Method for evaluating creep damage in the turbine casing

Abstract

To provide a method for evaluating creep damage of a turbine casing that can improve the accuracy of creep analysis.SOLUTION: A method for evaluating creep damage of a turbine casing includes: a step S4 of acquiring a measurement value of each of shape parameters indicating amounts related to deformation of a casing of a turbine from shape measurement results for the casing after operation of the turbine; a calculated value acquisition step S8 of acquiring a calculated value of each of the shape parameters by a creep analysis for the casing after operation of the turbine; and an adjustment step S10 of adjusting a boundary condition of the creep analysis on the basis of a difference between the calculated value and the measurement value for each of the shape parameters. The shape parameters include a first shape parameter indicating an amount of deformation of an axial cross section of the casing with respect to a first reference shape, a second shape parameter indicating a vertical symmetry of the deformation of the axial cross section of the casing with respect to the first reference shape, and a third shape parameter indicating an amount of deformation of a radial cross section of the casing with respect to a second reference shape.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for evaluating creep damage in a turbine casing.

Background Art

[0002] Since turbines such as steam turbines become hot during operation, creep deformation may occur in the turbine casing as the operation time elapses. The shape of the turbine casing after such creep deformation may be obtained by numerical analysis and used for turbine operation, maintenance, etc.

[0003] For example, Patent Document 1 describes obtaining simulation data related to the casing shape by numerical analysis using a turbine model that simulates the characteristics of a turbine, and adjusting the installation position of stationary bodies (such as diaphragms) inside the casing using the simulation data during turbine assembly. In the method of Patent Document 1, by performing numerical analysis under various initial conditions using a turbine model, a plurality of simulation data of the shape of the casing after turbine operation (i.e., after casing deformation) are obtained, and from the obtained plurality of simulation data, the one closest to the measured value of the shape of the casing after turbine operation is selected. Then, based on the selected simulation data, the adjustment amount of the installation position of the stationary body is calculated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In conventional creep analysis of steam turbine casings, the analysis conditions determined under the design conditions do not necessarily match the actual conditions of the actual machine, so there is room for improvement in the analysis accuracy.

[0006] In view of the above circumstances, at least one embodiment of the present invention aims to provide a method for evaluating creep damage to a turbine casing that can improve the accuracy of creep analysis. [Means for solving the problem]

[0007] A method for evaluating creep damage to a turbine casing according to at least one embodiment of the present invention is: A step of obtaining measured values ​​for each of at least one shape parameter that indicates the amount of deformation of the turbine casing from the shape measurement results of the turbine casing after the turbine has been operated, A calculation value acquisition step in which a calculated value is obtained for each of the at least one shape parameter by creep analysis of the casing after the operation of the turbine, An adjustment step in which the boundary conditions of the creep analysis are adjusted based on the difference between the calculated value and the measured value for each of the at least one shape parameter, Equipped with, The at least one shape parameter includes a first shape parameter indicating the amount of deformation relative to a first reference shape in the axial cross-section of the vehicle compartment, a second shape parameter indicating the vertical symmetry of the deformation relative to the first reference shape in the axial cross-section of the vehicle compartment, and a third shape parameter indicating the amount of deformation relative to a second reference shape in the radial cross-section of the vehicle compartment. [Effects of the Invention]

[0008] According to at least one embodiment of the present invention, a method for evaluating creep damage to a turbine casing is provided that can improve the accuracy of creep analysis. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a steam turbine, including a turbine casing, to which a creep damage evaluation method according to one embodiment is to be applied. [Figure 2] This is a diagram to explain the shape parameters. [Figure 3A] This is a diagram to explain the shape parameters. [Figure 3B] It is a diagram for explaining the shape parameter. [Figure 4] It is a flowchart of a creep damage evaluation method according to an embodiment. [Figure 5] It is a flowchart of a creep damage evaluation method according to an embodiment. [Figure 6] It is a graph for explaining the first adjustment step. [Figure 7] It is a graph for explaining the first adjustment step. [Figure 8] It is a graph for explaining the first adjustment step. [Figure 9] It is a graph for explaining the second adjustment step.

Best Mode for Carrying Out the Invention

[0010] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0011] (Configuration of Turbine) FIG. 1 is a schematic view of a steam turbine including a turbine chamber to which a creep damage evaluation method according to some embodiments is applied. Note that the application target of the creep damage evaluation method according to some embodiments is not limited to the turbine chamber of the steam turbine, and may be, for example, the turbine chamber of a gas turbine.

[0012] The steam turbine 1 shown in FIG. 1 includes a rotor (not shown) that can rotate around the central axis O, and a chamber 2 (turbine chamber) that houses the rotating part and the stationary part including the rotor. Note that the rotor is provided so as to penetrate the chamber 2 in the axial direction.

[0013] The passenger compartment 2 is configured to partition a space at atmospheric pressure and a space at a pressure higher or lower than atmospheric pressure. The passenger compartment 2 (outer passenger compartment) includes an upper half portion 4 located on the upper side and a lower half portion 6 located on the lower side in the vertical direction (i.e., the vertical direction). An upper flange portion 5 provided on the upper half portion 4 and a lower flange portion 7 provided on the lower half portion 6 are fastened by bolts not shown. The upper flange portion 5 and the lower flange portion 7 respectively have flange surfaces 5a and 7a that face each other when the upper half portion 4 and the lower half portion 6 are fastened.

[0014] The passenger compartment 2 is supported by a passenger compartment support portion 10 fixed to the base 12. In the illustrated embodiment, the upper half portion 4 of the passenger compartment 2 has cat foot portions 8 that project in the axial direction (the direction of the central axis O of the rotor), and is supported by the passenger compartment support portion 10 via the cat foot portions 8. In the passenger compartment 2 shown in FIG. 1, a pair of cat foot portions 8 are provided on both sides of the central axis O in a plan view at each of both axial ends of the upper half portion 4, that is, a total of four cat foot portions 8 are provided.

[0015] A pipe that functions as an inlet or outlet for the working fluid is connected to the passenger compartment 2. The steam turbine 1 shown in FIG. 1 is a high and medium pressure turbine having a high pressure turbine blade row and a medium pressure turbine blade row. Pipes that function as inlets or outlets for steam (working fluid), namely, high pressure steam inlet pipes 14, 15, a high pressure steam outlet pipe 16, a medium pressure steam inlet pipe 17, and a medium pressure steam outlet pipe 18, are connected to the passenger compartment 2.

[0016] (Description of Shape Parameters) Next, the shape parameters used in the creep damage evaluation method of the turbine passenger compartment according to some embodiments will be described. FIGS. 2, 3A, and 3B are diagrams for explaining the shape parameters, respectively. FIG. 2 is a diagram schematically showing an axial cross section (a cross section passing through the rotation axis O) of the passenger compartment 2 (the upper half portion 4 and the lower half portion 6), and FIGS. 3A and 3B are diagrams schematically showing a radial cross section (the A-A cross section in FIG. 2) at the axial center position of the passenger compartment 2 (the upper half portion 4 and the lower half portion 6).

[0017] The shape parameters are parameters that indicate the amount of deformation of the casing 2. Since the steam turbine 1 becomes hot during operation, creep deformation may occur in the casing 2 as the operating time progresses, as shown in Figures 2, 3A, and 3B. The shape parameters described above are used to evaluate creep damage based on such creep deformation of the casing 2.

[0018] Here, in Figures 2, 3A, and 3B, the dashed lines show the upper half 4' and lower half 6', respectively, which represent the shape (reference shape) of the steam turbine 1 before deformation (i.e., before operation or during design), while the solid lines show the shape of the steam turbine 1 after operation (shape after creep deformation). Figures 2, 3A, and 3B show the shape of the casing 2 (upper half 4(4') and lower half 6(6')) when the upper half 4(4') and lower half 6(6') are not connected to each other. Also, in Figures 2, 3A, and 3B, L1' and L2' represent the axial ends of the casing 2 before deformation (P in Figure 2). E1 or P E2 This is a straight line indicating the vertical position of flange surfaces 5a and 7a at the position indicated by ( ).

[0019] In some embodiments of the creep damage evaluation method, the first to third shape parameters described below are used.

[0020] The first shape parameter p1 is a parameter that indicates the amount of deformation relative to the first reference shape (the shape of the upper half 4' and lower half 6' in Figure 2) in the axial cross-section of the passenger compartment 2. The first shape parameter represents the amount of vertical displacement assuming that the upper half 4 and lower half 6 of the passenger compartment 2 deform symmetrically, and corresponds to the amount of creep deformation.

[0021] The first shape parameter p1 is the axial end of the upper half 4 and the lower half 6, respectively (P in Figure 2). E1 or P E2The first shape parameter p1 may be the average value of the vertical displacement of the flange surfaces 5a and 7a at the axial center (position Pc in Figure 2) relative to the flange surfaces 5a and 7a at position Pc. In this case, the first shape parameter p1 can be expressed by, for example, the following equation (A).

[0022] p1={(h_up_ol+h_up_il+h_up_or+h_up_ir) / 4+(h_low_ol+h_low_il+h_low_or+h_low_ir) / 4} / 2 …(A)

[0023] The meaning of each variable in equation (A) is shown in Figure 3A, but is as follows: h_up_ol: The vertical displacement of the outer peripheral edge 5b of the flange surface 5a of the upper half 4 on one side (the left side in Figure 3A). h_up_il: The vertical displacement of the inner peripheral edge 5c of the flange surface 5a of the upper half 4 on one side (the left side in Figure 3A). h_up_or: The vertical displacement of the outer peripheral edge 5b of the flange surface 5a of the upper half 4 on the other side (right-hand side in Figure 3A). h_up_ir: The vertical displacement of the inner peripheral edge 5c of the flange surface 5a of the upper half 4 on the other side (right-hand side in Figure 3A). h_low_ol: Amount of vertical displacement of the outer peripheral edge 7b of the flange surface 7a of the lower half 6 on one side (the left side in Figure 3A). h_low_il: The vertical displacement of the inner peripheral edge 7c of the flange surface 7a of the lower half 6 on one side (the left side in Figure 3A). h_low_or: The vertical displacement of the outer peripheral edge 7b of the flange surface 7a of the lower half 6 on the other side (right-hand side in Figure 3A). h_low_ir: The vertical displacement of the inner peripheral edge 7c of the flange surface 7a of the lower half 6 on the other side (right side in Figure 3A).

[0024] The second shape parameter p2 is a parameter that indicates the vertical symmetry of deformation with respect to the first reference shape (the shape of the upper half 4' and lower half 6' in Figure 2) in the axial cross-section of the passenger compartment 2. The second shape parameter p2 represents the deviation of the symmetry of the vertical deformation of the upper half 4 and lower half 6 of the passenger compartment 2 due to creep deformation and external forces.

[0025] The second shape parameter p2 is the axial end of the upper half 4 and the lower half 6, respectively (P in Figure 2). E1 or P E2 It may also be the difference in vertical displacement of flange surfaces 5a and 7a at the axial center (position Pc in Figure 2) relative to flange surfaces 5a and 7a at position (). In this case, the second shape parameter p2 can be expressed by, for example, the following equation (B).

[0026] p2={(h_up_ol+h_up_il+h_up_or+h_up_ir) / 4-(h_low_ol+h_low_il+h_low_or+h_low_ir) / 4} / 2 …(B)

[0027] Each variable in equation (B) is the same as each variable in equation (A) above.

[0028] The third shape parameter p3 is a parameter that indicates the amount of deformation relative to the second reference shape (the shape of the upper half 4' and lower half 6' in Figure 3A) in the radial cross-section of the passenger compartment 2.

[0029] The third shape parameter p3 may be the average value of the relative vertical displacement (mouth opening) of the inner edges 5c, 7c of the flange surfaces 5a, 7a with respect to the outer edges 5b, 7b in the radial cross-section of the upper half 4 and the lower half 6, respectively. In this case, the third shape parameter p3 can be expressed by, for example, the following formula (C1).

[0030] p3={(h_up_il-h_up_ol)+(h_up_ir-h_up_or)+(h_low_il-h_low_ol)+(h_low_ir-h_low_or)} / 4 …(C1)

[0031] Each variable in equation (C1) is the same as each variable in equations (A) and (B) above.

[0032] Alternatively, the third shape parameter p3 may be the average value of the inclination angles of the flange surfaces 5a and 7a in the radial cross-section for the upper half 4 and the lower half 6, respectively. In this case, the third shape parameter p3 can be expressed, for example, by the following formula (C2).

[0033] p3=(θ_up_l+θ_up_r+θ_low_l+θ_low_r) / 4 …(C2)

[0034] The meaning of each variable in equation (C2) is shown in Figure 3A, but is as follows: θ_up_l: Inclination angle of the flange surface 5a of the upper half 4 with respect to the horizontal plane on one side (the left side in Figure 3A) θ_up_r: Inclination angle of the flange surface 5a of the upper half 4 with respect to the horizontal plane on the other side (right side in Figure 3A) θ_low_l: Inclination angle of the flange surface 7a of the lower half 6 with respect to the horizontal plane on one side (the left side in Figure 3A) θ_low_r: Inclination angle of the flange surface 7a of the lower half 6 on the other side (right side in Figure 3A) with respect to the horizontal plane.

[0035] Alternatively, the third shape parameter p3 may represent the amount of elliptical deformation due to creep of the casing 2 before and after turbine operation. This amount of elliptical deformation can be calculated as the difference in roundness before and after turbine operation. The roundness q1 of the casing 2 before turbine operation can be expressed, for example, by the following formula (C3). The roundness q2 of the casing 2 after turbine operation can be expressed, for example, by the following formula (C4). In this case, the third shape parameter p3 can be expressed, for example, by the following formula (C5).

[0036] q1={(H_up0-L_up_in0÷2)+(H_low0-L_low_in0÷2)} / 2 …(C3) q2={(H_up-L_up_in÷2)+(H_low-L_low_in÷2)} / 2 …(C4) p3 = q2 - q1 …(C5)

[0037] The meaning of each variable in equations (C3) to (C5) is shown in Figure 3B, but is as follows: H_up0: Vertical dimensions of the upper half 4 before operation. H_low0: Vertical dimension of the lower half 6 before operation H_up: Vertical dimension of the upper half 4 after operation. H_low: Vertical dimension of the lower half 6 after operation. L_up_out0: Width of the outer edge 5b of the flange surface 5a of the upper half 4 before operation L_up_in0: Width of the inner edge 5c of the flange surface 5a of the upper half 4 before operation. L_low_out0: Width of the outer edge 7b of the flange surface 7a of the lower half 6 before operation. L_low_in0: Width of the inner edge 7c of the flange surface 7a of the lower half 6 before operation. L_up_out: Width of the outer edge 5b of the flange surface 5a of the upper half 4 after operation L_up_in: Width of the inner peripheral edge 5c of the flange surface 5a of the upper half 4 after operation L_low_out: Width of the outer edge 7b of the flange surface 7a of the lower half 6 after operation. L_low_in: Width of the inner edge 7c of the flange surface 7a of the lower half 6 after operation.

[0038] Alternatively, the elliptical deformation described above can be calculated as the difference in horizontal displacement of the outer edges 5b, 7b or inner edges 5c, 7c of the flange surfaces 5a, 7a of the upper half 4 and lower half 6 of the passenger compartment 2. In this case, the third shape parameter p3 can be expressed by, for example, the following formula (C6).

[0039] p3={(L_up_in-L_up_in0)÷2+(L_up_out-L_up_out0)÷2+(L_low_in-L_low_in0)÷2+(L_low_out-L_low_out0)÷2} / 4 …(C6)

[0040] Each variable in formula (C6) is the same as each variable in formulas (C3) to (C5) above.

[0041] (Creep damage evaluation method) The following describes creep damage evaluation methods for turbine casings according to several embodiments. The following describes the application of the creep damage evaluation methods according to several embodiments to the steam turbine 1 described above, but the application of the creep damage evaluation methods according to the present invention is not limited to the steam turbine 1 described above.

[0042] Figure 4 is a flowchart of a creep damage evaluation method according to one embodiment. First, an overview of a creep damage evaluation method according to one embodiment will be described. A creep damage evaluation method for a turbine casing according to several embodiments includes the steps of: obtaining measured values ​​for each of at least one shape parameter (the shape parameter described above) from the shape measurement results of the casing 2 after operation of the steam turbine 1 (S4); obtaining calculated values ​​for each of the shape parameters described above by creep analysis of the casing 2 after operation of the steam turbine 1 (S6); and adjusting the boundary conditions of the creep analysis based on the difference between the calculated value (obtained in step S4) and the measured value (obtained in step S6) for each of the at least one shape parameter (S9, S10). Here, the at least one shape parameter described above includes the first to third shape parameters described above (i.e., a first shape parameter indicating the amount of deformation relative to the first reference shape in the axial cross-section of the casing 2, a second shape parameter indicating the vertical symmetry of the deformation relative to the first reference shape in the axial cross-section of the casing 2, and a third shape parameter indicating the amount of deformation relative to the second reference shape in the radial cross-section of the casing 2).

[0043] In some embodiments, in step S4, the shape of the casing 2 before operation of the steam turbine 1 (i.e., before deformation of the casing 2) may be measured in order to obtain the measured value of the shape parameter (for example, the third shape parameter p3 explained using the above-described equations (C3) to (C6)). Alternatively, in step S4, the measured value of the shape parameter may be obtained from the shape measurement results of the casing 2 before and after operation of the steam turbine 1.

[0044] According to the methods of some embodiments described above, the shape of the casing 2 after operation of the steam turbine 1 is measured, and creep analysis is performed to obtain measured and calculated values ​​of the first to third shape parameters that indicate the amount of deformation of the casing 2, respectively. Based on the difference between the obtained calculated values ​​and the measured values, the boundary conditions of the creep analysis are adjusted. In other words, the creep analysis results are matched with the measured shape. This allows for appropriate adjustment of the boundary conditions of the creep analysis, and by performing the creep analysis using these adjusted boundary conditions (for example, step S12 described later), the accuracy of the creep analysis can be improved. Furthermore, the creep damage evaluation of the casing 2 can be appropriately performed using the results of the creep analysis performed using these adjusted boundary conditions (for example, step S14 described later).

[0045] Below, we will describe in more detail, with reference to the flowchart shown in Figure 4, the creep damage evaluation method for turbine casings according to several embodiments.

[0046] First, in step S2, the shape of the casing 2 after operation of the steam turbine 1 is measured during periodic inspections, etc. In step S2, the shapes of the upper half 4 and the lower half 6 are measured with the upper half 4 detached from the lower half 6 (i.e., in an unfastened state where the upper half 4 and the lower half 6 are not fastened together).

[0047] In step S2, the displacement of predetermined parts of the upper half 4 and lower half 6 at the axial center position of the vehicle compartment 2 (for example, corresponding to each variable included in the above equations (A) to (C6)) may be measured using an appropriate measuring instrument. In step S2, the shapes of the upper half 4 and lower half 6 are measured using a measuring instrument such as a 3D laser measuring instrument and 3D shape measurement data is acquired. Here, for the upper half 4 and lower half 6, the shapes of flange surfaces 5a, 7a and inner circumferential surfaces, etc., whose surface properties are specified during manufacturing may be measured.

[0048] When using a 3D laser measuring instrument, more specifically, for example, the surface shapes of the upper half 4 and lower half 6 are measured with the 3D laser measuring instrument to acquire multiple point data (point cloud data). Point cloud data is a collection of a large amount of coordinate information acquired by a laser measuring instrument, and refers to, for example, multiple combinations of X, Y, and Z coordinates. After removing noise from the acquired point cloud data, it may be converted into surface data (STL) to obtain measurement data.

[0049] Next, from the 3D shape measurement data obtained in step S2, the measured values ​​of each of at least one shape parameter that indicates the amount of deformation of the vehicle compartment 2 are obtained (S4). In this embodiment, in step S4, the measured values ​​of each of the first shape parameter p1, the second shape parameter p2, and the third shape parameter p3 described above are obtained. In this embodiment, the first to third shape parameters p1 to p3 are calculated from the above-mentioned equations (A), (B), and (C1), respectively.

[0050] In step S6, a creep analysis model is created to evaluate the creep damage of the casing 2. The creep analysis model is a numerical analysis model that, by inputting various input parameters, outputs simulation data of the shapes of the upper half 4 and lower half 6 of the casing 2 in an unfastened state after the operation of the steam turbine 1. The creep analysis model may also be a FEM (finite element method) model for performing high-temperature creep deformation analysis using finite element analysis.

[0051] The input parameters for the creep analysis model may include data indicating the material properties of the casing 2 (material data), design data for the steam turbine 1 (design data), and the operating time of the steam turbine 1. In step S6, the shape and analysis mesh of the creep analysis model (FEM model, etc.), as well as the mechanical and thermal boundary conditions, are created based on the design data for the steam turbine 1. Material property values ​​are also assigned to the elements created based on the material data for the casing 2. Finally, the creep analysis time is set based on the operating time of the steam turbine 1.

[0052] The material data mentioned above may include the name of the material used, Young's modulus, Poisson's ratio, 0.2% proof stress, coefficient of linear expansion, heat transfer coefficient, density, and / or the constitutive creep law (transition creep rate, steady-state creep rate, etc.).

[0053] The design data used as described above may include drawing data or CAD data, pressure conditions within the casing 2 (pressure distribution, etc.), temperature conditions within the casing 2 (temperature distribution of the working fluid (steam), etc.), heat transfer coefficient between the working fluid and the steam turbine components, flange fastening force, and / or pipe reaction force. The pipe reaction force refers to the force that the casing 2 receives from the piping connected to it (high-pressure steam inlet pipes 14, 15, high-pressure steam outlet pipe 16, medium-pressure steam inlet pipe 17, and medium-pressure steam outlet pipe 18) when fluid flows into or out of the casing 2.

[0054] The mechanical and thermal boundary conditions of the creep analysis model can be determined from the pressure and / or temperature conditions mentioned above.

[0055] Next, the calculated values ​​of each shape parameter (1st to 3rd shape parameter) are obtained by creep analysis using the creep analysis model created in step S6 (step S8).

[0056] In step S8, multiple values ​​may be set for the adjustment parameters related to determining the boundary conditions of the creep analysis, which are among the input parameters of the creep analysis model. By performing the creep analysis using each of the set values, multiple calculated values ​​of the shape parameters may be obtained. These multiple calculated values ​​of the shape parameters obtained in this way are used to adjust the boundary conditions in the subsequent steps for adjusting the boundary conditions (steps S9, S10).

[0057] The adjustment parameters involved in determining the boundary conditions may include the temperature of the working fluid (steam) inside the steam turbine 1 (hereinafter referred to as the fluid temperature), the heat transfer coefficient between the steam turbine 1 and the working fluid (steam) (hereinafter referred to as the heat transfer coefficient), the aforementioned pipe reaction force received by the steam turbine 1 from the piping (hereinafter referred to as the pipe reaction force), and / or the creep strain rate of the material of the casing 2 (hereinafter referred to as the creep strain rate).

[0058] Next, the boundary conditions for the creep analysis are adjusted using the difference between the calculated shape parameters obtained in step S8 and the measured shape parameters obtained in step S4 (S9, S10). In steps S9 and S10, adjustment parameters are found that reduce the difference between the calculated and measured shape parameters. In other words, the creep analysis results are matched with the measured shape. By determining (adjusting) the boundary conditions for the creep analysis using such adjustment parameters, the results of the creep analysis can be brought closer to the measured values, thereby improving the accuracy of the creep analysis.

[0059] The boundary conditions for creep analysis may be adjusted in two steps, S9 and S10, as described below.

[0060] First, in step S9, the adjustment parameters, fluid temperature and heat transfer coefficient, are adjusted based on the difference between the calculated and measured values ​​for each of the first shape parameter p1 and the third shape parameter p3 (first adjustment step). Alternatively, in step S9 (first adjustment step), the adjustment parameters, fluid temperature, heat transfer coefficient, and creep strain rate, may also be adjusted based on the difference between the calculated and measured values ​​for each of the first shape parameter p1 and the third shape parameter p3.

[0061] Then, after performing step S9 (first adjustment step), the adjustment parameter, the pipe reaction force, is adjusted based on the difference between the calculated value and the measured value for the second shape parameter p2 (step S10; second adjustment step).

[0062] The first and third shape parameters p1 and p3, which indicate the amount of deformation relative to the reference shape (first or second reference shape) in the axial or radial cross-section of the casing 2, are relatively heavily influenced by the working fluid temperature (hereinafter, fluid temperature), the heat transfer coefficient between the turbine and the working fluid (hereinafter, heat transfer coefficient), the creep strain rate, and the pipe reaction force (hereinafter, pipe reaction force) that the turbine receives from the piping. On the other hand, the second shape parameter, which indicates the vertical symmetry of the deformation relative to the first reference shape in the axial cross-section of the casing 2, is relatively heavily influenced by the aforementioned pipe reaction force, but is less affected by the fluid temperature, heat transfer coefficient, and creep strain rate.

[0063] In this regard, as described above, first, the fluid temperature and heat transfer coefficient (and creep strain rate), which are adjustment parameters related to boundary conditions, are adjusted based on the difference between the calculated and measured values ​​for the first shape parameter p1 and the third shape parameter p3. Then, the pipe reaction force, which is an adjustment parameter related to boundary conditions, is adjusted based on the difference between the calculated and measured values ​​for the second shape parameter. By adjusting the creep analysis results and the measured shape in this way in two stages, the boundary conditions can be adjusted efficiently.

[0064] In steps S9 and S10, the adjustment parameter that minimizes the difference between the calculated value and the measured value of the shape parameter may be determined by interpolation from the multiple calculated values ​​of the shape parameter obtained in step S8.

[0065] Furthermore, in steps S9 and S10, an index (e.g., root mean square error (RMSE)) is calculated that shows the average of the deviations between the two or more calculated values ​​and the measured values ​​for each of the two or more shape parameters obtained in step S8, and two or more adjustment parameters are found that minimize this index.

[0066] An example of the specific procedure for the steps of adjusting the boundary conditions (steps S9 and S10) will be described. Figures 6 to 8 are graphs illustrating step S9 (first adjustment step), and Figure 9 is a graph illustrating step S10 (second adjustment step).

[0067] In step S9, as shown in Figure 6, the adjustment parameters, namely the steam temperature (fluid temperature) and a combination of multiple values ​​for the heat transfer coefficient (here, for the fluid temperature, three points: reference value - maximum temperature × 0.1, reference value, and reference value + maximum temperature × 0.1; and for the heat transfer coefficient, three points: reference value × 0.1, reference value, and reference value × 10. A total of 3 × 3 = 9 combinations) are applied to the creep analysis model obtained in step S6 to calculate nine values ​​for the first shape parameter p1. In Figure 6, the numerical values ​​shown at each point are the calculated values ​​for the first shape parameter p1. Note that the values ​​of each adjustment parameter used in the creep analysis (reference values, maximum values, etc.) may be determined based on design values, etc.

[0068] Furthermore, as shown in Figure 7, the adjustment parameters, namely the steam temperature (fluid temperature) and a combination of multiple values ​​for the heat transfer coefficient (in this case, 3 x 3 = 9 combinations), are applied to the creep analysis model obtained in step S6 to calculate nine values ​​for the third shape parameter p3. Here, the combination of multiple values ​​for the steam temperature (fluid temperature) and heat transfer coefficient is the same as that used to calculate the multiple values ​​for the first shape parameter p1. In Figure 7, the numerical values ​​shown at each point are the calculated values ​​for the third shape parameter p3. Note that the values ​​of each adjustment parameter used in the creep analysis may be determined based on design values, etc.

[0069] Then, for each of the multiple (9) points in Figures 6 and 7, the root mean square error (RMSE) is calculated, which represents the average of the deviations between the calculated and measured values ​​of the first shape parameter p1 and the third shape parameter p3. The RMSE is calculated using the difference between the calculated and measured values ​​for the first shape parameter p1, and the difference between the calculated and measured values ​​for the third shape parameter p3. In Figure 8, the numerical values ​​shown for each point are the RMSE values ​​for the first shape parameter p1 and the third shape parameter p3. Based on the multiple calculated RMSE values ​​obtained as shown in Figure 8, the steam temperature and heat transfer coefficient that minimize the RMSE are determined. In Figure 8, (reference value × 5.5) is calculated as the heat transfer coefficient that minimizes the RMSE. Similarly, the steam temperature that minimizes the RMSE can be calculated. In this way, the adjustment parameters (in this case, steam temperature and heat transfer coefficient) that minimize the RMSE can be determined.

[0070] Furthermore, methods such as Bayesian optimization, grid search, random search, or steepest descent can be used to search for the combination of steam temperature and heat transfer coefficient that minimizes the aforementioned RMSE.

[0071] By following the above procedure, the values ​​for steam temperature and heat transfer coefficient necessary to determine the boundary conditions for creep analysis can be obtained.

[0072] Furthermore, even when using creep strain rate in addition to steam temperature and heat transfer coefficient as adjustment parameters in step S9 (first adjustment step), the combination of steam temperature, heat transfer coefficient, and creep strain rate that minimizes RMSE can be calculated using the same procedure.

[0073] Next, in step S10, as shown in Figure 9, the creep analysis model obtained in step S6 is applied to the adjustment parameter, the pipe reaction force (here, two values: the reference value and the reference value multiplied by 5), to calculate two values ​​for the second shape parameter p2. Note that the values ​​of each adjustment parameter used in the creep analysis may be determined based on design values, etc.

[0074] Then, using interpolation from the aforementioned two points in Figure 9, the value of the pipe reaction force (horizontal axis) that minimizes the difference between the calculated and measured values ​​of the second shape parameter (i.e., the difference becomes zero) is calculated. In this way, the adjustment parameter (in this case, the pipe reaction force) that minimizes the difference between the calculated and measured values ​​of the second shape parameter can be determined.

[0075] By following the above procedure, the values ​​of the pipe reaction forces necessary to determine the boundary conditions for creep analysis can be obtained.

[0076] Using the adjustment parameters (steam temperature, heat transfer coefficient, and pipe reaction force) obtained through the steps above, the boundary conditions for the creep analysis can be appropriately determined (adjusted).

[0077] Let's continue explaining the flowchart. In step S12, creep analysis is performed using the creep analysis model created in step S6 and the boundary conditions adjusted in the steps up to step S10. Since the boundary conditions adjusted in the steps up to step S10 are used in step S12, the accuracy of the creep analysis will be good.

[0078] Next, the remaining creep life of the vehicle compartment 2 is evaluated based on the results of the creep analysis in step S12 (S14). In step S14, creep strain contours may be output for the vehicle compartment 2 (upper half 4 and lower half 6) based on the analysis results in step S12. Alternatively, the remaining creep life may be calculated based on the creep strain data of the material and the creep strain contours described above. A creep life consumption contour diagram may be created based on the remaining creep life calculated in this way.

[0079] In step S12, a creep analysis may be performed based on the operating time up to the present, and in step S14, the remaining creep life of the vehicle compartment 2 at the present time may be evaluated.

[0080] Alternatively, in step S12, a creep analysis may be performed on the vehicle compartment 2 after a specified operating time has elapsed from the present (i.e., in the future), and in step S14, the remaining creep life of the vehicle compartment 2 after the specified operating time has elapsed may be evaluated based on the results of the creep analysis.

[0081] In this case, based on the highly accurate creep analysis results, the remaining creep life of the turbine casing 2 from the present time to after the specified operating time has elapsed can be accurately evaluated. Therefore, it can be used to help with turbine casing maintenance, for example, by determining whether or not it is necessary to replace any components between the present time and the specified time mentioned above.

[0082] After evaluating the remaining creep life of the vehicle compartment 2 in step S14, a decision may be made based on the evaluation result whether or not the vehicle compartment 2 can be used indefinitely (S22). In addition, the decision on whether or not to continue using the vehicle compartment 2 in step S22 may be made after correcting the evaluation result of the remaining creep life in step S14 by performing steps S16 to S20 described later.

[0083] Figure 5 is a flowchart illustrating an example of the procedure for step S22 (the step of determining whether the vehicle compartment can be used continuously). In this flow, first, it is determined whether the remaining creep life calculated in step S14 (or step S22 described later) is equal to or greater than a threshold (S24). If the remaining creep life is equal to or greater than the threshold (Yes in step S24), it is determined that vehicle compartment 2 can be used continuously (S26), and the flow ends. On the other hand, if the remaining creep life is less than the threshold (No in step S24), it is determined that vehicle compartment 2 cannot be used continuously (S28). In this case, measures such as conducting a material test on vehicle compartment 2 or replacing vehicle compartment 2 with a new one may be taken. The threshold mentioned above may be a value obtained by multiplying the operating time until the next operation by a safety factor.

[0084] The evaluation result of the remaining creep life in step S14 may be corrected by performing steps S16 to S20, which are described below.

[0085] In step S16, a sample is taken from the casing 2 after the operation of the steam turbine 1. In step S16, the sample may be taken from a sampling location determined based on the evaluation result of the creep remaining life of the casing 2 in step S14.

[0086] In the above-described embodiment, the sampling locations for material microstructure observation can be appropriately determined based on the evaluation results of the remaining creep life of the vehicle chamber based on creep analysis.

[0087] Next, the material structure of the sample taken in step S16 is observed (S18). Then, based on the results of the material structure observation in step S18, the evaluation result of the remaining creep life of the vehicle compartment 2 in step S14 is corrected (S20).

[0088] In step S20 described above, the creep remaining life evaluation results may be corrected as follows. First, the creep life consumption rate of the vehicle compartment 2 is calculated from the results of the material microstructure observation in step S18. Next, the creep remaining life evaluation results obtained in the creep analysis in step S14 are corrected based on the material microstructure observation results in step S18. For example, if the creep life consumption rate estimated from the material microstructure observation of the actual machine in step S18 is 40%, and the creep life consumption rate obtained from the creep analysis results in step S14 is 20%, the analysis results can be corrected by doubling the life consumption rate of the analysis results overall.

[0089] Furthermore, in material microstructure observation, the occurrence of creep voids at grain boundaries in the sample can be confirmed by observation using an electron microscope, etc., and the creep void ratio at the grain boundaries can be determined. The degree of damage can then be evaluated in relation to the creep damage rate.

[0090] In this way, by correcting the evaluation results of the remaining creep life of the casing 2 based on creep analysis, based on the results of material microstructure observation of samples taken from the casing 2 after operation of the steam turbine 1, the remaining creep life of the casing 2 can be evaluated more appropriately.

[0091] Instead of steps S18 and S20 described above, the sample taken in step S16 may be tested, and the evaluation result of the remaining creep life of the vehicle compartment 2 in step S14 may be corrected based on the test results.

[0092] The above-described test may also be a hardness test. In this case, the degree of creep damage can be evaluated from the relationship between the change in the material's hardness from the initial value and the Larson-Miller parameter. The Larson-Miller parameter is a parameter used to account for the effects of temperature and time during creep evaluation, and can be expressed as P = T(C + log tr) as a function of absolute temperature T and fracture time tr.

[0093] Alternatively, the above test may be a sample creep test. In this case, a specimen for the creep rupture test is cut from the actual machine (cabin 2), the test temperature and stress are set, and the rupture life is obtained by conducting the creep rupture test. Then, the creep rupture test is also performed on the new material at the same test temperature and stress as the specimen sampled from the actual machine, and the rupture time is obtained. By taking the ratio of the creep rupture life of the specimen sampled from the actual machine to the creep rupture life of the new material, the creep life consumption rate of the actual machine can be estimated.

[0094] Note that the steps shown in the flowchart in Figure 4 do not necessarily have to be performed in the order shown in the flowchart. For example, steps S2 and S4, which are performed to obtain measured values ​​of shape parameters, and steps S6 and S8, which are performed to obtain calculated values ​​of shape parameters, can be performed in either order. Also, steps S16, S18 and S20, which are performed to correct the evaluation results of the remaining creep life, can be performed as needed and may be omitted.

[0095] The contents described in each of the above embodiments can be understood, for example, as follows:

[0096] (1) A method for evaluating creep damage to a turbine casing according to at least one embodiment of the present invention is: Step (S4) is to obtain the measured values ​​of each of at least one shape parameter that indicates the amount of deformation of the turbine casing (2) from the shape measurement results of the turbine casing (2) after the turbine has been operated, A calculation value acquisition step (S8) is performed by creep analysis of the casing after the operation of the turbine to obtain the calculated values ​​of each of the at least one shape parameter, An adjustment step (S9, S10) is performed to adjust the boundary conditions of the creep analysis based on the difference between the calculated value and the measured value for each of the at least one shape parameter, Equipped with, The at least one shape parameter includes a first shape parameter indicating the amount of deformation relative to a first reference shape in the axial cross-section of the vehicle compartment, a second shape parameter indicating the vertical symmetry of the deformation relative to the first reference shape in the axial cross-section of the vehicle compartment, and a third shape parameter indicating the amount of deformation relative to a second reference shape in the radial cross-section of the vehicle compartment.

[0097] According to the method described in (1) above, the measured and calculated values ​​of the first to third shape parameters, which indicate the amount of deformation of the casing, are obtained by measuring the shape of the casing after turbine operation and performing creep analysis, respectively. Based on the difference between the obtained calculated values ​​and the measured values, the boundary conditions of the creep analysis are adjusted. In other words, the creep analysis results are matched with the measured shape. Here, the first shape parameter is a parameter that indicates the amount of deformation relative to the first reference shape (shape before deformation or at the time of design) in the axial cross-section of the casing, the second shape parameter is a parameter that indicates the vertical symmetry of the deformation relative to the first reference shape in the axial cross-section of the casing, and the third shape parameter is a parameter that indicates the amount of deformation relative to the second reference shape (shape before deformation or at the time of design) in the radial cross-section of the casing. This makes it possible to appropriately adjust the boundary conditions of the creep analysis, and by performing creep analysis using these adjusted boundary conditions, the accuracy of the creep analysis can be improved.

[0098] (2) In some embodiments, in the method of (1) above, The aforementioned passenger compartment includes an upper half (4) and a lower half (6), The upper and lower halves each have flange surfaces (5, 7) that face each other when fastened together. The first shape parameter includes the average value of the vertical displacement of the flange surface at the axial center relative to the flange surface at the axial end for each of the upper and lower halves.

[0099] In method (2) above, the average value of the vertical displacement of the flange surface at the axial center relative to the flange surface at the axial end for each of the upper and lower halves of the vehicle compartment is used as the first shape parameter, which indicates the amount of deformation relative to the first reference shape in the axial cross-section of the vehicle compartment. Therefore, the boundary conditions for creep analysis can be appropriately adjusted based on the difference between the calculated value and the measured value of this first shape parameter.

[0100] (3) In some embodiments, in the method of (1) or (2) above, The aforementioned passenger compartment includes an upper half and a lower half, The upper half and the lower half each have flange surfaces that face each other when fastened together, The second shape parameter includes the difference in the vertical displacement of the flange surface at the axial center relative to the flange surface at the axial end of the upper and lower halves, respectively.

[0101] In method (3) above, the difference in vertical displacement between the flange surface at the axial center and the flange surface at the axial end for each of the upper and lower halves of the vehicle compartment is used as a second shape parameter indicating the vertical symmetry of the deformation with respect to the first reference shape in the axial cross-section of the vehicle compartment. Therefore, the boundary conditions for creep analysis can be appropriately adjusted based on the difference between the calculated value and the measured value of this second shape parameter.

[0102] (4) In some embodiments, in any of the methods described in (1) to (3) above, The aforementioned passenger compartment includes an upper half and a lower half, The upper half and the lower half each have flange surfaces that face each other when fastened together, The third shape parameter includes the average value of the relative vertical displacement of the inner periphery (5c, 7c) of the flange surface with respect to the outer periphery (5b, 7b) in the radial cross-section for each of the upper and lower halves, or the average value of the inclination angle of the flange surface in the radial cross-section for each of the upper and lower halves.

[0103] In method (4) above, the third shape parameter used to indicate the amount of deformation relative to the second reference shape in the radial cross-section of the vehicle compartment is the average value of the relative vertical displacement of the inner edge of the flange surface with respect to the outer edge in the radial cross-section of the upper half and the lower half of the vehicle compartment, or the average value of the inclination angle of the flange surface in the radial cross-section of the upper half and the lower half of the vehicle compartment. Therefore, the boundary conditions for creep analysis can be appropriately adjusted based on the difference between the calculated value and the measured value of this third shape parameter.

[0104] (5) In some embodiments, in any of the methods described in (1) to (4) above, The boundary conditions are determined based on a plurality of adjustment parameters, including the temperature of the working fluid within the turbine, the heat transfer coefficient between the turbine and the working fluid, and the pipe reaction force that the turbine receives from the piping. The adjustment step described above is: A first adjustment step (S9) is performed to adjust the temperature and the heat transfer coefficient based on the difference between the calculated value and the measured value for each of the first and third shape parameters, After the first adjustment step, a second adjustment step (S10) is performed to adjust the pipe reaction force based on the difference between the calculated value and the measured value for the second shape parameter. Includes.

[0105] The first and third shape parameters, which indicate the amount of deformation relative to the reference shape (first or second reference shape) in the axial or radial cross-section of the casing, are relatively heavily influenced by the working fluid temperature (hereinafter, fluid temperature), the heat transfer coefficient between the turbine and the working fluid (hereinafter, heat transfer coefficient), and the pipe reaction force that the turbine receives from the piping (hereinafter, pipe reaction force). On the other hand, the second shape parameter, which indicates the vertical symmetry of the deformation relative to the first reference shape in the axial cross-section of the casing, is relatively heavily influenced by the aforementioned pipe reaction force, but is less affected by the fluid temperature and heat transfer coefficient.

[0106] In this regard, according to the method described in (5) above, in the step of adjusting the boundary conditions of the creep analysis based on the difference between the calculated and measured values ​​of the shape parameters, first, the fluid temperature and heat transfer coefficient, which are adjustment parameters related to the boundary conditions, are adjusted based on the difference between the calculated and measured values ​​of the first shape parameter and the third shape parameter, respectively. Then, the pipe reaction force, which is an adjustment parameter related to the boundary conditions, is adjusted based on the difference between the calculated and measured values ​​of the second shape parameter. In this way, by adjusting the creep analysis results and the measured shape in two stages, the boundary conditions can be adjusted efficiently.

[0107] (6) In some embodiments, in the method of (5) above, Multiple adjustment parameters further include the creep strain rate of the material of the vehicle cabin, In the first adjustment step, the temperature, the heat transfer coefficient, and the creep strain rate are adjusted based on the difference between the calculated value and the measured value for each of the first and third shape parameters.

[0108] The first to third shape parameters described above are relatively heavily influenced by the creep strain rate of the vehicle compartment material. In this respect, the method described in (6) above uses the material creep strain rate in addition to the fluid temperature, heat transfer coefficient, and pipe reaction force as adjustment parameters related to boundary conditions, making it possible to perform creep analysis that takes into account the variability in the creep characteristics of the material and to evaluate creep damage based on said analysis. Furthermore, according to the method described in (6) above, in the step of adjusting the boundary conditions of the creep analysis based on the difference between the calculated and measured values ​​of the shape parameters, first, the fluid temperature, heat transfer coefficient, and creep strain rate are adjusted based on the difference between the calculated and measured values ​​of the first and third shape parameters, respectively, and then the pipe reaction force is adjusted based on the difference between the calculated and measured values ​​of the second shape parameter. In this way, by adjusting the creep analysis results and the measured shape in two stages, the boundary conditions can be adjusted efficiently.

[0109] (7) In some embodiments, in the method of (5) or (6) above, In the calculated value acquisition step, the creep analysis is performed for each of the multiple values ​​of the adjustment parameter, thereby acquiring multiple calculated values ​​for one or more of the at least one shape parameter. In the adjustment step, the adjustment parameter that minimizes the difference between the calculated value and the measured value is determined from the plurality of calculated values ​​using interpolation.

[0110] According to the method described in (7) above, by applying interpolation to multiple calculated values ​​for the shape parameters, it is possible to appropriately determine the adjustment parameters that minimize the difference between the calculated values ​​and the measured values. Therefore, the boundary conditions can be appropriately adjusted.

[0111] (8) In some embodiments, in any of the methods described in (5) to (7) above, In the calculated value acquisition step, the creep analysis is performed for each of the two or more combinations of values ​​of the adjustment parameters, thereby acquiring multiple calculated values ​​for each of the two or more of the at least one shape parameter. In the adjustment step, an index is calculated that shows the average of the deviations of the multiple calculated values ​​from the measured values ​​for the two or more shape parameters, and the two or more adjustment parameters that minimize the index are determined.

[0112] According to the method described in (8) above, by calculating an index that shows the average deviation of multiple calculated values ​​from measured values ​​for two or more shape parameters, it is possible to find two or more adjustment parameters that minimize this index. Therefore, boundary conditions can be appropriately adjusted.

[0113] (9) In some embodiments, in any of the methods described in (1) to (8) above, The creep damage evaluation method described above is: An evaluation step (S14) is performed to evaluate the remaining creep life of the vehicle compartment based on the results of the creep analysis, using the boundary conditions adjusted in the adjustment step (S12) and the remaining creep life of the vehicle compartment based on the results of the creep analysis. It is equipped with.

[0114] According to the method described in (9) above, the remaining creep life of the vehicle compartment is evaluated based on the highly accurate creep analysis results obtained using the boundary conditions adjusted by the method described in (1) above, thus enabling the acquisition of highly accurate remaining creep life evaluation results.

[0115] (10) In some embodiments, in the method of (9) above, In the evaluation step, a creep analysis is performed on the vehicle compartment from the present time to after a specified operating time has elapsed, using the boundary conditions adjusted in the adjustment step, and the remaining creep life of the vehicle compartment after the specified operating time has elapsed is evaluated based on the results of the creep analysis.

[0116] According to the method described in (10) above, the remaining creep life of the turbine casing from the present time to after a specified operating time can be accurately evaluated based on the highly accurate creep analysis results obtained using the boundary conditions adjusted by the method described in (1) above. Therefore, it can be used to help with the maintenance of the turbine casing, for example, by determining whether or not it is necessary to replace any components between the present time and the specified time mentioned above.

[0117] (11) In some embodiments, in the method of (9) or (10) above, The creep damage evaluation method described above is: An observation step (S18) is performed to observe the material structure of the sample taken from the vehicle compartment, Based on the results of the material structure observation, a step (S20) is taken to correct the evaluation result of the remaining creep life of the vehicle compartment in the evaluation step, It is equipped with.

[0118] According to the method described in (11) above, the evaluation of the remaining creep life of the casing based on creep analysis is corrected based on the results of material microstructure observation of samples taken from the casing after turbine operation, thereby enabling a more appropriate evaluation of the remaining creep life of the casing.

[0119] (12) In some embodiments, in the method of (11) above, The creep damage evaluation method described above is: Based on the evaluation results of the remaining creep life of the vehicle compartment in the evaluation step, a decision step is made to determine the sampling location in the vehicle compartment, A sampling step (S16) is performed to collect the sample from the sample collection location determined in the above determination step, Equipped with, In the observation step, the material structure of the sample collected in the sampling step is observed.

[0120] According to the method described in (12) above, the sampling locations for material microstructure observation can be appropriately determined based on the evaluation results of the remaining creep life of the vehicle chamber based on creep analysis. By correcting the evaluation results of the remaining creep life of the vehicle chamber based on creep analysis based on the results of material microstructure observation of the sample taken based on this determination, the remaining creep life of the vehicle chamber can be evaluated more appropriately.

[0121] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0122] In this specification, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" shall not only describe such arrangements strictly, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. Furthermore, in this specification, expressions describing shapes such as quadrilaterals and cylindrical shapes shall not only represent geometrically precise quadrilaterals and cylindrical shapes, but also shapes that include uneven surfaces, chamfered surfaces, etc., to the extent that the same effect can be achieved. Furthermore, in this specification, the expressions “equipment,” “includes,” or “possess” of a component are not exclusive expressions that exclude the existence of other components. [Explanation of Symbols]

[0123] 1. Steam Turbine 2 Cabin 4 Upper part 4' upper half 5 Upper flange section 5a Flange surface 5b Outer edge 5c Inner periphery 6 lower half 6' lower half 7 Lower flange section 7a Flange surface 7b Outer edge 7c Inner edge 8 Cat's paw area 10 Cabin support part 12 Basics 14. High-pressure steam inlet piping 15. High-pressure steam inlet piping 16. High-pressure steam outlet piping 17. Medium-pressure steam inlet piping 18. Medium-pressure steam outlet piping O Rotation axis

Claims

1. A step of obtaining measured values ​​for each of at least one shape parameter that indicates the amount of deformation of the turbine casing from the shape measurement results of the turbine casing after the turbine has been operated, A calculation value acquisition step in which the calculated values ​​of each of the at least one shape parameter are obtained by creep analysis of the casing after the operation of the turbine, An adjustment step in which the boundary conditions of the creep analysis are adjusted based on the difference between the calculated value and the measured value for each of the at least one shape parameter, Equipped with, The at least one shape parameter includes a first shape parameter indicating the amount of deformation relative to a first reference shape in the axial cross-section of the vehicle compartment, a second shape parameter indicating the vertical symmetry of the deformation relative to the first reference shape in the axial cross-section of the vehicle compartment, and a third shape parameter indicating the amount of deformation relative to the second reference shape in the radial cross-section of the vehicle compartment. The aforementioned passenger compartment includes an upper half and a lower half, The upper half and the lower half each have flange surfaces that face each other when fastened together, The second shape parameter includes the difference in vertical displacement of the flange surface at the axial center relative to the flange surface at the axial end for each of the upper and lower halves. A method for evaluating creep damage in a turbine casing.

2. The first shape parameter includes the average value of the vertical displacement of the flange surface at the axial center relative to the flange surface at the axial end for each of the upper and lower halves. A method for evaluating creep damage to a turbine casing according to claim 1.

3. The third shape parameter includes the average value of the relative displacement in the vertical direction of the inner edge of the flange surface with respect to the outer edge in the radial cross-section for each of the upper and lower halves, or the average value of the inclination angle of the flange surface in the radial cross-section for each of the upper and lower halves. A method for evaluating creep damage to a turbine casing according to claim 1 or 2.

4. A step of obtaining measured values ​​for each of at least one shape parameter that indicates an amount relating to the deformation of the turbine casing from the shape measurement results of the turbine casing after the turbine has been operated, A calculation value acquisition step in which the calculated values ​​of each of the at least one shape parameter are obtained by creep analysis of the casing after the operation of the turbine, An adjustment step in which the boundary conditions of the creep analysis are adjusted based on the difference between the calculated value and the measured value for each of the at least one shape parameter, Equipped with, The at least one shape parameter includes a first shape parameter indicating the amount of deformation relative to a first reference shape in the axial cross-section of the vehicle compartment, a second shape parameter indicating the vertical symmetry of the deformation relative to the first reference shape in the axial cross-section of the vehicle compartment, and a third shape parameter indicating the amount of deformation relative to the second reference shape in the radial cross-section of the vehicle compartment. The boundary conditions are determined based on a plurality of adjustment parameters, including the temperature of the working fluid within the turbine, the heat transfer coefficient between the turbine and the working fluid, and the pipe reaction force that the turbine receives from the piping. The adjustment step described above is: A first adjustment step in which the temperature and the heat transfer coefficient are adjusted based on the difference between the calculated value and the measured value for each of the first and third shape parameters, After the first adjustment step, a second adjustment step is performed to adjust the pipe reaction force based on the difference between the calculated value and the measured value for the second shape parameter. including A method for evaluating creep damage in a turbine casing.

5. Multiple adjustment parameters further include the creep strain rate of the material of the vehicle cabin, In the first adjustment step, the temperature, the heat transfer coefficient, and the creep strain rate are adjusted based on the difference between the calculated value and the measured value for each of the first and third shape parameters. The method for evaluating creep damage to a turbine casing according to claim 4.

6. In the calculated value acquisition step, the creep analysis is performed for each of the multiple values ​​of the adjustment parameter, thereby acquiring multiple calculated values ​​for one or more of the at least one shape parameter. In the adjustment step, the adjustment parameter that minimizes the difference between the calculated value and the measured value is determined from the plurality of calculated values ​​using interpolation. The method for evaluating creep damage to a turbine casing according to claim 4.

7. In the calculated value acquisition step, the creep analysis is performed for each of the two or more combinations of values ​​of the adjustment parameters, thereby acquiring multiple calculated values ​​for each of the two or more of the at least one shape parameter. In the adjustment step, an index is calculated that represents the average of the deviations of the multiple calculated values ​​from the measured values ​​for the two or more shape parameters, and the two or more adjustment parameters that minimize the index are determined. The method for evaluating creep damage to a turbine casing according to claim 4.

8. An evaluation step in which creep analysis is performed on the vehicle compartment using the boundary conditions adjusted in the adjustment step, and the remaining creep life of the vehicle compartment is evaluated based on the results of the creep analysis. Equipped with A method for evaluating creep damage to a turbine casing according to claim 1 or 2.

9. In the evaluation step, a creep analysis is performed on the vehicle compartment from the present time to after a specified operating time has elapsed, using the boundary conditions adjusted in the adjustment step, and the remaining creep life of the vehicle compartment after the specified operating time has elapsed is evaluated based on the results of the creep analysis. The method for evaluating creep damage to a turbine casing according to claim 8.

10. An observation step in which the material structure of a sample taken from the vehicle compartment is observed, A step of correcting the evaluation result of the creep remaining life of the vehicle compartment in the evaluation step based on the results of the material structure observation, Equipped with The method for evaluating creep damage to a turbine casing according to claim 8.

11. A step of obtaining measured values ​​for each of at least one shape parameter that indicates an amount relating to the deformation of the turbine casing from the shape measurement results of the turbine casing after the turbine has been operated, A calculation value acquisition step in which the calculated values ​​of each of the at least one shape parameter are obtained by creep analysis of the casing after the operation of the turbine, An adjustment step in which the boundary conditions of the creep analysis are adjusted based on the difference between the calculated value and the measured value for each of the at least one shape parameter, Equipped with, The at least one shape parameter includes a first shape parameter indicating the amount of deformation relative to a first reference shape in the axial cross-section of the vehicle compartment, a second shape parameter indicating the vertical symmetry of the deformation relative to the first reference shape in the axial cross-section of the vehicle compartment, and a third shape parameter indicating the amount of deformation relative to the second reference shape in the radial cross-section of the vehicle compartment. An evaluation step in which creep analysis is performed on the vehicle compartment using the boundary conditions adjusted in the adjustment step, and the remaining creep life of the vehicle compartment is evaluated based on the results of the creep analysis, An observation step in which the material structure of a sample taken from the vehicle compartment is observed, A step of correcting the evaluation result of the creep remaining life of the vehicle compartment in the evaluation step based on the results of the material structure observation, Based on the evaluation results of the remaining creep life of the vehicle compartment in the evaluation step, a decision step is made to determine the sampling location in the vehicle compartment, A sampling step in which the sample is collected from the sample collection location determined in the above determination step, Equipped with, In the observation step, the material structure of the sample collected in the sampling step is observed. A method for evaluating creep damage in a turbine casing.

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