JP2006242887A - Crack occurrence predicting method for gas turbine component, and prediction system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely estimate the crack occurrence time of a gas turbine component, without destroying the gas turbine component and without using special measuring devices. <P>SOLUTION: Property values of a sensor 8 are measured, by mounting the sensor 8 in the heat-shielding coatings 9, 10 of the gas turbine component 11 having the heat-shielding coatings 9, 10 on the outside surface thereof. By using the correlation between the crack occurrence time of the material of the gas turbine component 11 that has been separately determined and the property values of the sensor 8, a method is performed to estimate the time until the crack occurs in the gas turbine component 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a crack generation prediction method and prediction system for a gas turbine component, and more particularly to a non-destructive estimation of a crack generation time after recoding of a gas turbine component having a thermal barrier coating on an outer surface. The present invention relates to a crack generation prediction method and a prediction system.

  In a gas turbine power plant, compressed air compressed by driving a compressor provided coaxially with the gas turbine is introduced into a combustor and combusted with fuel in the combustor. High-temperature combustion gas from combustion is introduced into the moving blade through the transition piece and the stationary blade, and the moving blade is driven to rotate to cause the gas turbine to work.

  Ni-based, Co-based, or Ni-Fe-based heat-resistant superalloys are used for the combustor liners, transition pieces, stationary blades, and moving blades that are the high-temperature components of this type of gas turbine. Cause damage. First, since it is in a high-temperature combustion gas atmosphere, material deterioration occurs, and creep damage accumulates due to centrifugal stress due to high-speed rotation of the rotor blades. Further, when the gas turbine is started, thermal fatigue occurs at the stage of transition from the relatively low temperature environment region to the high temperature environment region, and conversely from the high temperature environment region to the low temperature environment region when the gas turbine is stopped, and fatigue damage accumulates. These damages accumulate in a superimposed manner.

  By the way, for maintenance management of gas turbine high temperature parts, classify gas turbines of the same model or operation form based on the creep or fatigue life determined at the design stage of the equipment and the operation of the actual machine, the life set according to the environment in the location Then, the design life is corrected using the results of the preceding machines of each classified group, and the maintenance of the subsequent machines is performed. In recent years, a maintenance management method for efficiently and accurately predicting deterioration and damage of high-temperature components of a gas turbine is being adopted (see, for example, Patent Document 1). In any maintenance management method, repairs are repeated at regular inspections as necessary, and after reaching the management life, they are uniformly discarded and replaced with new ones.

  Among the high-temperature parts, the blades, in particular, are subject to material deterioration caused by operation, and the distortion caused by accumulated creep damage and fatigue damage increases, resulting in cracks. Subsequent use will cause cracks to develop, and if not repaired, there is a risk of destruction. Therefore, there is a need for a method for quantitatively estimating the strain in order to estimate the time until the crack occurs. The following methods are mainly known as methods for estimating the distortion of various components.

Cutting method: A method of mechanically cutting the measurement location to physically release some strain, and measuring the amount of deformation at this time with a strain gauge. X-ray diffraction method: X-rays at the measurement location Method of estimating distortion from the principle of X-ray diffraction by measuring the disorder of crystals due to irradiation
Japanese Patent Laid-Open No. 10-293049

  As described above, the cutting method and the X-ray diffraction method are known as methods for estimating the distortion of various components. However, in the cutting method, it is necessary to destroy the component whose distortion is to be estimated. The X-ray diffraction method has an advantage of non-destructive estimation, but has a problem that a special apparatus such as an X-ray irradiation apparatus and an X-ray detector is required.

  Therefore, an object of the present invention is to provide a method and system for predicting the crack occurrence time of a gas turbine part without destroying the gas turbine part and without using a special measuring device.

  According to the prediction method of the present invention, a sensor is mounted in the thermal barrier coating of the gas turbine part having the thermal barrier coating on the outer surface, the physical property value of the sensor is measured, and the material of the gas turbine part separately obtained is cracked. In this method, the time until a crack is generated in the gas turbine component is estimated using the correlation between the time when the gas is generated and the physical property value of the sensor.

  The prediction system of the present invention includes a sensor mounted in the thermal barrier coating of a gas turbine component having a thermal barrier coating on an outer surface, a measuring device that measures a physical property value of the sensor, and a material of the gas turbine component. A master curve creation device that holds correlation information between the time at which a crack occurs and the physical property value of the sensor, and the physical property value of the sensor measured for the gas turbine component using the correlation information. A crack generation time display device that estimates and displays the time until a crack occurs is provided.

  According to the present invention, it is possible to accurately estimate the crack generation time of a gas turbine component without destroying the gas turbine component and without using a special measuring device.

  Hereinafter, first and second embodiments of a crack generation prediction method and a prediction system for a gas turbine component according to the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the gas turbine component crack generation prediction system according to the present embodiment is attached to a portion where the crack generation time of the gas turbine component should be estimated using a refractory metal fiber as a sensor. Information obtained from the electrical resistance measuring device 1 that measures the electrical resistance value of the refractory metal fiber, the electrical resistance processing device 2 that computes the measured electrical resistance value, the master curve creation device 5, and the master curve creation device 5 Is provided with a crack generation time display device 6 for estimating the time until a crack is generated. The master curve creation device 5 creates a correlation characteristic between the electrical resistance value and strain of the refractory metal fiber measured in a laboratory or the like in advance, and stores the correlation characteristic, and the electrical resistance processing apparatus 2. And a calculation function unit that calculates and calculates a time until a crack occurs from the actual measurement value output from the correlation function of the storage function unit. The crack occurrence time display device 6 displays the time until a crack occurs at the present time based on the information output from the master curve creation device 5.

  FIG. 2 shows an example of data stored in the master curve creation device 5 as a correlation curve between the electrical resistance value and strain of a refractory metal fiber obtained by measurement in a laboratory or the like simulating a moving blade of a steam cooling structure. 7 is shown. FIG. 2 shows a strain caused by tension in a direction parallel to the coding interface in the case where a refractory metal fiber 8 is embedded in a bond coat 10 provided between a base material 11 and a top coat 9 as shown in FIG. Is added, and the electric resistance value and the time until cracking are obtained. The horizontal axis is the strain, and the vertical axis is the electrical resistance value. As can be seen from FIG. 2, the electrical resistance value increases as the strain increases, and the electrical resistance value becomes infinite when a crack occurs. In addition, in the master curve creating apparatus 5, the refractory metal fiber 8 is buried at a position shown in FIGS. 4A and 4B in addition to the above-mentioned FIG. 3, various high melting points such as tungsten alloy, molybdenum alloy, tantalum alloy, etc. Data of laboratories and the like in which the diameters of the metal and the refractory metal fiber are changed are also stored, and additional data can be input to improve the estimation accuracy.

  Here, an example is shown in which crack generation is predicted for the first stage blade of a gas turbine that has been recoated within the design recoating time in an actual plant. The top coat 9 and the bond coat 10 that have been applied to the first stage moving blade until the recoating are removed, and then the bond coat 10 is applied to the surface of the base material 11, and a refractory metal fiber is formed in the bond coat 10. A tungsten fiber was attached. FIG. 5 shows a schematic diagram in which the tungsten fiber 14 is mounted. It was attached to the entire circumference of the effective portion of the steam cooling blade 12 and embedded in the bond coat 10 in the depth direction as shown in FIG. Thereafter, the electrical resistance value between the measurement terminals 13 was measured after use for about 10,000 hours and about 20,000 hours, and the time until crack initiation was estimated and used until the estimated time. By observing the cross section of the blade used up to the estimated time, it was confirmed that a crack had occurred, and the time until the crack was generated could be accurately estimated. Similar results were obtained when the attachment position of the tungsten fiber 14 was the blade leading edge as shown in FIG. 6 or the blade root as shown in FIG.

  In the present embodiment, the thickness (Dt) of the top coat 9, the thickness (Db) of the bond coat 10, and the size (Df) of the refractory metal fiber 8 are Dt = 0.1 to 0.1 respectively. 2 mm, Db = 0.05 to 0.2 mm, and Df = 0.01 to 0.1 mm can be appropriately selected.

  As described above, according to the gas turbine component crack generation prediction method and prediction system of the present embodiment, the gas turbine component can be accurately obtained without destroying the gas turbine component, without using a special measuring device. Crack initiation time can be estimated.

(Second Embodiment)
As shown in FIG. 8, the gas turbine component crack generation prediction system according to the present embodiment uses an optical fiber as a sensor, and an optical fiber mounted at a site where the time at which a gas turbine component crack occurs should be estimated. Based on information obtained from the refractive index measuring device 3 for measuring the refractive index, the refractive index processing device 4 for computing the measured refractive index, the master curve creating device 5a, and the master curve creating device 5a. A crack occurrence time display 6 is provided for estimating the time until the occurrence of. The master curve creation device 5a includes a storage function unit that creates a correlation curve between the refractive index and distortion of an optical fiber measured in a laboratory or the like in advance and stores this correlation characteristic, and a refractive index processing device 4 for the optical fiber. A calculation function unit that calculates a time until a crack is generated from the output actual measurement value and the correlation characteristic stored in the storage function unit; The crack occurrence time display device 6 has a function of displaying the time until the occurrence of a crack at the present time based on the information output by the master curve creation device 5a.

  FIG. 9 shows, as an example of data stored in the master curve creation device 5a, a correlation curve 15 between the refractive index and strain of an optical fiber obtained by measurement in a laboratory or the like simulating a moving blade having a steam cooling structure. . 9, as shown in FIG. 10, an optical fiber 16 is embedded in the bond coat 10 provided between the base material 11 and the top coat 9, and strain due to tension is added in a direction parallel to the coding interface. The refractive index and the time until cracking are obtained. The horizontal axis is strain and the vertical axis is refractive index. As can be seen from FIG. 9, the refractive index decreases as the strain increases, and the refractive index becomes 0 when a crack occurs. In addition, the master curve creation device 5a also stores data such as a laboratory where the embedment position of the optical fiber 16 is changed as shown in FIGS. 11A and 11B and the diameter of the optical fiber in addition to FIG. In order to improve the estimation accuracy, additional data can be input.

  Here, an example is shown in which crack generation is predicted for the first stage blade of a gas turbine that has been recoated within the design recoating time in an actual plant. The top coat 9 and the bond coat 10 that had been applied to the first stage moving blade until the recoating were removed, and then the bond coat 10 was applied to the surface of the substrate 11 and an optical fiber was mounted in the bond coat 10. . FIG. 12 shows a schematic diagram in which the optical fiber 16 is mounted. The steam cooling blade 12 was attached to the entire circumference of the effective portion, and embedded in the bond coat 10 in the depth direction as shown in FIG. Thereafter, the refractive index between the measurement terminals 13 was measured after use for about 10,000 hours and about 20,000 hours, and the time until crack initiation was estimated and used until the estimated time. By observing the cross section of the blade used up to the estimated time, it was confirmed that a crack had occurred, and the time until the crack was generated could be accurately estimated. Similar results were obtained when the mounting position of the optical fiber 16 was the blade leading edge as shown in FIG. 13 or the blade root as shown in FIG.

  In the present embodiment, the thickness (Dt) of the top coat 9, the thickness (Db) of the bond coat 10, and the size (Df) of the optical fiber 16 are Dt = 0.1-2 mm, It can be appropriately selected from the ranges of Db = 0.05 to 0.2 mm and Df = 0.01 to 0.1 mm.

  As described above, according to the gas turbine component crack generation prediction method and prediction system of the present embodiment, the gas turbine component can be accurately obtained without destroying the gas turbine component and without using a special measuring device. Crack initiation time can be estimated.

The block diagram which shows the structure of the crack generation | occurrence | production prediction system of the gas turbine component of the 1st Embodiment of this invention. The figure which shows the correlation curve of the electrical resistance value and distortion of a refractory metal fiber, and demonstrates the effect | action of the crack generation | occurrence | production prediction system of the gas turbine component of the 1st Embodiment of this invention. Sectional drawing which shows the attachment position of the refractory metal fiber in the 1st Embodiment of this invention. Sectional drawing which shows the other example of the attachment position of the refractory metal fiber in the 1st Embodiment of this invention. The side view which shows the attachment position of the tungsten fiber to the gas turbine blade in the 1st Embodiment of this invention. The side view which shows the other example of the attachment position of the tungsten fiber to the gas turbine blade in the 1st Embodiment of this invention. The side view which shows the further another example of the attachment position of the tungsten fiber to the gas turbine blade in the 1st Embodiment of this invention. The block diagram which shows the structure of the crack generation | occurrence | production prediction system of the gas turbine component of the 2nd Embodiment of this invention. The figure which shows the correlation curve of the refractive index and distortion of an optical fiber, and demonstrates the effect | action of the crack generation | occurrence | production prediction system of the gas turbine component of the 2nd Embodiment of this invention. Sectional drawing which shows the mounting position of the optical fiber in the 2nd Embodiment of this invention. Sectional drawing which shows the other example of the mounting position of the optical fiber in the 2nd Embodiment of this invention. The side view which shows the attachment position of the optical fiber to the gas turbine blade in the 2nd Embodiment of this invention. The side view which shows the other example of the mounting position of the optical fiber to the gas turbine blade in the 2nd Embodiment of this invention. The side view which shows the further another example of the mounting position of the optical fiber to the gas turbine blade in the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrical resistance measuring apparatus, 2 ... Electrical resistance processing apparatus, 3 ... Refractive index measuring apparatus, 4 ... Refractive index processing apparatus, 5, 5a ... Master curve creation apparatus, 6 ... Crack generation time display apparatus, 7 ... Electrical resistance Correlation curve between value and strain, 8 ... refractory metal fiber, 9 ... top coat, 10 ... bond coat, 11 ... substrate, 12 ... steam cooling blade, 13 ... measuring terminal, 14 ... tungsten fiber, 15 ... refractive index Strain correlation curve, 16 ... optical fiber.

Claims (6)

  A sensor is installed in the thermal barrier coating of the gas turbine part having the thermal barrier coating on the outer surface, and the physical property value of the sensor is measured. The time when the crack occurs in the material of the gas turbine part separately obtained and the sensor A method for predicting a crack occurrence in a gas turbine component, wherein a time until a crack occurs in the gas turbine component is estimated using a correlation with a physical property value.   The method according to claim 1, wherein the sensor is a refractory metal fiber, and the physical property value is an electrical resistance value.   The method according to claim 1, wherein the sensor is an optical fiber, and the physical property value is a refractive index.   The method for predicting crack occurrence in a gas turbine component according to claim 1, wherein the sensor is mounted on the surface of the base of the gas turbine component, the surface of the bond coating, or the bond coating.   The method according to claim 1, wherein the sensor has a thickness that varies depending on a mounting portion and is broken when a crack occurs in the base material. A sensor mounted in the thermal barrier coating of a gas turbine component having a thermal barrier coating on the outer surface, a measuring device for measuring physical properties of the sensor, and a time at which a crack occurs in the material of the gas turbine component; A master curve creation device that holds correlation information with the physical property value of the sensor, and from the physical property value of the sensor measured for the gas turbine component using the correlation information, until a crack occurs in the gas turbine component A crack occurrence prediction system for a gas turbine component, comprising: a crack occurrence time display device that estimates and displays time.

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