Clearance estimation device and clearance estimation method

Abstract

To provide a clearance estimation device which can estimate a size of a clearance during an operation of a rotating machine, and a clearance estimation method.SOLUTION: A clearance estimation device for estimating a size of a clearance which is formed between a rotating member of a rotating machine and a stationary member arranged at an external peripheral side of the rotating member comprises: a heater attached to a wall face facing the clearance of the rotating member or the stationary member, and heating fluid which flows in the clearance; at least one sensor device which is constituted of at least one temperature sensor for acquiring a temperature of fluid which flows around the heater; and a clearance estimation part for estimating the size of the clearance on the basis of a change amount of the temperature of the fluid acquired by at least one temperature sensor, and a change amount of an output of the heater.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a clearance estimation device and a clearance estimation method for estimating the magnitude of a clearance formed between a rotating member and a stationary member of a rotary machine. [Background technology]

[0002] In rotary machines such as steam turbines, the clearance of the seal portion inevitably increases over time. The increase in the clearance over time is generally caused by starting and stopping the rotary machine, shaft vibration during operation, creep deformation of the casing over time, etc. For this reason, in order to operate the rotary machine for a long period of time, it may be necessary to periodically replace the members constituting the seal portion, such as the seal ring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-195720 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, when the outer casing of a rotating machine is opened during periodic inspection of the rotating machine, the seal clearance is actually measured using a lead wire or the like, and the timing of replacing the seal ring is determined from the measurement results (see Patent Document 1). Patent Document 1 also discloses a method of using the above measurement results to correct the internal efficiency degradation rate curve over time and grasp the amount of performance degradation of the rotating machine.

[0005] When estimating the clearance expansion amount over time using the measurement results from each regular inspection, the same measurement results are used until the next regular inspection, so there is a possibility that the estimated value will differ from the actual value. In addition, while past data can be used for rotating machines that have a track record of operation in the past or similar rotating machines, it is difficult to estimate the clearance expansion amount for rotating machines that do not have past data. In addition, past data for similar rotating machines is only a reference value, so there is a possibility that deviations will occur in the estimated value of the clearance expansion amount.

[0006] In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a clearance estimation device and a clearance estimation method that can estimate the magnitude of a clearance while a rotating machine is in operation. [Means for solving the problem]

[0007] A clearance estimation device according to at least one embodiment of the present disclosure, 1. A clearance estimation device for estimating a size of a clearance formed between a rotating member of a rotary machine and a stationary member arranged on an outer periphery side of the rotating member, comprising: At least one sensor device including a heater attached to a wall surface of the rotating member or the stationary member facing the clearance and configured to heat a fluid flowing through the clearance, and at least one temperature sensor configured to acquire a temperature of the fluid flowing around the heater; and a clearance estimation unit that estimates the size of the clearance based on the amount of change in temperature of the fluid acquired by the at least one temperature sensor and the amount of change in output of the heater.

[0008] A method for estimating clearance according to at least one embodiment of the present disclosure includes: 1. A clearance estimation method for estimating a size of a clearance formed between a rotating member of a rotary machine and a stationary member arranged on an outer periphery side of the rotating member, comprising: a heating step of heating the fluid flowing through the clearance by a heater attached to a wall surface of the rotating member or the stationary member facing the clearance; a fluid temperature acquisition step of acquiring a temperature of the fluid flowing around the heater by at least one temperature sensor; and a clearance estimation step of estimating the size of the clearance based on the amount of change in the temperature of the fluid acquired in the fluid temperature acquisition step and the amount of change in the output of the heater. Effect of the Invention

[0009] According to at least one embodiment of the present disclosure, a clearance estimation device and a clearance estimation method are provided that are capable of estimating the magnitude of a clearance during operation of a rotating machine. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view taken along an axial direction of a rotating machine equipped with a clearance estimation device according to an embodiment of the present disclosure. [Diagram 2] 1 is a schematic cross-sectional view perpendicular to an axial direction of a rotating machine equipped with a clearance estimation device according to an embodiment of the present disclosure; [Diagram 3] FIG. 1 is a schematic diagram of a sensor device according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a schematic diagram of a clearance estimation device according to an embodiment of the present disclosure. [Diagram 5] FIG. 2 is an explanatory diagram for explaining a relationship between a clearance of a rotary machine and an absolute velocity of a fluid in an embodiment of the present disclosure. [Figure 6] 1 is an explanatory diagram for explaining an example of adjustment control of the output of a heater by an output adjustment device according to an embodiment of the present disclosure. FIG. [Figure 7] FIG. 11 is an explanatory diagram for explaining the relationship between the absolute velocity of the fluid and the heater output when the heater output is adjusted so that the temperature of the fluid flowing through the clearance of a rotating machine in one embodiment of the present disclosure is kept at a predetermined constant temperature. [Figure 8] 1 is a schematic cross-sectional view taken along an axial direction of a rotating machine equipped with a clearance estimation device according to an embodiment of the present disclosure. [Figure 9] 1 is a schematic cross-sectional view taken along an axial direction of a rotating machine equipped with a clearance estimation device according to an embodiment of the present disclosure. [Figure 10] FIG. 2 is an explanatory diagram for explaining a relationship between a clearance of a rotary machine and a flow angle of a fluid in an embodiment of the present disclosure. [Figure 11] FIG. 1 is a schematic diagram of a sensor device according to an embodiment of the present disclosure. [Figure 12] FIG. 11 is an explanatory diagram for explaining an example of a method for calculating a flow angle of a fluid in an embodiment of the present disclosure. [Figure 13] 1 is a schematic cross-sectional view perpendicular to an axial direction of a rotating machine equipped with a clearance estimation device according to an embodiment of the present disclosure; [Figure 14] 1 is an explanatory diagram for explaining an increase in the size of a clearance over time in a rotating machine according to an embodiment of the present disclosure; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure.

[0012] (Rotating Machinery) Fig. 1 is a schematic cross-sectional view along the axial direction of a rotating machine 2 equipped with a clearance estimation device 1 according to an embodiment of the present disclosure. Fig. 2 is a schematic cross-sectional view perpendicular to the axial direction of the rotating machine 2 equipped with a clearance estimation device 1 according to an embodiment of the present disclosure. As shown in Figs. 1 and 2, the rotating machine 2 includes a rotating member 3 and a stationary member 4 arranged on the outer periphery side of the rotating member 3. A clearance 5 is formed between the rotating member 3 and the stationary member 4.

[0013] A clearance estimation device 1 and a clearance estimation method according to some embodiments are intended to estimate the magnitude of a clearance 5. In the following embodiments, a steam turbine will be taken as an example of a rotating machine 2. Note that the clearance estimation device 1 and the clearance estimation method according to the present disclosure can also be applied to a rotating machine 2 other than a steam turbine, such as a gas turbine.

[0014] (Rotating parts) The rotating member 3 is configured to rotate about the central axis CA (radial center) during operation of the rotating machine 2. The rotating member 3 includes at least a rotating shaft 3A configured to extend along the central axis CA and rotate about the central axis CA (radial center). The rotating member 3 may further include another member that is fixed to the rotating shaft 3A and rotates about the central axis CA (radial center) in conjunction with the rotation of the rotating shaft 3A. The rotating machine 2 may include a bearing (not shown) that rotatably supports the rotating member 3.

[0015] Hereinafter, the direction in which the central axis CA of the rotating member 3 extends is defined as the axial direction of the rotating member 3 (rotating machine 2), the direction perpendicular to the central axis CA is defined as the radial direction of the rotating member 3 (rotating machine 2), and the circumferential direction about the central axis CA is defined as the circumferential direction of the rotating member 3 (rotating machine 2). Hereinafter, the axial direction, radial direction, and circumferential direction of the rotating member 3 (rotating machine 2) may be simply referred to as the axial direction, radial direction, and circumferential direction.

[0016] (Stationary member) The stationary member 4 is configured to be stationary (not rotate) even when the rotating member 3 rotates during operation of the rotary machine 2. The stationary member 4 includes at least a housing 4A arranged to surround the outer circumferential side (outside in the radial direction) of the rotating member 3 and configured to rotatably accommodate the rotating member 3. The stationary member 4 may further include another member fixed to the housing 4A. As shown in FIG. 2, the housing 4A may be configured of a plurality of housings 4B, 4C arranged side by side in the circumferential direction. In the embodiment shown in FIG. 2, the housing 4A includes an upper housing 4B that extends along the circumferential direction above the central axis CA and covers the outer circumferential side of the rotating shaft 3A, and a lower housing 4C that extends along the circumferential direction below the central axis CA and covers the outer circumferential side of the rotating shaft 3A.

[0017] (clearance) The rotating member 3 has a rotating side wall surface 31 which is a wall surface facing the clearance 5. The stationary member 4 has a stationary side wall surface 41 which is a wall surface facing the clearance 5. The stationary side wall surface 41 is provided radially outward from the rotating side wall surface 31 and faces the rotating side wall surface 31 across the clearance 5. The clearance 5 is a radial gap defined by the rotating side wall surface 31 and the stationary side wall surface 41. In the illustrated embodiment, the rotating side wall surface 31 includes an outer peripheral surface of the rotating shaft 3A, and the stationary side wall surface 41 includes an inner peripheral surface of the housing 4A. The clearance 5 is formed in an annular shape extending along the circumferential direction of the rotating machine 2, as shown in FIG. 2.

[0018] 2, the rotary machine (steam turbine) 2 may further include an outer casing 21 arranged on the outer circumferential side of the stationary member 4. An annular gap 22 extending along the circumferential direction is formed between the inner circumferential surface of the outer casing 21 and the outer circumferential surface of the stationary member 4. The outer casing 21 may be composed of a plurality of outer casings 21A, 21B arranged side by side in the circumferential direction.

[0019] In the embodiment shown in Fig. 2, the outer casing 21 includes a first outer casing 21A extending along the circumferential direction above the central axis CA to cover the outer periphery of the upper housing 4B, and a second outer casing 21B extending along the circumferential direction below the central axis CA to cover the outer periphery of the lower housing 4B. Each of the first outer casing 21A and the second outer casing 21B has flanges 211, 212, 213, and 214 protruding radially outward from both ends in the circumferential direction. Each of the first outer casing 21A and the second outer casing 21B is fixed to each other by fastening the flanges 211 and 213 on one side of each other and the flanges 212 and 214 on the other side of each other with fastening members (bolts, nuts, etc.) not shown in the figure, thereby forming an annular body.

[0020] The clearance 5 has a higher pressure on one side in the axial direction than on the other side. As shown in FIG. 1, the high-pressure side space 50A, which is formed on one side in the axial direction (left side in the figure) of the clearance 5 and connected to the clearance 5, has a higher pressure than the low-pressure side space 50B, which is formed on the other side in the axial direction (right side in the figure) of the clearance 5 and connected to the clearance 5. Each of the high-pressure side space 50A and the low-pressure side space 50B is a space formed between the rotating member 3 and the stationary member 4. The main flow of the fluid passing through the clearance 5 flows from the one side in the axial direction (left side in the figure) to the other side (right side in the figure) due to the pressure difference between the high-pressure side space 50A and the low-pressure side space 50B. Hereinafter, the upstream side US in the flow direction of the fluid means the one side in the axial direction (high pressure side), and the downstream side LS in the flow direction of the fluid means the other side in the axial direction (low pressure side).

[0021] (Clearance Estimation Device) Fig. 3 is a schematic diagram of a sensor device 6 (6A, 6C) according to an embodiment of the present disclosure. Fig. 4 is a schematic diagram of a clearance estimation device 1 according to an embodiment of the present disclosure. As shown in Figs. 1 and 4, the clearance estimation device 1 according to some embodiments includes at least one sensor device 6 including a heater 7 and at least one temperature sensor 8, and a clearance estimation unit 9.

[0022] (Sensor device) The heater 7 of the sensor device 6 is attached to the rotating side wall surface 31, which is the wall surface facing the clearance 5 of the rotating member 3, or the stationary side wall surface 41, which is the wall surface facing the clearance 5 of the stationary member 4. The heater 7 is configured to heat the fluid flowing through the clearance 5. The heater 7 heats the fluid flowing around the heater 7 to a temperature higher than the atmospheric temperature, so that a temperature field TF (see FIG. 3) that is higher than the atmospheric temperature is formed around the heater 7.

[0023] At least one temperature sensor 8 of the sensor device 6 is configured to acquire (measure) the temperature of a fluid flowing around the heater 7 of the sensor device 6. In the illustrated embodiment, the at least one temperature sensor 8 of the sensor device 6 is arranged to surround the heater 7 of the sensor device 6, and includes a plurality of temperature sensors 8 arranged side by side in a circumferential direction centered on the center of gravity C1 of the heater 7. Each of the plurality of temperature sensors 8 is preferably arranged in the vicinity of the heater 7, specifically, at a position where the temperature of the fluid flowing through the temperature field TF formed by the heater 7 can be acquired (measured).

[0024] In the illustrated embodiment, as shown in FIG. 3, the sensor device 6 is made of a MEMS (Micro Electro Mechanical System) sensor manufactured using semiconductor microfabrication technology. A MEMS sensor is a sensor configured by integrating mechanical parts and electronic circuits into one. In the embodiment shown in FIG. 3, the sensor device 6 has a flexible structure that can be attached to the rotating side wall surface 31 or the stationary side wall surface 41, which are curved walls. The sensor device 6 has a flexible substrate 61 having a front surface 62 and a back surface 63. The back surface 63 of the flexible substrate 61 is attached to the rotating side wall surface 31 or the stationary side wall surface 41.

[0025] In the illustrated embodiment, the heater 7 and the multiple temperature sensors 8 are laminated on a surface 62 of a flexible substrate 61. The flexible substrate 61 is preferably a non-conductive sheet made of a non-conductive material such as a polyimide film. In the embodiment shown in FIG. 3, the heater 7 and the multiple temperature sensors 8 are sensor elements made of a conductive material. The heater 7 and the multiple temperature sensors 8 are preferably conductive patterns made of a conductive material and laminated on the surface 62 of the flexible substrate 61. The heater 7 is a planar heating element configured to generate heat when a voltage is applied from a power source (not shown).

[0026] (First Clearance Estimation Method) Fig. 5 is an explanatory diagram for explaining the relationship between the clearance 5 of the rotary machine 2 and the absolute velocity V1 of the fluid in an embodiment of the present disclosure. The symbols CL1, CL2, and CL3 in Fig. 5 represent the size of the clearance 5, for example, the average value of the radial distance from the rotating side wall surface 31 to the stationary side wall surface 41. The symbol CL1 represents the smallest size of the clearance 5, and the symbol CL3 represents the largest size of the clearance 5. As shown in Fig. 5, when the clearance 5 is enlarged, the flow rate of the fluid passing through the clearance 5 increases, and therefore the velocity (absolute velocity) V1 of the fluid flowing around the heater 7 increases.

[0027] The inventors have noted that as the clearance 5 expands, the flow rate of the fluid passing through the clearance 5 increases, so that the speed of the fluid flowing around the heater 7 increases and the amount of heat removed from the periphery of the heater 7 increases. The inventors have then found that the size of the clearance 5 can be estimated based on the amount of change in the temperature of the fluid acquired by the temperature sensor 8 and the amount of change in the output of the heater 7, which are parameters capable of grasping the state of the amount of heat removed from the periphery of the heater 7.

[0028] (Clearance Estimation Section) The clearance estimation unit 9 according to some embodiments is configured to estimate the size of the clearance 5 (e.g., radial distance D1, see FIG. 1 ) based on the amount of change in temperature of the fluid acquired by at least one temperature sensor 8 and the amount of change in the output of the heater 7. In the illustrated embodiment, the clearance estimation unit 9 includes an electronic control unit 90 for estimating the size of the clearance 5. As shown in FIG. 4 , the electronic control unit 90 may be configured as a microcomputer including an input device 91 (input interface), an output device 92 (output interface), a storage device 93 (memory such as ROM or RAM, external storage device, etc.), and a calculation device 94 (CPU). The electronic control unit 90 may realize each operation in the clearance estimation unit 9 (calculation of the size of the clearance 5 in clearance calculation units 12 and 12A described later, etc.) by the CPU operating (e.g., calculating data, etc.) according to instructions of a program loaded in the main storage device of the memory.

[0029] In the illustrated embodiment, the clearance estimation unit 9 is configured so that various signals from sensors constituting the clearance estimation device 1, such as the sensor device 6, are input to a storage device 93 and a calculation device 94 via an input device 91. The clearance estimation unit 9 may be configured so that a signal indicating the output of the heater 7 from either the heater 7 or an output adjustment device 10 described below is input to the storage device 93 and the calculation device 94 via the input device 91. The storage device 93 is configured to store various signals from the sensors constituting the clearance estimation device 1 and the output of the heater 7. The calculation device 94 is configured to execute various controls in accordance with a control program stored in the storage device 93.

[0030] According to the above configuration, the clearance estimation device 1 including the sensor device 6 and the clearance estimation unit 9 can estimate the magnitude of the clearance 5 based on the amount of change in the temperature of the fluid acquired by the temperature sensor 8 and the amount of change in the output of the heater 7 while the rotating machine 2 is in operation. By estimating the magnitude of the clearance 5 of the seal part while the rotating machine 2 is in operation using the clearance estimation device 1, it is possible to grasp the performance deterioration of the seal part before periodic replacement, and therefore to grasp the appropriate replacement time for the members constituting the seal part. By replacing the members constituting the seal part at the appropriate replacement time, it is possible to shorten the operating period of the rotating machine 2 with the performance of the seal part in a deteriorated state, and therefore it is possible to suppress a decrease in the efficiency of the rotating machine 2.

[0031] When the seal portion is sealed by a labyrinth seal formed on at least one of the rotating side wall surface 31 or the stationary side wall surface 41, the rotating member 3 and the stationary member 4 correspond to the components constituting the seal portion to be replaced as described above. When the seal portion is sealed by a seal member such as a seal ring attached to at least one of the rotating side wall surface 31 or the stationary side wall surface 41, the seal member corresponds to the components constituting the seal portion to be replaced as described above.

[0032] The size of the clearance 5 estimated by the clearance estimation unit 9 may be the radial distance D1 from the rotating side wall surface 31 to the stationary side wall surface 41. This radial distance D1 may be a representative value indicating the radial distance of the clearance 5, such as an average value. The size of the clearance 5 estimated by the clearance estimation unit 9 may indicate an increase in the radial distance D1 of the clearance 5 from an initial value. The initial value may be the radial distance (actual measurement value or design value) of the clearance 5 at the start of operation of the rotating machine 2, or may be the actual measurement value of the radial distance of the clearance 5 at the time of maintenance of the rotating machine 2. In addition, when the clearance 5 to be estimated by the clearance estimation unit 9 is the clearance 5 of the seal part of the rotating machine 2, the size of the clearance 5 estimated by the clearance estimation unit 9 is not limited to one that can be quantitatively evaluated, and may be a judgment index indicating whether or not it is necessary to replace a seal member constituting the seal part.

[0033] A clearance estimation method (first clearance estimation method) according to some embodiments includes a heating step of heating the fluid flowing through the clearance 5 by the heater 7 described above, a fluid temperature acquisition step of acquiring the temperature of the fluid flowing around the heater 7 by at least one temperature sensor 8 described above, and a clearance estimation step of estimating the size of the clearance 5 based on the amount of change in the temperature of the fluid acquired in the fluid temperature acquisition step and the amount of change in the output of the heater 7. In the fluid temperature acquisition step, the temperature of the fluid during the execution of the heating step is acquired. Before the clearance estimation step, a heater acquisition step of acquiring the output of the heater 7 during the execution of the heating step from the heater 7 or the like is performed.

[0034] According to the first clearance estimation method, the size of the clearance 5 (for example, the radial distance D1) can be estimated based on the amount of change in the temperature of the fluid and the amount of change in the output of the heater 7 acquired in the fluid temperature acquisition step.

[0035] (Output adjustment device) 6 is an explanatory diagram for explaining an example of adjustment control of the output of the heater 7 by the output adjustment device 10 in one embodiment of the present disclosure. As shown in FIG 1, the clearance estimation device 1 according to some embodiments further includes an output adjustment device (controller) 10 that adjusts the output of the heater 7 so that the temperature of the fluid acquired by the above-mentioned at least one temperature sensor 8 becomes a predetermined constant temperature T1 (see FIG 6).

[0036] The predetermined constant temperature T1 is set to be higher than an ambient temperature T0 of the fluid flowing through the clearance 5. The ambient temperature T0 is the temperature of the fluid flowing at a position separated from the temperature field TF formed by the heater 7 in the clearance 5. The clearance estimation device 1 may further include a temperature sensor 11 configured to acquire (measure) the ambient temperature T0.

[0037] In one embodiment, an upper threshold T2 is set by adding a preset tolerance to the predetermined constant temperature T1, and a lower threshold T3 is set by subtracting the preset tolerance from the predetermined constant temperature T1. When the temperature of the fluid (obtained fluid temperature T) obtained by the temperature sensor 8 described above exceeds the upper threshold T2, the output adjustment device 10 reduces the output of the heater 7 until the obtained fluid temperature T falls to the predetermined constant temperature T1. When the obtained fluid temperature T does not reach the lower threshold T3, the output adjustment device 10 increases the output of the heater 7 until the obtained fluid temperature T rises to the predetermined constant temperature T1. The predetermined constant temperature T1, the upper threshold T2, and the lower threshold T3 may be set by, for example, the output adjustment device 10 or the calculation device 94 of the clearance estimation unit 9. In this case, a signal related to the ambient temperature T0 is transmitted from the temperature sensor 11 to the output adjustment device 10 or the calculation device 94. Furthermore, signals related to the predetermined constant temperature T1, the upper threshold T2, and the lower threshold T3 set in the output adjustment device 10 may be transmitted from the arithmetic device 94. Furthermore, the predetermined constant temperature T1, the upper threshold T2, and the lower threshold T3 may be preset values.

[0038] 7 is an explanatory diagram for explaining the relationship between the absolute velocity V1 of the fluid and the output HO of the heater 7 when the output HO of the heater 7 is adjusted so that the temperature T of the fluid flowing through the clearance 5 of the rotating machine 2 in one embodiment of the present disclosure becomes a predetermined constant temperature T1. As shown in Fig. 7, there is a proportional relationship between the absolute velocity V1 of the fluid and the output HO of the heater 7. When the output HO of the heater 7 is increased compared to before (when the operation of the rotating machine 2 is started, at the time of the most recent maintenance, or at the time of the most recent clearance estimation), the absolute velocity V1 of the fluid has increased due to the clearance 5 having become larger than before due to aging or the like.

[0039] The above-mentioned clearance estimation unit 9 is configured to estimate the size of the clearance 5 based on the amount of change in the output of the heater 7 when the temperature of the fluid acquired by at least one of the above-mentioned temperature sensors 8 is maintained at a predetermined constant temperature T1.

[0040] According to the above configuration, the output adjustment device 10 adjusts the output of the heater 7 so that the temperature of the fluid flowing around the heater 7 becomes a predetermined constant temperature. In this case, the amount of change in the temperature of the fluid acquired by the temperature sensor 8 becomes extremely small, and therefore it can be excluded from parameters that can grasp the state of the amount of heat removed from the periphery of the heater 7. Therefore, the clearance estimation unit 9 can estimate the size of the clearance 5 based on the amount of change in the output of the heater 7 in a state in which the temperature of the fluid flowing around the heater 7 is maintained at a predetermined constant temperature.

[0041] 1 and 2, in the clearance estimation device 1 according to some embodiments, the at least one sensor device 6 described above is attached to the stationary side wall surface 41 described above. In this case, compared to the case where the sensor device 6 is attached to the rotation side wall surface 31 of the rotating member 3, which is a rotating body, the transmission structure for transmitting power, signals, etc. to the sensor device 6 can be simplified and wear of the transmission structure can be suppressed. Note that in some other embodiments, the sensor device 6 may be attached to the rotation side wall surface 31 described above.

[0042] 1 , in the clearance estimation device 1 according to some embodiments, the above-mentioned rotating member 3 includes a rotating-side fin 32 protruding from the rotating-side wall surface 31 toward the stationary-side wall surface 41. The above-mentioned at least one sensor device 6 includes a first sensor device 6A attached to the above-mentioned stationary-side wall surface 41 and disposed on the downstream side LS of the rotating-side fin 32 in the flow direction of the fluid flowing through the clearance 5.

[0043] In the embodiment shown in FIG. 1, the rotating member 3 includes a small diameter portion 33, a large diameter portion 34 having an outer diameter larger than that of the small diameter portion 33, and a downstream small diameter portion 35 having an outer diameter smaller than that of the large diameter portion 34. The large diameter portion 34 is provided adjacent to the small diameter portion 33 on the downstream side LS of the fluid flow direction from the small diameter portion 33. The downstream small diameter portion 35 is provided adjacent to the large diameter portion 34 on the downstream side LS of the fluid flow direction from the large diameter portion 34. In the illustrated embodiment, an outer circumferential surface 341 of the large diameter portion 34 corresponds to the rotating side wall surface 31. An inner circumferential surface of the housing 4A facing the outer circumferential surface 341 of the large diameter portion 34 with a clearance 5 therebetween corresponds to the stationary side wall surface 41. In the embodiment shown in FIG. 1, the downstream small diameter portion 35 has an outer diameter larger than that of the small diameter portion 33.

[0044] In the illustrated embodiment, the stationary member 4 includes at least one (in the illustrated example, multiple) stationary side fins 42 (42A, 42B) protruding from the stationary side wall surface 41 toward the wall surface 341 facing the clearance 5 of the large diameter portion 34. The multiple stationary side fins 42 include an upstream stationary side fin 42A and a downstream stationary side fin 42B. The upstream stationary side fin 42A is provided downstream LS of the upstream step surface 36 which is the boundary between the small diameter portion 33 and the large diameter portion 34 in the fluid flow direction, and upstream US of the rotating side fin 32. The downstream stationary side fin 42B is provided downstream LS of the rotating side fin 32, and upstream US of the downstream step surface 37 which is the boundary between the large diameter portion 34 and the downstream small diameter portion 35 in the fluid flow direction. No rotating-side fins are provided on the large diameter portion 34 on the upstream side US of the upstream stationary-side fin 42A and on the downstream side LS of the downstream stationary-side fin 42B. In the illustrated embodiment, the rotating-side fin 32 and the multiple stationary-side fins 42 are formed in a thin plate shape.

[0045] In the illustrated embodiment, the first sensor device 6A is disposed upstream US of the downstream stationary-side fin 42B in the flow direction of the fluid. The fluid that passes through the tip clearance of the rotating-side fin 32 flows along the stationary-side wall surface 41 to which the first sensor device 6A is attached. When the clearance 5 increases, the tip clearance of the rotating-side fin 32 increases, and the speed of the fluid that passes through the tip clearance increases.

[0046] According to the above configuration, the first sensor device 6A is disposed at a location where it is easy to grasp the change in the speed of the fluid flowing through the clearance 5 according to the change in the size of the clearance 5, thereby making it possible to more accurately estimate the size of the clearance 5. Note that the sensor device 6 may include, instead of or together with the first sensor device 6A, a sensor device 6C attached to the stationary-side wall surface 41 on the downstream side LS of the upstream stationary-side fin 42A in the fluid flow direction and on the upstream side US of the rotating-side fin 32.

[0047] (First clearance calculation part) In the clearance estimation device 1 according to some embodiments, the above-mentioned clearance estimation unit 9 includes a first clearance calculation unit 12 shown in Fig. 4. The first clearance calculation unit 12 is configured to calculate the size of the clearance 5 (e.g., radial distance D1) from the amount of change in the temperature of the fluid (acquired fluid temperature) acquired by the at least one temperature sensor 8 and the amount of change in the output of the heater 7, based on first association information that associates the amount of change in the temperature of the fluid (acquired fluid temperature) acquired by the at least one temperature sensor 8, the amount of change in the output of the heater 7, and the size of the clearance 5.

[0048] The first association information indicates a correspondence relationship between the amount of change in the acquired fluid temperature, the amount of change in the output of the heater 7, and the size of the clearance 5, and may be any information that can acquire the size of the clearance 5 corresponding to the input information as output information when the amount of change in the acquired fluid temperature and the amount of change in the output of the heater 7 are input information. The first association information includes a list, a table, a map, a function, a machine learning model, or the like that indicates the correspondence relationship between the input information and the output information. The first association information may be created based on steady-state test data, or may be created based on past actual values, experimental values, numerical analysis results, or the like other than steady-state test data.

[0049] In some embodiments, the first association information may indicate a correspondence relationship between an amount of change in the output of the heater 7 in a state in which the obtained fluid temperature is held at a predetermined constant temperature and the magnitude of the clearance 5. The first clearance calculation unit 12 may calculate the magnitude of the clearance 5 from the amount of change in the output of the heater 7 in a state in which the obtained fluid temperature is held at a predetermined constant temperature, based on the first association information.

[0050] In some embodiments, the first association information may include second association information indicating a correspondence relationship between the amount of change in the acquired fluid temperature, the amount of change in the output of the heater 7, and the absolute velocity of the fluid, and third association information indicating a correspondence relationship between the absolute velocity of the fluid and the magnitude of the clearance 5. The first clearance calculation unit 12 may calculate the absolute velocity of the fluid from the amount of change in the acquired fluid temperature and the amount of change in the output of the heater 7 based on the second association information, and then calculate the magnitude of the clearance 5 from the calculated absolute velocity of the fluid based on the third association information.

[0051] The first association information is acquired in advance before first clearance calculation section 12 calculates the magnitude of clearance 5. The first association information may be stored in storage device 93 in advance, and first clearance calculation section 12 may refer to the first association information stored in storage device 93 when calculating the magnitude of clearance 5.

[0052] According to the above configuration, the clearance calculation unit 12 can calculate the size of the clearance 5 from the amount of change in the temperature of the fluid acquired by the temperature sensor 8 and the amount of change in the output of the heater 7 based on the first association information prepared in advance.

[0053] (Display) 4, the clearance estimation device 1 according to some embodiments further includes a display unit (display) 13 configured to display the magnitude of clearance 5 (e.g., radial distance D1) which is the calculation result calculated by the clearance calculation unit 12. The display unit 13 has a display screen 131 for displaying the calculation result calculated by the clearance calculation unit 12, and the calculation result is displayed on the display screen 131, so that a person viewing the display screen 131 can recognize the calculation result.

[0054] According to the above configuration, by displaying the size of the clearance 5 calculated by the clearance calculation unit 12 on the display unit 13, a person who visually checks the display on the display unit 13 can easily understand the size of the clearance 5.

[0055] (Second Clearance Estimation Method) 8 and 9 are schematic cross-sectional views along the axial direction of a rotating machine 2 equipped with a clearance estimation device 1 according to an embodiment of the present disclosure. The rotating machine 2 shown in FIG. 9 has a larger clearance 5 than the rotating machine 2 shown in FIG. 8 due to aging or the like. FIG. 10 is an explanatory diagram for explaining the relationship between the clearance 5 of the rotating machine 2 and the flow angle θ of a fluid in an embodiment of the present disclosure. FIG. 11 is a schematic diagram of a sensor device 6 (6B) according to an embodiment of the present disclosure.

[0056] As shown in Fig. 11, in the circumferential direction centered on the center C1 of the heater 7, the other side in the axial direction (the right side in the figure, downstream side LS) with respect to the center C1 of the heater 7 is defined as 0°, and one side in the axial direction centered on the center C1 of the heater 7 is defined as the positive direction, and the flow angle θ and flow direction FD of the fluid flowing around the heater 7 are defined. When the flow direction FD is in the + (plus) range, that is, when the flow angle θ satisfies either of the conditions of 0°≦θ<90° or 270°<θ≦360°, the fluid flowing around the heater 7 flows from the upstream side US in the axial direction to the downstream side LS (see Fig. 8). When the flow direction FD is in the - (minus) range, that is, when the flow angle θ satisfies the condition of 90°<θ<270°, the fluid flowing around the heater 7 flows from the downstream side LS in the axial direction to the upstream side US (see Fig. 9).

[0057] The symbols CL1, CL2, and CL3 in Fig. 10 represent the size of the clearance 5, for example, the average value of the radial distance from the rotating side wall surface 31 to the stationary side wall surface 41. Symbol CL1 represents the smallest size of the clearance 5, and symbol CL3 represents the largest size of the clearance 5. As shown in Fig. 10, when the clearance 5 increases, the vortex pattern (see Figs. 8 and 9) of the fluid guided into the clearance 5 changes, and the flow angle θ changes. As shown in Fig. 10, when the clearance 5 increases, the flow direction FD may shift from the + (plus) range to the - (minus) range.

[0058] The present inventors have noticed that when the size of the clearance 5 increases, the flow rate of the fluid passing through the clearance 5 increases, and therefore the flow (vortex pattern) of the fluid flowing through the clearance 5 changes. The present inventors have found that by comparing the amount of change in the temperature of the fluid acquired by each of the multiple temperature sensors 8, which is a parameter capable of grasping the state of the temperature field TF formed by the heater 7, it is possible to grasp the flow of the fluid flowing around the heater 7 and to estimate the size of the clearance 5.

[0059] In the clearance estimation device 1 according to some embodiments, as shown in Fig. 11, the at least one sensor device 6 includes a second sensor device 6B including a plurality of temperature sensors 8 (8A, 8B, 8C, 8D, 8E, 8F) arranged to surround the heater 7 as the at least one temperature sensor 8. The plurality of temperature sensors 8 (8A to 8F) are arranged side by side in the circumferential direction centered on the center of gravity C1 of the heater 7. The clearance estimation unit 9 described above is also configured to estimate the size of the clearance 5 (for example, the radial distance D1) by further comparing the amount of change in the temperature of the fluid acquired by each of the plurality of temperature sensors 8 constituting the second sensor device 6B.

[0060] Fig. 12 is an explanatory diagram for explaining an example of a method for calculating a flow angle θ of a fluid in an embodiment of the present disclosure. As shown in Fig. 11, the plurality of temperature sensors 8 (8A to 8F) includes a plurality of sets of temperature sensors 8, each set being a pair of temperature sensors 8 arranged at positions facing each other across the center of gravity C1 of the heater 7. The temperature sensors 8 of each set (e.g., 8A and 8B) are arranged at positions where the circumferential centers are separated by 180° in the circumferential direction centered on the center of gravity C1 of the heater 7. In the illustrated embodiment, the temperature sensors 8 of each set are arranged at positions where the circumferential centers are separated by 60° in the circumferential direction centered on the center of gravity C1 of the heater 7 with respect to the temperature sensors 8 of the other sets.

[0061] 12 shows a graph in which the horizontal axis represents the circumferential angle (circumferential position) of each set of temperature sensors 8 in the circumferential direction centered on the center of gravity C1 of the heater 7, and the vertical axis represents the temperature difference (voltage difference output from the pair of temperature sensors 8) of each set of temperature sensors 8. Note that for the circumferential angle of each set of temperature sensors 8, the circumferential angle of the temperature sensors 8 existing in the + (plus) range described above is used. Information regarding the flow direction of the fluid flowing around the heater 7 can be obtained from the temperature difference (voltage difference output from the pair of temperature sensors 8) of each set of temperature sensors 8.

[0062] As shown in FIG. 12, for each of the plurality of sets of temperature sensors 8, the phase difference between a cosine waveform (cosine wave) CW1 passing through plots P1, P2, and P3 showing the temperature difference between a pair of temperature sensors 8 in each set and the circumferential angle of each set of temperature sensors 8, and a pre-prepared cosine waveform (cosine wave) CW2 with a flow angle of 0° is the fluid flow angle θ. Since the fluid flow angle θ changes with the change in the size of the clearance 5, the size of the clearance 5 can be estimated by comparing the amount of change in the fluid temperature acquired by each of the plurality of temperature sensors 8 and determining the fluid flow angle θ. Note that the amount of change in the fluid temperature acquired by each of the plurality of temperature sensors 8 includes information on the flow direction of the fluid flowing around the heater 7, so the size of the clearance 5 may be estimated directly from the amount of change in the fluid temperature acquired by each of the plurality of temperature sensors 8.

[0063] According to the above configuration, the clearance estimation device 1 including the sensor device 6 and the clearance estimation unit 9 can grasp the flow direction and flow angle of the fluid by comparing the amount of change in the temperature of the fluid acquired by each of the multiple temperature sensors 8 during operation of the rotating machine 2, and can estimate the size of the clearance 5. Note that in some embodiments, the above-mentioned clearance estimation unit 9 is also configured to estimate the size of the clearance 5 by comparing the amount of change in the temperature of the fluid acquired by each of the multiple temperature sensors 8 constituting the second sensor device 6B. The clearance estimation unit 9 does not have to be configured to estimate the size of the clearance 5 based on the amount of change in the temperature of the fluid acquired by at least one temperature sensor 8 and the amount of change in the output of the heater 7.

[0064] A clearance estimation method (second clearance estimation method) according to some embodiments includes a heating step of heating the fluid flowing through the above-mentioned clearance 5 by the above-mentioned heater 7, a fluid temperature acquisition step of acquiring the temperature of the fluid flowing around the heater 7 by a plurality of temperature sensors 8 arranged to surround the heater 7, and a clearance estimation step of estimating the size of the clearance 5 by comparing the amount of change in the fluid temperature acquired by each of the plurality of temperature sensors 8 in the above-mentioned fluid temperature acquisition step. In the above-mentioned fluid temperature acquisition step, the temperature of the fluid during the execution of the above-mentioned heating step is acquired.

[0065] According to the second clearance estimation method, by comparing the amount of change in fluid temperature acquired by each of the multiple temperature sensors 8 in the fluid temperature acquisition step, the flow direction and flow angle of the fluid can be determined, and the size of the clearance 5 (e.g., radial distance D1) can be estimated.

[0066] In the clearance estimation device 1 according to some embodiments, as shown in Figures 8 and 9, the above-mentioned second sensor device 6B is attached to the stationary side wall surface 41 and is disposed downstream LS of the upstream step surface 36 which is the boundary between the small diameter section 33 and the large diameter section 34 in the fluid flow direction, and upstream US of the upstream stationary side fin 42A which is disposed most upstream of the above-mentioned multiple stationary side fins 42A, 42B.

[0067] According to the above configuration, by arranging the second sensor device 6B in a location where it is easy to grasp the change in the flow (vortex pattern) of the fluid flowing through the clearance 5 in response to the change in the size of the clearance 5, the size of the clearance 5 can be estimated more accurately.

[0068] (Second Clearance Calculation Section) In the clearance estimation device 1 according to some embodiments, the above-mentioned clearance estimation unit 9 includes a second clearance calculation unit 12A shown in Fig. 4. The second clearance calculation unit 12A is configured to calculate the size of the clearance 5 (e.g., radial distance D1) from the amount of change in the temperature of the fluid (acquired fluid temperature) acquired by the multiple temperature sensors 8 of the second sensor device 6B, based on fourth association information that associates the amount of change in the temperature of the fluid (acquired fluid temperature) acquired by the multiple temperature sensors 8 of the second sensor device 6B and the size of the clearance 5.

[0069] The fourth association information indicates a correspondence relationship between the amount of change in the fluid temperature acquired by the plurality of temperature sensors 8 of the second sensor device 6B and the size of the clearance 5, and may be any information that can acquire the size of the clearance 5 corresponding to the input information as output information when the amount of change in the acquired fluid temperature is input information. The fourth association information includes a list, a table, a map, a function, a machine learning model, or the like that indicates the correspondence relationship between the input information and the output information. The fourth association information may be created based on steady-state test data, or may be created based on past actual values, experimental values, numerical analysis results, or the like other than steady-state test data.

[0070] In some embodiments, the fourth association information may indicate a correspondence relationship between information indicating the temperature difference between a pair of temperature sensors 8 in each of the multiple sets of temperature sensors 8 and the circumferential angle of each of the temperature sensors 8, and the magnitude of the clearance 5. The second clearance calculation unit 12A may calculate the magnitude of the clearance 5 from information indicating the temperature difference between a pair of temperature sensors 8 in each of the multiple sets of temperature sensors 8 and the circumferential angle of each of the temperature sensors 8, based on the fourth association information.

[0071] In some embodiments, the fourth association information may include information indicating a correspondence relationship between a temperature difference between a pair of temperature sensors 8 in each of the multiple sets of temperature sensors 8 and a circumferential angle of the temperature sensors 8 in each of the multiple sets of temperature sensors 8, a flow angle θ of a fluid flowing around the heater 7 surrounded by the multiple sets of temperature sensors 8, and sixth association information indicating a correspondence relationship between the flow angle θ of a fluid flowing around the heater 7 and the size of the clearance 5. The second clearance calculation unit 12A may calculate the flow angle θ of the fluid from information indicating a temperature difference between a pair of temperature sensors 8 in each of the multiple sets of temperature sensors 8 and a circumferential angle of the temperature sensors 8 in each of the multiple sets of temperature sensors 8 based on the fifth association information, and then calculate the size of the clearance 5 from the calculated flow angle θ based on the sixth association information.

[0072] The fourth association information is acquired in advance before second clearance calculation section 12A calculates the magnitude of clearance 5. The fourth association information may be stored in storage device 93 in advance, and second clearance calculation section 12A may refer to the fourth association information stored in storage device 93 when calculating the magnitude of clearance 5.

[0073] According to the above configuration, clearance calculation unit 12A can calculate the magnitude of clearance 5 from the amount of change in temperature of the fluid acquired by the plurality of temperature sensors 8, based on the fourth association information prepared in advance. Note that the above-mentioned clearance estimation unit 9 may include both first clearance calculation unit 12 and second clearance calculation unit 12A, or may include either first clearance calculation unit 12 or second clearance calculation unit 12A.

[0074] (Display) In the clearance estimation device 1 according to some embodiments, the above-mentioned display unit 13 is configured to display the magnitude of clearance 5 (for example, radial distance D1) which is the calculation result calculated by second clearance calculation unit 12A. The calculation result calculated by second clearance calculation unit 12A is displayed on display screen 131.

[0075] According to the above configuration, by displaying the magnitude of clearance 5 calculated by clearance calculation unit 12A on display unit 13, a person who visually checks the display by display unit 13 can easily understand the magnitude of clearance 5. Note that display unit 13 may be configured to display both the calculation results calculated by first clearance calculation unit 12 and the calculation results calculated by second clearance calculation unit 12A on display screen 131 simultaneously or separately.

[0076] In the clearance estimation device 1 according to some embodiments, the above-mentioned sensor device 6 (6A, 6B, 6C) is made of a MEMS sensor. In one embodiment, the sensor device 6 made of a MEMS sensor has a maximum diameter (diameter) of 2 mm or less and a thickness of 0.1 mm or less. By making the sensor device 6 a MEMS sensor with a relatively small thickness, it is possible to prevent the sensor device 6 from interfering with the flow of the fluid flowing through the clearance 5, and therefore the size of the clearance 5 can be estimated with higher accuracy by the above method.

[0077] FIG. 13 is a schematic cross-sectional view perpendicular to the axial direction of a rotating machine 2 equipped with a clearance estimation device 1 according to an embodiment of the present disclosure. FIG. 14 is an explanatory diagram for explaining an increase in the size of a clearance 5 over time in a rotating machine 2 according to an embodiment of the present disclosure. In the clearance estimation device 1 according to some embodiments, as shown in FIG. 13, at least one type of sensor device 6 among the above-mentioned multiple types of sensor devices 6 (6A, 6B, 6C) includes multiple sensor devices 6 (6D, 6E, 6F, 6G) arranged at a position where at least a part of the sensor device 6 overlaps with the other sensor devices 6 in the axial direction and arranged at intervals from each other in the circumferential direction. Note that being arranged at a position where at least a part of the sensor device 6 overlaps with the other sensor devices 6 in the axial direction means that the multiple sensor devices 6 (6D, 6E, 6F, 6G) are displayed in a cross section perpendicular to the axial direction as shown in FIG. 14.

[0078] In the illustrated embodiment, the multiple sensor devices 6 include a sensor device 6D arranged above the rotating shaft 3A, a sensor device 6E arranged below the rotating shaft 3A, and a pair of sensor devices 6F, 6G arranged on the sides of the rotating shaft 3A so as to sandwich the rotating shaft 3A. As shown in Fig. 14, the degree of expansion of the clearance 5 due to aging or the like may differ in the circumferential direction. In Fig. 14, the amount of expansion of the clearance 5 is greater above and below the rotating shaft 3A than on the sides of the rotating shaft 3A.

[0079] According to the above configuration, the plurality of sensor devices 6 (6D, 6E, 6F, 6G) can grasp the distribution of the size of the clearance 5 in the circumferential direction. When the seal member constituting the seal portion is composed of a plurality of seal members arranged in a line in the circumferential direction, the distribution of the size of the clearance 5 in the circumferential direction can be taken into consideration and an appropriate replacement time can be determined for each of the plurality of seal members. By replacing the plurality of seal members constituting the seal portion at the appropriate replacement time, the excessive effect of the seal members can be suppressed. In addition, by replacing the plurality of seal members constituting the seal portion at the appropriate replacement time, the operating period of the rotary machine 2 with the performance of the seal portion degraded can be shortened, and therefore a decrease in the efficiency of the rotary machine 2 can be suppressed.

[0080] In this specification, expressions expressing relative or absolute configuration, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," do not only strictly represent such a configuration, but also represent a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions indicating that things are in an equal state, such as "identical," "equal," and "homogeneous," not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions describing shapes such as a rectangular shape or a cylindrical shape do not only refer to shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect is obtained. In addition, in this specification, the expressions "comprise," "include," or "have" a certain element are not exclusive expressions that exclude the presence of other elements.

[0081] The present disclosure is not limited to the above-described embodiments, and includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0082] The contents described in the above-mentioned embodiments can be understood, for example, as follows.

[0083] 1) A clearance estimation device (1) according to at least one embodiment of the present disclosure includes: A clearance estimation device (1) for estimating a size of a clearance (5) formed between a rotating member (3) of a rotating machine (2) and a stationary member (4) arranged on an outer periphery side of the rotating member (3), comprising: at least one sensor device (6) including a heater (7) attached to a wall surface (31, 41) of the rotating member (3) or the stationary member (4) facing the clearance (5) and configured to heat a fluid flowing through the clearance (5), and at least one temperature sensor (8) configured to acquire a temperature of the fluid flowing around the heater (7); and a clearance estimation unit (9) that estimates the size of the clearance (5) based on the amount of change in temperature of the fluid acquired by the at least one temperature sensor (8) and the amount of change in output of the heater (7).

[0084] The inventors have noticed that as the size of the clearance (5) increases, the flow rate of the fluid passing through the clearance (5) increases, so that the speed of the fluid flowing around the heater (7) increases, and the amount of heat removed from the periphery of the heater (7) increases. The inventors have then found that the size of the clearance (5) can be estimated based on the amount of change in the temperature of the fluid acquired by the temperature sensor (8) and the amount of change in the output of the heater (7), which are parameters capable of grasping the state of the amount of heat removed from the periphery of the heater (7).

[0085] According to the above configuration 1), the clearance estimation device (1) including the sensor device (6) and the clearance estimation unit (9) can estimate the magnitude of the clearance (5) based on the amount of change in temperature of the fluid acquired by the temperature sensor (8) during operation of the rotating machine (2) and the amount of change in output of the heater (7).

[0086] 2) In some embodiments, the clearance estimation device (1) according to 1) above comprises: an output adjustment device (10) that adjusts the output of the heater (6) so that the temperature of the fluid acquired by the at least one temperature sensor (8) becomes a predetermined constant temperature; The clearance estimation unit (9) is configured to estimate the magnitude of the clearance (5) based on an amount of change in the output of the heater (7) in a state in which the temperature of the fluid is maintained at the predetermined constant temperature.

[0087] According to the above configuration 2), the output of the heater (6) is adjusted by the output adjustment device (10) so that the temperature of the fluid flowing around the heater (7) is kept at a predetermined constant temperature. In this case, the amount of change in the temperature of the fluid acquired by the temperature sensor (8) is extremely small, and therefore can be excluded from parameters that can grasp the state of the amount of heat removed from the periphery of the heater (7). Therefore, the clearance estimation unit (9) can estimate the size of the clearance (5) based on the amount of change in the output of the heater (7) in a state in which the temperature of the fluid flowing around the heater (7) is kept at a predetermined constant temperature.

[0088] 3) In some embodiments, the clearance estimation device (1) according to 1) above comprises: The at least one sensor device (6) is attached to a stationary side wall surface (41) of the stationary member (4), which is a wall surface facing the clearance (5).

[0089] According to the above configuration 3), the sensor device 6 is attached to the stationary side wall surface 41. In this case, the transmission structure for transmitting power, signals, etc. to the sensor device 6 can be simplified and wear of the transmission structure can be suppressed, compared with the case where the sensor device 6 is attached to the rotating side wall surface 31 of the rotating member 3, which is a rotating body.

[0090] 4) In some embodiments, the clearance estimation device (1) according to 3) above, the rotating member (3) includes a rotating-side fin (32) protruding from a rotating-side wall surface (31), which is a wall surface of the rotating member (3) facing the clearance (5), toward the stationary-side wall surface (41); The at least one sensor device (6) includes a first sensor device (6A) arranged downstream of the rotation-side fin (32) in the flow direction of the fluid.

[0091] According to the above configuration 4), by disposing the first sensor device (6A) at a location where it is easy to grasp a change in the speed of the fluid flowing through the clearance (5) in response to a change in the size of the clearance (5), it is possible to estimate the size of the clearance (5) with greater accuracy.

[0092] 5) In some embodiments, the clearance estimation device (1) according to 3) or 4) above, The rotating member (3) is A small diameter portion (33); a large diameter portion (34) having an outer diameter larger than that of the small diameter portion (33), the large diameter portion (34) being provided adjacent to the small diameter portion (33) on a downstream side in the flow direction of the fluid than the small diameter portion (33), the stationary member (4) includes at least one stationary side fin (42) protruding from the stationary side wall surface (41) toward a wall surface (341) of the large diameter portion (34) facing the clearance (5), The at least one sensor device (6) a second sensor device (6B) including a plurality of temperature sensors (8) arranged to surround the heater (7) as the at least one temperature sensor (8), the second sensor device (6B) being arranged downstream of a boundary between the small diameter portion (33) and the large diameter portion (34) in a flow direction of the fluid and upstream of a stationary side fin (42A) arranged on the most upstream side of the at least one stationary side fin (42); The clearance estimation unit (9) further comprises: The second sensor device (6B) is also configured to estimate the size of the clearance (5) by comparing the amount of change in temperature of the fluid acquired by each of the plurality of temperature sensors (8) constituting the second sensor device (6B).

[0093] The inventors have noticed that when the size of the clearance (5) increases, the flow rate of the fluid passing through the clearance (5) increases, and therefore the flow (vortex pattern) of the fluid flowing through the clearance (5) changes. The inventors have found that by comparing the amount of change in the temperature of the fluid acquired by each of the multiple temperature sensors (8), which is a parameter capable of grasping the state of the temperature field formed by the heater (7), it is possible to grasp the flow of the fluid flowing around the heater (7) and to estimate the size of the clearance (5).

[0094] According to the above configuration 5), the clearance estimation unit (9) can estimate the size of the clearance (5) not only based on the above-mentioned amount of change in temperature of the fluid and the output of the heater (7), but also by comparing the amount of change in temperature of the fluid acquired by each of the plurality of temperature sensors (8) constituting the second sensor device (6B). By arranging the second sensor device (6B) at a location where a change in the flow (vortex pattern) of the fluid flowing through the clearance (5) corresponding to a change in the size of the clearance (5) can be easily grasped, the size of the clearance (5) can be estimated with higher accuracy.

[0095] 6) In some embodiments, the clearance estimation device (1) according to any one of 1) to 5) above, The clearance estimation unit (9) and a clearance calculation unit (12) configured to calculate the magnitude of the clearance (5) from the amount of change in temperature of the fluid acquired by the at least one temperature sensor (8) and the amount of change in output of the heater (7) based on association information correlating the amount of change in temperature of the fluid acquired by the at least one temperature sensor (8), the amount of change in output of the heater (7), and the magnitude of the clearance (5).

[0096] According to the above configuration 6), the clearance calculation unit (12) can calculate the magnitude of the clearance (5) from the amount of change in temperature of the fluid acquired by the temperature sensor (8) and the amount of change in output of the heater (7) based on the association information prepared in advance.

[0097] 7) In some embodiments, the clearance estimation device (1) according to 6) above, The device further includes a display unit (13) configured to display the magnitude of the clearance (5) calculated by the clearance calculation unit (12).

[0098] According to the above configuration 7), by displaying the magnitude of the clearance (5) calculated by the clearance calculation unit (12) on the display unit (13), a person who visually checks the display on the display unit (12) can easily understand the magnitude of the clearance (5).

[0099] 8) The clearance estimation device (1) according to at least one embodiment of the present disclosure includes: A clearance estimation device (1) for estimating a size of a clearance (5) formed between a rotating member (3) of a rotating machine (2) and a stationary member (4) arranged on an outer periphery side of the rotating member (3), comprising: at least one sensor device (6) including a heater (7) attached to a wall surface (31, 41) of the rotating member (3) or the stationary member (4) facing the clearance (5) and configured to heat a fluid flowing through the clearance (5), and a plurality of temperature sensors (8) arranged to surround the heater (7), the plurality of temperature sensors (8) configured to acquire a temperature of the fluid flowing around the heater (7); and a clearance estimation unit (9) that estimates the magnitude of the clearance (5) by comparing the amount of change in the temperature of the fluid acquired by each of the plurality of temperature sensors (8).

[0100] The inventors have noticed that when the size of the clearance (5) increases, the flow rate of the fluid passing through the clearance (5) increases, and therefore the flow (vortex pattern) of the fluid flowing through the clearance (5) changes. The inventors have found that by comparing the amount of change in the temperature of the fluid acquired by each of the multiple temperature sensors (8), which is a parameter capable of grasping the state of the temperature field formed by the heater (7), it is possible to grasp the flow of the fluid flowing around the heater (7) and to estimate the size of the clearance (5).

[0101] According to the above configuration 8), the clearance estimation device (1) including the sensor device (6) and the clearance estimation unit (9) can estimate the magnitude of the clearance (5) by comparing the amount of change in temperature of the fluid acquired by each of the plurality of temperature sensors (8) during operation of the rotating machine (2).

[0102] 9) In some embodiments, the clearance estimation device (1) according to 8) above, The rotating member (3) is A small diameter portion (33); a large diameter portion (34) having an outer diameter larger than that of the small diameter portion (33), the large diameter portion (34) being provided adjacent to the small diameter portion (33) on a downstream side in the flow direction of the fluid than the small diameter portion (33), the stationary member (4) includes at least one stationary-side fin (42) protruding from a stationary-side wall surface (41), which is a wall surface of the stationary member (4) facing the clearance (5), toward a wall surface (341) of the large diameter portion (34) facing the clearance (5); the at least one sensor device (6) is a second sensor device (6B) attached to the stationary side wall surface (41) and including a plurality of temperature sensors (8) arranged to surround the heater (7) as the at least one temperature sensor (8), the second sensor device (6B) being arranged downstream of a boundary between the small diameter portion (33) and the large diameter portion (34) in the flow direction of the fluid and upstream of the stationary side fin (42A) arranged most upstream of the at least one stationary side fin (42); The clearance estimation unit (9) is configured to estimate the magnitude of the clearance (5) by comparing the amount of change in the temperature of the fluid acquired by each of the plurality of temperature sensors (8) constituting the second sensor device (6B).

[0103] According to the above configuration 9), by disposing the second sensor device (6B) in a location where it is easy to grasp a change in the flow (vortex pattern) of the fluid flowing through the clearance (5) in response to a change in the size of the clearance (5), it is possible to estimate the size of the clearance (5) with higher accuracy.

[0104] 10) In some embodiments, the clearance estimation device (1) according to any one of 1) to 9) above, The at least one sensor device (6) comprises a MEMS sensor.

[0105] According to the above configuration 10), by making the sensor device (6) a MEMS sensor having a comparatively small thickness, it is possible to prevent the sensor device (6) from interfering with the flow of the fluid passing through the clearance (5), and therefore it is possible to estimate the size of the clearance (5) with higher accuracy.

[0106] 11) In some embodiments, the clearance estimation device (1) according to any one of 1) to 10) above, The at least one sensor device (6) includes a plurality of sensor devices (6) arranged at positions at which they at least partially overlap with other sensor devices (6) in the axial direction and arranged at intervals from one another in the circumferential direction.

[0107] According to the configuration of 11) above, the plurality of sensor devices (6) can grasp the distribution of the size of the clearance (5) in the circumferential direction. When the seal member constituting the seal portion is composed of a plurality of seal members arranged in a line in the circumferential direction, the distribution of the size of the clearance (5) in the circumferential direction can be taken into consideration and an appropriate replacement time can be determined for each of the plurality of seal members. By replacing the plurality of seal members constituting the seal portion at the appropriate replacement time, excessive effects of the seal members can be suppressed. In addition, by replacing the plurality of seal members constituting the seal portion at the appropriate replacement time, the operating period of the rotary machine (2) with the performance of the seal portion degraded can be shortened, and therefore a decrease in efficiency of the rotary machine (2) can be suppressed.

[0108] 12) A method for estimating clearance according to at least one embodiment of the present disclosure, comprising: A clearance estimation method for estimating a size of a clearance (5) formed between a rotating member (3) of a rotating machine (2) and a stationary member (4) arranged on an outer periphery side of the rotating member (3), comprising: a heating step of heating the fluid flowing through the clearance (5) by a heater (7) attached to a wall surface (31, 41) of the rotating member (3) or the stationary member (4) facing the clearance (5); a fluid temperature acquisition step of acquiring a temperature of the fluid flowing around the heater (7) by at least one temperature sensor (8); and a clearance estimation step of estimating the size of the clearance (5) based on the amount of change in the temperature of the fluid acquired in the fluid temperature acquisition step and the amount of change in the output of the heater (7).

[0109] The present inventors have found that the size of the clearance (5) can be estimated based on the amount of change in the temperature of the fluid acquired by the temperature sensor (8) and the amount of change in the output of the heater (7), which are parameters capable of grasping the state of the amount of heat removed from the surroundings of the heater (7). According to the method of 12) above, the size of the clearance (5) can be estimated based on the amount of change in the temperature of the fluid and the amount of change in the output of the heater (7), which are acquired in the fluid temperature acquisition step.

[0110] 13) A method for estimating clearance according to at least one embodiment of the present disclosure, comprising: A clearance estimation method for estimating a size of a clearance (5) formed between a rotating member (3) of a rotating machine (2) and a stationary member (4) arranged on an outer periphery side of the rotating member (3), comprising: a heating step of heating the fluid flowing through the clearance (5) by a heater (7) attached to a wall surface (31, 41) of the rotating member (3) or the stationary member (4) facing the clearance (5); a fluid temperature acquisition step of acquiring a temperature of the fluid flowing around the heater (7) by a plurality of temperature sensors (8) arranged to surround the heater (7); and a clearance estimation step of estimating the size of the clearance (5) by comparing the amount of change in the temperature of the fluid acquired by each of the plurality of temperature sensors (8) in the fluid temperature acquisition step.

[0111] The inventors have found that by comparing the amount of change in the temperature of the fluid acquired by each of the plurality of temperature sensors (8), which is a parameter capable of grasping the state of the temperature field formed by the heater (7), it is possible to grasp the flow of the fluid flowing around the heater (7) and estimate the size of the clearance (5). According to the method of 13) above, by comparing the amount of change in the temperature of the fluid acquired by each of the plurality of temperature sensors (8) in the fluid temperature acquisition step, it is possible to estimate the size of the clearance (5). [Explanation of symbols]

[0112] 1. Clearance Estimation Device 2 Rotating Machinery 3 Rotating parts 3A Rotating Shaft 4 Stationary Members 4A, 4B, 4C Housing 5. Clearance 6, 6A, 6B, 6C Sensor device 7 Heater 8,11 Temperature sensor 9 Clearance Estimation Section 10 Output adjustment device 11,11A Clearance calculation section 12 Display section 21, 21A, 21B Outer casing 22 Gap 31 Rotating side wall 32 Rotating fin 33 Small diameter section 34 Large diameter section 35 Downstream small diameter section 36 Upstream step surface 37 Downstream step surface 41 Stationary side wall 42, 42A, 42B Stationary fin 50A High pressure space 50B Low pressure space 61 Flexible Board 62 Surface 63 Back side 90 Electronic Control Unit 91 Input Devices 92 Output Device 93 Storage device 94 Arithmetic unit 131 Display Screen C1 Center of gravity CA center axis FD Flow direction HO Output LS downstream side T Obtain fluid temperature T0 Ambient temperature T1 constant temperature TF temperature field US upstream V1 Absolute velocity

Claims

1. 1. A clearance estimation device for estimating a size of a clearance formed between a rotating member of a rotary machine and a stationary member arranged on an outer periphery side of the rotating member, comprising: at least one sensor device including a heater attached to a wall surface of the rotating member or the stationary member facing the clearance and configured to heat a fluid flowing through the clearance, and at least one temperature sensor configured to acquire a temperature of the fluid flowing around the heater; a clearance estimation unit that estimates the size of the clearance based on an amount of change in the temperature of the fluid acquired by the at least one temperature sensor and an amount of change in an output of the heater. Clearance Estimation Device.

2. an output adjusting device that adjusts the output of the heater so that the temperature of the fluid acquired by the at least one temperature sensor becomes a predetermined constant temperature; the clearance estimation unit is configured to estimate the magnitude of the clearance based on an amount of change in the output of the heater in a state in which the temperature of the fluid is maintained at the predetermined constant temperature; The clearance estimation device according to claim 1 .

3. The at least one sensor device is attached to a stationary side wall surface, which is a wall surface of the stationary member facing the clearance. The clearance estimation device according to claim 1 or 2.

4. the rotating member includes a rotating-side fin protruding from a rotating-side wall surface, which is a wall surface of the rotating member facing the clearance, toward the stationary-side wall surface, The at least one sensor device includes a first sensor device disposed downstream of the rotating fin in the flow direction of the fluid. The clearance estimation device according to claim 3 .

5. The rotating member is A small diameter portion; a large diameter portion having an outer diameter larger than that of the small diameter portion, the large diameter portion being provided adjacent to the small diameter portion on a downstream side in a flow direction of the fluid than the small diameter portion, the stationary member includes at least one stationary side fin protruding from the stationary side wall surface toward a wall surface of the large diameter portion facing the clearance, The at least one sensor device a second sensor device including a plurality of temperature sensors arranged to surround the heater as the at least one temperature sensor, the second sensor device being arranged downstream of a boundary between the small diameter portion and the large diameter portion in a flow direction of the fluid and upstream of a stationary side fin arranged most upstream among the at least one stationary side fin; The clearance estimation unit further comprises: The second sensor device is also configured to estimate the size of the clearance by comparing the amount of change in the temperature of the fluid acquired by each of the plurality of temperature sensors constituting the second sensor device. The clearance estimation device according to claim 3 .

6. The clearance estimation unit includes: and a clearance calculation unit configured to calculate the size of the clearance from the amount of change in temperature of the fluid acquired by the at least one temperature sensor and the amount of change in output of the heater based on association information that associates the amount of change in temperature of the fluid acquired by the at least one temperature sensor, the amount of change in output of the heater, and the size of the clearance. The clearance estimation device according to claim 1 or 2.

7. Further comprising a display unit configured to display the magnitude of the clearance calculated by the clearance calculation unit. The clearance estimation device according to claim 6 .

8. 1. A clearance estimation device for estimating a size of a clearance formed between a rotating member of a rotary machine and a stationary member arranged on an outer periphery side of the rotating member, comprising: At least one sensor device including a heater attached to a wall surface of the rotating member or the stationary member facing the clearance and configured to heat a fluid flowing through the clearance, and a plurality of temperature sensors arranged to surround the heater, the plurality of temperature sensors configured to acquire a temperature of the fluid flowing around the heater; a clearance estimation unit that estimates the size of the clearance by comparing the amount of change in the temperature of the fluid acquired by each of the plurality of temperature sensors. Clearance Estimation Device.

9. The rotating member is A small diameter portion; a large diameter portion having an outer diameter larger than that of the small diameter portion, the large diameter portion being provided adjacent to the small diameter portion on a downstream side in a flow direction of the fluid than the small diameter portion, the stationary member includes at least one stationary-side fin protruding from a stationary-side wall surface, which is a wall surface of the stationary member facing the clearance, toward a wall surface of the large diameter portion facing the clearance, the at least one sensor device is attached to the stationary side wall surface, and includes a second sensor device including a plurality of temperature sensors arranged to surround the heater as the at least one temperature sensor, the second sensor device being arranged downstream of a boundary between the small diameter portion and the large diameter portion in the flow direction of the fluid and upstream of a stationary side fin arranged most upstream among the at least one stationary side fin; The clearance estimation unit is configured to estimate the magnitude of the clearance by comparing the amount of change in the temperature of the fluid acquired by each of the plurality of temperature sensors constituting the second sensor device. The clearance estimation device according to claim 8.

10. the at least one sensor device comprises a MEMS sensor; The clearance estimation device according to any one of claims 1, 2, 8 and 9.

11. The at least one sensor device includes a plurality of sensor devices arranged at positions at which the sensor devices at least partially overlap with other sensor devices in the axial direction and arranged at intervals from each other in the circumferential direction. The clearance estimation device according to any one of claims 1, 2, 8 and 9.

12. 1. A clearance estimation method for estimating a size of a clearance formed between a rotating member of a rotary machine and a stationary member arranged on an outer periphery side of the rotating member, comprising: a heating step of heating the fluid flowing through the clearance by a heater attached to a wall surface of the rotating member or the stationary member facing the clearance; a fluid temperature acquisition step of acquiring a temperature of the fluid flowing around the heater by at least one temperature sensor; a clearance estimation step of estimating a size of the clearance based on an amount of change in the temperature of the fluid acquired in the fluid temperature acquisition step and an amount of change in an output of the heater. Clearance estimation methods.

13. 1. A clearance estimation method for estimating a size of a clearance formed between a rotating member of a rotary machine and a stationary member arranged on an outer periphery side of the rotating member, comprising: a heating step of heating the fluid flowing through the clearance by a heater attached to a wall surface of the rotating member or the stationary member facing the clearance; a fluid temperature acquisition step of acquiring a temperature of the fluid flowing around the heater by a plurality of temperature sensors arranged to surround the heater; a clearance estimation step of estimating a size of the clearance by comparing amounts of change in the temperature of the fluid acquired by each of the plurality of temperature sensors in the fluid temperature acquisition step. Clearance estimation methods.

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