotating part 4 is discharged to the outside from the discharge part 5 provided in the stationary part 2. When the rotating machinery 1 is running, at least one of the stationary part 2 or the rotating part 4 deforms due to heat or other factors, causing the gap D to narrow, sometimes resulting in friction. Such friction can be detected based on the AE signal detected by the AE sensor 10 described later.

[0039] The rotating part 4 is, for example, a rotor (rotating shaft) capable of rotating using power based on the working fluid W. The rotating part 4 has moving blades 4a for receiving the working fluid W, and the rotating part 4 is driven to rotate by receiving the working fluid W through the moving blades 4a. The rotating machinery 1 is, for example, a steam turbine that uses steam as the working fluid W.

[0040] The rotating part 4 is supported by a pair of bearings 6a and 6b (radial bearings) to enable it to rotate. Bearing 6a is located at one end of the rotating part 4, and bearing 6b is located at the other end of the rotating part 4. Bearings 6a and 6b are respectively housed in bearing housings 7a and 7b.

[0041] One embodiment of the friction position identification device 100 is a device for identifying the location of friction when friction occurs in a rotating machine 1 having the above-described structure. In the rotating machine 1, for example, a seal installed on a stationary part 2 that has undergone thermal deformation may sometimes rub against a rotating part 4. The friction position identification device 100 includes at least one AE sensor 10, at least one shaft vibration sensor 20, and a calculation unit 30 that performs calculations for identifying the friction position based on the at least one AE sensor 10 and the at least one shaft vibration sensor 20.

[0042] AE sensor 10 is a sensor used to detect AE signals from rotating machinery 1. AE waves generated at the friction-generating location propagate as elastic waves to the stationary part 2 and the rotating part 4, and are detected as AE signals by each AE sensor 10 installed on the rotating machinery 1. AE waves generally have frequencies in the acoustic wave range of several tens of kHz to several MHz, and are detected as AE signals by the AE sensor 10. In this embodiment, the configuration is such that AE waves from the friction-generating location can be detected by a single AE sensor 10 installed on the bearing 6a (bearing housing 7a).

[0043] In addition, Figure 1 The example shown is a case where a single AE sensor 10 is located in bearing 6a (bearing housing 7a), but it can also be located in bearing 6b (bearing housing 7b).

[0044] The shaft vibration sensor 20 is a sensor used to detect shaft vibration signals of the rotating machinery 1. The shaft vibration sensor 20 is configured such that its detection unit faces the rotating part 4, which is the object of shaft vibration detection, and is configured to detect shaft vibration based on the distance between the detection unit and the rotating part 4. In this embodiment, a single shaft vibration sensor 20 is installed on the bearing 6a (bearing housing 7a) to detect shaft vibration from the friction-generating part.

[0045] In addition, Figure 1 The example shown is a case where a single shaft vibration sensor 20 is installed in bearing 6a (bearing housing 7a), but it can also be installed in bearing 6b (bearing housing 7b).

[0046] In addition, Figure 1In the example, the AE sensor 10 and the shaft vibration sensor 20 are located at different axial positions in a common bearing 6a (bearing housing 7a), but they can be located in different bearings (e.g., one is located in bearing 6a (bearing housing 7a) and the other is located in bearing 6b (bearing housing 7b)), or they can be located at the same axial position.

[0047] The arithmetic unit 30 is configured to perform calculations to identify the friction position based on the detection results of the AE sensor 10 and the shaft vibration sensor 20. It may be composed of, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and a computer-readable storage medium. Furthermore, as an example, a series of processes for implementing various functions are stored in the form of a program in the storage medium, etc. The CPU reads this program into the RAM, etc., and performs information processing / computation to achieve various functions. Alternatively, the program may be pre-installed in ROM or other storage media, provided in a state stored in a computer-readable storage medium, or transmitted via a wired or wireless communication unit. Computer-readable storage media include magnetic disks, optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, etc.

[0048] The arithmetic unit 30 includes a friction determination unit 32 for determining whether friction exists and a friction position identification unit 34 for identifying the location of friction occurrence when friction is determined to exist. Furthermore, regarding the friction determination method related to the presence or absence of friction in the friction determination unit 32, following a known example and omitting details, friction can be determined early by judging based on the AE signal detected by the AE sensor 10.

[0049] Next, the friction position identification method implemented by the friction position identification device 100 having the above structure will be described. Figure 2 This is a flowchart illustrating a friction position identification method according to one embodiment.

[0050] First, the friction determination unit 32 determines whether there is friction (step S100). The friction determination in step S100 is performed, for example, based on the AE signal detected by the AE sensor 10. When the friction determination unit 32 determines that there is friction (step S100: Yes), the friction position identification unit 34 acquires the AE signal detected by the AE sensor 10 and the shaft vibration signal detected by the shaft vibration sensor 20 (step S101).

[0051] Here, Figure 3A and Figure 3B This is a schematic diagram showing the internal state of the rotating machinery 1. Figure 4 Is Figure 2 An example of the AE signal and shaft vibration signal acquired in step S101. For example... Figure 3A and Figure 3B As shown, the rotating part 4 is driven to rotate inside the stationary part 2. At this time, the highest point Ph in the rotating part 4, located on the outermost radial side, moves on a track K (e.g., a roughly circular track with a oscillating rotation center O') that is eccentric relative to the center O of the stationary part 2. Figure 3A The image shows the state of the shaft vibration sensor 20, which is installed at the highest point Ph closest to the position in the stationary part 2 at an angle φvib from the predetermined reference position Pr. Figure 3B The diagram shows the state of friction caused by the contact between the high point Ph and the stationary part 2.

[0052] exist Figure 4 The diagram illustrates the time variations of the AE signal and shaft vibration signal simultaneously detected by the AE sensor 10 and the shaft vibration sensor 20. This detection of the AE signal based on the AE sensor 10 and the shaft vibration signal based on the shaft vibration sensor 20 is continuous. In step S101, the determination of friction is used as a trigger, and the detection of the AE signal and shaft vibration signal is performed within a predetermined time. This predetermined time is appropriately set to acquire AE signals and shaft vibration signals sufficient to determine the AE phase θrub and shaft vibration phase θvib, which will be described later.

[0053] AE signals typically have waveforms with amplitude variations at a predetermined frequency. When friction occurs in rotating machinery 1, such as... Figure 4 As shown, a component synchronized with the rotational speed of the rotating machine 1 (speed synchronization component) appears on the envelope Lh determined based on the peak value of the waveform contained in the AE signal. Such a speed synchronization component exhibits behavior that varies periodically by displaying the maximum peak value.

[0054] Furthermore, the shaft vibration signal has an amplitude corresponding to the distance between the shaft vibration sensor 20 mounted on the stationary part 2 and the rotating part 4, such as... Figure 4 The waveform changes periodically as shown. This shaft vibration signal is obtained as a sine wave with a maximum peak value at the moment when the shaft vibration sensor 20 passes through the high point position Ph.

[0055] Next, the friction position identification unit 34 calculates the AE phase θrub based on the AE signal acquired in step S101 (step S102). Figure 4 As shown, the AE phase θrub is determined to be the phase corresponding to the peak value of the envelope Lh determined based on the time variation of the AE signal (the rotation angle θ when the rotational synchronization component of the envelope Lh of the AE signal becomes maximum).

[0056] Furthermore, the friction position identification unit 34 calculates the shaft vibration phase θvib based on the shaft vibration signal acquired in step S101 (step S103). For example... Figure 4 As shown, the shaft vibration phase θvib is determined to be the phase corresponding to the high point position Ph of the rotating part 4 determined based on the time change of the shaft vibration signal (the amplitude of the shaft vibration signal becomes the maximum rotation angle θ).

[0057] Next, the friction position identification unit 34 identifies the circumferential position of the friction-generating part in the rotating machine 1 based on the difference Δθ between the AE phase θrub obtained in step S102 and the shaft vibration phase θvib obtained in step S103 (step S104). Specifically, the circumferential position φrub where friction occurs is identified using the mounting angle φvib of the shaft vibration sensor 20 in the stationary unit 2 and the following formula.

[0058] φrub=φvib+Δθ=φvib+(θrub-θvib) (1)

[0059] Furthermore, φvib and φrub are angles relative to the reference position Pr defined for the stationary part 2. The reference position Pr can be, for example, the position of a single-pulse meter (not shown) used to count the rotational speed of the rotating part 4. And θvib and θrub are rotation angles θ relative to the reference angle of the rotating part 4; for example, the angle between the position of the single-pulse mark provided on the rotating part 4 and the position of the single-pulse meter provided on the stationary part 2 can be used as the reference angle.

[0060] Furthermore, in rotating machinery 1 that does not have a single-pulse meter, the circumferential position of the friction-generating location can be similarly identified by using the rotation angle θ at which the shaft vibration displacement becomes maximum as a reference angle. In this case, θvib = 0, and θrub is the relative rotation angle from the rotation angle at which the shaft vibration displacement becomes maximum.

[0061] As explained above, according to this embodiment, the circumferential position of the friction-generating location can be accurately identified based on the AE signal detected by a single AE sensor 10 and the shaft vibration signal detected by the shaft vibration sensor 20. This circumferential position identification does not require complex structures or calculations and is less susceptible to noise, thus enabling highly reliable identification of the friction location under various conditions.

[0062] Then, by identifying the circumferential position of the friction-generating part, effective countermeasures for the rotating machine 1 can be determined based on the identification results. For example, when the stationary part 2 is composed of two shells divided into upper and lower sections, if the circumferential position of the friction-generating part is on the upper side, the countermeasures can be effectively narrowed down by opening only the upper shell. Furthermore, if the circumferential position of the friction-generating part is on the lower side, it is possible to determine in advance whether it is necessary to lift the rotating part 4 to repair the lower shell, and to efficiently formulate a work plan. Moreover, when a mechanism is provided that can adjust the clearance D by heating or cooling the stationary part 2, it is possible to determine in which direction the clearance D should be adjusted based on the circumferential position of the friction-generating part, and to operate or control the mechanism based on the determination result.

[0063] In the aforementioned embodiments, the circumferential position can be well identified when conditions are met: i) the track K at the high point position Ph on the cross section perpendicular to the axial direction is approximately circular; ii) the axial position of the friction-generating part is near the shaft vibration sensor 20; or iii) the shaft vibration phase θvib is aligned axially. However, the identification accuracy may decrease when any of these conditions are not met. Such a problem can be well solved by the following embodiments.

[0064] Figure 5 This is a schematic diagram showing the mounting position of the shaft vibration sensor 20 in the friction position identification device 100 according to another embodiment, viewed from the axial direction. In this embodiment, the track K has an approximately elliptical shape relative to the oscillation rotation center O´, and on the same cross section perpendicular to the axial direction, a first shaft vibration sensor 20a and a second shaft vibration sensor 20b with different mounting angles are provided as shaft vibration sensors 20. That is, the mounting angle φvib1 of the first shaft vibration sensor 20a and the mounting angle φvib2 of the second shaft vibration sensor 20b are different. In this embodiment, a case where the mounting angle φvib1 of the first shaft vibration sensor 20a and the mounting angle φvib2 of the second shaft vibration sensor 20b differ by 90 degrees is specifically shown.

[0065] Next, a friction position identification method that can be implemented by the friction position identification device 100 with the above-described structure will be described. Figure 6 This is a flowchart illustrating a friction position identification method according to another embodiment.

[0066] First, the friction determination unit 32 determines whether there is friction, just like in step S100 (step S200). When the friction determination unit 32 determines that there is friction (step S200: Yes), the friction position identification unit 34 acquires the AE signal detected by the AE sensor 10 and the shaft vibration signal detected by the first shaft vibration sensor 20a and the second shaft vibration sensor 20b, respectively (step S201).

[0067] Here, Figure 7 Is Figure 6 This is an example of the AE signal detected by the AE sensor 10 and the shaft vibration signals detected by the first axis vibration sensor 20a and the second axis vibration sensor 20b, acquired in step S201. The shaft vibration signal detected by the first axis vibration sensor 20a and the shaft vibration signal detected by the second axis vibration sensor 20b have a predetermined phase difference. This phase difference corresponds to the mounting angle φvib1 of the first axis vibration sensor 20a and the mounting angle φvib2 of the second axis vibration sensor 20b.

[0068] Next, the friction position identification unit 34 determines the shaft vibration trajectory of the rotating unit 4 based on the shaft vibration signal obtained in step S201 (step S202). The shaft vibration trajectory is determined by creating a trajectory diagram Fo based on the shaft vibration signal detected by the first shaft vibration sensor 20a and the shaft vibration signal detected by the second shaft vibration sensor 20b. Here, Figure 8A Is Figure 6 An example of the trajectory diagram Fo created in step S202. Figure 8B Based on Figure 8A An example of identifying the circumferential frictional position of the normal direction Dh determined by the trajectory diagram Fo. Figure 8A The trajectory diagram Fo shows that the trajectory K has an approximately elliptical shape relative to the high point position Ph of the oscillation rotation center O´ on a plane defined by a first direction corresponding to the mounting direction of the first axis vibration sensor 20a and a second direction corresponding to the mounting direction of the second axis vibration sensor 20b.

[0069] Next, the friction position identification unit 34 calculates the AE phase θrub based on the AE signal acquired in step S201 (step S203). In step S203, similarly to step S102 described above, as follows... Figure 7 As shown, the AE phase θrub is determined to be the phase corresponding to the peak value of the envelope determined based on the time variation of the AE signal (the rotation angle θ when the rotational synchronization component of the envelope Lh of the AE signal becomes maximum).

[0070] Next, as Figure 8AAs shown, the friction position identification unit 34 determines the tangent Ls in the trajectory K obtained in step S202 that passes through the position corresponding to the AE phase θrub obtained in step S203, and then determines the normal direction Dh of the tangent Ls (step S204). Furthermore, as... Figure 8B As shown, the friction position identification unit 34 identifies the circumferential position of the friction as the intersection point Pc of a straight line passing through the center of the position stationary unit 2 and parallel to the normal direction Dh with the stationary unit 2 (step S205).

[0071] Thus, in this embodiment, the circumferential position of the friction-generating location can be identified based on the track K (track diagram Fo) generated by the shaft vibration signals detected by the first shaft vibration sensor 20a and the second shaft vibration sensor 20b installed at different locations. This identification method can effectively identify the circumferential position even when the track K at the high point Ph on a section perpendicular to the axial direction is not approximately circular, such as an ellipse.

[0072] then, Figure 9 This diagram illustrates the structure of a friction position identification device 100 according to another embodiment. In this embodiment, the friction position identification device 100 includes a third-axis vibration sensor 20c and a fourth-axis vibration sensor 20d respectively disposed at different axial positions as shaft vibration sensors 20. The third-axis vibration sensor 20c and the fourth-axis vibration sensor 20d are respectively disposed in the bearing housing 7a of the bearing 6a and the bearing housing 7b of the bearing 6b.

[0073] In addition, Figure 9 In the example, with Figure 1 Similarly, the AE sensor 10 and the third-axis vibration sensor 20c are also located in different axial positions in a common bearing 6a (bearing housing 7a), but they can be located in different bearings (for example, one is located in bearing 6a (bearing housing 7a) and the other is located in bearing 6b (bearing housing 7b)), or they can be located in the same axial position.

[0074] Figure 10 It means that it can be generated by Figure 9 A flowchart of the friction position identification method implemented by the friction position identification device 100. Furthermore, in this embodiment, it is assumed that the deformation generated in the rotating part 4 during the operation of the rotating machinery 1 is sufficiently small and can be considered as a rigid body.

[0075] First, the friction determination unit 32 determines whether friction exists, similar to steps S100 and S200 described above (step S300). When the friction determination unit 32 determines that friction exists (step S300: Yes), the friction position identification unit 34 estimates the axial position of the rotating part 4 where friction occurs (step S301). The axial position can be estimated, for example, based on the design specifications of the stationary part 2 and the rotating part 4 of the rotating machinery 1 (for example, estimating the location prone to friction based on the distribution of the clearance D along the axial direction), or through numerical analysis, or based on the measurement results of a sensor (not shown) capable of measuring the clearance D.

[0076] Next, the friction position identification unit 34 calculates the AE phase θrub based on the AE signal acquired in step S301, similar to step S102 described above (step S302). The AE phase θrub is determined to be the phase corresponding to the peak value of the envelope Lh determined based on the time change of the AE signal (the rotation angle θ when the rotational speed synchronization component of the envelope Lh of the AE signal becomes maximum).

[0077] Next, as Figure 11 As shown, the friction position identification unit 34 performs linear interpolation on the shaft vibration vector V1 (amplitude A, phase α) corresponding to the shaft vibration signal detected by the third shaft vibration sensor 20c and the shaft vibration vector V2 (amplitude B, phase β) corresponding to the shaft vibration signal detected by the fourth shaft vibration sensor 20d to determine the shaft vibration phase θvib at the axial position (step S303). Specifically, as... Figure 9 As shown, if the axial distance from the third axis vibration sensor 20c to the friction generation position is set as L1 and the axial distance from the fourth axis vibration sensor 20d to the friction generation position is set as L2, then the axial vibration phase θvib at the friction generation position can be calculated by the following formula.

[0078]

[0079] Where α is the phase delay of the shaft vibration at the position of the third shaft vibration sensor 20c, β is the phase delay of the shaft vibration at the position of the fourth shaft vibration sensor 20d, and k=L1 / (L1+L2).

[0080] Next, the friction position identification unit 34 identifies the circumferential position of the friction-generating part based on the difference between the AE phase θrub obtained in step S302 and the shaft vibration phase θvib obtained in step S303, in the same manner as the aforementioned step S104 (step S304).

[0081] According to this embodiment, even when the axial position where friction occurs is far from the shaft vibration sensor 20, the circumferential position of friction can be well identified at any axial position by using linear interpolation of the shaft vibration vector based on the shaft vibration signals detected by the third shaft vibration sensor 20c and the fourth shaft vibration sensor 20d, which are arranged at different positions along the axial direction.

[0082] Figure 12 It means that it can be generated by Figure 9 The flowchart shows another friction position identification method implemented by the friction position identification device 100. This embodiment can also be applied to situations where the deformation of the rotating part 4 cannot be ignored and it cannot be approximated as a rigid body mode.

[0083] First, the friction determination unit 32 determines whether friction exists, similar to steps S100, S200, and S300 described above (step S400). When the friction determination unit 32 determines that friction exists (step S400: Yes), the friction position identification unit 34 determines the vibration mode that can be excited at the rotational speed at which friction occurs (step S401). For example, by performing mode analysis in advance before implementing this method to obtain the relationship between the rotational speed of the rotating unit 4 and the types of vibration modes excited at each rotational speed, in step S401, the rotational speed at which friction occurs is applied to this relationship to determine which vibration mode can be excited.

[0084] Next, the friction position identification unit 34 determines whether the number of vibration modes determined in step S401 is less than or equal to the number of shaft vibration sensors 20 disposed at different axial positions (step S402). In this embodiment, the case in which the condition of step S402 is met by determining two vibration modes in step S401 (the case in which the number of vibration modes is equal to the number of shaft vibration sensors 20) will be described.

[0085] Additionally, when the number of vibration modes is less than the number of shaft vibration sensors 20 configured at different axial positions (step S402: No), the following identification method is invalid, and the process ends.

[0086] When the number of vibration modes is less than the number of shaft vibration sensors 20 arranged at different axial positions (step S402: Yes), the friction position identification unit 34 calculates the amplitude ratio of the axial position of the shaft vibration sensor 20 to the axial position of the friction generation location through mode analysis for each vibration mode determined in step S401 (step S403). Here, as a specific example of step S403, the following situation will be explained: for the first vibration mode, the ratio of the vibration amplitude in the third shaft vibration sensor 20c, the vibration amplitude in the fourth shaft vibration sensor 20d, and the vibration amplitude at the friction generation location is calculated to be 1:β1:γ1, and for the second vibration mode, the ratio of the vibration amplitude in the third shaft vibration sensor 20c, the vibration amplitude in the fourth shaft vibration sensor 20d, and the vibration amplitude at the friction generation location is calculated to be 1:β2:γ2.

[0087] Next, the friction position identification unit 34 defines the shaft vibration vector corresponding to the shaft vibration signals detected by the third-axis vibration sensor 20c and the fourth-axis vibration sensor 20d as a vector plotting the amplitude and phase delay of the shaft vibration signals on a polar coordinate system (step S404). Here, using the excitation force coefficients k1 and k2 of each mode, the shaft vibration vector corresponding to the third-axis vibration sensor 20c is expressed by the following formula. The shaft vibration vector corresponding to the 4th axis vibration sensor 20d .

[0088]

[0089] Then, the friction position identification unit 34 solves equations (3) and (4) simultaneously to obtain the excitation force coefficients k1 and k2 (step S405), and uses the excitation force coefficients k1 and k2 to calculate the axial vibration vector at the axial position of the friction generation location using the following formula. (Step S406).

[0090]

[0091] Next, the friction position identification unit 34 determines the friction position based on the value calculated in step S406. The shaft vibration phase θvib is determined (step S407). Then, the friction position identification unit 34, based on the AE signal detected by the AE sensor 10, calculates the AE phase θrub in the same manner as in step S102 (step S408). Next, the friction position identification unit 34, based on the difference between the shaft vibration phase θvib calculated in step S407 and the AE phase θrub calculated in step S408, identifies the circumferential position of the friction-generating location in the same manner as in step S104 (step S409).

[0092] As explained above, according to this embodiment, even when the deformation of the rotating part 4 cannot be ignored and it cannot be approximated as a rigid body mode, pattern analysis can be used to identify the circumferential contact position at any axial position.

[0093] Furthermore, the constituent elements in the above embodiments can be appropriately replaced with well-known constituent elements without departing from the spirit of the present invention, and the above embodiments can be appropriately combined.

[0094] The contents described in the above embodiments can be understood as follows, for example.

[0095] (1) The friction position identification device for rotating machinery according to one method is a friction position identification device (e.g., the friction position identification device 30 of the above embodiment) for rotating machinery (e.g., the rotating machinery 1 of the above embodiment) having a fixed part (e.g., the fixed part 2 of the above embodiment) and a rotating part (e.g., the rotating part 4 of the above embodiment), which includes:

[0096] At least one AE sensor (e.g., AE sensor 10 of the above embodiment) is used to detect the AE signal of the rotating machinery;

[0097] At least one shaft vibration sensor (e.g., the shaft vibration sensor 20 of the above embodiment) is used to detect the shaft vibration signal of the rotating part; and

[0098] The friction position identification unit (e.g., the friction position identification unit 34 in the above embodiment) is used to identify the circumferential position of the friction-generating part in the rotating machinery when friction is generated in the rotating machinery, based on the difference between the AE phase (e.g., the AE phase θrub in the above embodiment) and the shaft vibration phase (e.g., the shaft vibration phase θvib in the above embodiment). The AE phase corresponds to the peak value of the envelope determined based on the time change of the AE signal, and the shaft vibration phase corresponds to the high point position of the rotating part (e.g., the high point position Ph in the above embodiment) determined based on the time change of the shaft vibration signal.

[0099] According to the method described in (1) above, the circumferential position where friction occurs can be well identified based on the AE signal detected by a small number of AE sensors and the shaft vibration signal detected by the shaft vibration sensor. In such circumferential position identification, no complex structure or calculation is required, and it is not easily affected by noise. Therefore, the identification of friction position with high reliability can be performed under various conditions.

[0100] (2) In another manner, in the manner described in (1) above,

[0101] If the circumferential position is set as φrub, the installation position of the shaft vibration sensor relative to the reference position is set as φvib, the AE phase is set as θrub, and the shaft vibration phase is set as θvib, then the circumferential position φrub is expressed by the following formula.

[0102] φrub = φvib + (θrub - θvib)

[0103] According to the above (2), the circumferential position of the friction-generating part can be well identified based on the difference between the AE phase and the shaft vibration phase.

[0104] (3) In another manner, in the manner described in (1) or (2) above,

[0105] The at least one shaft vibration sensor is configured to detect a shaft vibration signal having an amplitude corresponding to the size of a gap (e.g., gap D in the above embodiment) between the shaft vibration sensor disposed on the fixed portion and the rotating portion.

[0106] The friction position identification unit determines the high point position based on the maximum peak contained in the time variation of the amplitude.

[0107] According to the above (3), the high point position required to determine the shaft vibration phase can be well determined based on the time change of the amplitude of the shaft vibration signal detected by the shaft vibration sensor.

[0108] (4) In another manner, in the manner described in (1) above,

[0109] The at least one shaft vibration sensor includes a first shaft vibration sensor (e.g., the first shaft vibration sensor 20a in the above embodiment) and a second shaft vibration sensor (e.g., the second shaft vibration sensor 20b in the above embodiment) with different mounting angles.

[0110] The friction position identification unit calculates the trajectory of the high point position based on the shaft vibration signals detected by the first shaft vibration sensor and the second shaft vibration sensor, and identifies the circumferential position based on the trajectory and the AE phase.

[0111] According to the above (4), even if the track at the high point has a non-circular shape such as an ellipse, the circumferential position of the friction-generating part can be well identified based on the track at the high point obtained from the shaft vibration signals detected by multiple shaft vibration sensors and the AE phase based on the AE signal detected by the AE sensor.

[0112] (5) In another manner, in the manner described in (4) above,

[0113] The friction position identification unit identifies the circumferential position by using the normal direction of the tangent line drawn on the track corresponding to the AE phase.

[0114] According to the above (5), the point corresponding to the AE phase is plotted on the track, and the normal direction of the tangent passing through the point is determined, so as to identify the circumferential position.

[0115] (6) In another manner, in any of the manners (1) to (5) above,

[0116] The at least one axial vibration sensor includes a third axial vibration sensor (e.g., the third axial vibration sensor 20c in the above embodiment) and a fourth axial vibration sensor (e.g., the fourth axial vibration sensor 20d in the above embodiment) respectively disposed at different axial positions.

[0117] The friction position identification unit calculates the axial position based on linear interpolation of the axial vibration vectors of the axial vibration signals detected by the third axial vibration sensor and the fourth axial vibration sensor, respectively.

[0118] According to the above (6), by linearly interpolating the shaft vibration vector based on the shaft vibration signals detected by two shaft vibration sensors located at different axial positions, the circumferential position can be properly identified even when there is a friction-generating part at the axial position between the two shaft vibration sensors.

[0119] (7) In another manner, in any of the manners (1) to (6) above,

[0120] The at least one shaft vibration sensor includes a fifth shaft vibration sensor (e.g., the fifth shaft vibration sensor 20e) and a sixth shaft vibration sensor (e.g., the sixth shaft vibration sensor 20f) respectively disposed at different axial positions.

[0121] The friction position identification unit uses the fifth-axis vibration sensor, the sixth-axis vibration sensor, and a coefficient of the vibration amplitude ratio at the friction generation location to calculate the axial vibration vector corresponding to the friction generation location for each vibration mode obtained through mode analysis. This vector is then used as the linear sum of the axial vibration vectors corresponding to the fifth-axis vibration sensor and the sixth-axis vibration sensor, respectively, to identify the circumferential position.

[0122] According to the method described in (7) above, for each vibration mode, the shaft vibration vector at the friction-generating location is calculated using the vibration sensors of each shaft and the coefficient corresponding to the vibration amplitude ratio at the friction-generating location. This vector is then used as the linear sum of the shaft vibration vectors corresponding to each shaft vibration sensor, thereby enabling the identification of the circumferential position of the friction. Even when the rotating part of the rotating machinery cannot be considered a rigid body due to deformation such as torsion during operation, such circumferential position identification can still be performed effectively.

[0123] (8) In another manner, in any of the methods (1) to (7) above,

[0124] The shaft vibration sensor and the AE sensor are disposed in a bearing housing (for example, bearing housing 7 in the above embodiment), which houses a bearing that supports the rotating part so that it can rotate relative to the stationary part (for example, bearing 6 in the above embodiment).

[0125] According to the above (8), by setting the shaft vibration sensor and AE sensor in the bearing housing that houses the rotating shaft as a rotatable bearing, the shaft vibration or AE wave can be appropriately detected based on friction.

[0126] (9) In another manner, in any of the manners (1) to (8) above,

[0127] The rotating machinery is a steam turbine.

[0128] According to the above (9), the circumferential position of friction generated in the steam turbine can be well identified.

[0129] (10) One method for identifying the friction position of a rotating machine is a method for identifying the friction position of a rotating machine (e.g., the rotating machine 1 of the above embodiment) having a fixed part (e.g., the fixed part 2 in the above embodiment) and a rotating part (e.g., the rotating part 4 in the above embodiment), which includes the following steps:

[0130] Detect the AE signal of the rotating machinery;

[0131] Detect the shaft vibration signal of the rotating part; and

[0132] When friction occurs in the rotating machinery, the circumferential position of the friction-generating part in the rotating machinery is identified based on the difference between the AE phase (e.g., the AE phase θrub in the above embodiment) and the shaft vibration phase. The AE phase corresponds to the peak value of the envelope determined based on the time variation of the AE signal, and the shaft vibration phase corresponds to the high point position of the rotating part (e.g., the high point position Ph in the above embodiment) determined based on the time variation of the shaft vibration signal.

[0133] According to the method described in (10) above, the circumferential position where friction occurs can be well identified based on the AE signal detected by a small number of AE sensors and the shaft vibration signal detected by the shaft vibration sensor. In such circumferential position identification, no complex structure or calculation is required, and it is not easily affected by noise. Therefore, the identification of friction position with high reliability can be performed under various conditions.

[0134] Symbol Explanation

[0135] 1-Rotating machinery, 2-Stationary part, 3-Supply part, 4-Rotating part, 4a-Moving blade, 5-Discharge part, 6a, 6b-Bearings, 7a, 7b-Bearing housings, 10-AE sensor, 20-Shaft vibration sensor, 30-Calculation unit, 32-Friction determination unit, 34-Friction position identification unit, 100-Friction position identification device, D-Clearance, Dh-Normal direction, Fo-Trajectory line diagram, K-Trajectory, Lh-Envelope, Ls-Tangent, Ph-High point position.

Claims

1. A friction position identification device for rotating machinery, the rotating machinery comprising a fixed part and a rotating part, the friction position identification device comprising: At least one AE sensor is provided for detecting the AE signal of the rotating machinery; At least one shaft vibration sensor is used to detect the shaft vibration signal of the rotating part; and The friction position identification unit is used to identify the circumferential position of the friction-generating part in the rotating machinery based on the difference between the AE phase and the shaft vibration phase when friction is generated in the rotating machinery. The AE phase corresponds to the peak value of the envelope determined based on the time change of the AE signal, and the shaft vibration phase corresponds to the high point position of the rotating part determined based on the time change of the shaft vibration signal.

2. The friction position identification device for rotating machinery according to claim 1, wherein, If the circumferential position is defined as φrub, the mounting position of the shaft vibration sensor relative to the reference position is defined as φvib, the AE phase is defined as θrub, and the shaft vibration phase is defined as θvib, then the circumferential position φrub is expressed by the following formula. φrub=φvib+(θrub-θvib).

3. The friction position identification device for rotating machinery according to claim 1 or 2, wherein, The at least one shaft vibration sensor is configured to detect a shaft vibration signal having an amplitude corresponding to the size of the gap between the shaft vibration sensor disposed on the fixed portion and the rotating portion. The friction position identification unit determines the high point position based on the maximum peak contained in the time variation of the amplitude.

4. The friction position identification device for rotating machinery according to claim 1, wherein, The at least one shaft vibration sensor includes a first shaft vibration sensor and a second shaft vibration sensor with different mounting angles. The friction position identification unit calculates the trajectory of the high point position based on the shaft vibration signals detected by the first shaft vibration sensor and the second shaft vibration sensor, and identifies the circumferential position based on the trajectory and the AE phase.

5. The friction position identification device for rotating machinery according to claim 4, wherein, The friction position identification unit identifies the circumferential position by using the normal direction of the tangent line drawn on the track corresponding to the AE phase.

6. The friction position identification device for rotating machinery according to claim 1 or 2, wherein, The at least one shaft vibration sensor includes a third shaft vibration sensor and a fourth shaft vibration sensor respectively disposed at different axial positions. The friction position identification unit calculates the axial position using linear interpolation of the axial vibration vector based on the axial vibration signals detected by the third axial vibration sensor and the fourth axial vibration sensor, respectively.

7. The friction position identification device for rotating machinery according to claim 1 or 2, wherein, The at least one shaft vibration sensor includes a fifth shaft vibration sensor and a sixth shaft vibration sensor respectively disposed at different axial positions. The friction position identification unit uses a coefficient that specifies the ratio of vibration amplitude at the 5th axis vibration sensor, the 6th axis vibration sensor, and the friction generation location to calculate the axis vibration vector corresponding to the friction generation location for each vibration mode obtained through mode analysis. This vector is then used as the linear sum of the axis vibration vectors corresponding to the 5th axis vibration sensor and the 6th axis vibration sensor, respectively, thereby identifying the circumferential position.

8. The friction position identification device for rotating machinery according to claim 1 or 2, wherein, The shaft vibration sensor and the AE sensor are disposed in a bearing housing, which houses a bearing that supports the rotating part so that it can rotate relative to the fixed part.

9. The friction position identification device for rotating machinery according to claim 1 or 2, wherein, The rotating machinery is a steam turbine.

10. A method for identifying the friction position of rotating machinery, the rotating machinery comprising a fixed part and a rotating part, the method comprising the following steps: Detect the AE signal of the rotating machinery; Detect the shaft vibration signal of the rotating part; and When friction occurs in the rotating machinery, the circumferential position of the friction-generating part in the rotating machinery is identified based on the difference between the AE phase and the shaft vibration phase. The AE phase corresponds to the peak value of the envelope determined based on the time change of the AE signal, and the shaft vibration phase corresponds to the high point position of the rotating part determined based on the time change of the shaft vibration signal.

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