JPH1181906A - Hybrid buffer body of turbine rotor blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid buffer body of a new turbine rotor blade capable of easily being incorporated into a turbine disk and displaying an excellent buffer action. SOLUTION: A seal damper part 9 arranged at a gap between a platform 6 of a turbine rotor blade 2 and a turbine disk 1 and a buffer part 10 interposed between an embedding part 4 of the turbine rotor blade 2 and a mounting groove 3 of the turbine disk 1 are integrally constituted, As a result, an initial adaptation to the embedding part 4 of the turbine rotor blade 2 is improved and an excellent buffer action can be displayed because this hybrid buffer body becomes easy to be incorporated into the turbine disk 1 and the buffer part 10 moves without fail according to the movement of the seal damper part 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid shock absorber used to prevent combustion gas leakage and vibration of a turbine blade when a ceramic turbine blade of a ceramic gas turbine is mounted on a turbine disk. It is.

[0002]

2. Description of the Related Art In recent years, turbine blades of gas turbines have been made of ceramics which are lightweight and have excellent heat resistance and corrosion resistance. However, in general, ceramics are fragile and stretch like metal. Since it can hardly be expected, there is a drawback that if excessive stress concentrates locally, it will be destroyed at once. Therefore, when using a ceramic turbine blade, it is necessary to use various cushioning materials (dampers) in order to prevent damage caused by stress concentration on the ceramic turbine blade which occurs during high-speed rotation. is there.

For example, as shown in FIG. 5, a number of turbine blades a are generally radially mounted on a peripheral surface of a disk-shaped metal turbine disk b at a predetermined pitch. a slide-fitting, from the axial direction of the turbine disk b, an insertion portion d having the same flask shape from the bottom of the turbine blade a into a mounting groove c having a flask-shaped cross section formed on the outer peripheral portion of the turbine disk b. It can be implanted and attached. Therefore, when a centrifugal force is applied to the turbine blade a with the rotation of the turbine disk b, the turbine blade a moves so as to protrude outward, thereby causing the shoulder e of the implanted portion d to be in the mounting groove c. A large stress is concentrated on the contact surface between the shoulder portion e and the constricted portion f, being strongly pressed against the constricted portion f.

However, these contact surfaces are extremely precisely machined before the turbine blade a is assembled so as to have as complete a surface contact as possible, but slight machining and assembly errors are unavoidable. Therefore, there is a possibility that the stress concentration may cause breakage from the shoulder e. Therefore, for example, by interposing buffer members h, h made of a relatively soft metal plate such as nickel on both contact surfaces of the shoulder portion e and the constricted portion f, the stress is uniformly dispersed, and the stress concentration is increased. The destruction is to be prevented beforehand.
No. 5219).

On the other hand, as shown in FIGS. 5 and 6, the turbine blade a during operation generates a so-called nozzle wake in the circumferential direction due to pressure fluctuation of the combustion gas G sent from the stationary blade j. However, since this vibration is generated with the shoulder e of the turbine rotor blade a as a fulcrum, breakage due to stress concentration cannot be effectively prevented only by the cushioning materials h and h described above. Therefore, as shown in the drawing, a box-shaped damper k is provided to bridge the back surface of the adjacent platform p between the turbine disk b and the platform p of the turbine blade a, and the damper k is moved by centrifugal force. Vibration is suppressed by closely adhering to the back surface of the platform p and applying a frictional force between the adjacent turbine blades a, a, and a fulcrum of the vibration is moved to a contact portion between the turbine blades a. The burden is eased (Japanese Patent Application No. 4-56089).

Further, the damper k fills a gap between the platform p and the turbine disk b to prevent the leakage of the combustion gas G from the platform p,
An important function of preventing a drop in turbine thermal efficiency by also exerting a sealing function to prevent blow-through of the turbine disk cooling gas g flowing from the inlet n of the disk cover m.

[0007]

By the way, as described above, the damper k and the cushioning member h are conventionally separate members and are incorporated independently of each other. The two must be mounted separately as one set together with the wing a, which is disadvantageous in that the assembling work is difficult and skill is required.

Further, in order to sufficiently exert the buffer effect of the buffer material h, when the gas turbine is started, it slides positively at the interface between the mounting groove c of the turbine disk b and the implanted portion d of the turbine blade a. It is necessary to generate the initial adaptation of the buffer material h by causing the shock absorbing material h. However, in the conventional method, since the buffer material h is difficult to move, it is difficult for such a slip to occur and it is difficult to obtain a sufficient buffering action by the initial familiarity.

Therefore, the present invention has been devised in order to effectively solve such a problem, and an object of the present invention is to easily incorporate the turbine disk into a turbine disk and to exhibit a good cushioning effect. The present invention is to provide a novel turbine rotor blade hybrid shock absorber.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a turbine rotor which is disposed in a gap between a platform of a turbine rotor blade and a turbine disk and is closely attached to a back surface of the platform by centrifugal force. A box-shaped seal damper for damping the wings and preventing the leakage of combustion gas from the gap, and implants that are integrally provided on both sides of the lower end of the seal damper and extend from the lower surface of the platform. And a pair of plate-shaped buffer portions interposed between the portion and the mounting groove of the turbine disk to reduce the concentration of stress applied to the implanted portion.

That is, according to the present invention, the seal damper and the buffer, which have conventionally been separately formed and incorporated, are integrally formed as one member.

Therefore, since the seal damper and the buffer, which have been conventionally performed separately, can be simultaneously mounted, the mounting operation can be easily performed.

Further, since the two members are formed as one member, the buffer portion always moves with the movement of the seal damper portion when the turbine is started. The frictional force at the interface between the moving blade and the implanted portion is reduced, and the initial familiarity between the two is easily caused. Therefore, the concentration of stress applied to the interface is relieved and a good buffering action is exhibited, so that the reliability of the turbine blade can be improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, a plurality of turbine blades 2, 2... Are embedded at a predetermined pitch and radially attached to the outer peripheral surface of a disk-shaped turbine disk 1. This turbine disk 1 is similar to the conventional one.
The turbine blade 2 is made of a heat-resistant metal such as Inconel or rhenium, and the other turbine blade 2 is integrally formed of ceramics such as silicon nitride or silicon carbide.

On the outer periphery of the turbine disk 1, there are formed a large number of mounting grooves 3 each having a necked opening and having a flask-shaped cross section. The turbine blade 2 is attached to the turbine disk 1 by slidingly fitting the implanted portion 4 of the turbine disk 1 in the axial direction of the turbine disk 1. In order to facilitate installation, for example, between the implanted portion 4 of the turbine blade 2 and the mounting groove 3 of the turbine disk 1 into which the implanted portion 4 is slid, for example, 0. Suitable gap h ₁ is formed along the periphery of the implanting portion 4 about several mm.

The turbine blade 2 has a neck portion 5 at the upper portion of the implant portion 4 and a substantially flat platform 6 is formed at the upper portion of the neck portion 5. A blade 7 extending in the radial direction is formed. Furthermore, as shown in FIG. 3, between the platform 6 and the outer peripheral surface of the turbine disc 1 for example, the fixed gap h ₂ of several mm~ tens several mm height are formed, next Fit Platform 6,
6 Likewise for example, even during constant gap h ₃ of about 0.1~0.3mm is formed.

The gap h ₂ below the platform 6 and the gap h ₁ between the implant portion 4 and the mounting groove 3 are integrally filled with the gaps h ₂ and h _1. A hybrid buffer 8 according to the present invention is provided.

As shown in FIGS. 3 and 4, the hybrid shock absorber 8 is provided on the platform 6 of the turbine blade a.
And box-like sealing damper portion 9 interposed in the gap h ₂ between the outer peripheral surface of the turbine disk 1, provided on both sides of the seal damper unit 9, neck portion 11 of the mounting groove 3 and the implanting portion 4 of the shoulder is constructed from the implanting portion is a plate-shaped bent along the four buffer portions 10 Metropolitan to be interposed in the gap h ₁ between the parts 12.

That is, when the turbine disk 1 rotates and a centrifugal force is applied to the turbine rotor blade 2 and the shoulder portion 12 of the implanted portion 4 strongly presses the buffer portion 10, the buffer portion 10
Are plastically deformed in accordance with the surface shapes of the shoulder portion 12 and the constricted portion 11, whereby stress concentration on the shoulder portion 12 is reduced. On the other hand, the seal damper portion 9 is arranged so that the bottom portion (platform 6 side) is open and bridges the back surface portions of the adjacent platforms 6 and 6, and the seal damper portion 9 is formed by centrifugal force.
Is pressed against the back surfaces of the platforms 6, 6 and suppresses vibration by applying a frictional force between the adjacent turbine blades 2, _2, and fills a gap h ₂ at the lower portion of the platform 6 to reduce the vibration from the lower portion of the platform 6. Leakage of combustion gas is prevented. Note that the seal damper portion 9 and the buffer portion 10 are integrally formed of a relatively soft metal such as nickel, as in the related art, and are appropriately plastically deformed.

As shown in FIG. 2, the hybrid shock absorber 8 and the turbine blade 2 have a pair of covers 14 whose end faces located radially inside the turbine disk 1 are attached to both surfaces of the turbine disk 1. , 15. That is, this cover 1
4 and 15 are formed in a substantially disk shape, and their fitting portions 16 and 16 are formed.
Are fixed to the recesses 17, 17 on both surfaces of the turbine disk 1 by shrink fitting or the like, and the projections 18, 18 inside the outer peripheral portions 19, 19 serve as the implanted portion 4 of the turbine blade 2 and the hybrid buffer 8. It comes into contact with the seal damper portion 8 to prevent displacement and dropping due to its sliding movement. Further, the outer peripheral portions 19,
Reference numeral 19 designates a space between the turbine disk 1 and the turbine rotor blade 2 to form a passage for cooling air g. The cooling air g introduced from an inlet 20 provided on the cover 15 side is covered by the cover 14. The turbine disk 1 is cooled by exhausting air from an exhaust port 21 provided on the side. A ring-shaped seal portion 22 is formed on the outer peripheral portion 19 of the cover 15 located on the upstream side in the flow direction of the combustion gas G so as to protrude therefrom.
The combustion gas G that has passed through 3 is sealed so as not to flow inward in the radial direction of the turbine disk 1.

The operation of the present embodiment will be described above.

First, when assembling the gas turbine,
Since the platform 6 of the turbine rotor blade 2 has a mid-high shape with a raised central portion, it is necessary to insert the hybrid buffer 8 simultaneously with the insertion (slide fitting) of the turbine rotor blade 2. At that time, the conventional turbine blade 2
At the same time, the seal damper and the cushioning material were inserted little by little. However, the implanted portion of the buffer layer had a twist angle, so that if the insertion angle was incorrect, the implant was easily damaged. However, since the hybrid shock absorber 8 of the present invention can be inserted along the twist angle because the seal damper portion 9 and the shock absorber 10 are integrated, the assembly can be easily and reliably performed, and the shock absorber can be easily assembled. Bending scratches and the like do not occur in the portion 10, and damage to the turbine blade 2 due to uneven stress can be prevented.

Next, the operation of the gas turbine incorporating the hybrid buffer body 8 of the present invention in this way is started,
When the turbine disk 1 rotates, the hybrid buffer 8 moves radially outward of the turbine disk 1 together with the turbine blade 2 by centrifugal force and is strongly pressed against the back surface of the platform 6 of the turbine blade 2. As a result, the seal damper portion 9 of the hybrid cushioning member 8 located at the lower portion of the platform 6 is pressed so as to bridge between the back surfaces of the adjacent platforms 6, so that the vibration of the turbine blades 2 and 2 due to nozzle wake and the like. Is effectively suppressed. Further, since the hybrid buffer 8 is made of a relatively soft metal as described above, it is appropriately plastically deformed by the pressing force and adheres to the back surface of the platform 6. As a result, even if the back surface of the platform 6 has some irregularities, the stress is effectively dispersed without the seal damper portion 9 being in point contact with the platform 6, so that the destruction of the platform 6 due to stress concentration is effectively prevented. Can be prevented. In addition, since the contact area between the platform 6 and the seal damper portion 9 is increased, the weight of the seal damper portion 9 is reduced, so that a high vibration damping effect can be exhibited even if the pressing force is small.

Further, at this time, the seal damper portion 9 is also deformed in the spreading direction by the centrifugal force, and comes into close contact with the neck portion 5 of the turbine rotor blade 2 so as to exhibit a further vibration-proof effect.
By tightly contacting the inner surfaces of the covers 14 and 15, not only the combustion gas G can be blown from the bottom of the platform 6 but also the cooling air g can be reliably sealed. Accordingly, it is also possible to effectively prevent a decrease in the thermal efficiency of the entire gas turbine due to blow-by of the combustion gas G, deterioration of the cooling of the turbine disk 1, and the like.

On the other hand, the cushioning portions 10 provided on the seal damper portion 9 are necessarily pulled together with the turbine blade 2 by the radial movement of the seal damper portion 9 radially outward due to centrifugal force. Moving. For this reason,
Since the frictional force generated at the interface between the implanted portion 4 of the turbine rotor blade 2 and the mounting groove 3 of the turbine disk 1 is reduced and the initial adaptation of both interfaces is more likely to occur, the implanted portion 4 of the turbine rotor blade 2 is increased. It is possible to effectively prevent the concentration of stress applied to the substrate.

Therefore, the initial fitting of the interface between the implanted portion 4 of the turbine blade 2 and the mounting groove 3 of the turbine disk 1 can be reliably generated, so that a good damping action is exhibited and the turbine blade 2 Can be reliably prevented.

[0028]

As described above, according to the present invention, incorporation into a turbine disk is facilitated, and assembling work efficiency is improved, and a good damping action can be exerted on turbine blades. It is possible to exhibit excellent effects such as providing a highly reliable gas turbine.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a side view showing one embodiment of the present invention.

FIG. 3 is a partially enlarged view showing an S part in FIG. 1;

FIG. 4 is a perspective view showing an embodiment of a hybrid buffer according to the present invention.

FIG. 5 is a front view showing an example of a conventional seal damper.

FIG. 6 is a side view showing an example of a conventional seal damper.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbine disk 2 Turbine rotor blade 3 Mounting groove 4 Implanted part 6 Platform 8 Hybrid buffer 9 Seal damper part 10 Buffer part

Claims (1)

[Claims] 1. A turbine blade is disposed in a gap between a platform of a turbine blade and a turbine disk. The turbine blade is in close contact with a back surface of the platform by centrifugal force to dampen an adjacent turbine blade and to reduce a leak of combustion gas from the gap. A seal damper part having a box shape to prevent it, and a seal damper part provided integrally on both sides of a lower end part of the seal damper part, interposed between an implant part extending from the lower surface of the platform and a mounting groove of the turbine disk. A hybrid shock absorber for a turbine rotor blade, comprising a pair of plate-shaped shock absorbers for reducing stress concentration applied to the implanted portion.