JP2021147999A - Gas turbine compressor - Google Patents

Abstract

To predict and prevent fretting fatigue damage which may occur in accompany with vibration at a contact end portion of a moving blade and a rotor disc, in a dovetail groove as a blade planting portion of the moving blade.SOLUTION: In a gas turbine combustor, a plurality of gap sensors are disposed on an inner surface of a casing while changing intervals in a circumferential direction, a vibration amplitude of a blade tip end is measured by measuring a gap to a tip of a moving blade by using the gap sensors, a master curve is created in advance on a relation between the vibration amplitude and a contact portion wear amount of the moving blade and the rotor disc in a dovetail groove, and a time point when a value of the vibration amplitude changed in accompany with an operation, reaches a limit value of the contact portion wear amount, is predicted by using the master curve.SELECTED DRAWING: Figure 2

Description

The present invention relates to a gas turbine compressor, and more particularly to a gas turbine compressor in which moving blades are implanted on the outer periphery of a disk-shaped rotor disk via a dovetail-shaped blade implanting portion.

FIG. 1 shows a general structural cross section of a gas turbine provided with a compressor in which moving blades are implanted via a dovetail-shaped blade implanting portion on the outer periphery of a disk-shaped rotor disk.

As shown in FIG. 1, the gas turbine is roughly divided into a compressor 1, a combustor 2, and a turbine 3.

The compressor 1 adiabatically compresses the air sucked from the atmosphere as a working fluid, and the combustor 2 produces a high-temperature and high-pressure gas by mixing fuel with the compressed air supplied from the compressor 1 and burning it. The turbine 3 generates rotational power when the combustion gas introduced from the compressor 2 expands, and the exhaust from the turbine 3 is released into the air.

Usually, the moving blades of the compressor 1 are fitted and fixed to the dovetail groove, which is a blade implanting portion provided on the outer peripheral portion of the rotating rotor disk.

Since the fitting portion between the moving blade and the dovetail groove of the compressor 1 has a contact surface, the contact surface may be worn due to minute vibrations due to the rotation and the vibration force of the fluid acting on the moving blade. There is.

In general, a minute relative displacement occurs at the contact end between the moving blade and the dovetail groove of the compressor 1, but there is a concern that the relative displacement may increase due to the progress of wear and fretting fatigue damage may occur. Will be done.

It is generally difficult to predict the amount of Frettin fatigue loss described above until just before the final rupture, and it is an extremely useful technique to predict its occurrence in advance.

As an example of vibration measurement of a rotating blade of a gas turbine, there is a "detector mounting device for measuring rotary blade vibration" described in Patent Document 1. The "rotor blade vibration measurement detector mounting device" described in Patent Document 1 proposes a structure in which a laser displacement meter is arranged at the tip of the rotor blade.

Japanese Unexamined Patent Publication No. 08-094432

In recent years, as the performance of gas turbines has improved, designs that increase the pressure ratio of the compressor at the same time as burning at a high temperature are becoming mainstream, and the load acting on the rotor blades of the compressor tends to increase. There is an urgent need to develop a technology to measure wear with high accuracy.

However, although the "detector mounting device for measuring rotor blade vibration" described in Patent Document 1 described above can measure the vibration of the rotor blade of the compressor, it can measure the wear of the dovetail groove, which is the implantable portion of the rotor blade. It is not intended and a new method for measuring the wear of the dovetail groove is needed.

The present invention has been made in view of the above points, and an object of the present invention is that in a dovetail groove which is a blade implanting portion of a moving blade, there is a concern that it may occur due to vibration at the contact end between the moving blade and the rotor disk. An object of the present invention is to provide a gas turbine compressor capable of predicting and preventing fretting fatigue damage.

In order to achieve the above object, the gas turbine compressor of the present invention has a rotor disk in which air is taken in from the inlet and the rotor blades are implanted in a dovetail groove which is a rotor blade implanting portion provided on the outer periphery. On the outer peripheral side of the rotor disk, a casing in which the rotor blade is implanted in a groove which is a rotor blade implanting portion is arranged on the inner surface, and the rotor disk rotates to compress air while flowing in the direction of the rotation axis. In a gas turbine compressor, a plurality of gap sensors are arranged on the inner surface of the casing at different intervals in the circumferential direction, and the gap sensors are used to determine the tip of the rotor blade or the root of the rotor blade. Alternatively, the vibration amplitude and / or frequency of the tip of the blade is measured by measuring the gap with the outer circumference of the rotor disk, and the vibration amplitude and / or the frequency and the contact between the rotor blade and the rotor disk in the dovetail groove. A master curve is prepared in advance for the relationship of the amount of wear of the part, and the master curve is used at the time when the value of the vibration amplitude and / or the frequency that changes with operation reaches the limit value of the amount of wear of the contact part. Predict or
Alternatively, a master curve is prepared in advance regarding the relationship between the vibration amplitude and / or the frequency and the crack depth at the base of the rotor blade, and the value of the vibration amplitude and / or the frequency that changes with operation. It is characterized in that the time point corresponding to the occurrence of the crack is predicted by using the master curve.

According to the present invention, it is possible to predict and prevent fretting fatigue damage that may occur due to vibration at the contact end between the rotor blade and the rotor disk in the dovetail groove, which is the blade implanting portion of the rotor blade. can.

It is a figure which shows the structural example of a general gas turbine. In the first embodiment of the gas turbine compressor of the present invention, the gaps between the blade tip and the gap sensor are La, La', La ", respectively, for a plurality of gap sensors installed at intervals d1, d2 ... In the circumferential direction. It is a figure which shows the example of the measurement of the blade tip vibration measured by. It is a figure which shows typically the relationship between time and blade tip gap in Example 1 of the gas turbine compressor of this invention. FIG. 5 is a diagram schematically showing a form of fretting damage when a rectangular member on which a load P acts comes into contact with a base material at a surface pressure p in the first embodiment of the gas turbine compressor of the present invention. It is a figure which shows the relationship between the general high cycle fatigue limit σ _W and the fretting fatigue limit σ _{WF which decreased by fretting damage.} It is a figure which shows the compressor moving blade which was implanted in the dub tail in a normal gas turbine compressor. It is a figure which shows the compressor moving blade which was implanted in the dovetail which the wear thinning δ progressed more than the gas turbine compressor shown in FIG. _{It is a figure which shows typically the relationship between the fatigue limit σ W of} Example 1 of the gas turbine compressor of this invention, and the wear amount δ at the contact surface of a dovetail groove. Relationship wear amount [delta] and wear thinning limit amount [delta] _C with vibration amplitude ΔL in the contact surface of the dovetail groove of the first embodiment of a gas turbine compressor of the present invention (master curve) is a diagram showing schematic form. It is a figure which shows typically the relationship between the vibration amplitude ΔL and the operation time t of Example 1 of the gas turbine compressor of this invention. It is a figure which shows typically the relationship (master curve) of the wear amount δ and the frequency F in the contact surface of the dovetail groove of Example 2 of the gas turbine compressor of this invention. It is a figure which shows typically the relationship between the frequency F and the operation time t of Example 2 of the gas turbine compressor of this invention. It is a figure which shows the state which the crack of the depth a exists at the root of the moving blade fitted to the dovetail groove shown in FIG. It is a figure which shows typically the relationship (master curve) of the crack depth a and the vibration amplitude ΔL shown in FIG. It is a figure which shows typically the relationship between the crack depth a and the frequency F shown in FIG.

Hereinafter, the gas turbine compressor of the present invention will be described based on the illustrated examples. In each figure, the same reference numerals are used for the same components.

FIG. 2 is implanted in a dovetail groove 5 provided on the outer peripheral portion of the rotor disk 4 in the first embodiment of the gas turbine compressor of the present invention, and is formed in the circumferential direction at a blade tip peripheral speed V along the rotation direction 6. In the rotating compressor vane 7, a plurality of gap sensors (for example, laser sensors) 8 arranged at intervals d1, d2 ... In the circumferential direction are used to form a gap sensor 8 and a tip 7a of the compressor vane 7. It is a figure which shows the state of measuring the distance La'with the tip 7a' of the compressor drive blade 7 and the distance La'with the tip 7a" of the compressor drive blade 7 at each circumferential position.

By measuring the gap (distance La, La', La ") between the tips 7a, 7a', 7a" of the compressor moving blade 7 using the gap sensor 8 shown in FIG. 2, the vibration amplitude and / or of the blade tip is measured. Measure the frequency.

It should be noted that the distance between the gap sensor 8 and the base 7b of the compressor moving blade 7 or the distance between the gap sensor 8 and the outer circumference 4c of the rotor disk 4 may be measured instead of the distance between the gap sensor 8 and the tip 7a of the compressor moving blade 7. ..

In FIG. 3, the horizontal axis is the time t, and the vertical axis is the tip 7a of the gap sensor 8 and the compressor blade 7, or the base 7b of the gap sensor 8 and the compressor blade 7, the gap sensor 8 and the outer circumference 4c of the rotor disk 4. The relationship between the distances La, La', and La'is shown.

As shown in the figure, when the compressor vane 7 is not vibrating, the distance La between the gap sensor 8 and the tip 7a of the compressor vane 7 remains constant, but when it is vibrating, it is constant. It can be seen that the waveforms of the amplitude L and the period T are fluctuating.

FIG. 4 is a diagram schematically showing a form of fretting damage when the rectangular member 9 on which the load P acts comes into contact with the base material 13 at the surface pressure p.

As shown in the figure, when a load P is applied to the upper surface of the rectangular member 9, an average surface pressure p acts on the contact surface between the rectangular member 9 and the base material 13, and the rectangular member 9 and the base material 13 It can be seen that the relative slip s acts at the contact end portion of the above, and the crack 12 is generated from the vicinity of the contact end between the rectangular member 9 and the base material 13.

FIG. 5 is a diagram showing fatigue strength of a general material when the horizontal axis is the load repetition number N and the vertical axis is the variable stress piece amplitude σa.

As shown in the figure, the general high-cycle fatigue limit σw of the round bar smoothing material has a higher fluctuating stress piece amplitude σa than the fretting fatigue limit σwF in which damage occurs near the contact end when the round bar smoothing material has a contact portion. You can see that.

FIG. 6 shows a state in which one compressor moving blade 7 is fitted into a dovetail groove 5 provided in the outer peripheral portion 10 of the rotor disk 4 in a normal gas turbine combustor.

FIG. 7 shows a state in which the gap between the compressor drive blade 7 and the rotor disk 4 has become wear thinning δ (wear thinning δ has progressed) at the contact surface 11 of the dovetail groove 5 in FIG.

FIG. 8 shows an example of the relationship between the fatigue limit σw of Example 1 of the gas turbine combustor of the present invention and the amount of wear δ on the contact surface 11 of the dovetail groove 5.

As shown in the figure, _{based on an arbitrary fretting fatigue limit σ wF} , a wear limit amount δc having a correlation with this can be obtained.

FIG. 9 shows an example of the relationship between the amount of wear δ and the vibration amplitude ΔL on the contact surface 11 of the dovetail groove 5 of the first embodiment of the gas turbine combustor of the present invention.

As shown in the figure, the relationship (master curve) between the limit value δc of the wear amount δ and the limit value ΔLc of the vibration amplitude corresponding to the decrease in the fretting fatigue limit can be obtained.

FIG. 10 shows an example of the relationship between the vibration amplitude ΔL and the operating time t according to the first embodiment of the gas turbine combustor of the present invention.

As shown in the figure, the operation time ct that reaches the limit value ΔLc of the vibration amplitude ΔL that correlates with the occurrence of fretting damage can be obtained by using the master curve shown in FIG.

FIG. 11 shows an example of the relationship (master curve) between the amount of wear δ and the frequency F (1 / T) on the contact surface 11 of the dovetail groove 5 of the second embodiment of the gas turbine combustor of the present invention.

As shown in the figure, the limit value Fc of the frequency F corresponding to the limit value δc of the wear amount δ that correlates with the reduction of the fretting fatigue limit can be obtained by using the master curve.

FIG. 12 shows an example of the relationship between the frequency F (1 / T) and the operating time t according to the second embodiment of the gas turbine combustor of the present invention.

As shown in the figure, the operation time tc that reaches the limit value Fc of the frequency F having a correlation with the occurrence of fretting damage can be obtained by using the master curve shown in FIG.

FIG. 13 shows a state in which a crack 12 having a depth a is present at the root 7b of the compressor blade 7 fitted in the dovetail groove 5 provided on the outer peripheral portion 10 of the rotor disk 4 shown in FIG. ..

FIG. 14 shows an example of the relationship (master curve) between the depth a of the crack 12 and the vibration amplitude ΔL shown in FIG.

As shown in the figure, the limit value ΔLc of the vibration amplitude ΔL corresponding to the limit crack depth ac of the crack 12 depth a can be obtained. Further, using FIG. 10, it is possible to obtain the operating time ct that reaches the limit value ΔLc of the vibration amplitude ΔL.

FIG. 15 shows an example of the relationship between the depth a of the crack 12 and the frequency F (1 / T).

As shown in the figure, the limit value Fc of the frequency F corresponding to the limit crack depth ac of the depth a of the crack 12 can be obtained by using the master curve shown in FIG. Further, using FIG. 12, the operating time ct that reaches the limit value Fc of the frequency F can be obtained.

Next, an example of predicting and preventing fretting fatigue damage that may occur due to vibration at the contact end between the compressor vane 7 and the rotor disk 4 by utilizing the characteristics shown in each of the above figures. Will be described.

In the first embodiment of the present invention, gaps (distance La,) with the tips 7a, 7a', 7a of the compressor blade 7 are used by using a plurality of gap sensors 8 installed on the inner surface of the casing at different intervals in the circumferential direction. By measuring La', La "), the vibration amplitude ΔL of the tips 7a, 7a', 7a" of the compressor blade 7 is measured, and the measured vibration amplitude ΔL and the compressor blade 7 and the rotor in the dovetail groove 5 are measured. A master curve (see FIG. 9) is prepared in advance for the relationship of the amount of wear δ on the contact surface 11 of the disk 4, and as shown in FIG. 10, the value of the vibration amplitude ΔL that changes with operation is the rotor disk. The time point (operating time tc) at which the limit value δc of the amount of wear δ on the contact surface 11 of 4 and the limit value ΔLc of the vibration amplitude ΔL corresponding to the limit value δc can be reached can be predicted by using the master curve of FIG.

According to this embodiment, signals are acquired from a plurality of gap sensors 8 provided in the circumferential direction of the inner surface of the casing so as to face the tips 7a, 7a', 7a "of the compressor blade 7. By calculating the vibration amplitude ΔL of the tips 7a, 7a', 7a ″ of the compressor moving blade 7 and using the correlation diagram of the wear amount δ and the vibration amplitude ΔL of the dovetail groove 5 which is the wing implanting portion in advance, the wear amount δ It is possible to predict and prevent fretting fatigue damage that may occur due to vibration at the contact end between the compressor moving blade 7 and the rotor disk 4 in the dovetail groove 5 of the blade implant. can.

In the second embodiment of the present invention, gaps (distance La,) with the tips 7a, 7a', 7a of the compressor blade 7 are used by using a plurality of gap sensors 8 installed on the inner surface of the casing at different intervals in the circumferential direction. By measuring La', La "), the frequency F (1 / T) of the tips 7a, 7a', 7a" of the compressor blade 7 is measured, and the measured frequency F and the compression blade in the dovetail groove 5 are measured. A master curve (see FIG. 11) is prepared in advance for the relationship between the wear amount δ on the contact surface 11 of the rotor disk 4 and the rotor disk 4, and as shown in FIG. 12, the value of the frequency F that changes with operation is The time point (operating time tc) at which the limit value δc of the amount of wear δ on the contact surface 11 of the rotor disk 4 and the limit value Fc of the frequency F corresponding to the limit value δc can be reached can be predicted by using the master curve of FIG.

Even in this example, the same effect as in the first embodiment can be obtained.

The vibration amplitude ΔL of the tips 7a, 7a', 7a ″ of the compressor moving blade 7 of Example 1 and the frequency F of Example 2 were measured, and the measured vibration amplitude ΔL and frequency F and the compression in the dovetail groove 5 were measured. A master curve (see FIGS. 9 and 11) was prepared in advance for the relationship between the amount of wear δ on the contact surface 11 of the mobile blade 7 and the rotor disk 4, and as shown in FIGS. 10 and 11, the operation was performed. The values of the vibration amplitude ΔL and the frequency F that change with it correspond to the limit value δc of the wear amount δ on the contact surface 11 of the rotor disk 4, and the limit value ΔLc of the vibration amplitude ΔL and the frequency F corresponding to the limit value δc of the wear amount δ. The time point at which the limit value Fc is reached (operating time tc) may be predicted by using the master curves of FIGS. 9 and 11.

In Example 3 of the present invention, gaps (distance La,) with the tips 7a, 7a', 7a of the compressor moving blade 7 are used by using a plurality of gap sensors 8 installed on the inner surface of the casing at different intervals in the circumferential direction. By measuring La', La "), the vibration amplitude ΔL of the tips 7a, 7a', 7a" of the compressor moving blade 7 is measured, and the measured vibration amplitude ΔL and the depth of the crack 12 at the base of the moving blade 12 are measured. A master curve (see FIG. 14) was prepared in advance for the relationship of a, and the limit value ΔLc of the vibration amplitude ΔL corresponding to the limit crack depth ac of the crack 12 depth a was obtained from this master curve. Further, using FIG. 10, the operating time ct to reach the limit value ΔLc of the vibration amplitude ΔL is obtained, and as shown in FIG. 15, the limit of the depth a of the crack 12 is obtained using the master curve shown in FIG. The limit value Fc of the frequency F corresponding to the crack depth ac can be obtained.

Even in this example, the same effect as in the first embodiment can be obtained.

In the fourth embodiment of the present invention, gaps (distance La,) with the tips 7a, 7a', 7a of the compressor blades 7 are used by using a plurality of gap sensors 8 installed on the inner surface of the casing at different intervals in the circumferential direction. By measuring La', La "), the frequency F of the tips 7a, 7a', 7a" of the rotor blade 7 is measured, and the measured frequency F and the depth a of the crack 12 at the base of the rotor blade are a. A master curve is prepared in advance, and the limit value Fc of the frequency F corresponding to the limit crack depth ac of the depth a of the crack 12 is obtained from this master curve, and as shown in FIG. , The limit value Fc of the frequency F corresponding to the limit crack depth ac of the depth a of the crack 12 can be obtained by using the master curve shown in FIG.

Even in this example, the same effect as in the first embodiment can be obtained.

The vibration amplitude ΔL of the tips 7a, 7a', 7a ″ of the compressor rotor blade 7 of Example 1 and the frequency F of Example 2 were measured, and the measured vibration amplitude ΔL and frequency F of the rotor blade root portion were measured. Even if a master curve is prepared in advance for the relationship of the depth a of the crack 12 and the limit value Fc of the frequency F corresponding to the limit crack depth ac of the depth a of the crack 12 is obtained from this master curve. good.

It should be noted that the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1 ... Compressor, 2 ... Combustor, 3 ... Turbine, 4 ... Rotor disk, 4c ... Rotor disk outer circumference, 5 ... Dove tail groove, 6 ... Rotation direction, 7 ... Compressor blade, 7a, 7a', 7a "... The tip of the compressor blade, 7b ... the root of the compressor blade, 8 ... the gap sensor, 9 ... the rectangular member, 10 ... the outer periphery of the rotor disk, 11 ... the contact surface of the dovetail groove, 12 ... the crack, 13 ... the base material.

Claims (3)

It has a rotor disk in which air is taken in from the inlet and the rotor blades are implanted in the dovetail groove, which is a rotor blade implanting portion provided on the outer periphery. A gas turbine compressor in which a casing in which a stationary blade is implanted is arranged in a certain groove, and the rotor disk rotates to compress air while flowing in the direction of the rotation axis.
A plurality of gap sensors are arranged on the inner surface of the casing at different intervals in the circumferential direction, and the gap sensors are used with the tip of the moving blade, the base of the moving blade, or the outer circumference of the rotor disk. By measuring the gap, the vibration amplitude and / or frequency of the tip of the blade is measured,
A master curve is prepared in advance regarding the relationship between the vibration amplitude and / or the frequency and the amount of wear at the contact portion between the rotor blade and the rotor disk in the dovetail groove.
A gas turbine compressor characterized in that the time point at which the vibration amplitude and / or the frequency value that changes with operation reaches the limit value of the contact portion wear amount is predicted by using the master curve. The gas turbine compressor according to claim 1.
The limit value of the contact portion wear amount is determined by the contact portion wear amount and a limit value capable of causing fretting fatigue damage at the contact portion between the moving blade and the rotor disk in the dovetail groove. Gas turbine compressor. It has a rotor disk in which air is taken in from the inlet and the rotor blades are implanted in the dovetail groove, which is a rotor blade implanting portion provided on the outer periphery. A gas turbine compressor in which a casing in which a stationary blade is implanted is arranged in a certain groove, and the rotor disk rotates to compress air while flowing in the direction of the rotation axis.
A plurality of gap sensors are arranged on the inner surface of the casing at different intervals in the circumferential direction, and the gap sensors are used with the tip of the moving blade, the base of the moving blade, or the outer circumference of the rotor disk. By measuring the gap, the vibration amplitude and / or frequency of the tip of the blade is measured,
A master curve is prepared in advance regarding the relationship between the vibration amplitude and / or the frequency and the crack depth at the base of the rotor blade.
A gas turbine compressor characterized in that the time point at which the vibration amplitude and / or the frequency value that changes with operation corresponds to the occurrence of the crack is predicted by using the master curve.

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