JP2006029190A - Method for diagnosing life of high temperature part in gas turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for accurately performing life diagnosis of a high temperature part of a gas turbine. <P>SOLUTION: Local gas temperature transmitted to each high temperature part is calculated for each assumed operation condition by performing CFD analysis by giving a plurality of boundary conditions corresponding to a plurality of operation conditions assumed in actual operation in relation to combustion gas of main flow and mixing fluid at first. A correlation chart of each assumed operation condition and local gas temperature is created for each high temperature part based on a CFD analysis result next. Corresponding local gas temperature for each operation condition at a time of actual operation is extracted from the correlation chart based on the correlation chart and operation condition accumulated accompanying actual operation for a desired high temperature part and operation time for each extracted local gas temperature is extracted from operation information next. Each extracted operation time is weighted by weighting factor determined for each local gas temperature and each weighted operation time is accumulated next. Then, remaining life is determined by comparing accumulated operation time with reference value determined for the high temperature part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for diagnosing the lifetime of high-temperature components in a gas turbine such as a power generation facility or a jet engine.

  In general, a gas turbine includes a compressor, a combustor, and a turbine as main components. A combustor is disposed between a compressor and a turbine that are directly connected to each other through a main shaft, and air serving as a working fluid is used as a main shaft. , And the compressed air is introduced into the combustor and combusted together with the fuel. The high-temperature and high-pressure combustion gas is discharged to the turbine to drive the main shaft together with the turbine. Such a gas turbine is used as a drive source for power generation equipment by connecting a generator or the like to the front end of the main shaft, and as a jet engine by disposing an exhaust port for combustion gas injection in front of the turbine. Be utilized.

  Specifically, as shown in FIG. 5, the gas turbine 1 is mainly composed of a compressor 2, a combustor 3, and a turbine 4. The combustor 3 is attached to a casing 5 having a cavity formed between the compressor 2 and the turbine 4, and an inner cylinder 6 having a combustion region, and a tail cylinder 7 connected to the front end of the inner cylinder 6. The outer cylinder 8 concentrically with the inner cylinder 6, the pilot fuel nozzle 9 disposed from the rear end on the central axis of the inner cylinder 6, and circumferentially spaced around the pilot fuel nozzle 9 A plurality of main fuel nozzles 10, a bypass duct 11 connected to the side wall of the transition piece 7 and opening to the passenger compartment 5, a bypass valve 12 provided in the bypass duct 11, and the degree of opening and closing of the bypass valve 12 A variable bypass valve mechanism 13 is provided.

  In the turbine 4, a rotor disk 15 is provided on the main shaft in a plurality of stages coaxially with the main shaft, and a plurality of blades 16 extend radially from the outer periphery of each rotor disk 15. The rotor disk 15 and the rotor blade 16 rotate together with the main shaft. In addition, stationary vanes 17 are provided to the turbine 4 main body in such a manner that the blades 16 are alternately arranged along the main shaft.

  Under such a configuration, the compressed air compressed by the compressor 2 flows into the passenger compartment 5 (see the white arrow in the figure), and the outer peripheral surface of the inner cylinder 6 and the inner peripheral surface of the outer cylinder 8. After being passed through the tubular space formed by the above, it is reversed approximately 180 degrees (see solid arrow in the figure) and introduced into the inner cylinder 6 from the rear end side. Subsequently, it is mixed with the fuel ejected from the pilot fuel nozzle 9 and burned as a diffusion flame, and at the same time, it is mixed with the fuel ejected from the main fuel nozzle 10 and released into the diffusion flame, thereby being discharged into the main flame. And burns to produce high-temperature and high-pressure combustion gas. This combustion gas is discharged from its front end via the inside of the transition piece 7 and introduced into the turbine 4.

  The combustion gas sent to the turbine 4 flows through the moving blades 16 and the stationary blades 17 alternately, and is then discharged to the outside. At that time, the moving blade 16 receives lift from the combustion gas and rotates with the rotor disk 15, thereby rotating the main shaft. A part of the compressed air in the passenger compartment 5 is supplied from the bypass duct 11 into the tail cylinder 7, thereby adjusting the combustion gas concentration in the inner cylinder 6.

  By the way, in such a gas turbine 1, periodic maintenance and inspection and accompanying parts replacement are indispensable. Since the high-temperature and high-pressure combustion gas flows, among the various components constituting the gas turbine 1, in particular, the moving blade 16 and the stationary blade 17 that are present in the combustion gas flow path and are heated by the combustion gas to become high temperature. This is because high-temperature parts such as these are damaged due to the influence of heat as the operation progresses.

  On the other hand, maintenance inspections including replacement of high-temperature parts are very expensive. From the viewpoint of long-term cost reduction, damage to high-temperature parts is required so that maintenance inspections can be performed at an appropriate timing while ensuring safety. It is important to determine the degree of the above and accurately determine the remaining life. In addition, since the degree of damage to the high-temperature parts varies greatly depending on the actual operating conditions of the gas turbine 1 for each plant, it is important to consider the actual operating conditions when determining the degree of damage. The operating conditions here include the pressure (atmospheric pressure) and temperature (atmospheric temperature) of the air sucked into the compressor 2, the pressure in the passenger compartment 5 (vehicle compartment pressure), and the degree of opening and closing of the bypass valve 12 (bypass valve). Opening), the ratio between the passenger compartment pressure and the atmospheric pressure (pressure ratio), the combustion gas temperature distribution (combustor outlet gas temperature distribution) and the combustion gas pressure distribution (combustor outlet gas pressure distribution) at the outlet of the tail cylinder 7 The combustion gas temperature at the inlet of the turbine 4 (turbine inlet gas temperature), the combustion gas temperature at the outlet (turbine outlet gas temperature), the temperature of the combustion gas released to the outside (exhaust gas temperature), and the like correspond.

As a method for determining the degree of damage to a high-temperature part, there is a method of diagnosing the lifetime of a high-temperature part by using FEM (Finite Element Method) analysis or CFD (Computational Fluid Dynamics) analysis (for example, Patent Document 1). In this life diagnosis method, boundary conditions are determined based on information from sensors installed at appropriate positions of the gas turbine and actual operating conditions, and the degree of damage of the high-temperature parts is estimated by FEM analysis.
JP 2002-108440 A

  However, according to the conventional life diagnosis method described above, the calculation method of the heat flow from the mainstream combustion gas, which originally heats the high-temperature parts, is not specified, and the most important local gas temperature is predicted. Accuracy is a problem. For example, depending on the high-temperature parts, the local gas temperature may vary widely between the analysis value and the actual value. This is because the fluid flowing through the actual turbine 4 includes a mixed fluid intentionally mixed in addition to the mainstream combustion gas, and the influence of the temperature and flow rate of the mixed fluid cannot be ignored.

  In that case, the extent of damage to the high-temperature parts is estimated based on the local gas temperature of the analysis value far from the actual value, and as a result, the remaining life is judged with the degree of damage different from the actual situation. Will be. Therefore, there is a problem that the life judgment of high temperature parts is not accurate.

  Therefore, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a life diagnosis method capable of accurately determining the life of high temperature components in a gas turbine.

  To achieve the above object, according to the present invention, in a life diagnosis method for a high-temperature part that is heated by heat from the mainstream combustion gas among the parts constituting the gas turbine, the following first to fifth steps are performed. Including. First, as a preliminary preparation, the first and second steps are sequentially performed. In the first step, CFD analysis is performed on the mainstream combustion gas and the mixed fluid mixed therein, by giving a plurality of boundary conditions corresponding to a plurality of operating conditions assumed in actual operation, and for each assumed operating condition. Next, the local gas temperature transmitted to each high temperature component is calculated. In the subsequent second step, a correlation diagram between each assumed operating condition and the local gas temperature is created for each high-temperature part based on the result of the CFD analysis in the first step.

  Subsequently, as the actual life evaluation scene, the third to fifth steps are sequentially performed. In the third step, for the desired high-temperature part, based on the correlation diagram created in the second step and the operation information accumulated with the actual operation, the correlation diagram corresponds to each operating condition during actual operation. The local gas temperature is extracted, and the operation time for each extracted local gas temperature is extracted from the operation information. In the subsequent fourth step, each operation time extracted in the third step is weighted with a weighting factor determined for each local gas temperature, and each weighted operation time is accumulated. In the fifth step, the remaining service life is determined by comparing the accumulated operation time in the fourth step with a reference value determined for the high temperature component.

  As a result, in the CFD analysis, the heat flow of the mixed fluid is analyzed along with the mainstream combustion gas, so that the analysis value of the local gas temperature is equal to the actual value regardless of the high-temperature parts. Therefore, the degree of damage of the high-temperature component estimated based on the local gas temperature is also close to the actual situation, and it is possible to accurately determine the life of the high-temperature component. In this case, it is possible to determine the life effectively against creep deformation and high temperature oxidation occurring in the high temperature part.

  In addition, as the actual life evaluation scene, the following third to fifth steps may be sequentially performed. In the third step, for the desired high-temperature part, based on the correlation diagram created in the second step and the operation information accumulated with the actual operation, the correlation diagram corresponds to each operating condition during actual operation. The local gas temperature is extracted, and the operation start / stop count for each extracted local gas temperature is extracted from the operation information. In the subsequent fourth step, each operation start / stop count extracted in the third step is weighted with a weighting factor determined for each local gas temperature, and each weighted operation start / stop count is accumulated. In the fifth step, the remaining life is determined by comparing the cumulative operation start / stop count in the fourth step with a reference value determined for the high temperature component.

  Even in such a case, in the CFD analysis, the analysis value of the local gas temperature becomes equal to the actual value regardless of the high temperature component, so that it is possible to accurately determine the life of the high temperature component. In this case, it is possible to determine the life effectively against the low cycle fatigue generated in the high temperature part.

  According to the life diagnosis method for high-temperature parts in the gas turbine of the present invention, it is possible to accurately determine the life of high-temperature parts, so that the timing of maintenance and inspection of the gas turbine can be accurately determined, and as a result Long-term cost reduction can be realized.

  Hereinafter, a life diagnosis method for high-temperature components in a gas turbine according to an embodiment of the present invention will be described according to the procedure shown in FIG. The life diagnosis procedure of the present embodiment is roughly divided into a preliminary preparation stage and an actual life evaluation stage for high-temperature components.

  First, the preliminary preparation stage will be described. In step # 5, CFD analysis is performed using a generally available CFD analysis program. In this CFD analysis, the heat flow of the mainstream combustion gas and the mixed fluid mixed therein is used as an analysis target. Examples of the mixed fluid include so-called film cooling air for preventing an excessive temperature rise of the disk rotor 15, the moving blade 16 and the stationary blade 17, and so-called sealing air for preventing leakage of combustion gas from the distribution path. To do.

  For example, as shown in FIG. 2, as film cooling air (see solid arrows in the figure), the film cooling air is ejected from a plurality of ejection holes 16 a provided on the surface of the rotor blade 16 to the combustion gas flow path. One that flows along the surface while covering the surface, similarly, is ejected from the plurality of ejection holes 17a provided on the surface of the stationary blade 17 to the flow path of the combustion gas, and covers the surface of the stationary blade 17 along the surface. There is something that flows. Some are ejected from a plurality of ejection holes 15 a provided on the outer peripheral surface of the rotor disk 15 to the flow path of the combustion gas and flow along the outer peripheral surface of the rotor disk 15. As the sealing air (see the broken line arrow in the figure), there is air that is ejected from the gap between the rotor disks 15 to the combustion gas flow path.

  The CFD analysis is performed by giving boundary conditions corresponding to various operating conditions assumed in actual driving. The operating conditions here are atmospheric pressure, atmospheric temperature, passenger compartment pressure, bypass valve opening, pressure ratio, combustor outlet gas temperature distribution and combustor outlet gas pressure distribution, turbine inlet gas temperature and turbine outlet gas temperature, This corresponds to the exhaust gas temperature. The mixing temperature and mixing flow rate of the mixed fluid are determined according to the operating conditions.

  Then, the local gas temperature transmitted to each high-temperature component (the disk rotor 15, the moving blade 16, the stationary blade 17, the tail cylinder 7, etc.) is calculated by CFD analysis for each assumed various operating conditions.

  Next, in step # 10, a correlation diagram between each assumed operating condition and the local gas temperature is created for each high-temperature part based on the result of the CFD analysis. For example, as shown in FIG. 3, the local gas temperature is plotted on the vertical axis and the pressure ratio is plotted on the horizontal axis for each high-temperature component, and the turbine inlet temperature contour lines T1, T2, T3. Draw contour lines B1, B2, B3. Now you are ready.

  Next, actual life evaluation of high-temperature parts will be described. First, in an actual plant (gas turbine 1), desired high-temperature components (disk rotor 15, moving blade 16, stationary blade 17, tail cylinder 7, etc.) to be evaluated for life are selected. Subsequently, in step # 15, based on the operation information accumulated with the actual operation, that is, based on the history data sequentially measured and remotely monitored by the actual gas turbine 1, the operation condition (pressure) at the actual operation is determined. The local gas temperature corresponding to each ratio, turbine inlet temperature, bypass valve opening) is extracted from the above correlation diagram.

  Next, in step # 20, the operation time of the gas turbine 1 for each extracted local gas temperature is extracted from the operation information (history data). Incidentally, the operation time for each local gas temperature extracted in this way is summarized as shown in FIG. 4, for example.

  Next, in step # 25, each operation time is weighted by multiplying each extracted operation time by a weighting factor determined in advance for each local gas temperature. The weighting factor is determined to be larger as the local gas temperature is higher. This is because the degree of damage actually received by the high-temperature component varies significantly depending on the local gas temperature transmitted to the high-temperature component. Here, the weighting factor is determined in advance for each local temperature. For this setting, for example, FEM analysis is performed in advance for each high-temperature part using each local temperature as a boundary condition, and the degree of creep deformation is quantified. The weighting factor. Note that, instead of the degree of creep deformation, the degree of high-temperature oxidation may be digitized and used as a weighting factor.

  Next, in step # 30, the weighted operation times are accumulated. In step # 35, the accumulated operation time is compared with a reference value determined for the high temperature part to determine the remaining life against creep deformation and high temperature oxidation. This completes the life evaluation of actual high-temperature parts.

  According to such a life diagnosis method, in the CFD analysis, since the heat flow of the mixed fluid is analyzed together with the mainstream combustion gas, the analysis value of the local gas temperature becomes equal to the actual value regardless of the high temperature parts. . Therefore, the degree of damage of the high-temperature component estimated based on the local gas temperature is also close to the actual situation, and it is possible to accurately determine the life of the high-temperature component. In the case of this embodiment, the life can be judged effectively against creep deformation and high temperature oxidation. If it does so, the timing of the maintenance inspection of the gas turbine 1 can be determined exactly, and, as a result, long-term cost reduction is realizable.

  In addition, since the results of CFD analysis are preliminarily summarized in a correlation diagram, and the actual lifetime can be determined using this correlation diagram, CFD analysis time that originally requires a long time is not required when determining the actual lifetime. This is advantageous in that it can be performed in a short time.

  Of the operating conditions as boundary conditions used in the CFD analysis, the combustor outlet gas temperature distribution and the combustor outlet gas pressure distribution are based on data obtained in a combustion experiment conducted in advance on a trial basis. It is also possible to calculate from the pressure ratio or the like. In this way, the local gas temperature can be calculated with higher accuracy.

  In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in steps # 20 to # 30, the operation time to be extracted or weighted may be replaced with the number of operation start / stop times of the gas turbine 1. In this case, by setting the weighting factor based on the degree of low cycle fatigue of the high temperature part, the life evaluation of the high temperature part can be effectively performed for the low cycle fatigue.

  The present invention is useful for diagnosing the life of high-temperature components in a gas turbine.

It is a flowchart which shows the procedure of the lifetime diagnosis of the high temperature components in the gas turbine which is one Embodiment of this invention. It is a schematic diagram which shows an example of the mixing fluid. It is a schematic diagram which shows an example of the correlation diagram of each assumption operating condition and local gas temperature in a certain high temperature component produced from CFD analysis. It is a schematic diagram which shows an example which put together the operation time for each local gas temperature extracted from the correlation diagram and actual operation information. It is a longitudinal cross-sectional view near the combustor of a general gas turbine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas turbine 2 Compressor 3 Combustor 4 Turbine 5 Casing 6 Inner cylinder 7 Outer cylinder 8 Outer cylinder 9 Pilot fuel nozzle 10 Main fuel nozzle 11 Bypass duct 12 Bypass valve 13 Bypass valve variable mechanism 15 Rotor disk 16 Moving blade 17 Static Wings

Claims (2)

In the life diagnosis method for high-temperature parts that are heated by the mainstream combustion gas among the parts that constitute the gas turbine,
For the mainstream combustion gas and the mixed fluid mixed in it, CFD analysis is performed by giving a plurality of boundary conditions corresponding to a plurality of operating conditions assumed in actual operation. A first step of calculating a local gas temperature transmitted to
A second step of creating a correlation diagram between each assumed operating condition and the local gas temperature for each high-temperature component based on the result of the CFD analysis in the first step;
Based on the correlation diagram created in the second step for the desired high-temperature parts and the operation information accumulated during actual operation, the corresponding local gas temperature is extracted for each operating condition during actual operation from the correlation diagram. A third step of extracting the operation time for each extracted local gas temperature from the operation information;
A fourth step of weighting each operation time extracted in the third step with a weighting factor determined for each local gas temperature, and accumulating each weighted operation time;
A fifth step of judging the remaining life by comparing the accumulated operation time in the fourth step with a reference value determined for the high temperature part;
A life diagnosis method for high-temperature components in a gas turbine, comprising: In the life diagnosis method for high-temperature parts that are heated by heat from the mainstream combustion gas among the parts constituting the gas turbine,
For the mainstream combustion gas and the mixed fluid mixed in it, CFD analysis is performed by giving a plurality of boundary conditions corresponding to a plurality of operating conditions assumed in actual operation. A first step of calculating a local gas temperature transmitted to
A second step of creating a correlation diagram between each assumed operating condition and the local gas temperature for each high-temperature component based on the result of the CFD analysis in the first step;
Based on the correlation diagram created in the second step for the desired high-temperature parts and the operation information accumulated during actual operation, the corresponding local gas temperature is extracted for each operating condition during actual operation from the correlation diagram. A third step of extracting the number of operation start / stop times for each extracted local gas temperature from the operation information;
A fourth step of weighting each operation start / stop frequency extracted in the third step with a weighting factor determined for each local gas temperature, and accumulating each weighted operation start / stop frequency;
A fifth step of judging the remaining life by comparing the cumulative operation start / stop count in the fourth step with a reference value determined for the high temperature part;
A life diagnosis method for high-temperature components in a gas turbine, comprising:

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