Method for estimating the flange surface pressure distribution in a rotary machine, method for assessing fluid leakage from flange intermediate surfaces, and program and apparatus for carrying out these methods

Abstract

A method for estimating a flange surface pressure distribution includes: a reference model receive step for receiving a three-dimensional reference shape model of a rotary machine; a measured coordinate receive step for receiving measured three-dimensional coordinate data at a plurality of positions on an upper flange surface and a lower flange surface when a housing is in an open state; a condition receive step for receiving a tightening torque and an elastic coefficient of a plurality of bolts, elastic coefficients and weights of an upper and lower housing half, and the like; a modified model generation step for generating a three-dimensional modified shape model by modifying the three-dimensional reference shape model based on the measured three-dimensional coordinate data at the plurality of positions;and a pressure distribution estimation step to obtain, by using the three-dimensional modified shape model and under the conditions received in the condition receive step, a pressure distribution of a flange surface in a fixed state.

Description

Method for estimating flange surface pressure distribution in rotary machinery, method for evaluating fluid leakage from between flange surfaces, and program and device for executing these methods

[0001] The present disclosure relates to a method for estimating the surface pressure distribution on flange surfaces of an upper half casing and a lower half casing that cover the outer periphery of a rotor in a rotary machine, a method for evaluating fluid leakage from between flange surfaces, and a program and apparatus for executing these methods. This application claims priority to Japanese Patent Application No. 2022-027441, filed on February 25, 2022, the contents of which are incorporated herein by reference.

[0002] A rotary machine such as a steam turbine includes a rotor rotatable about a horizontally extending axis, a casing that covers the outer periphery of the rotor, and stationary components such as a diaphragm that are disposed within and attached to the casing. The casing generally includes an upper half-casing on the upper side, a lower half-casing on the lower side, and a plurality of bolts that fasten the upper and lower half-casings together. The upper half-casing has an upper flange with an upper flange surface facing downward. The lower half-casing has a lower flange with an upper flange surface facing upward and vertically opposing the upper flange surface.

[0003] During inspection of a rotating machine, the upper half casing is removed from the lower half casing to open the machine, and multiple components constituting the rotating machine are inspected and repaired as necessary. Casings in rotating machines such as steam turbines can undergo inelastic deformation such as creep deformation due to heat during operation. Therefore, the lower half casing and the upper half casing in the open state after operation are technically deformed from the time of shipment from the factory. After the inspection is completed, the multiple components are assembled. This assembly process includes a step of fastening the upper half casing to the lower half casing using multiple bolts to create a fastened state. In the process of changing the lower half casing and the upper half casing from the open state to the fastened state, the lower half casing and the upper half casing are further deformed.

[0004] In such rotating machines, the sealing performance between the upper flange and the lower flange is important, as described in the following Non-Patent Document 1. In this Non-Patent Document 1, the method for checking the sealing performance involves first applying paint to one of the objects to be checked, and then fastening the upper flange and the lower flange with bolts. The bolts are then removed, and the state of paint adhesion on the remaining object to be checked is checked.

[0005] "Valqua Technology Magazine Summer Issue No. 33 Summer 2017", edited and published by Nippon Valqua Industries Co., Ltd., August 31, 2017, p. 10

[0006] In the technology described in Non-Patent Document 1, in order to check the sealing between the upper flange and the lower flange, the upper flange and the lower flange must be fastened together with bolts, and then the bolts must be removed to return the upper and lower casing halves to an open state. Therefore, the technology described in Non-Patent Document 1 has the problem that it takes time and effort to check the sealing between the upper flange and the lower flange.

[0007] Therefore, an object of the present disclosure is to provide a technology that can reduce the effort required to check the sealing between two flanges.

[0008] A method for estimating flange surface pressure distribution in a rotary machine, as one aspect for achieving the above-mentioned object, is applied to the following rotary machine. The rotary machine includes a rotor rotatable about an axis extending horizontally, a casing through which a working fluid can flow and which covers the outer periphery of the rotor, and a stationary component disposed within the casing and attached to the casing. The casing has an upper half-casing on an upper side, a lower half-casing on a lower side, and a plurality of bolts fastening the upper half-casing and the lower half-casing together. The upper half-casing has an upper flange having an upper flange surface facing downward. The lower half-casing has a lower flange having a lower flange surface facing upward and facing the upper flange surface in the vertical direction. The upper flange and the lower flange are formed with bolt holes that penetrate in the vertical direction and through which each of the plurality of bolts can be inserted. In the above method for estimating flange surface distribution in a rotary machine, a reference model receiving step of receiving a three-dimensional reference shape model of the rotary machine that has been acquired in advance; an actual coordinate receiving step of receiving measured three-dimensional coordinate data at a plurality of positions on the upper flange surface and measured three-dimensional coordinate data at a plurality of positions on the lower flange surface in an open state in which the upper half casing and the lower half casing are not fastened by the plurality of bolts after the rotary machine has been disassembled; and a step of receiving measured three-dimensional coordinate data at a plurality of positions on the lower flange surface, the tightening torque of the plurality of bolts, the elastic modulus of the plurality of bolts, the elastic modulus of the upper half casing and the lower half casing, and the elastic modulus of the upper half casing and the lower half casing. a condition receiving process for receiving conditions including the weight of the casing and the weight of the stationary part; a modified model creation process for modifying the three-dimensional reference shape model based on the measured three-dimensional coordinate data at multiple positions received in the measured coordinate receiving process to create a three-dimensional modified shape model; and a pressure distribution estimation process for using the three-dimensional modified shape model to determine the pressure distribution on one of the lower flange surface and the upper flange surface when the upper half casing and the lower half casing are in a fastened state fastened with the multiple bolts under the conditions received in the condition receiving process.

[0009] Typically, when checking the sealing between the upper flange and the lower flange, paint is first applied to one of the objects to be checked, and then the upper flange and the lower flange are fastened together with bolts. The bolts are then removed, the upper casing half and the lower casing half are returned to an open state, and the paint adhesion condition of the remaining object to be checked is checked. However, in this embodiment, the pressure distribution on one of the upper flange surface and the lower flange surface when the casing is in a fastened state is estimated. Therefore, in this embodiment, there is no need to take the trouble of fastening the casing from an open state and then returning it to an open state in order to check the sealing between the upper flange and the lower flange, thereby reducing the effort required to check the sealing.

[0010] A program for estimating flange surface pressure distribution in a rotary machine, as one aspect for achieving the above-mentioned object, is applied to the following rotary machine. The rotary machine includes a rotor rotatable about an axis extending horizontally, a casing through which a working fluid can flow and which covers the outer periphery of the rotor, and a stationary component disposed within the casing and attached to the casing. The casing has an upper half-casing on an upper side, a lower half-casing on a lower side, and a plurality of bolts fastening the upper half-casing and the lower half-casing together. The upper half-casing has an upper flange having an upper flange surface facing downward. The lower half-casing has a lower flange having a lower flange surface facing upward and facing the upper flange surface in the vertical direction. The upper flange and the lower flange are formed with bolt holes that penetrate in the vertical direction and through which each of the plurality of bolts can be inserted. The program for estimating flange surface distribution in the above rotary machine is a reference model receiving step of receiving a three-dimensional reference shape model of the rotary machine that has been acquired in advance; an actual coordinate receiving step of receiving measured three-dimensional coordinate data at a plurality of positions on the upper flange surface and measured three-dimensional coordinate data at a plurality of positions on the lower flange surface in an open state in which the upper half casing and the lower half casing are not fastened by the plurality of bolts after the rotary machine has been disassembled; and a step of receiving measured three-dimensional coordinate data at a plurality of positions on the lower flange surface after disassembling the rotary machine and in which the upper half casing and the lower half casing are not fastened by the plurality of bolts. The computer is caused to execute a condition receiving process for receiving conditions including the weight of the stationary part and the weight of the stationary part; a modified model creation process for modifying the three-dimensional reference shape model based on the measured three-dimensional coordinate data at multiple positions received in the measured coordinate receiving process to create a three-dimensional modified shape model; and a pressure distribution estimation process for using the three-dimensional modified shape model to determine the pressure distribution on one of the lower flange surface and the upper flange surface when the upper half casing and the lower half casing are in a fastened state fastened with the multiple bolts under the conditions received in the condition receiving process.

[0011] By having a computer execute the program of this aspect, it is possible to reduce the effort required to check the sealing between the upper flange surface and the lower flange surface, as in the method of the previous aspect.

[0012] As one aspect for achieving the above object, an estimation device for flange surface pressure distribution in a rotary machine is applied to the following rotary machine. The rotary machine includes a rotor rotatable about an axis extending horizontally, a casing through which a working fluid can flow and which covers the outer periphery of the rotor, and a stationary component disposed within the casing and attached to the casing. The casing has an upper half-casing on an upper side, a lower half-casing on a lower side, and a plurality of bolts fastening the upper half-casing and the lower half-casing together. The upper half-casing has an upper flange having an upper flange surface facing downward. The lower half-casing has a lower flange having a lower flange surface facing upward and facing the upper flange surface in the vertical direction. The upper flange and the lower flange are formed with bolt holes that penetrate in the vertical direction and through which each of the plurality of bolts can be inserted. The estimation device for flange surface pressure distribution in the above rotary machine is a reference model receiving unit that receives a three-dimensional reference shape model of the rotary machine that has been acquired in advance; an actual coordinate receiving unit that receives measured three-dimensional coordinate data at a plurality of positions on the upper flange surface and measured three-dimensional coordinate data at a plurality of positions on the lower flange surface in an open state in which the upper half casing and the lower half casing are not fastened by the plurality of bolts after the rotary machine has been disassembled; and a measuring unit that receives measured three-dimensional coordinate data at a plurality of positions on the lower flange surface, the tightening torque of the plurality of bolts, the elastic modulus of the plurality of bolts, the elastic modulus of the upper half casing and the lower half casing, and the elastic modulus of the upper half casing and the lower half casing. The system comprises a condition receiving unit that receives conditions including the weight of the casing and the weight of the stationary part; a modified model creation unit that modifies the three-dimensional reference shape model based on the measured three-dimensional coordinate data at multiple positions received by the measured coordinate receiving unit to create a three-dimensional modified shape model; and a pressure distribution estimation unit that uses the three-dimensional modified shape model to calculate the pressure distribution on one of the lower flange surface and the upper flange surface when the upper half casing and the lower half casing are in a fastened state fastened with the multiple bolts under the conditions received by the condition receiving unit.

[0013] In this aspect, as in the method of the previous aspect, the effort required to check the sealing between the upper flange surface and the lower flange surface can be reduced.

[0014] In one aspect of the present disclosure, the flange surface pressure distribution in a rotary machine can be estimated, thereby reducing the effort required to check the sealing performance between two flanges.

[0015] FIG. 1 is a schematic diagram showing a schematic configuration of a steam turbine as a rotary machine in an embodiment according to the present disclosure. FIG. 2 is a schematic diagram showing a schematic outer shape of a steam turbine as a rotary machine in an embodiment according to the present disclosure. FIG. 3 is a plan view of a main part of an upper half casing and a main part of a lower half casing in an embodiment according to the present disclosure. FIG. 4 is a cross-sectional view of a casing in an open state in an embodiment according to the present disclosure. FIG. 5 is a cross-sectional view of a casing in a fastened state in an embodiment according to the present disclosure. FIG. 6 is a functional block diagram of a leak evaluation device in an embodiment according to the present disclosure. FIG. 7 is a flowchart showing an execution procedure of a leak evaluation method in an embodiment according to the present disclosure. FIG. 8 is an explanatory diagram showing positions at which measured three-dimensional coordinate data is acquired on a flange surface in an embodiment according to the present disclosure. FIG. 9 is an image diagram showing a relative positional relationship between a three-dimensional reference shape model and points indicated by measured three-dimensional coordinate data at multiple positions on an actual flange surface in an embodiment according to the present disclosure. FIG. 10 is an explanatory diagram for explaining multiple polygon data in an embodiment according to the present disclosure. FIG. 11 is an explanatory diagram for explaining extraction of specific multiple polygon data from multiple polygon data in an embodiment according to the present disclosure. FIG. 1 is an image diagram showing the relative positional relationship between a three-dimensional reference shape model and points extracted by a polygon data extraction process from points indicated by measured three-dimensional coordinate data at multiple positions on the actual flange surface in an embodiment according to the present disclosure. FIG. 2 is an explanatory diagram showing a process of obtaining surface shape data of the flange surface using measured three-dimensional coordinate data at multiple positions on the actual flange surface in an embodiment according to the present disclosure. FIG. 3 is an explanatory diagram showing a process of creating a three-dimensional corrected shape model in an embodiment according to the present disclosure. FIG. 4 is an explanatory diagram showing a surface pressure distribution on the flange surface in an embodiment according to the present disclosure. FIG. 5 is an explanatory diagram showing a high-leak region on the flange surface in an embodiment according to the present disclosure. FIG. 6 is an explanatory diagram showing a creep model in an embodiment according to the present disclosure.

[0016] Hereinafter, embodiments of a method for estimating flange surface pressure distribution in a rotary machine, a method for evaluating leakage from between flange surfaces, a program for executing these methods, and an apparatus for executing these methods according to the present disclosure will be described.

[0017] [Embodiment of Rotating Machine] A rotating machine according to this embodiment will be described with reference to FIGS. 1 to 5. FIG.

[0018] 1 and 2 , the rotary machine of this embodiment is a steam turbine 10. This steam turbine 10 includes a rotor 15 that rotates about an axis Ar that extends horizontally, a casing 30 that covers the outer periphery of the rotor 15, a first bearing device 12a and a second bearing device 12b that rotatably support the rotor 15, a plurality of diaphragms 20, a first shaft seal device 13a and a second shaft seal device 13b that seal a gap between the casing 30 and the rotor 15, and a base 11 that supports the casing 30 from below.

[0019] Here, the direction in which the axis Ar extends is referred to as the axial direction Dy, the circumferential direction relative to the axis Ar is simply referred to as the circumferential direction Dc, and the radial direction relative to the axis Ar is simply referred to as the radial direction Dr. In addition, in this radial direction Dr, the side closer to the axis Ar is referred to as the radially inner side Dri, and the side farther away from the axis Ar is referred to as the radially outer side Dro. In addition, U used in the symbols in the figures refers to the upper half, and L refers to the lower half.

[0020] The rotor 15 has a rotor shaft 16 extending in the axial direction Dy and a plurality of moving blade rows 17 attached to the rotor shaft 16 and aligned in the axial direction Dy. Each of the plurality of moving blade rows 17 has a plurality of moving blades aligned in the circumferential direction Dc relative to the axis Ar. Both ends of the rotor shaft 16 protrude from the casing 30 in the axial direction Dy. One end of the rotor shaft 16 in the axial direction Dy is rotatably supported by a first bearing device 12a attached to the frame 11. The other end of the rotor shaft 16 in the axial direction Dy is rotatably supported by a second bearing device 12b attached to the frame 11.

[0021] The first shaft seal device 13a is provided at one end in the axial direction Dy of the casing 30. The second shaft seal device 13b is provided at the other end in the axial direction Dy of the casing 30. Both the first shaft seal device 13a and the second shaft seal device 13b are devices that seal the gap between the rotor shaft 16 and the casing 30.

[0022] The multiple diaphragms 20 are arranged in the axial direction Dy inside the casing 30. Each of the multiple diaphragms 20 has a lower half diaphragm 20L constituting a portion below the axis Ar and an upper half diaphragm 20U constituting a portion above the axis Ar. Each of the lower half diaphragm 20L and the upper half diaphragm 20U has a plurality of stator vanes 22 arranged in the circumferential direction Dc, a diaphragm inner ring 23 connecting radially inner portions Dri of the multiple stator vanes 22 to each other, a diaphragm outer ring 24 connecting radially outer portions Dro of the multiple stator vanes 22 to each other, and a sealing device 25 attached to the radially inner side Dri of the diaphragm inner ring 23. This sealing device 25 seals the gap between the diaphragm inner ring 23 and the rotor shaft 16.

[0023] The first shaft seal device 13 a and second shaft seal device 13 b described above, as well as the multiple diaphragms 20, are all stationary components that extend in the circumferential direction about the axis Ar and are attached to the casing 30.

[0024] 2, the casing 30 has a lower half casing 30L constituting a portion below the axis Ar, an upper half casing 30U constituting a portion above the axis Ar, and a plurality of bolts 39 for fastening the upper half casing 30U to the lower half casing 30L. The lower half casing 30L has a lower half casing main body 31L extending in the circumferential direction Dc, lower flanges 32L protruding radially outward in the direction Dro from both ends of the lower half casing main body 31L in the circumferential direction Dc, and first and second supported portions 35a and 35b connected to the lower flange 32L and supported from below by the frame 11. The upper half casing 30U has an upper half casing main body 31U extending in the circumferential direction Dc and upper flanges 32U protruding radially outward in the direction Dro from both ends of the upper half casing main body 31U in the circumferential direction Dc.

[0025] 2 to 5, the surface of the lower flange 32L facing upward forms a lower flange surface 33L. The surface of the upper flange 32U facing downward forms an upper flange surface 33U. The lower flange surface 33L and the upper flange surface 33U face each other in the vertical direction Dz.

[0026] The first supported portion 35a protrudes from one of both sides of the lower flange 32L in the axial direction Dy to one side. The second supported portion 35b protrudes from the other of both sides of the lower flange 32L in the axial direction Dy to the other side. Therefore, the second supported portion 35b is spaced apart in the axial direction Dy from the first supported portion 35a. In this embodiment, an upper surface 35ap of the first supported portion 35a and an upper surface 35bp of the second supported portion 35b are surfaces that are continuous with the lower flange surface 33L.

[0027] The lower flange 32L and the upper flange 32U are formed with bolt holes 34 that penetrate in the vertical direction Dz and through which a plurality of bolts 39 can be inserted, respectively. The lower half casing 30L and the upper half casing 30U are fastened together by the bolts 39 that are inserted through the bolt holes 34 of the lower flange 32L and the bolt holes 34 of the upper flange 32U.

[0028] A plurality of stationary component storage sections 36 are formed on the inner circumferential surfaces of the lower half casing body 31L and the upper half casing body 30U, respectively, to store the plurality of stationary components described above. Each stationary component storage section 36 of the lower half casing body 31L is a groove recessed radially outward from the inner circumferential surface of the lower half casing body 31L and extending in the circumferential direction Dc. Similarly, each stationary component storage section 36 of the upper half casing body 31U is a groove recessed radially outward from the inner circumferential surface of the upper half casing body 31U and extending in the circumferential direction Dc. The diaphragm 20, which is a type of stationary component, is supported by a portion of the stationary component storage section 36 extending in the circumferential direction Dc, near the flange surface.

[0029] The inner peripheral surface of the casing 30 is exposed to high-temperature steam during operation of the steam turbine 10. For this reason, inelastic deformation such as creep deformation may occur in the casing 30 during operation of the steam turbine 10. As a result of this deformation, in an open state in which the upper half casing 30U is not fastened to the lower half casing 30L, the positions of the lower flange surface 33L and the upper flange surface 33U in the vertical direction Dz change depending on their positions in the axial direction Dy, as shown in FIG.

[0030] When the upper half casing 30U deformed as described above is fastened to the lower half casing 30L deformed as described above to put the casing 30 in a fastened state, the positions of the lower flange surface 33L and the upper flange surface 33U in the vertical direction Dz further change depending on the positions in the axial direction Dy, as shown in Fig. 5. In other words, when the casing changes from the open state to the fastened state, the upper flange surface 33U and the lower flange surface 33L are deformed.

[0031] In the steam turbine 10, the sealing performance between the upper flange surface 33U and the lower flange surface 33L is important to prevent steam leakage from between the upper flange surface 33U and the lower flange surface 33L. As described above, the casing deforms when it changes from an open state to a fastened state. Therefore, even if the shapes of the upper flange surface and the lower flange surface in the open state are known in advance, it is not possible to immediately determine the sealing performance between the upper flange surface 33U and the lower flange surface 33L from these surface shapes.

[0032] Therefore, we will explain embodiments of a flange surface pressure distribution estimation device that estimates the surface pressure distribution on the flange surfaces of a steam turbine 10, which is a rotary machine, a method for evaluating leakage from between flange surfaces, a program for executing these methods, and a device that executes these methods.

[0033] [Embodiment of Flange Surface Pressure Distribution Estimation Device and Leak Evaluation Device] A flange surface pressure distribution estimation device and a leak evaluation device in this embodiment will be described with reference to FIG.

[0034] The leak evaluation device 50 in this embodiment includes a flange surface pressure distribution estimation device 50a. This leak evaluation device 50 is a computer. This leak evaluation device 50 includes a CPU (Central Processing Unit) 60 that performs various calculations, a memory 57 that serves as a work area for the CPU 60, an auxiliary storage device 58 such as a hard disk drive device, a manual input device (input device) 51 such as a keyboard or a mouse, a display device (output device) 52, an input / output interface 53 for the manual input device 51 and the display device 52, a device interface (input device) 54 for transmitting and receiving data to and from a three-dimensional shape measurement device 69 such as a three-dimensional laser measurement device, a communication interface (input / output device) 55 for communicating with the outside via a network N, and a storage / playback device (input / output device) 56 that stores and plays back data on a disk-type storage medium D, which is a type of non-transitory storage medium.

[0035] A leak evaluation program 58p is pre-stored in the auxiliary storage device 58. The leak evaluation program 58p includes a flange surface pressure distribution estimation program 58pa. The leak evaluation program 58p is loaded into the auxiliary storage device 58 from a disk-type storage medium D, which is a type of non-transitory storage medium, via the storage / playback device 56. The leak evaluation program 58p may also be loaded into the auxiliary storage device 58 from an external device via the communication interface 55.

[0036] The CPU 60 functionally includes a reference model receiving unit 61, a measured coordinate receiving unit 63, a condition receiving unit 64, a modified model creation unit 65, a pressure distribution estimation unit 66, and a leak evaluation unit 67. Each of these functional units 61, 63 to 67 functions when the CPU 60 executes a leak evaluation program 58p stored in the auxiliary storage device 58. Of the above functional units 61, 63 to 67, the functional units 61, 63 to 66, excluding the leak evaluation unit 67, function when the CPU 60 executes a flange surface pressure distribution estimation program 58pa included in the leak evaluation program 58p. The flange surface pressure distribution estimation device 50a included in the leak evaluation device 50 includes the above functional units 61, 63 to 66, excluding the leak evaluation unit 67, of the above functional units 61, 63 to 67. The operation of each of the above functional units 61, 63 to 67 will be described later.

[0037] "First embodiment of a method for estimating flange surface pressure distribution in a rotary machine and a method for evaluating fluid leakage from between flange surfaces" A method for estimating flange surface pressure distribution and a method for evaluating fluid leakage from between flange surfaces in this embodiment will be described with reference to the flowchart shown in Fig. 7. The method for estimating flange surface pressure distribution and the method for evaluating fluid leakage from between flange surfaces are executed by the leak evaluation device 50 described above.

[0038] An operator inputs a previously acquired three-dimensional reference shape model 80 of the steam turbine 10 to the leak evaluation device 50. This input method may be any of input using the manual input device 51, input from a computer on which the three-dimensional reference shape model 80 is stored via the network N, and input from a disk-type storage medium D on which the three-dimensional reference shape model 80 is stored via the storage / reproduction device 56. As described above, the reference model receiving unit 61 of the leak evaluation device 50 receives the input of the three-dimensional reference shape model 80 from outside and stores it in the auxiliary storage device 58 (reference model receiving step S1).

[0039] The three-dimensional reference shape model 80 is a model in which the components constituting the steam turbine 10 are divided into a plurality of infinitesimal elements using a mesh in order to simulate deformation of the components using the finite element method or the like. This three-dimensional reference shape model 80 may be a model represented by three-dimensional design data created when the steam turbine 10 was designed, or may be a model represented by three-dimensional data obtained by actual measurements, for example, before the steam turbine 10 was shipped from the factory or during the previous periodic inspection. In other words, this three-dimensional reference shape model 80 may be a model represented by three-dimensional data obtained before operation before the periodic inspection. From this three-dimensional reference shape model 80, three-dimensional coordinate data for each position of the multiple components constituting the steam turbine 10 can be obtained.

[0040] The steam turbine 10 is disassembled and reassembled each time an inspection or the like is performed. When disassembly of the steam turbine 10 is complete, the upper half casing 30U is removed from the lower half casing 30L, as shown in FIG. 4 . As a result, the casing 30 is in an open state in which the upper half casing 30U and the lower half casing 30L are not fastened together by the bolts 39. Furthermore, the rotor 15, the multiple diaphragms 20, the first shaft seal device 13a, and the second shaft seal device 13b are removed from the casing 30 and disposed outside the casing 30. Note that, although the lower half casing 30L may be removed from the frame 11 when disassembly of the steam turbine 10 is complete, it is assumed here that the lower half casing 30L is supported by the frame 11.

[0041] After disassembling the steam turbine 10 as described above and opening the casing 30, the worker uses a three-dimensional shape measuring device 69, such as a three-dimensional laser measuring device, to measure three-dimensional coordinate values ​​at multiple positions 78 on the upper flange surface 33U and multiple positions 78 on the lower flange surface 33L, as shown in FIG. 8 . At this time, it is desirable to ensure a sufficient number of measurement points to accurately reproduce the detailed shapes of the upper flange surface 33U and the lower flange surface 33L. The worker then transfers the three-dimensional coordinate values ​​at the multiple positions 78 on the upper flange surface 33U and the multiple positions 78 on the lower flange surface 33L as measured three-dimensional coordinate data from the three-dimensional shape measuring device 69 to the leak evaluation device 50. The measured coordinate receiving unit 63 of the leak evaluation device 50 receives the measured three-dimensional coordinate data at the multiple positions 78 on the upper flange surface 33U and the measured three-dimensional coordinate data at the multiple positions 78 on the lower flange surface 33L (measured coordinate receiving step S3).

[0042] The three-dimensional coordinate data in this embodiment includes coordinate values ​​indicating the position in the axial direction Dy extending horizontally, coordinate values ​​indicating the position in the up-down direction Dz perpendicular to the axial direction Dy, and coordinate values ​​indicating the position in the lateral direction Dx extending horizontally and perpendicular to the axial direction Dy.

[0043] The operator further inputs the conditions for the steam leak evaluation using the manual input device 51 or the like. The condition receiving unit 64 of the leak evaluation device 50 receives these conditions (condition receiving step S4). These conditions include the tightening torque of the plurality of bolts 39, the elastic modulus of the plurality of bolts 39, the elastic modulus of the upper half casing 30U and the lower half casing 30L, the weights of the upper half casing 30U and the lower half casing 30L, and the weight of stationary parts.

[0044] When the measured coordinate receiving unit 63 receives multiple measured three-dimensional coordinate data and the condition receiving unit 64 receives conditions, the modified model creation unit 65 of the leak evaluation device 50 modifies the three-dimensional reference shape model 80 based on the measured three-dimensional coordinate data at multiple positions 78 received by the measured coordinate receiving unit 63, and creates a three-dimensional modified shape model 80m (see Figure 14) (modified model creation process S5).

[0045] For example, as shown in Fig. 9, points 85 indicated by a plurality of measured three-dimensional coordinate data exist with variation within a certain range of accuracy on a flange surface 81 of a three-dimensional reference shape model 80. The modified model creation unit 65 first creates a plurality of polygon data using the plurality of measured three-dimensional coordinate data. Polygon data is data that defines a polygonal plane. As shown in Fig. 10, the modified model creation unit 65 connects, with line segments, a plurality of points 85 that are close to each other among the points 85 indicated by the measured three-dimensional coordinate data at a plurality of positions, and defines a polygonal plane enclosed by these line segments as a polygon 86.

[0046] The modified model creation unit 65 then extracts, from the plurality of polygon data, a plurality of polygon data satisfying a certain condition, as shown in FIG. 11 . In FIG. 11 , a pattern is applied to polygons 86 a identified by the extracted polygon data, while no pattern is applied to polygons 86 b identified by the non-extracted polygon data. The XY plane in FIG. 11 is a plane parallel to the flange surface 81 of the three-dimensional reference shape model 80. The aforementioned condition is that the inclination of the polygon 86 identified by the polygon data relative to the flange surface 81 of the three-dimensional reference shape model 80 is within a predetermined inclination. The modified model creation unit 65 first calculates the normal n of each of the plurality of polygons 86. Next, the modified model creation unit 65 calculates the angle α between the normal p to the flange surface 81 of the three-dimensional reference shape model 80 and the normal n of the polygon 86 for each of the plurality of polygons 86. Then, the corrected model creating unit 65 extracts from the plurality of polygon data pieces a plurality of polygon data pieces in which the angle α between the perpendicular p to the flange surface 81 and the normal n of the polygon 86 is within a predetermined angle (predetermined inclination).

[0047] This data extraction process is performed to exclude measured three-dimensional coordinate data of points on the wall surface of the flange surface edge and points on the inner peripheral surfaces of the bolt holes 34 that penetrate the flange surface from the measured three-dimensional coordinate data of the plurality of points 85 received in the measured coordinate receiving step S3. Therefore, the number of points 85 after this extraction process is smaller than the number of points 85 before, as shown in Fig. 12. In particular, with respect to the surface 82 inclined with respect to the flange surface 81 in the three-dimensional reference shape model 80, the number of points 85 after the extraction process is significantly smaller than the number of points 85 before.

[0048] 13, the modified model creation unit 65 next divides the virtual three-dimensional space including the flange surface 81 into a plurality of three-dimensional blocks 83. Then, the modified model creation unit 65 determines a representative point 87 in the target three-dimensional block 83 for each of the plurality of three-dimensional blocks 83. Specifically, the modified model creation unit 65 determines the median point of the plurality of points 85 included in the target three-dimensional block 83 from among the plurality of points 85 included in the polygon 86a specified by the plurality of polygon data extracted in the extraction process as the representative point 87 in the target three-dimensional block 83.

[0049] The measured three-dimensional coordinate data for point 85 obtained by the three-dimensional shape measuring device 69 contains errors. For example, if the three-dimensional shape measuring device 69 is a three-dimensional laser measuring device, the presence of a minute floating object between the measurement target and the three-dimensional laser measuring device will result in errors in the measured three-dimensional coordinate data measured by the three-dimensional laser measuring device. Therefore, in this embodiment, the median point of the multiple points 85 contained in the three-dimensional block 83 is set as a representative point 87 in the three-dimensional block 83, thereby narrowing the error range of the three-dimensional coordinate data for point 85 obtained by the three-dimensional shape measuring device 69. Note that if the number of multiple points 85 contained in the three-dimensional block 83 is extremely small, the representative point 87 is not set from the three-dimensional block 83. This is because, if the number of points 85 is extremely small, even if a representative point 87 is set from the multiple points 85, the error range of the three-dimensional coordinate data of the representative point 87 does not necessarily narrow.

[0050] The representative point 87 may be determined by a robust estimation or a biweight estimation based on the Lorentz distribution of a plurality of points 85 included in the polygon 86a specified by a plurality of polygon data extracted in the extraction process.

[0051] The corrected model creation unit 65 connects the representative points 87 of each of the plurality of three-dimensional blocks 83 with planes or curved surfaces as complementary surfaces to create surface shape data of complementary surfaces including the representative points 87 of each of the plurality of three-dimensional blocks 83. This surface shape data is expressed by a function F that indicates the shape of the entire flange surface.

[0052] 14 , the modified model creation unit 65 modifies the three-dimensional reference shape model 80 using this function F to create a three-dimensional modified shape model 80m. Specifically, the modified model creation unit 65 converts the coordinate value zg, of the coordinate values ​​xg indicating the position in the lateral direction Dx, the coordinate value yg indicating the position in the axial direction Dy, and the coordinate values ​​zg indicating the position in the up-down direction Dz, for each grid 84 included in the flange surface 81 of the three-dimensional reference shape model 80, into a coordinate value zm for the coordinate values ​​xg and yg calculated by the function F. As described above, the modified model creation unit 65 changes the coordinate value zg for each grid 84 included in the flange surface 81 of the three-dimensional reference shape model 80, and creates a three-dimensional modified shape model 80m. This completes the modified model creation process S5.

[0053] Once the three-dimensional corrected shape model 80m is created, the pressure distribution estimation unit 66 uses this three-dimensional corrected shape model 80m to simulate the distribution of pressure acting on one of the upper flange surface 33U and the lower flange surface 33L under the conditions accepted in the condition acceptance step S4 (pressure distribution estimation step S6). Here, the pressure distribution estimation unit 66 first simulates the pressure acting on the mesh flange surface for all meshes in the three-dimensional corrected shape model 80m, including surfaces forming the flange surfaces (hereinafter referred to as mesh flange surfaces). The pressure distribution estimation unit 66 then determines the region of the flange surface where the mesh flange surface is located within a predetermined pressure range as the region of the flange surface where pressure within the predetermined pressure range is applied. The pressure distribution estimation unit 66 displays the distribution of pressure acting on the flange surface on the display device 52, as shown in FIG. 15 , for example.

[0054] The above-described operation of the leak evaluation device 50 is performed by the flange surface pressure distribution estimation device 50 a included in the leak evaluation device 50 .

[0055] Once the pressure distribution on the flange surface has been determined, the leak evaluation unit 67 of the leak evaluation device 50 determines high-leakage regions within this flange surface where steam is likely to leak (leak evaluation step S7). Here, the leak evaluation unit 67 determines regions where the value obtained by dividing the pressure indicated by the previously determined pressure distribution by the maximum pressure or rated pressure of the steam (working fluid) is less than a predetermined allowable value, and defines these regions as high-leakage regions. For example, as shown in FIG. 16 , the leak evaluation unit 67 displays high-leakage regions 89 within the flange surface on the display device 52.

[0056] If a high-leakage region 89 exists on the flange surface, the worker sets a high tightening torque for the bolt 39 inserted into the bolt hole 34 closest to this high-leakage region 89. In this case, the worker changes the material of this bolt 39 as necessary so that the bolt 39 can withstand the tightening torque that is set.

[0057] As explained in the Background Art section, when checking the sealing between the upper flange 32U and the lower flange 32L, paint is first applied to one of the objects to be checked, and then the upper flange 32U and the lower flange 32L are fastened together with the bolts 39. The bolts 39 are then removed, the upper casing half 30U and the lower casing half 30L are returned to an open state, and the paint adhesion condition of the remaining object to be checked is checked. However, in this embodiment, the pressure distribution applied to one of the upper flange surface 33U and the lower flange surface 33L when the casing 30 is in a fastened state is estimated by simulation. Therefore, in this embodiment, there is no need to take the trouble of fastening the casing 30 from an open state and then returning it to an open state to check the sealing between the upper flange 32U and the lower flange 32L, thereby reducing the effort required to check the sealing.

[0058] Furthermore, in this embodiment, the high leakage area 89 can be estimated on the flange surface, so that the sealing performance can be easily confirmed.

[0059] In this embodiment, the pressure distribution on the flange surface and the high leak area 89 are displayed on the display device 52. However, when the high leak area 89 is displayed on the display device 52, it is not necessary to display the pressure distribution on the flange surface on the display device 52.

[0060] In this embodiment, the distribution of pressure applied to the flange surface and the high leak region 89 are estimated. However, it is also possible to estimate the distribution of pressure applied to the flange surface without estimating the high leak region 89.

[0061] In this embodiment, the reference model receiving step S1 is followed by the measured coordinate receiving step S3, which is then followed by the condition receiving step S4. However, the reference model receiving step S1 and the measured coordinate receiving step S3 may be performed in any order as long as they are performed before the corrected model creation step S5. Furthermore, the condition receiving step S4 may be performed in any order as long as it is performed before the pressure distribution estimation step S6.

[0062] "Second embodiment of a method for estimating flange surface pressure distribution in a rotary machine and a method for evaluating fluid leakage from between flange surfaces" In the first embodiment, the pressure distribution acting on the flange surfaces and the high leakage region 89 are estimated when the casing 30 is in a fastened state. On the other hand, in the present embodiment, the pressure distribution acting on the flange surfaces and the high leakage region 89 are estimated when the casing 30 is in a fastened state and the steam turbine 10 is in operation.

[0063] The device that executes the method in this embodiment is the same as the device 50 described with reference to Fig. 6. The execution procedure of this method is the same as the execution procedure described with reference to the flowchart shown in Fig. 7. However, in this embodiment, the conditions accepted in the condition accepting step S4 are different from the conditions accepted in the condition accepting step S4 in the first embodiment.

[0064] In the condition receiving step S4 of this embodiment, in addition to the conditions received in the condition receiving step S4 of the first embodiment, the condition receiving unit 64 receives as conditions the pressure distribution and temperature distribution inside the casing 30 when the steam turbine 10 is operating, the temperature outside the casing 30, the thrust force acting on the stationary components, the linear expansion coefficient according to the temperature of the bolts 39, the linear expansion coefficient according to the temperature of the upper half casing 30U and the lower half casing 30L, and the thermal conductivity according to the temperature.

[0065] In the pressure distribution estimation step S6 in this embodiment, the pressure distribution estimation unit 66 uses the conditions received in the condition receiving step S4 to simulate the distribution of pressure acting on the flange surface when the casing 30 is in a fastened state and the steam turbine 10 is operating.

[0066] In the leak evaluation step S7 in this embodiment, the leak evaluation unit 67 also determines a high leak area 89 in this flange surface where steam is likely to leak.

[0067] In this embodiment, the pressure distribution on the flange surface when the casing 30 is in a fastened state and the steam turbine 10 is in operation is estimated by simulation. Therefore, in this embodiment, it is possible to confirm the sealing performance when the steam turbine 10 is in operation.

[0068] In addition, in the condition reception process S4 of this embodiment, in order to improve the accuracy of the pressure distribution simulation, the heat transfer coefficient between the steam and the casing 30 may also be received according to the temperatures of the upper half casing 30U and the lower half casing 30L.

[0069] "Third embodiment of a method for estimating flange surface pressure distribution in a rotary machine and a method for evaluating fluid leakage from between flange surfaces" In the first embodiment, the pressure distribution acting on the flange surfaces and the high leakage region 89 are estimated when the casing 30 is in a fastened state. On the other hand, in the present embodiment, the pressure distribution acting on the flange surfaces and the high leakage region 89 are estimated when the casing 30 is in a fastened state, the steam turbine 10 is in operation, and after a change in the steam flow rate.

[0070] The device that executes the method in this embodiment is the same as the device 50 described with reference to Fig. 6. The execution procedure of this method is the same as the execution procedure described with reference to the flowchart shown in Fig. 7. However, in this embodiment, the conditions accepted in the condition accepting step S4 are different from the conditions accepted in the condition accepting step S4 in the first embodiment.

[0071] In the condition receiving step S4 of the present embodiment, in addition to the conditions received in the condition receiving step S4 of the first embodiment, the condition receiving unit 64 receives as conditions the temperature outside the casing 30, the thrust force acting on the stationary components, the linear expansion coefficient depending on the temperature of the bolts 39, the linear expansion coefficient depending on the temperatures of the upper half casing 30U and the lower half casing 30L, and the thermal conductivity depending on the temperatures, when the steam turbine 10 is in operation, as in the condition receiving step S4 of the second embodiment. Furthermore, the condition receiving unit 64 receives as conditions the time from the start to the end of the change in the flow rate of steam flowing into the casing 30 when the steam turbine 10 is in operation, the pressure distribution and temperature distribution inside the casing 30 before and after the change in the steam flow rate, and the thrust force acting on the stationary components before and after the change in the steam flow rate.

[0072] In the pressure distribution estimation step S6 in this embodiment, the pressure distribution estimation unit 66 uses the conditions received in the condition receiving step S4 to simulate the distribution of pressure acting on the flange surface when the casing 30 is in a fastened state, the steam turbine 10 is in operation, and after a change in the steam flow rate.

[0073] In the leak evaluation step S7 in this embodiment, the leak evaluation unit 67 also determines a high leak area 89 in the flange surface where steam is likely to leak.

[0074] In this embodiment, the pressure distribution on the flange surface after a change in the steam flow rate while the casing 30 is fastened and the steam turbine 10 is operating is estimated by simulation. Therefore, in this embodiment, it is possible to confirm the sealing performance after a change in the steam flow rate while the steam turbine 10 is operating. Therefore, this embodiment is effective for confirming the sealing performance at the start of the steam turbine 10 and when the flow rate of steam flowing into the steam turbine 10 changes suddenly.

[0075] "Fourth embodiment of a method for estimating flange surface pressure distribution in a rotary machine and a method for evaluating fluid leakage from between flange surfaces" In the first embodiment, the pressure distribution acting on the flange surfaces and the high leakage region 89 when the casing 30 is in a fastened state are estimated. On the other hand, in the present embodiment, the pressure distribution on the flange surfaces after creep deformation is estimated when the casing 30 is in a fastened state and at a planned time when the casing 30 will be in an open state after the steam turbine 10 has been operated from the present time onwards.

[0076] The apparatus for executing the method of this embodiment is basically the same as the apparatus 50 described with reference to FIG. 6. However, as shown in FIG. 6, this apparatus further includes a creep model receiving unit 62 as a functional unit. The execution procedure of this method is also basically the same as the execution procedure described with reference to the flowchart shown in FIG. 7. However, in the execution procedure of this method, as shown in the flowchart of FIG. 7, the creep model receiving step S2 is executed after the reference model receiving step S1 and before the measured coordinate receiving step S3. Furthermore, in this embodiment, the conditions received in the condition receiving step S4 are different from the conditions received in the condition receiving step S4 in the first embodiment.

[0077] In the creep model receiving step S2 in this embodiment, the creep model receiving unit 62 receives a creep model. This creep model is a model that indicates the creep strain ε with time during rated operation for the upper half casing 30U and the lower half casing 30L, as shown in Fig. 17 .

[0078] In the condition receiving step S4 of the present embodiment, in addition to the conditions received in the condition receiving step S4 of the first embodiment, the condition receiving unit 64 receives as conditions the pressure distribution and temperature distribution inside the casing 30, the temperature outside the casing 30, the thrust force acting on the stationary components, the linear expansion coefficient according to the temperature of the bolts 39, the linear expansion coefficient according to the temperatures of the upper half casing 30U and the lower half casing 30L, and the thermal conductivity according to the temperatures, when the steam turbine 10 is in operation, as in the condition receiving step S4 of the second embodiment. Furthermore, the condition receiving unit 64 receives as conditions the accumulated operating time of the steam turbine 10 up to the present time and the accumulated operating time from the present time until the casing 30 is in an open state after the steam turbine 10 has started operating.

[0079] In the pressure distribution estimation step S6 in this embodiment, the pressure distribution estimation unit 66 uses the conditions received in the condition receiving step S4 to simulate the pressure distribution on the flange surface after creep deformation at the planned time when the casing 30 is to be opened after the steam turbine 10 is operated from the present time onwards.

[0080] The creep deformation up to the present time is reflected in the measured three-dimensional coordinate data received in the measured coordinate receiving step S3. Therefore, as shown in Figure 17, the pressure distribution on the flange surface after creep deformation at the scheduled opening time is simulated using the difference Δε between the creep strain ε2 corresponding to the cumulative operating time from the present time until the scheduled opening time when the casing 30 will be in the open state after the steam turbine 10 has been operated, and the creep strain ε1 corresponding to the cumulative operating time of the steam turbine 10 up to the present time.

[0081] In the leak evaluation step S7 in this embodiment, the leak evaluation unit 67 also determines a high leak area 89 in the flange surface where steam is likely to leak.

[0082] In this embodiment, the pressure distribution on the flange surface after creep deformation is estimated at a time when the casing 30 is scheduled to be opened after the steam turbine 10 has been operated from the present time onward. Therefore, in this embodiment, it is possible to confirm the sealing performance taking into account creep deformation when the steam turbine 10 is operated from the present time onward.

[0083] The creep model receiving step S2 may be performed at any stage before the corrected model creating step S5.

[0084] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above embodiments. Various additions, modifications, substitutions, partial deletions, etc. are possible within the scope of the conceptual idea and spirit of the present invention derived from the content defined in the claims and their equivalents.

[0085] [Additional Note] The method of estimating the flange surface pressure distribution in the rotary machine in the above embodiment can be understood, for example, as follows.

[0086] (1) The flange surface pressure distribution estimation method of the first aspect is applied to the following rotary machine. This rotary machine includes a rotor 15 rotatable about an axis Ar extending horizontally, a casing 30 through which a working fluid can flow and which covers the outer periphery of the rotor 15, and a stationary component disposed within and attached to the casing 30. The casing 30 includes an upper half casing 30U on an upper side, a lower half casing 30L on a lower side, and a plurality of bolts 39 that fasten the upper half casing 30U and the lower half casing 30L together. The upper half casing 30U includes an upper flange 32U having an upper flange surface 33U facing downward. The lower half casing 30L includes a lower flange 32L having an upper flange surface 33L facing upward and facing opposite the upper flange surface 33U in the vertical direction Dz. The upper flange 32U and the lower flange 32L are formed with bolt holes 34 that penetrate in the up-down direction Dz and through which the plurality of bolts 39 can be inserted, respectively.The above-described method for estimating flange surface pressure distribution in a rotary machine includes a reference model receiving step S1 for receiving a three-dimensional reference shape model 80 of the rotary machine that has been acquired in advance; a measured coordinate receiving step S3 for receiving measured three-dimensional coordinate data at a plurality of positions in the upper flange surface 33U and a plurality of positions in the lower flange surface 33L in an open state in which the upper half casing 30U and the lower half casing 30L are not fastened by the plurality of bolts 39 after the rotary machine has been disassembled; and a measured three-dimensional coordinate data at a plurality of positions in the lower flange surface 33L for receiving measured three-dimensional coordinate data at a plurality of positions in the upper flange surface 33U and a plurality of positions in the lower flange surface 33L in an open state in which the upper half casing 30U and the lower half casing 30L are not fastened by the plurality of bolts 39. a condition receiving step S4 for receiving conditions including the weight of the casing 30U and the weight of the stationary parts; a modified model creating step S5 for modifying the three-dimensional reference shape model 80 based on the measured three-dimensional coordinate data at the multiple positions received in the measured coordinate receiving step S3 to create a three-dimensional modified shape model 80m; and a pressure distribution estimating step S6 for using the three-dimensional modified shape model 80m to determine the pressure distribution on one of the lower flange surface 33L and the upper flange surface 33U when the upper half casing 30U and the lower half casing 30L are in a fastened state in which they are fastened with the multiple bolts 39 under the conditions received in the condition receiving step S4.

[0087] Conventionally, when checking the sealing between the upper flange 32U and the lower flange 32L, paint is first applied to one of the objects to be checked, and then the upper flange 32U and the lower flange 32L are fastened with bolts 39. Then, the bolts 39 are removed, the upper casing half 30U and the lower casing half 30L are returned to an open state, and the paint adhesion condition of the remaining object to be checked is checked. However, in this embodiment, the pressure distribution on one of the upper flange surface 33U and the lower flange surface 33L when the casing 30 is in a fastened state is estimated. Therefore, in this embodiment, there is no need to take the trouble of fastening the casing 30 from an open state and then returning it to an open state to check the sealing between the upper flange 32U and the lower flange 32L, thereby reducing the effort required to check the sealing.

[0088] (2) A second aspect of the flange surface pressure distribution estimation method is the flange surface pressure distribution estimation method of the first aspect, wherein the condition receiving step S4 receives, as the conditions, the pressure distribution and temperature distribution inside the casing 30, the temperature outside the casing 30, the thrust force acting on the stationary components, the linear expansion coefficient according to the temperature of the bolt 39, the linear expansion coefficient according to the temperature of the upper half casing 30U and the lower half casing 30L, and the thermal conductivity according to the temperature, when the rotating machine is operating. The pressure distribution estimation step S6 uses the conditions received in the condition receiving step S4 to determine the pressure distribution on the one flange surface when the casing 30 is in the fastened state and the rotating machine is operating.

[0089] In this aspect, the pressure distribution on the one flange surface when the casing 30 is in a fastened state and the rotary machine is in operation is estimated, so that the sealing performance can be confirmed when the rotary machine is in operation.

[0090] (3) A third aspect of the flange surface pressure distribution estimation method is the flange surface pressure distribution estimation method of the second aspect, wherein the condition receiving step S4 receives, as the conditions, a time period from the start of a change in the flow rate of the working fluid flowing into the casing 30 to the end of the change, a pressure distribution and a temperature distribution inside the casing 30 before and after the change in the flow rate of the working fluid, and a thrust force acting on the stationary component before and after the change in the flow rate of the working fluid, when the rotary machine is in operation. In the pressure distribution estimation step S6, the pressure distribution on the one flange surface after a change in the flow rate of the working fluid flowing into the casing 30 is obtained using the conditions received in the condition receiving step S4.

[0091] In this aspect, the pressure distribution on the one flange surface is estimated after a change in the flow rate of the working fluid while the casing 30 is in a fastened state and the rotary machine is in operation. Therefore, in this aspect, it is possible to check the sealability after a change in the flow rate of the working fluid while the rotary machine is in operation. Therefore, this aspect is effective for checking the sealability at the start of the rotary machine or when the flow rate of the working fluid flowing into the rotary machine changes suddenly.

[0092] (4) A fourth aspect of the flange surface pressure distribution estimation method is the flange surface pressure distribution estimation method of the second aspect, further comprising: a creep model receiving step S2 for receiving a creep model indicating creep strain over time for the upper half casing 30U and the lower half casing 30L. The condition receiving step S4 receives, as the conditions, an accumulated operating time of the rotary machine up to the present time and an accumulated operating time until the casing 30 is in an open state after the rotary machine has been operated from the present time onward. The pressure distribution estimation step S6 uses the condition received in the condition receiving step S4 to determine the pressure distribution on the one flange surface after creep deformation at a planned time when the casing 30 will be in an open state after the rotary machine has been operated from the present time onward.

[0093] In this aspect, the pressure distribution on the one flange surface after creep deformation at a planned time when the casing 30 will be opened after the rotary machine has been operated from the present time onward is estimated. Therefore, in this aspect, it is possible to confirm the sealing performance taking into account creep deformation when the rotary machine is operated from the present time onward.

[0094] The method for evaluating leakage in a rotary machine in the above embodiment can be understood, for example, as follows.

[0095] (5) The leak evaluation method in the fifth aspect executes the flange surface pressure distribution estimation method in any one of the first to fourth aspects, and also executes a leak evaluation step S7 in which a region where the value obtained by dividing the pressure indicated by the pressure distribution obtained in the pressure distribution estimation step S6 by the maximum pressure or rated pressure of the working fluid is less than a predetermined allowable value is executed.

[0096] In this embodiment, it is possible to easily check the areas within the flange surfaces where the working fluid is likely to leak from between the upper flange surface 33U and the lower flange surface 33L, making it even easier to check the sealing performance.

[0097] The program for estimating flange surface pressure distribution in the rotary machine in the above embodiment can be understood, for example, as follows.

[0098] (6) The flange surface pressure distribution estimation program according to the sixth aspect is applied to the following rotary machine. This rotary machine includes a rotor 15 rotatable about an axis Ar extending horizontally, a casing 30 through which a working fluid can flow and which covers the outer periphery of the rotor 15, and a stationary component disposed within and attached to the casing 30. The casing 30 includes an upper half casing 30U on an upper side, a lower half casing 30L on a lower side, and a plurality of bolts 39 that fasten the upper half casing 30U and the lower half casing 30L together. The upper half casing 30U includes an upper flange 32U having an upper flange surface 33U facing downward. The lower half casing 30L includes a lower flange 32L having an upper flange surface 33L facing upward and facing the upper flange surface 33U in the vertical direction Dz. The upper flange 32U and the lower flange 32L are formed with bolt holes 34 that penetrate in the up-down direction Dz and through which the plurality of bolts 39 can be inserted, respectively.The above-described program for estimating flange surface pressure distribution in the rotary machine includes a reference model receiving step S1 for receiving a three-dimensional reference shape model 80 of the rotary machine that has been acquired in advance; a measured coordinate receiving step S3 for receiving measured three-dimensional coordinate data at a plurality of positions in the upper flange surface 33U and a plurality of positions in the lower flange surface 33L in an open state in which the upper half casing 30U and the lower half casing 30L are not fastened by the plurality of bolts 39 after the rotary machine has been disassembled; and a measured three-dimensional coordinate data at a plurality of positions in the lower flange surface 33L for receiving measured three-dimensional coordinate data at a plurality of positions in the upper flange surface 33U and a plurality of positions in the lower flange surface 33L in an open state in which the upper half casing 30U and the lower half casing 30L are not fastened by the plurality of bolts 39. The computer is caused to execute a condition receiving process S4 for receiving conditions including the weight of L and the weight of the stationary parts; a modified model creation process S5 for modifying the three-dimensional reference shape model 80 based on the measured three-dimensional coordinate data at multiple positions received in the measured coordinate receiving process S3 to create a three-dimensional modified shape model 80m; and a pressure distribution estimation process S6 for using the three-dimensional modified shape model 80m to determine the pressure distribution on one of the lower flange surface 33L and the upper flange surface 33U when the upper half casing 30U and the lower half casing 30L are in a fastened state fastened with the multiple bolts 39 under the conditions received in the condition receiving process S4.

[0099] By having a computer execute the program of this aspect, it is possible to reduce the effort required to check the sealing performance between the upper flange surface 33U and the lower flange surface 33L, as in the method of the first aspect.

[0100] (7) A flange surface pressure distribution estimation program according to a seventh aspect is the flange surface pressure distribution estimation program according to the sixth aspect, wherein the condition receiving step S4 receives, as the conditions, a pressure distribution and a temperature distribution inside the casing 30, a temperature outside the casing 30, a thrust force acting on the stationary components, a linear expansion coefficient according to the temperature of the bolt 39, a linear expansion coefficient according to the temperatures of the upper half casing 30U and the lower half casing 30L, and a thermal conductivity according to the temperatures, when the rotating machine is operating. The pressure distribution estimation step S6 uses the conditions received in the condition receiving step S4 to determine the pressure distribution on the one flange surface when the casing 30 is in the fastened state and the rotating machine is operating.

[0101] By causing a computer to execute the program of this aspect, it is possible to check the sealability of the rotary machine while it is in operation, similar to the method of the second aspect.

[0102] (8) An eighth aspect of the flange surface pressure distribution estimation program is the flange surface pressure distribution estimation program of the seventh aspect, wherein the condition receiving step S4 receives, as the conditions, a time period from the start of a change in the flow rate of the working fluid flowing into the casing 30 to the end of the change, a pressure distribution and a temperature distribution inside the casing 30 before and after the change in the flow rate of the working fluid, and a thrust force acting on the stationary component before and after the change in the flow rate of the working fluid, when the rotary machine is in operation. The pressure distribution estimation step S6 uses the conditions received in the condition receiving step S4 to determine the pressure distribution on the one flange surface after a change in the flow rate of the working fluid flowing into the casing 30, when the rotary machine is in operation.

[0103] By causing a computer to execute the program of this aspect, it is possible to check the sealability after a change in the flow rate of the working fluid while the rotary machine is in operation, in the same way as in the method of the third aspect.

[0104] (9) A ninth aspect of the flange surface pressure distribution estimation program is the flange surface pressure distribution estimation program of the seventh aspect, wherein the computer is caused to execute a creep model receiving step S2 for receiving a creep model indicating creep strain over time for the upper half casing 30U and the lower half casing 30L. The condition receiving step S4 receives, as the conditions, an accumulated operating time of the rotary machine up to the present time and an accumulated operating time until the casing 30 is in an open state after the rotary machine has been operated from the present time onward. The pressure distribution estimation step S6 uses the condition received in the condition receiving step S4 to calculate the pressure distribution on the one flange surface after creep deformation at a planned time when the casing 30 will be in an open state after the rotary machine has been operated from the present time onward.

[0105] By executing the program of this aspect on a computer, it is possible to check the sealing performance taking into account creep deformation that will occur when the rotating machine is operated from the present time onwards, as in the method of the fourth aspect.

[0106] The program for evaluating leakage in a rotary machine in the above embodiment can be understood, for example, as follows.

[0107] (10) The leak evaluation program in the tenth aspect includes a flange surface pressure distribution estimation program in any one of the sixth to ninth aspects, and causes the computer to execute a leak evaluation step S7 in which the area where the value obtained by dividing the pressure indicated by the pressure distribution obtained in the pressure distribution estimation step S6 by the maximum pressure or rated pressure of the working fluid is less than a predetermined allowable value is determined.

[0108] By executing the program of this embodiment on a computer, it is possible to easily identify areas within the flange surface that are likely to leak working fluid between the upper flange surface 33U and the lower flange surface 33L, as with the method of the fifth embodiment.

[0109] The device for estimating flange surface pressure distribution in a rotary machine according to the above embodiment can be understood, for example, as follows.

[0110] (11) A flange surface pressure distribution estimation device according to an eleventh aspect is applied to the following rotary machine. This rotary machine includes a rotor 15 rotatable about an axis Ar extending horizontally, a casing 30 through which a working fluid can flow and which covers the outer periphery of the rotor 15, and a stationary component disposed within and attached to the casing 30. The casing 30 includes an upper half casing 30U on an upper side, a lower half casing 30L on a lower side, and a plurality of bolts 39 that fasten the upper half casing 30U and the lower half casing 30L together. The upper half casing 30U includes an upper flange 32U having an upper flange surface 33U facing downward. The lower half casing 30L includes a lower flange 32L having an upper flange surface 33L facing upward and facing opposite the upper flange surface 33U in the vertical direction Dz. The upper flange 32U and the lower flange 32L are formed with bolt holes 34 that penetrate in the up-down direction Dz and through which the plurality of bolts 39 can be inserted, respectively.The flange surface pressure distribution estimation device 50a in the rotary machine described above includes: a reference model receiving unit 61 that receives a three-dimensional reference shape model 80 of the rotary machine that has been acquired in advance; an actual coordinate receiving unit 63 that receives measured three-dimensional coordinate data at a plurality of positions in the upper flange surface 33U and a plurality of positions in the lower flange surface 33L in an open state in which the upper half casing 30U and the lower half casing 30L are not fastened by the plurality of bolts 39 after the rotary machine has been disassembled; and a tightening torque of the plurality of bolts 39, elastic moduli of the plurality of bolts 39, elastic moduli of the upper half casing 30U and the lower half casing 30L, and a torque of the upper half casing 30U and the lower half casing 30L. a modified model creation unit 65 that modifies the three-dimensional reference shape model 80 based on the measured three-dimensional coordinate data at multiple positions received by the measured coordinate receiving unit 63 to create a three-dimensional modified shape model 80m; and a pressure distribution estimation unit 66 that uses the three-dimensional modified shape model 80m to determine the pressure distribution on one of the lower flange surface 33L and the upper flange surface 33U when the upper half casing 30U and the lower half casing 30L are in a fastened state fastened with the multiple bolts 39 under the conditions received by the condition receiving unit 64.

[0111] In this embodiment, similar to the method in the first embodiment, the effort required to check the sealing between the upper flange surface 33U and the lower flange surface 33L can be reduced.

[0112] (12) A flange surface pressure distribution estimation device according to a twelfth aspect is the flange surface pressure distribution estimation device 50a according to the eleventh aspect, wherein the condition receiving unit 64 receives, as the conditions, the pressure distribution and temperature distribution inside the casing 30, the temperature outside the casing 30, the thrust force acting on the stationary components, the linear expansion coefficient according to the temperature of the bolt 39, the linear expansion coefficient according to the temperature of the upper half casing 30U and the lower half casing 30L, and the thermal conductivity according to the temperature, when the rotating machine is in operation. The pressure distribution estimation unit 66 uses the conditions received by the condition receiving unit 64 to determine the pressure distribution on the one flange surface when the casing 30 is in the fastened state and the rotating machine is in operation.

[0113] In this embodiment, similar to the method in the second embodiment, it is possible to check the sealability while the rotary machine is in operation.

[0114] (13) A thirteenth aspect of the flange surface pressure distribution estimation device is the flange surface pressure distribution estimation device 50a of the twelfth aspect, wherein the condition receiving unit 64 receives, as the conditions, a time period from the start of a change in the flow rate of the working fluid flowing into the casing 30 to the end of the change, a pressure distribution and a temperature distribution inside the casing 30 before and after the change in the flow rate of the working fluid, and a thrust force acting on the stationary component before and after the change in the flow rate of the working fluid, while the rotary machine is operating. The pressure distribution estimation unit 66 uses the conditions received by the condition receiving unit 64 to determine the pressure distribution on the one flange surface after a change in the flow rate of the working fluid flowing into the casing 30 while the rotary machine is operating.

[0115] In this aspect, similarly to the method in the third aspect, it is possible to check the sealability after a change in the flow rate of the working fluid while the rotary machine is in operation.

[0116] (14) A fourteenth aspect of the flange surface pressure distribution estimation device is the flange surface pressure distribution estimation device 50a of the twelfth aspect, further comprising: a creep model receiving unit 62 that receives a creep model indicating creep strain over time for the upper half casing 30U and the lower half casing 30L. The condition receiving unit 64 receives, as the conditions, an accumulated operating time of the rotary machine up to the present time and an accumulated operating time until the casing 30 is in an open state after the rotary machine has been operated from the present time onward. The pressure distribution estimation unit 66 uses the conditions received by the condition receiving unit 64 to calculate the pressure distribution on the one flange surface after creep deformation at a planned time when the casing 30 will be in an open state after the rotary machine has been operated from the present time onward.

[0117] By executing the program of this aspect on a computer, it is possible to check the sealing performance taking into account creep deformation that will occur when the rotating machine is operated from the present time onwards, as in the method of the fourth aspect.

[0118] The leak evaluation device for a rotary machine in the above embodiment can be understood, for example, as follows.

[0119] (15) A leak evaluation device in a fifteenth aspect includes the flange surface pressure distribution estimation device 50a in any one of the eleventh to fourteenth aspects, and also includes a leak evaluation unit 67 that determines an area where the value obtained by dividing the pressure indicated by the pressure distribution determined by the pressure distribution estimation unit 66 by the maximum pressure or rated pressure of the working fluid is less than a predetermined allowable value.

[0120] In this embodiment, similar to the method in the fifth embodiment, it is possible to easily check the areas within the flange surfaces where the working fluid is likely to leak from between the upper flange surface 33U and the lower flange surface 33L.

[0121] According to one aspect of the present disclosure, it is possible to estimate the flange surface pressure distribution in a rotary machine, thereby reducing the effort required to check the sealing performance between two flanges.

[0122] 10: Steam turbine (rotating machine) 11: Frame 12a: First bearing device 12b: Second bearing device 13a: First shaft seal device (stationary part) 13b: Second shaft seal device (stationary part) 15: Rotor 16: Rotor shaft 17: Row of moving blades 20: Diaphragm (stationary part) 20L: Lower half diaphragm 20U: Upper half diaphragm 22: Stationary blade 23: Diaphragm inner ring 24: Diaphragm outer ring 25: Seal device 30: Casing 30L: Lower half casing 30U: Upper half casing 31L: Lower half casing body 31U: Upper half casing body 32L: Lower flange 32U: Upper flange 33L: Lower flange surface 33U: Upper flange surface 34: Bolt hole 35a: First supported part 35ap: Upper surface 35b: Second supported part 35bp: Upper surface 36: Stationary parts storage section 39: Bolt 50: Leak evaluation device 50a: Flange surface pressure distribution estimation device 51: Manual input device 52: Display device 53: Input / output interface 54: Device interface 55: Communication interface 56: Storage / playback device 57: Memory 58: Auxiliary storage device 58d: Reference three-dimensional shape data 58p: Leak evaluation program 58pa: Flange surface pressure distribution estimation program 60: CPU 61: Reference model reception section 62: Creep model reception section 63: Measured coordinate reception section 64: Condition reception section 65: Corrected model creation section 66: Pressure distribution estimation section 67: Leak evaluation section 69: Three-dimensional shape measuring device 80: Three-dimensional reference shape model 80m: Three-dimensional corrected shape model 81: Flange surface 82: Surface inclined with respect to the flange surface 83: Three-dimensional block 85: Point 86, 86a, 86b: Polygon (polygonal plane) 87: Representative point 89: High leak area Ar: Axis Dc: Circumferential direction Dr: Radial direction Dri: Radial inner side Dro: Radial outer side Dx: Lateral direction Dy: Axial direction Dz: Vertical direction

Claims

1. A method for estimating flange surface pressure distribution in a rotary machine, comprising: a rotor rotatable about an axis extending horizontally; a casing through which a working fluid can flow and which covers the outer periphery of the rotor; and a stationary part disposed within and attached to the casing, wherein the casing has an upper half-casing on an upper side, a lower half-casing on a lower side, and a plurality of bolts fastening the upper half-casing and the lower half-casing together, wherein the upper half-casing has an upper flange having an upper flange surface facing downward, and the lower half-casing has a lower flange having a lower flange surface facing upward and vertically opposing the upper flange surface, and the upper flange and the lower flange have bolt holes formed therein that penetrate in the vertical direction and through which each of the plurality of bolts can be inserted, the method comprising: a reference model receiving step of receiving a three-dimensional reference shape model of the rotary machine that has been acquired in advance; a measured coordinate receiving step of receiving measured three-dimensional coordinate data at a plurality of positions on the upper flange surface and measured three-dimensional coordinate data at a plurality of positions on the lower flange surface after the rotary machine has been disassembled and in an open state in which the upper half casing and the lower half casing are not fastened together with the plurality of bolts; a condition receiving step of receiving conditions including the tightening torque of the plurality of bolts, the elastic modulus of the plurality of bolts, the elastic modulus of the upper half casing and the lower half casing, the weights of the upper half casing and the lower half casing, and the weight of the stationary component; a corrected model creating step of correcting the three-dimensional reference shape model based on the measured three-dimensional coordinate data at the plurality of positions received in the measured coordinate receiving step, and creating a three-dimensional corrected shape model; and a pressure distribution estimating step of using the three-dimensional corrected shape model to determine the pressure distribution on one of the lower flange surface and the upper flange surface when the upper half casing and the lower half casing are fastened together with the plurality of bolts under the conditions received in the condition receiving step. A method for estimating flange surface pressure distribution.

2. A method for estimating flange surface pressure distribution as set forth in claim 1, wherein the condition receiving step receives as the conditions the pressure distribution and temperature distribution inside the casing when the rotating machine is in operation, the temperature outside the casing, the thrust force acting on the stationary parts, the linear expansion coefficient depending on the temperature of the bolt, the linear expansion coefficient depending on the temperature of the upper half casing and the lower half casing, and the thermal conductivity depending on the temperature, and the pressure distribution estimation step uses the conditions received in the condition receiving step to determine the pressure distribution on the one flange surface when the casing is in the fastened state and the rotating machine is in operation.

3. A method for estimating flange surface pressure distribution as set forth in claim 2, wherein the condition receiving step receives, as the conditions, a time period from the start of a change in the flow rate of the working fluid flowing into the casing to the end of the change, a pressure distribution and a temperature distribution inside the casing before and after the change in the flow rate of the working fluid, and a thrust force acting on the stationary part before and after the change in the flow rate of the working fluid when the rotary machine is in operation; and the pressure distribution estimation step uses the conditions received in the condition receiving step to determine the pressure distribution on the one flange surface after a change in the flow rate of the working fluid flowing into the casing when the rotary machine is in operation.

4. A method for estimating flange surface pressure distribution as set forth in claim 2, comprising: executing a creep model acceptance step for accepting a creep model indicating creep strain over time for the upper half casing and the lower half casing; in the condition acceptance step, accepting as the conditions an accumulated operating time of the rotating machine up to the present time and an accumulated operating time until the casing is in an open state after the rotating machine has been operated from the present time onwards; and in the pressure distribution estimation step, using the conditions accepted in the condition acceptance step, determining the pressure distribution on one of the flange surfaces after creep deformation at a planned time when the casing will be in an open state after the rotating machine has been operated from the present time onwards.

5. A leak evaluation method comprising: carrying out the flange surface pressure distribution estimation method set forth in any one of claims 1 to 4; and carrying out a leak evaluation step of determining an area where the value obtained by dividing the pressure indicated by the pressure distribution determined in the pressure distribution estimation step by the maximum pressure or rated pressure of the working fluid is less than a predetermined allowable value.

6. A rotary machine comprising: a rotor rotatable about an axis extending in the horizontal direction; a casing through which a working fluid can flow and which covers the outer periphery of the rotor; and a stationary part disposed within the casing and attached to the casing, wherein the casing has an upper half-casing on an upper side, a lower half-casing on a lower side, and a plurality of bolts fastening the upper half-casing and the lower half-casing together, the upper half-casing having an upper flange with an upper flange surface facing downward, and the lower half-casing having a lower flange with a lower flange surface facing upward and facing the upper flange surface in the vertical direction, and the upper flange and the lower flange having bolt holes that penetrate in the vertical direction and through which each of the plurality of bolts can be inserted. A rotary machine comprising: a reference model receiving step of receiving a three-dimensional reference shape model of the rotary machine that has been acquired in advance; a measured coordinate receiving step of receiving measured three-dimensional coordinate data at a plurality of positions on the upper flange surface and measured three-dimensional coordinate data at a plurality of positions on the lower flange surface after the rotary machine has been disassembled and in an open state in which the upper half casing and the lower half casing are not fastened together with the plurality of bolts; a condition receiving step of receiving conditions including the tightening torque of the plurality of bolts, the elastic modulus of the plurality of bolts, the elastic modulus of the upper half casing and the lower half casing, the weights of the upper half casing and the lower half casing, and the weight of the stationary component; a corrected model creating step of correcting the three-dimensional reference shape model based on the measured three-dimensional coordinate data at the plurality of positions received in the measured coordinate receiving step, and creating a three-dimensional corrected shape model; and a pressure distribution estimating step of using the three-dimensional corrected shape model to determine the pressure distribution on one of the lower flange surface and the upper flange surface when the upper half casing and the lower half casing are fastened together with the plurality of bolts under the conditions received in the condition receiving step. A flange surface pressure distribution estimation program that runs on a computer.

7. A flange surface pressure distribution estimation program as set forth in claim 6, wherein the condition receiving step receives as the conditions the pressure distribution and temperature distribution inside the casing when the rotating machine is in operation, the temperature outside the casing, the thrust force acting on the stationary parts, the linear expansion coefficient depending on the temperature of the bolt, the linear expansion coefficient depending on the temperature of the upper half casing and the lower half casing, and the thermal conductivity depending on the temperature, and the pressure distribution estimation step uses the conditions received in the condition receiving step to determine the pressure distribution on the one flange surface when the casing is in the fastened state and the rotating machine is in operation.

8. A flange surface pressure distribution estimation program as set forth in claim 7, wherein the condition receiving step receives, as the conditions, a time period from the start of a change in the flow rate of the working fluid flowing into the casing to the end of the change, a pressure distribution and a temperature distribution inside the casing before and after the change in the flow rate of the working fluid, and a thrust force acting on the stationary part before and after the change in the flow rate of the working fluid when the rotary machine is in operation; and the pressure distribution estimation step uses the conditions received in the condition receiving step to determine the pressure distribution on the one flange surface after a change in the flow rate of the working fluid flowing into the casing when the rotary machine is in operation.

9. A flange surface pressure distribution estimation program as set forth in claim 7, wherein the computer is caused to execute a creep model reception step for receiving a creep model indicating creep strain over time for the upper half casing and the lower half casing, wherein the condition reception step receives, as the conditions, the accumulated operating time of the rotating machine up to the present time and the accumulated operating time until the casing is in an open state after the rotating machine has been operated from the present time onwards, and wherein the pressure distribution estimation step uses the conditions received in the condition reception step to determine the pressure distribution on one of the flange surfaces after creep deformation at the planned time when the casing will be in an open state after the rotating machine has been operated from the present time onwards.

10. A leak evaluation program having a flange surface pressure distribution estimation program according to any one of claims 6 to 9, and causing the computer to execute a leak evaluation process for determining an area where the value obtained by dividing the pressure indicated by the pressure distribution determined in the pressure distribution estimation process by the maximum pressure or rated pressure of the working fluid is less than a predetermined allowable value.

11. An estimation device for flange surface pressure distribution in a rotary machine, comprising: a rotor rotatable about an axis extending horizontally; a casing through which a working fluid can flow and covering the outer periphery of the rotor; and a stationary part disposed within and attached to the casing, wherein the casing has an upper half-casing on an upper side, a lower half-casing on a lower side, and a plurality of bolts fastening the upper half-casing and the lower half-casing together, wherein the upper half-casing has an upper flange having an upper flange surface facing downward, and the lower half-casing has a lower flange having a lower flange surface facing upward and facing the upper flange surface in the vertical direction, and the upper flange and the lower flange have bolt holes formed therein that penetrate in the vertical direction and through which each of the plurality of bolts can be inserted, the estimation device comprising: a reference model receiving unit that receives a three-dimensional reference shape model of the rotary machine that has been acquired in advance; a measured coordinate receiving unit that receives measured three-dimensional coordinate data at a plurality of positions on the upper flange surface and measured three-dimensional coordinate data at a plurality of positions on the lower flange surface after the rotary machine has been disassembled and in an open state in which the upper half casing and the lower half casing are not fastened together with the plurality of bolts; a condition receiving unit that receives conditions including the tightening torque of the plurality of bolts, the elastic modulus of the plurality of bolts, the elastic modulus of the upper half casing and the lower half casing, the weights of the upper half casing and the lower half casing, and the weight of the stationary component; a corrected model creating unit that corrects the three-dimensional reference shape model based on the measured three-dimensional coordinate data at the plurality of positions received by the measured coordinate receiving unit, and creates a three-dimensional corrected shape model; and a pressure distribution estimating unit that uses the three-dimensional corrected shape model to determine the pressure distribution on one of the lower flange surface and the upper flange surface when the upper half casing and the lower half casing are fastened together with the plurality of bolts under the conditions received by the condition receiving unit. A flange surface pressure distribution estimation device comprising:

12. A flange surface pressure distribution estimation device as defined in claim 11, wherein the condition receiving unit receives as the conditions the pressure distribution and temperature distribution inside the casing when the rotating machine is in operation, the temperature outside the casing, the thrust force acting on the stationary parts, the linear expansion coefficient depending on the temperature of the bolt, the linear expansion coefficient depending on the temperature of the upper half casing and the lower half casing, and the thermal conductivity depending on the temperature, and the pressure distribution estimation unit uses the conditions received by the condition receiving unit to determine the pressure distribution on the one flange surface when the casing is in the fastened state and the rotating machine is in operation.

13. A flange surface pressure distribution estimation device as defined in claim 12, wherein the condition receiving unit receives as the conditions the time period from the start of the change in the flow rate of the working fluid flowing into the casing to the end of the change, the pressure distribution and temperature distribution inside the casing before and after the change in the flow rate of the working fluid, and the thrust force acting on the stationary parts before and after the change in the flow rate of the working fluid, when the rotating machine is in operation; and the pressure distribution estimation unit uses the conditions received by the condition receiving unit to determine the pressure distribution on the one flange surface after the change in the flow rate of the working fluid flowing into the casing, when the rotating machine is in operation.

14. A flange surface pressure distribution estimation device as defined in claim 12, further comprising a creep model receiving unit that receives a creep model indicating creep strain over time for the upper half casing and the lower half casing, wherein the condition receiving unit receives as the conditions the accumulated operating time of the rotating machine up to the present time and the accumulated operating time until the casing is in an open state after the rotating machine has been operated from the present time onwards, and the pressure distribution estimation unit uses the conditions received by the condition receiving unit to determine the pressure distribution on one of the flange surfaces after creep deformation at the planned time when the casing will be in an open state after the rotating machine has been operated from the present time onwards.

15. A leak evaluation device comprising the flange surface pressure distribution estimation device according to any one of claims 11 to 14, and a leak evaluation unit that determines an area where the value obtained by dividing the pressure indicated by the pressure distribution determined by the pressure distribution estimation unit by the maximum pressure or rated pressure of the working fluid is less than a predetermined allowable value.

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