KR102095032B1 - Turbine blade forming method - Google Patents

Abstract

A turbine blade forming method is disclosed. This embodiment relates to a turbine blade forming method with improved precision even when the internal shape of the turbine blade is complicated by applying injection molding method in combination with casting molding for the turbine blade.

Description

Turbine blade forming method

The present invention relates to a turbine blade forming method, and more particularly, to shape a turbine blade by applying a molding method of a turbine blade installed in a specific stage in combination with a casting method and a machining method.

In general, a turbine (turbine) is a power generator that converts thermal energy of a fluid, such as gas or steam, into a rotational force that is mechanical energy, and a rotor including a plurality of buckets to be axially rotated by a fluid. It comprises a (rotor) and a casing that is installed around a circumference of the rotor and is provided with a plurality of diaphrams.

The gas turbine comprises a compressor section and a combustor and turbine section, and external air is sucked and compressed by rotation of the compressor section, and then sent to the combustor, and combustion is performed by mixing compressed air and fuel in the combustor.

The combustion state generated in the combustor is an isothermal heating process, and the combustion gas temperature is raised to a temperature that the turbine metal can withstand. The gas turbine combustor corresponds to a portion that has high energy by reacting high-temperature and high-pressure air from the compressor with fuel and transmits it to the turbine to drive the turbine.

Since the turbine blade is operated in a corrosive atmosphere under high temperature and high stress, it is made of a Ni (nickel) based heat resistant alloy, which is a material having excellent heat resistance and corrosion resistance.

The Ni-based heat-resistant alloy as described above is manufactured by adding elements such as aluminum (AL) and titanium (TI) to improve high-temperature strength, and the added elements such as aluminum and titanium have strong reactivity with the atmosphere. It is difficult to control and is manufactured through vacuum melting and casting operations.

As an example, the turbine blades provided in the turbine are also Ni-based heat-resistant alloys, which require vacuum melting and casting, and because of the characteristics of the product, require high quality such as high surface roughness, particle refinement, and strict internal defect control. It is produced by the vacuum precision casting method used.

Looking briefly at this vacuum precision casting method, the vacuum precision casting method produces a model of wax or a similar material in the same way as the product to be cast, and then a slurry in which fillers, binders, etc. are mixed on the wax model surface. ), And the work of putting refractory is repeated several times to produce a mold.

After drying the mold, the mold is heated to remove the wax inside the mold, and then the mold is fired at high temperature to produce the mold.

Using the mold produced in this way, the metal is melted and injected in a vacuum furnace, and then the mold is removed, and a cast product is produced through post-treatment.

Turbine blades are produced by performing this manufacturing method, but due to the characteristics of the turbine blades, it is a component that requires not only high internal defect control and mechanical properties, but also high dimensional accuracy. There is a need for a turbine blade manufacturing method that satisfies the error range.

Referring to the attached Figure 1, the turbine blades of three or more stages, except for the turbine blades provided in the first or second stage turbine among the plurality of unit turbines constituting the turbine, become thinner and thicker from the hub to the tip. The layout of the passage through which it moves is also complicated.

In the turbine blade, a ceramic core 70 made of ceramic for molding is located inside the blade mold BM. Then, after a certain time has elapsed after the casting liquid is injected into the blade mold BM, the ceramic core 70 is removed to manufacture a blade having a passage.

In particular, since the passage is formed by a curved path, when the entire inner region of the turbine blade is manufactured through casting molding, molding may be unstable at a specific location.

In this case, the operator had to re-manufacture three or more turbine blades, thereby causing a problem in that the work speed was lowered and the work efficiency was reduced due to the re-production.

In addition, even if the operator normally produced three or more turbine blades by the existing casting method, even if it was not confirmed with the naked eye, fine drilling or bonding could occur internally.

In this case, fixation may occur after the turbine blade is installed in the turbine, which may cause a larger problem due to operation stoppage, and thus, a countermeasure is needed.

In particular, because the casting operation is due to the characteristics of the same casting conditions, even when the casting operation is performed, the dimension deformation may occur flexibly. In addition, if necessary, an operation for properly correcting the generated deformation should be added.

Japanese Patent Publication JP 2017-526532

Embodiments of the present invention can provide a turbine blade forming method capable of manufacturing turbine blades with stable quality regardless of the thickness of the tip by changing the manufacturing method of the turbine blade located in a specific stage constituting the turbine blade.

Turbine blade forming method according to an embodiment of the present invention is a first molding step (ST100) that is molded for the first molded product 100 by injection molding in a first mold (M1) having a partial internal shape of the turbine blade ); Turbine excluding the insertion region (S) after the first molding product (100) is inserted inside the second mold (M2) having an insertion region (S) inside so that the first molding product (100) is inserted A second molding step (ST200) of molding the second molded article 200 to be formed of the remaining regions of the blade; A third molding step (ST300) of removing the first molded article 100 formed inside the second molded article 200; And a fourth forming step (ST400) of processing a passage for movement of cooling air with respect to the second molded product 200 from which the first molded product 100 is removed.

The first molded article 100 is formed on the inner side adjacent to the hub among the entire section from the hub constituting the turbine blade to the tip.

The first molded article 100 is molded while maintaining the shape of the cooling passage formed inside the turbine blade.

The first molded article 100 is characterized in that an inorganic material is used.

The first molded product 100 and the second molded product 200 are molded from different materials.

The first molded article 100 and the second molded article 200 are characterized in that the melting temperature is different from each other.

After the first molding step (ST200), the first molding product supporting step (ST110) for supporting the first molded product 100 from the inside of the second molded product 200 is further included.

The second molding step ST200 includes a casting liquid injection step ST210 in which the casting liquid is injected while the first molded article 200 is positioned in the insertion region S.

In the third molding step (ST300), removal of the first molded product 100 formed inside the second molded product 200 is performed in an underwater environment.

In the fourth forming step (ST400), drilling is performed from the upper side of the tip constituting the turbine blade toward the hub constituting the turbine blade, and the drilling forming step (ST410) is performed on the first molded product 100. ).

The present embodiment is characterized in that the turbine blade manufactured according to the turbine blade forming method is used to manufacture a three-stage turbine blade or a high-stage turbine blade provided after the third stage turbine blade.

Provided is a gas turbine equipped with a turbine blade manufactured according to the turbine blade forming method according to this embodiment.

Embodiments of the present invention may form a turbine blade with minimal shape change in consideration of the characteristics of the turbine blade, which becomes thinner as the thickness increases from the hub to the tip among the turbine blade forming methods.

In the embodiments of the present invention, molding stability is improved for a three-stage turbine blade or a three-stage or more turbine blade among a plurality of turbine blades provided in the turbine.

Embodiments of the present invention provides a molding method that can easily perform the forming of the passage through which the cooling air moves inside the turbine blade, so that it is possible to simultaneously improve the worker's work speed and improve the manufacturing efficiency of the turbine blade. .

In addition, since the molding of the passage of the turbine blade, which was difficult to process, is easily performed, molding stability can be improved.

1 is a view showing a configuration used to form a conventional turbine blade.
Figure 2 is a longitudinal cross-sectional view illustrating a gas turbine equipped with a turbine blade produced by a turbine blade forming method according to an embodiment of the present invention.
Figure 3 is a flow chart showing a turbine blade forming method according to an embodiment of the present invention.
4 is a view showing a first molded article molded by an exemplary embodiment of the present invention.
FIG. 5 is a view showing a state in which a first molded article previously manufactured by an example of the present invention is inserted into an insertion region formed in a second molded article.
6 is a view showing a state in which the first molded article according to an exemplary embodiment of the present invention is inserted into the insertion region of the second molded article.
7 is a view showing a state in which the casting liquid is injected into the second molded article according to an exemplary embodiment of the present invention.
8 is a view showing a state in which drilling is performed from the tip of the turbine blade to the insertion region produced by an exemplary embodiment of the present invention.
9 is a view showing a turbine blade formed by FIGS. 3 to 9 according to an exemplary embodiment of the present invention.

Prior to the detailed description, a gas turbine equipped with a turbine blade formed by the turbine blade forming method of the present invention will be described with reference to the drawings. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to a user's or operator's intention or practice, and the following examples do not limit the scope of the present invention, but rather the scope of the present invention. It is merely exemplary of the components presented in the claims.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar elements throughout the specification. Throughout the specification, when a part “includes” a certain component, this means that other components may be further provided instead of excluding the other component, unless specifically stated to the contrary.

Referring to the attached Figure 2, the gas turbine 1 according to an embodiment of the present invention is a compressor 20 for compressing high pressure by inhaling air, and the air compressed by the compressor 20 with fuel It may include a combustor (10) for mixing and combustion, and a turbine (30) for generating power while rotating turbine blades by using high-temperature, high-pressure combustion gas discharged from the combustor (10).

Specifically, the gas turbine (1) is provided with a casing (2), described with reference to the flow direction of the air, the compressor 20 is located on the upstream side of the casing (2), the turbine 30 on the downstream side It is placed. In addition, between the compressor 20 and the turbine 30, a rotational force transmission unit 40 as a torque transmission member for transmitting rotational torque generated by the turbine 30 to the compressor 20 is disposed.

In addition, the rear side of the casing (2) is provided with a diffuser (50) through which the combustion gas passing through the turbine (30) is discharged, and a combustor receiving compressed air to the front of the diffuser (50) for combustion 10 is arranged.

The compressor 20 is provided with a plurality of (for example, 14) compressor rotor disks 22, and the respective compressor rotor disks 22 are fastened so as not to be spaced apart in the axial direction by a tie rod 60. have.

The tie rod 60 is arranged to penetrate the center of the plurality of compressor rotor disks 22, one end of which is fastened in the compressor rotor disk 22 located on the upstream side, and the other end of the plurality of compressor rotor disks 22 It is fixed at 40.

Since the shape of the tie rod 60 can be formed in various structures depending on the gas turbine, it is not necessarily limited to the shape shown in FIG. 1. That is, as shown, one tie rod may have a form passing through the central portion of the rotor disk, or a plurality of tie rods may have a form arranged in a circumferential shape, and mixing of these is possible.

Each of the compressor rotor disks 22 is aligned along the axial direction of each other with the tie rod 60 penetrating the center. Here, each neighboring compressor rotor disk 22 is arranged such that the opposing surface is compressed by the tie rod 60 so that relative rotation is impossible.

A plurality of compressor blades 24 are radially coupled to the outer circumferential surface of the compressor rotor disk 22. Each compressor blade 24 is provided with a root 26 to be fastened to the compressor rotor disk 22.

The root 26 is fastened in a tangential type and an axial type. It may be selected according to the required structure of a commercial gas turbine, and may have a commonly known dovetail or fir-tree shape.

In some cases, the blade may be fastened to the rotor disk using a fastening device other than the above-mentioned type, for example, a key or a bolt.

In addition, a vane (not shown) which is fixedly disposed on the casing 2 is positioned between each of the compressor rotor disks 22. Unlike the compressor rotor disk 22, the vane is fixed so as not to rotate, and the flow of compressed air passing through the compressor blade 24 of the compressor rotor disk 22 is aligned to compress the rotor disk located downstream. It serves to guide the air to the blade.

As described above, after the outside air is sucked into the interior through the compressor 20 and passes through a plurality of the compressor blades 24 and vanes and is compressed in multiple stages, it is supplied to the turbine 30 via the combustor 10. Can be.

The combustor 10 mixes and burns compressed air introduced from the compressor 20 with fuel to produce high-temperature, high-pressure combustion gas with high energy, and to the heat-resistant limit that combustors and turbine parts can withstand through isostatic combustion. The combustion gas temperature is increased.

The combustor 10 constituting the combustion device system of the gas turbine is made of a can type, and a plurality of combustors 10 are installed along the circumferential direction of the gas turbine 1.

The combustor 10 includes a burner including a fuel injection nozzle, a combustor liner forming a combustion chamber, and a transition piece that becomes a connection between the combustor 10 and the turbine 30. It can be made including.

Specifically, the liner provides a combustion space in which fuel injected by the fuel injection nozzle is mixed with compressed air of the compressor 20 and burned. The liner may include a flame cylinder providing a combustion space in which fuel mixed with air is burned, and a flow sleeve surrounding the flame cylinder to form an annular space. In addition, a fuel injection nozzle may be coupled to the front end of the liner, and an ignition plug may be coupled to the sidewall.

On the other hand, a transition piece is connected to the rear end of the liner so as to send the combustion gas burned by the spark plug to the turbine 30 side. The transition piece, the outer wall portion is cooled by compressed air supplied from the compressor 20 to prevent damage due to the high temperature of the combustion gas.

The turbine 30 is basically similar to the structure of the compressor 20. That is, the turbine 30 is also provided with a plurality of turbine rotor disks 32 similar to the compressor rotor disk 22 of the compressor. In addition, it includes a plurality of turbine blades 34 disposed radially on the outer circumferential surface of the turbine rotor disk 32. At this time, the turbine blade 34 may be coupled to the turbine rotor disk 32 in a dovetail or the like manner.

In the gas turbine having the structure as described above, the introduced air is compressed in the compressor 20, and after being burned in the combustor 10, it is sent to the turbine 30 to drive the turbine, and the diffuser 50 ) To the atmosphere.

Here, the gas turbine is only one embodiment of the present invention, and the combustion device of the present invention, which will be described in detail below, can be applied to all general gas turbines.

A turbine blade forming method according to an embodiment of the present invention will be described with reference to the drawings. For reference, FIG. 3 is a flow chart showing a turbine blade forming method according to an embodiment of the present invention, FIG. 4 is a view showing a first molded article molded by an exemplary embodiment of the present invention, and FIG. 5 is the present invention 1 is a view showing a state in which a first molded article previously manufactured by an example is inserted into an insertion region formed in a second molded article.

2 or 3 to 5 or 9, the turbine blade forming method according to an embodiment of the present invention is injection molded in a first mold M1 partially having an internal shape of the turbine blade. The first molding step (ST100) in which molding is performed on the first molded article 100 and the second mold M2 inside the second mold M2 having an insertion region S therein to insert the first molded article 100 1 After the molded article 100 is inserted, a second molding step (ST200) for forming the second molded article 200 to be formed of the remaining regions of the turbine blade except for the insertion region S, and the second molded article 200 3) a third molding step (ST300) for removing the first molded article 100 formed inside, and a passage for movement of cooling air for the second molded article 200 from which the first molded article 100 is removed. And a fourth forming step (ST400) for processing.

Prior to the detailed description, the second mold M2 is a mold different from the first mold M1 and corresponds to a mold made by modeling the internal shape of a turbine blade.

In this embodiment, although the casting molding method is partially applied, the molding for the passage formed in the turbine blade 34 (see FIG. 9) and the cooling air moves through the injection molding method rather than the casting molding method described above. It is possible to easily perform a stable molding for a complicated internal flow path by performing a molding for the beforehand.

This embodiment is to produce a three-stage turbine blade or a high-stage turbine blade provided after the third stage turbine blade, rather than being manufactured for forming a first or second stage turbine blade among a plurality of turbine blades provided in the turbine. Is used.

For example, the three-stage turbine blade is configured to have a structure different from the structure of the one-stage or two-stage turbine blade. For example, although the thickness of the section from the hub to the tip of the first stage turbine blade becomes thinner, the casting method maintains a sufficiently stable thickness.

On the other hand, from the three-stage turbine blade, the thickness from the hub to the tip becomes thinner than the above-described one-stage turbine blade, which makes manufacturing through casting molding considerably disadvantageous.

This embodiment improves molding stability for the tip portion of which the thickness becomes thinner by performing molding through the above-described molding method from the three-stage turbine blade for optimized molding according to the number of stages of such a turbine blade.

The first forming step (ST100) according to the present embodiment is the tip 34b from the hub 34a (see FIG. 9) rather than the entire shape of the turbine blade 34 (see FIG. 9) in the first mold M1 ( Of the entire section leading to FIG. 9), molding is performed on the inner side adjacent to the hub 34a.

The hub 34a corresponds to the lower side of the turbine blade 34 based on the drawing, and only a portion corresponding to a position below 1/2 in the entire section leading to the tip 34b based on the hub 34a Molding is performed on the first molded article 100 to be molded.

When the first molded product 100 is injection molded, it is possible to accurately mold a passage having a complicated path, thereby compensating for a disadvantage that may occur during casting molding. Injection molding can be easily molded even when the shape of the first molded product 100 is complex.

In addition, when the first molded product 100 is manufactured by an injection molding method, molding may be unstable at a specific location, or the frequency of occurrence of defective products may be reduced, which may be advantageous for molding the first molded product 100 having a complicated shape or path. .

The first molded product 100 is a portion corresponding to a passage through which cooling air moves from the inside of the turbine blade 34. In the present exemplary embodiment, the molding of the passage is secondly performed after injection molding rather than casting molding. The second molded article 200 is molded by being positioned in the insertion region S of the inside of the mold M2.

The first molded product 100 is inserted into the insertion region S of the inside of the second mold M2, the insertion region S being adjacent to the hub 34a of the entire region of the turbine blade 34. Is applicable.

In addition, the insertion region S is a section in which the thickness of the turbine blade 34 is kept thicker than the tip 34b, and the shape of the passage corresponds to the region into which the first molded product 100 precisely molded by injection molding is inserted. .

As an example, the first molded article 100 is made of an inorganic material, for example, a ceramic core is used.

The first molded product 100 and the second molded product 200 are formed of different materials, for example, the first molded product 100 is composed of the aforementioned ceramic core, and the second molded product 200 Is made of a castable material.

The first molded article 100 and the second molded article 200 are maintained at different melting temperatures from each other. For example, the first molded article 100 is melted at a specific temperature.

The first molded article 100 and the second molded article 200 maintain a different shrinkage rate, and by using these characteristics, it is possible to perform stable turbine blade 34 molding.

Referring to FIG. 7, after the first molding step ST100 is performed, before the first molding step ST200 is carried out, the first molded product 100 is transferred to the second molded product 200. A first molded product support step (ST110) for supporting from the inside is performed.

The reason why the first molded article is supported is to prevent movement or position fluctuation of the first molded article 100 when high temperature casting liquid is injected into the second mold M2, and torsion while the casting liquid is cured It prevents the occurrence of defects. For reference, a plurality of support bars (B) of the type shown in the drawings are used.

In the second molding step ST 200, the first molded product 100 is positioned in the insertion region S after the first molding step ST100 described above. Then, the casting solution is injected into the state in which the first molded article 200 is positioned in the insertion region S (ST210).

The casting liquid is injected in a state in which the second mold M2 is erected vertically, and is injected from the hub 34a of the turbine blade 34 and moved to the tip 34b.

When the casting liquid is injected, the casting liquid is filled on the outside of the first molded product 100 and molding is performed on the remaining areas except for the insertion region S in which the first molded product 100 is located.

In addition, when all of the pre-injected casting liquid is cured after a specific time has elapsed, removal of the first molded product 100 is performed (ST300).

The first molded article 100 is removed from the first molded article 100 formed inside the second molded article 200 in an underwater environment. For example, the chemical reaction is removed by inducing a chemical reaction, and for this purpose, the second mold M2 may be immersed in a water tank or chamber having a predetermined size.

When all of the first molded product 100 is removed from the inside of the second molded product 200, the second molded product 200 is molded into an empty space corresponding to a passage.

Referring to FIG. 8, in the fourth forming step (ST400), drilling is performed from the upper side of the tip constituting the turbine blade to the hub constituting the turbine blade, and the first molded product 100 is processed. Further comprising the drilling forming step (ST410) is made.

As shown in the drawing, the drilling molding is a state in which the passage portion of the serpentine shape has already been molded by the first molded product 100, so the first molded product at the tip 34b using a drilling equipment rather than a curved molding method. It is carried out toward the insertion region S where 100 is located.

Drilling is sequentially performed from left to right based on the drawing, but may be performed in a different order.

The turbine blade manufactured according to the turbine blade forming method according to this embodiment is used to manufacture a three-stage turbine blade or a high-stage turbine blade provided after the third stage turbine blade.

This embodiment provides a gas turbine equipped with a turbine blade 34 manufactured according to the blade forming method described above. The turbine blade 34 can be applied to most turbines regardless of the medium that operates the turbine.

As described above, one embodiment of the present invention has been described, but those skilled in the art can add, change, delete, or add components within the scope of the present invention as described in the claims. The present invention may be variously modified and changed by the like, and it will be said that this is also included within the scope of the present invention.

2: casing
10: combustor
20 compressor
30: turbine
34: turbine blade
100: first molded article
200: second molded article

Claims (12)

A first molding step (ST100) in which molding is performed on the first molded product 100 by injection molding in a first mold M1 partially having an internal shape of a turbine blade;
Turbine excluding the insertion region (S) after the first molding product (100) is inserted into the second mold (M2) having an insertion region (S) inside so that the first molding product (100) is inserted A second molding step (ST200) of molding the second molded article 200 to be formed of the remaining regions of the blade;
A third molding step (ST300) of removing the first molded article 100 formed inside the second molded article 200; And
Including the fourth molding step (ST400) for processing the passage for the movement of the cooling air for the second molded article 200, the first molded article 100 is removed,
The first forming step (ST100) is a tip from a hub constituting the turbine blade to form a three-stage turbine blade or a high-stage turbine blade provided after the third stage turbine blade among a plurality of turbine blades provided in the turbine. In order to improve the molding stability for the tip portion where the thickness becomes thinner in the entire section leading up, only the portion of the passage corresponding to the position of 1/2 below the entire section from the hub to the tip is partially formed,
The fourth shaping step (ST400) further comprises a drilling shaping step (ST410) in which drilling is performed in the direction of the hub in which the first molded product is located at the tip after shaping for the passage of the turbine blade is already made. .
delete According to claim 1,
The first molded product 100, the turbine blade forming method is formed while the shape of the cooling passage formed inside the turbine blade is maintained. According to claim 1,
The first molded article 100 is a turbine blade forming method in which an inorganic material is used. According to claim 1,
Turbine blade forming method wherein the first molded product 100 and the second molded product 200 are molded from different materials. According to claim 1,
The first molded article 100 and the second molded article 200 is a turbine blade forming method having different melting temperatures from each other. According to claim 1,
Turbine blade forming method further comprises a first molded product support step (ST110) for supporting the first molded product 100 from the inside of the second molded product 200 after the first molding step (ST200). According to claim 1,
The second molding step (ST200) is a turbine blade forming method comprising a casting liquid injection step (ST210) in which the casting liquid is injected while the first molded product 100 is located in the insertion region (S). According to claim 1,
The third molding step (ST300) is a turbine blade forming method in which the removal of the first molded product 100 formed inside the second molded product 200 in an underwater environment. delete delete Gas turbine equipped with a turbine blade produced according to the turbine blade forming method according to claim 1.

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