JP3715352B2 - Blade temperature monitoring device and gas turbine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blade temperature monitoring device for a gas turbine in which a cooling fluid is circulated.
[0002]
[Prior art]
FIG. 4 is a cross-sectional view of the turbine inlet of the gas turbine of the gas turbine power plant.
The compressor 1 is provided coaxially with the gas turbine 2, and supplies air compressed by driving the compressor 1 to the combustor 3. The fuel burns in the liner portion 3a of the combustor 3, and the high-temperature combustion gas is guided to the moving blade 6 through the transition piece 4 and the stationary blade 5 of the gas turbine. The rotation of the rotor blade 6 causes the gas turbine 2 to work.
When an abnormality occurs in a blade, mechanical damage occurs in the blade due to temperature rise, and it is often noticed abnormally only when shaft vibration occurs due to this damage.
[0003]
[Problems to be solved by the invention]
Since the gas turbine is a precision rotating machine, the blades are in contact with other blades and parts that move at high speed with a small clearance. Therefore, even if slight mechanical damage occurs, it often spreads to the surroundings and causes damage almost throughout the machine. From the above, before the blade causes mechanical damage, it is necessary to detect an abnormality in the cooling fluid and the like and an abnormality in the blade temperature due to this.
[0004]
An object of the present invention is to obtain a blade temperature monitoring device that enables early detection of an abnormality by monitoring the surface temperature of a gas turbine blade and determining the presence or absence of an abnormality and the cause of the abnormality.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a gas turbine blade through which a cooling fluid is circulated, and a temperature at which multiple surface temperatures are detected in the blade length direction from the blade root to the tip of the blade. A detector and a determination means for determining whether or not an abnormality has occurred from a blade surface temperature pattern during operation obtained by the temperature detector and determining the cause of the abnormality from a plurality of abnormality causes prepared in advance. A blade temperature monitoring device and a gas turbine are provided.
Thereby, when the blade surface temperature abnormality occurs, the presence or absence of the abnormality and the cause thereof can be determined.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 is a sectional view showing the vicinity of a temperature detector according to an embodiment of a blade temperature monitoring device according to the present invention and enlarging a turbine inlet portion of a gas turbine.
[0007]
A transition piece 4 for introducing combustion gas is connected to the turbine inlet of the turbine casing 11. A stationary blade 5 is formed at the tip of the transition piece 4. The stationary blade 5 has an outer ring portion 5 a held by a shroud 12 fixed to the inner surface of the turbine casing 11. A moving blade 6 is disposed behind the stationary blade 5. The rotor blade 6 is rooted at the tip of the turbine rotor 13. A shroud 14 connected to the shroud 12 is provided on the inner surface of the turbine casing 11 facing the tip of the moving blade 6.
[0008]
A mounting hole 15 is provided in the turbine casing 11 and the outer ring portion 5a. The attachment hole 15 is provided with a detection unit 16 of a radiation thermometer which is a temperature detector. A lens 17 is attached to the tip of the detection unit 16 of the radiation thermometer so that the temperature of the surface 6a of the moving blade can be measured. Two detectors 16 of the radiation thermometer are further provided at locations not shown in the drawing, and each of the detectors 16 measures different locations in the length direction of the moving blade 6.
[0009]
A radiation thermometer, for example, measures the amount of infrared rays radiated from a measurement object and obtains the temperature thereby, and can measure a distant object in a short time, so the temperature of a high-speed rotating body such as the surface temperature of a gas turbine blade Can be measured from the stationary part by synchronizing with the rotation.
[0010]
The detection unit 16 of the radiation thermometer is connected to a main body 18 of the radiation thermometer, and the main body 18 of the radiation thermometer is connected to a determination means 19 composed of a computer.
FIG. 2 is a schematic diagram in which the moving blade 6 and a temperature detector indicated by a radiation thermometer in FIG. 1 are extracted.
[0011]
The three temperature detectors 20a, 20b, and 20c measure the temperatures of the temperatures of the portions 21a, 21b, and 21c on the blade surface, respectively. The determination means 19 determines the presence or absence of an abnormality and the cause of the abnormality from the measured temperature. The display device 22 displays the determination result of the determination unit 19. In the figure, d indicates the flow of the cooling fluid, and 23 indicates the flow path of the cooling fluid.
[0012]
The moving blade 6 and the stationary blade 5 of the gas turbine are used in a state where they are exposed to a high-temperature gas flow. Therefore, since the strength of the structural material rapidly decreases as it is due to high temperatures as it is, there are many cases where a cooling fluid is circulated inside and used while cooling.
[0013]
When the flow rate of the fluid changes due to clogging of foreign matter in the cooling fluid flow path 23, fluid leakage due to a broken hole, or the like, the blade cooling conditions change, so the blade surface temperature in the operating state changes. Therefore, the blade surface temperature at normal time is measured, and compared with the blade surface temperature measurement value in the same operating state. Can be determined to have occurred.
[0014]
As an index indicating the same operation state, gas turbine output, rotation speed, IGV angle, fuel flow rate, and the like can be used.
For blade temperature distribution abnormality, a plurality of blade surface temperature detectors are installed in the blade length direction, and the cause of abnormality can be determined by obtaining the temperature distribution. In the example of FIG. 2, three units are installed.
[0015]
FIG. 3 is a table of determination logic of the determination unit 19.
When the cooling fluid passage 23 is clogged, the flow rate of the cooling fluid decreases, and the temperature rises at all measurement points from the blade root to the tip. Therefore, when the temperature at all measurement points rises above the normal measurement point in the same operating state, it can be determined that the cooling fluid flow path 23 is clogged or blocked (1).
[0016]
If a crack or hole occurs between the blade root and tip, and the cooling fluid leaks out, the flow rate of the cooling fluid increases from the blade root to the hole, and from the hole. It drops to the tip. Therefore, if the temperature from the blade root to a specific measurement point is lower than normal and the temperature from the next measurement point to the tip is higher than normal, the crack between the specific measurement point and the next measurement point Alternatively, it can be determined that the broken hole is the cause of the temperature distribution abnormality (2), (3).
[0017]
If the cooling fluid outlet at the tip of the blade and the flow channel ahead of it, the flow of cooling fluid that passes through the blade increases when the flow channel expands due to the occurrence of a broken hole or friction. Therefore, the temperature decreases at all points from the blade root to the tip. Therefore, if the temperature is lower than normal at all measurement points from the root of the blade to the tip, the cooling fluid outlet at the tip of the blade and the flow path due to broken holes or wear in the flow path ahead of it. It can be determined that the expansion is the cause of the temperature distribution abnormality (4).
[0018]
The blade temperature monitoring is more important when the temperature rises than when the temperature drops, leading to mechanical damage. However, the blade cooling fluid, particularly in the blade 6, is centrifuged toward the blade tip. Since the force is applied and circulates from the root of the blade toward the tip, the tip of the blade is easily affected when the flow rate is reduced, such as blockage of the flow path 23 or fluid leakage, and an abnormal temperature rise is likely to occur. When the number of temperature detectors is limited to, for example, only one, it is better to measure the tip of the blade from the cooling surface, but the gas flow of the gas turbine is at the center of the flow path, that is, the root and tip of the blade. The middle part of the temperature is high, and the temperature decreases as it goes to the end. Therefore, when the number of temperature detectors to be installed is one from the measurement result of the temperature distribution of the gas flow of the gas turbine or the occurrence of troubles in the cooling fluid flow path, as shown in FIG. It is optimal to measure a position 21d that is 75% of the chord length reaching the tip.
[0019]
As the blade surface temperature detecting means, a radiation thermometer is suitable particularly for rotating parts such as moving blades, but a method using a thermocouple is also conceivable.
In this embodiment, a plurality of radiation thermometers are used to measure the temperature at a plurality of points.However, the radiation thermometer has a swing function, and a plurality of points are measured with a single radiation thermometer. Also good.
[0020]
As described above, according to this embodiment, when an abnormality occurs in the gas turbine blade, this is immediately detected, and the cause is determined and displayed, thereby minimizing the outage period for abnormality and repairing. It is possible to improve the economics of facilities and to effectively use resources.
[0021]
【The invention's effect】
According to the present invention, for a gas turbine blade having a cooling fluid flow path therein, it is possible to determine the presence / absence of an abnormality and the cause from the surface temperature distribution of the blade.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the vicinity of a temperature detector according to an embodiment of the present invention and enlarging a turbine inlet portion of a gas turbine.
FIG. 2 is a schematic diagram in which a moving blade and a temperature detector according to an embodiment of the present invention are extracted.
FIG. 3 is a table of determination logic of a determination unit according to the embodiment of the present invention.
FIG. 4 is a cross-sectional view of a turbine inlet of a gas turbine of a gas turbine power plant.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Gas turbine, 5 ... Stator blade, 6 ... Moving blade, 16 ... Detection part of radiation thermometer, 18 ... Main body of radiation thermometer, 19 ... Determination means, 20a, 20b, 20c ... Temperature detector, 21a, 21b , 21c, 21d ... measurement points, 23 ... channels.

Claims (6)

A gas turbine blade for circulating a cooling fluid therein;
A temperature detector for detecting the surface temperature at a plurality of points in the blade length direction from the blade root to the tip of the blade;
A blade temperature monitoring device comprising: a blade surface temperature pattern during operation obtained by the temperature detector; and a determination means for determining whether or not an abnormality has occurred and a plurality of previously prepared abnormality causes. .   The blade temperature monitoring apparatus according to claim 1, wherein a radiation thermometer is used as the temperature detector.   The blade temperature monitoring device according to claim 1, wherein the determination unit determines that the blade surface temperature is abnormal when the blade surface temperature is a predetermined value or more away from the actual value in the same operation state. The determination means determines that the cause of the abnormality is a clogging path of the cooling fluid when all of the measured values of the temperature detector from the blade root to the tip are higher than a normal value in the same operating state by a certain value or more. The blade temperature monitoring device according to claim 1, wherein The determination means is such that the measured value of the temperature detector from the blade root to the tip is lower than the normal value in the same operation state by a certain value or more on the root side with the position between the root and the tip as a boundary. However, if the tip side is higher than the normal value in the same operating state by a certain value or more, the cause of the abnormality is the breakage of the cooling fluid flow channel between the measurement point that is higher than the normal value and the measurement point that is lower than the normal value. The blade temperature monitoring device according to claim 1 , wherein the blade temperature is determined to be generated. A gas turbine comprising the blade temperature monitoring device according to claim 1.

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