JP6138575B2 - Axial turbomachinery rotor blades - Google Patents

Description

  The present invention relates to a moving blade of an axial-flow turbomachine.

  Steam turbines, which are large-scale axial-flow turbomachines, are generally composed of high-pressure, medium-pressure, and low-pressure turbines. Among them, low-pressure turbines with low steam pressure, which is the working fluid, have blade lengths of the last stage blades. There are cases in which the size exceeds 1 meter.

  By increasing the final stage blade length, the ring area of the blade can be increased, and more steam kinetic energy can be converted into rotational energy of the moving blade than in the case of a short blade, thereby improving efficiency.

  In addition, since the output is increased by extending the blade length, compared to a steam turbine with a short last stage blade, a turbine with a long blade can generate the same output power in a small cabin, thus reducing the manufacturing cost. There is an advantage that it can be suppressed.

  As described above, it is effective to lengthen the last stage moving blade for a highly efficient and low cost steam turbine, but if the blade length increases, it becomes a severe condition from the viewpoint of strength reliability. In other words, longer blades not only increase the centrifugal stress acting on the blade root, but also increase the number of vibration modes that must be avoided because the natural frequency of the vibration mode of the moving blades decreases due to the weight of the blades. Challenges arise.

  As a prior art in this technical field, there is JP-A-2007-270842 (Patent Document 1). This publication includes the step of filling one or more pockets in a bucket with a polymer composite material having continuous fibers in a resin matrix, where the fibers are obtained by a preselected frequency tuning or damping method of the bucket. Has a determined orientation. The turbine blade includes at least one bucket, the bucket including a metal matrix with one or more pockets filled with a polymer composite material having continuous fibers bonded within a resin matrix, the fibers Is described as having an orientation determined by preselected frequency tuning of the bucket.

  Moreover, there exists Unexamined-Japanese-Patent No. 2009-74545 (patent document 2). This publication describes that the turbine component includes a mounting structure for mounting the turbine component, a core made of a structural material coupled to the mounting structure, and a plastic airfoil that wraps at least part of the core. Has been.

JP 2007-270842 A JP 2009-74545 A

  Since a general steam turbine blade structure is formed only of a metal material, it is necessary to reduce the volume of the metal material in order to reduce the weight. However, in the low-pressure turbine final stage moving blade, there is a problem that it is difficult to reduce the weight further because the thickness of the conventional blade structure is reduced to a limit strength that can withstand static stress and resonance stress.

  In addition, since the centrifugal force of the object is proportional to the mass and the radius of rotation, to reduce the centrifugal force, the portion near the tip of the blade with a large radius of rotation is reduced in weight, acting on the blade below the blade tip. Since the centrifugal force can be reduced, particularly by reducing the weight of the shroud cover at the tip of the blade, the centrifugal force can be greatly reduced.

  However, since the shroud cover is connected in contact with the adjacent blades, it is necessary to ensure the strength to withstand the reaction force caused by the contact, and a moving blade structure having a thick and strong cover is desirable.

  Patent Document 1 describes a structure in which a moving blade has a pocket and the pocket is filled with a polymer composite material. In this structure, it is possible to reduce the weight of the portion using the polymer composite material as compared with the wing composed only of the metal material.

  In Patent Document 2, a moving blade including a core and a plastic airfoil portion that wraps at least a part of the core is described. Even in the structure of Patent Document 2, as in Patent Document 1, the weight can be reduced as compared with a blade composed of only a metal material. However, neither document describes the weight reduction of the shroud cover at the blade tip.

  Therefore, the present invention provides a turbine blade of an axial-flow turbomachine combining a metal material and a non-metal material, which reduces the weight of the shroud cover at the blade tip and suppresses a decrease in cover strength due to the weight reduction.

  In order to solve the above problems, in the present invention, a wing portion formed of a metal base material and having a twisted portion, and a wing portion formed integrally with the same metallic base material as the wing portion at the tip, and rotated. In a rotor blade of an axial-flow turbomachine having a shroud cover having contact portions at both ends in the circumferential direction, which are in contact with the shroud cover of adjacent blades due to centrifugal force at the time, a part of each of the blade portion and the shroud cover portion is It is formed by bonding with a high-tensile sheet made of a non-metallic material having a specific gravity smaller than that of a metal base material, and an airfoil forming member is provided on the high-tensile sheet of the wing part to form a wing shape. .

  According to the present invention, it is possible not only to reduce the weight of the shroud cover but also to suppress the strength reduction due to the weight reduction of the cover portion, with respect to the moving blade structure composed of only a conventional metal material.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is an example of the moving blade of the last stage of a steam turbine. It is an example of the tip structure of the moving blade of a general steam turbine. It is the schematic which shows the front-end | tip structure of the turbine rotor blade which concerns on 1st Example of this invention. It is the schematic which shows the cross section of the shroud cover of the turbine bucket which concerns on 1st Example of this invention. It is the schematic which shows the completed structure of the moving blade manufactured in the 1st Example of this invention. It is the schematic which shows the front-end | tip structure of the turbine bucket which concerns on 2nd Example of this invention. It is the schematic which shows the front-end | tip structure of the turbine rotor blade which concerns on 3rd Example of this invention. It is the schematic which shows the front-end | tip structure of the turbine bucket which concerns on the 4th Example of this invention. It is the schematic which shows the front-end | tip structure of the turbine bucket which concerns on the 5th Example of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, although the Example described below is an example which applied this invention to the steam turbine as an example of a turbine rotor blade, this invention is applicable not only to a steam turbine but to the blade | wing of a gas turbine or a compressor. It is.

  An example of the moving blade of the steam turbine to which a present Example is applied is shown. The moving blade shown in FIG. 1 is a schematic diagram of the moving blade used in the final stage of the low-pressure turbine.

  The moving blade used in the final stage includes, as main components, a blade portion 1 formed by three-dimensionally twisting from the blade root to the blade tip, and a shroud cover 2 formed integrally with the blade portion at the tip of the blade portion 1. , A tie boss 3 that is a connecting member that protrudes from the blade back side and blade abdomen side of the middle part of the wing part 1, a platform that is provided at the root side end of the wing part 1 and forms the inner peripheral surface of the steam channel 4. It has a blade root part 5 provided at the lower part of the platform 4.

  On the other hand, on the disk part 6 side of the rotor, a plurality of disk grooves 7 for fitting the blade root part 5 are provided in the circumferential direction as a structure for fixing the moving blade. The disk groove 7 is a groove cut in a straight line or in an arc so that the blade root part 5 can be inserted from the axial end surface of the disk portion 6 toward the other end surface.

  In FIG. 1, the disk groove 7 is shaped from the axial end surface of the disk portion 6 toward the other end surface, but there are various shapes depending on the shape of the blade root portion 5. Is a shape that can be fitted into the disk groove 7.

  The centrifugal force acting on the moving blade is supported by the rotor by fitting the moving blade implantation portion 5 into the disk groove 7 and engaging the moving blade and the rotor. When the rotor rotates, centrifugal force acts on the blade portion 1 from the blade root toward the blade tip as the rotor rotates.

  Since the wing part 1 is twisted, untwisting is generated in the wing part 1 due to centrifugal force, and the shroud cover 2 and the tie boss 3 are shroud covers of adjacent moving blades due to the twisting return force of the wing by the untwisting. The wings are in contact with each other to connect the wings.

  FIG. 2 shows a state where the shroud cover 2 is connected by twisting back by untwisting during turbine operation in which centrifugal force acts on the blades. The shroud cover 2 has a blade abdomen projection 9 projecting to the ventral side of the wing at the circumferential blade trailing edge side end and a blade back projection part projecting to the back of the blade at the circumferential blade front edge side end. 10 and. The blade belly side protrusion 9 and the blade back protrusion 10 constitute a contact portion that comes into contact with the shroud cover of the adjacent blade by the centrifugal force when the blade rotates. When the rotor blades rotate, a rotational force in the direction indicated by the arrow 8 acts on the shroud cover 2 by twisting back by untwisting. As the shroud cover 2 rotates, the blade back side protrusion 10 and the blade blade side protrusion 9 of the moving blade adjacent to the blade back side protrusion 10 are pressure-bonded and connected at the contact surface.

  FIG. 3 is a view for explaining the structure of the blade tip of the present embodiment.

  In the present embodiment, the shroud cover 2 has a structure formed of a cover metal core 12a that is a base material and a high-tensile sheet 11 that is a non-metallic material adhesively bonded onto the cover metal core 12a.

  In FIG. 3, a part of the wing portion 1 is also formed by a high-tensile sheet 11, and the high-tensile sheet 11 is bonded and bonded onto the wing metal core 12 b that is a base material. It has a structure. Here, the wing part metal core 12b to which the high-tension sheet 11 is bonded and bonded has a structure that is thinner than the finally manufactured wing shape. Note that the high-tension sheet 11 that is adhesively bonded to part of the cover metal core 12a and the wing metal core 12b is the same member.

  The region formed by the wing metal core 12b and the high-tensile sheet 11 reduced in thickness than the wing shape needs to finally become the wing shape, and on the wing metal core 12b and the high-tensile sheet 11, An airfoil forming member 14 having a structure different from that of the high tension sheet 11 is attached.

  As a mounting method, it is desirable in terms of weight reduction to form a wing shape by laminating members of the same material as the high-tensile sheet 11 around the reduced-thickness portion. There is no need to wrap and laminate, and it is determined from constraints such as adhesive bondability.

  For example, a wing-shaped mold may be installed around the wing metal core 12b and the high-tensile sheet 11, and a wing shape may be manufactured by pouring a filler. In short, it is only necessary that the airfoil can be finally formed.

  The wing lower portion 13 closer to the blade root side than the portion composed of the wing metal core 12b, the high-tensile sheet 11 and the airfoil forming member 14 is made of the same steel or titanium as the cover metal core 12a and the wing metal core 12b. The cover part metal core 12a, the wing part metal core 12b, and the wing lower part 13 are manufactured in an integral structure.

  As a material of the high-tensile sheet 11 which is a non-metallic material, a composite material such as a carbon fiber reinforced plastic having a specific gravity smaller than that of the metal part core 12 which is a base material for bonding and bonding the high-tensile sheet 11 is used.

  Further, the strength and thickness of the high tension sheet 11 can be adjusted by laminating, and the number of laminated sheets is determined by the shape of the shroud cover 2 and the required strength. In addition, the fiber direction of the high-tensile sheet 11 to be laminated is adjusted so as to increase in the direction in which the strength is desired.

  Here, the shroud cover 2 shown in FIG. 2 has a structure in which a blade back-side protrusion 10 and a blade blade-side protrusion 9 of a moving blade adjacent to the blade back-side protrusion 10 are connected by pressure bonding at a contact surface. However, the blade back-side protrusion 10 and the blade-side protrusion 9 of the moving blade adjacent to the blade back-side protrusion 10 are made of a base material so that the same structure is obtained in this embodiment of FIG. The metal core 12 is formed of the same metal material.

    The reason is that the contact surface of the adjacent shroud cover 2 is a portion where a material composition variation or local contact stress occurs due to frictional heat, and therefore a metal material is preferable. Since the blade back side protrusion 10 and the blade belly side protrusion 9 are made of the same metal material as the base metal core 12, the friction damping characteristics between the shroud covers of adjacent blades can be maintained. Thus, it is possible to provide a turbine blade having improved strength reliability.

  FIG. 4 shows a sectional view of the tip structure of the rotor blade of this embodiment.

  In this embodiment, the high tension sheet 11 of the same member is placed on the abdominal side of the wing and the back side of the wing by laminating the cover metal core 12a and the wing metal core 12b so as to cover the high tension sheet. It is adhesively bonded.

  However, when the number of stacked layers differs between the flank side and the back side surface of the wing due to the shape or the like, it is not necessary to bond and bond the flank side surface and the back side surface of the wing with the same high-tension sheet 11 in all stacks. In short, there is no problem as long as the laminated structure satisfies the cover strength.

  FIG. 5 shows a final blade structure according to this embodiment.

  As a final structure, as shown in FIG. 3, an airfoil forming member 14 having a structure different from that of the high tension sheet 11 is mounted on the high tension sheet 11 adhesively bonded to the wing metal core 12b. The mold forming member 14 has a structure for forming an airfoil.

  The boundary 15 between the airfoil forming member 14 and the lower blade region 13, that is, the blade height position, is determined from the viewpoint of tie boss height, airfoil shape, and blade strength.

  According to the present embodiment, a non-metallic material having a specific gravity smaller than that of the metal core 12 that is the base material is used for a part of the shroud cover 2 at the tip of the moving blade, so that only the conventional metal material is used. As compared with the shroud cover 2 to be made, the weight can be reduced.

  Further, when a non-metallic material having a small specific gravity is used not only for the shroud cover 2 but also for the airfoil forming member 14, in addition to the weight reduction of the shroud cover 2, the weight of the wing portion 1 can be reduced. .

  Furthermore, since the cover metal 12a and the wing metal core 12b constituting the shroud cover 2 are bonded and bonded with the same high-tensile sheet 11, when the high-tensile sheet 11 which is a non-metallic material having high tensile strength is used. Since the strength increases with respect to the bending direction of the wing, there is an advantage that a decrease in the cover strength can be suppressed even if the volume of the metal material of the shroud cover 2 part is reduced.

  That is, in the configuration shown in the present embodiment, when a blade length similar to that of a long blade made of a single metal material is formed, the blade portion below the portion using the non-metallic material is reduced by weight reduction, the blade Not only can the stress acting on the root portion and the disk groove be reduced, but also the strength reduction of the shroud cover 2 due to weight reduction can be suppressed, so that strength reliability can be ensured.

  Next, a second embodiment of the present invention will be described.

  FIG. 6 is a diagram illustrating an example of an adhesive bonding method for the high-tension sheet 11. Here, the same components as those described in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and portions different from those in the first embodiment are described.

  In FIG. 6, as in the first embodiment, the high-tensile sheet 11 of the same member is bonded and bonded onto the cover metal core 12a and the wing metal core 12b. Here, a different point from Example 1 is the point which installed the latching means which hooks a high tension sheet | seat and latches between the wing | blade part metal core 12b and the wing | blade lower area | region 13. FIG.

  Here, the latching means for the high-tensile sheet is provided with a latching hole 16 in the latching metal core 12c even if the adhesive force between the high-tensile sheet 11 and the metal core 12 is weak. By hooking the high tension sheet 11, it becomes an anchor in the direction in which the centrifugal force is applied to the high tension sheet 11, so that the adhesion between the high tension sheet 11 and the metal core 12 is prevented from being lowered by the centrifugal force. .

  The latching hole 16 may have a structure penetrating from the flank side to the back side of the wing. In this case, both ends of the high tension sheet 11 on the abdomen side and the back side can be adhesively bonded. That is, since the same material is joined, the strength of the high tension sheet 11 is increased.

  The latching part metal core 12c is manufactured as an integral structure with the cover part metal core 12a, the wing part metal core 12b, and the wing lower region 13. Further, like the wing metal core 12b, the latching metal core 12c has a structure that is thinner than the airfoil that is finally manufactured. Similar to the method described in 1, the final airfoil is formed by mounting the airfoil forming member 14.

  According to the present embodiment, since the high tension sheet latching means is installed, the adhesive bondability between the high tension sheet 11 and the metal core 12 is reduced even when the centrifugal force is large as compared with the first embodiment. There is an advantage that it can be suppressed. That is, by suppressing the decrease in adhesive bondability, it is possible to suppress the decrease in cover strength that is adhesively bonded with the high-tensile sheet.

  Next, a third embodiment of the present invention will be described.

  FIG. 7 is a view showing a tip structure of a turbine rotor blade according to a third embodiment of the present invention. Here, the same components as those described in the first to second embodiments are denoted by the same reference numerals, description thereof is omitted, and portions different from the above-described embodiment are described.

  In FIG. 7, similarly to the first to second embodiments, the metal core 12 and the high-tensile sheet 11 are bonded and joined. Here, a different point from the structure of Example 1 and Example 2 is a point from which the shape of the wing | blade part metal core 12b which adhere | attaches the high tension sheet | seat 11 differs.

  In FIG. 7, the surface shape of the wing metal core 12 b is thinned only in the vicinity where the high-tensile sheet 11 is bonded and joined. Here, the size of the thinned portion 18 is not necessarily matched with the size of the high tension sheet 11, and there is no problem as long as the high tension sheet 11 can be bonded and bonded.

The thinned portion 18 formed by the wing metal core 12b and the high-tensile sheet 11 reduced in thickness than the wing shape needs to finally form the wing shape, and the wing metal core 12b and the high-tensile sheet 11 An embedding member 19 forming a blade surface is mounted on the wing.

  As the mounting method of the embedded member 19, for example, there is a method of forming a wing shape by pouring a filler of a non-metallic material, a method of pouring a metallic material melted at a high temperature, There is a method of welding with wearing.

  According to the present embodiment, as compared with the first and second embodiments, the thinned region of the wing metal core 12b is small, so that there is an advantage that it is easy to manufacture. Moreover, since the wing | blade part metal core 12 forms a wing leading edge part, there exists an advantage that it is easy to weld and install the erosion shield which is a metal material.

  Next, a fourth embodiment of the present invention will be described.

  FIG. 8 is a view showing a turbine blade structure according to the fourth embodiment of the present invention. Here, the same components as those described in the first to third embodiments are denoted by the same reference numerals, description thereof is omitted, and portions different from the embodiments described above are described.

  In FIG. 8, similarly to the first to third embodiments, the metal core 12 and the high-tensile sheet 11 are bonded and joined. Here, the difference from the configurations of the first to third embodiments is that the shape of the wing metal core 12b for bonding and joining the high-tensile sheet 11 is different.

  In FIG. 8, the shape of the wing part metal core 12 b is thinner than the wing shape, but has a structure formed from the vicinity of the front edge to the vicinity of the rear edge of the wing part. Here, the region formed by the wing metal core 12b and the high tension sheet 11 reduced in thickness than the wing shape needs to finally form the wing shape, and the wing metal core 12b and the high tension sheet 11 are formed. On the top, the blade back side airfoil forming member 20a from the blade back side and the blade back side airfoil forming member 20b from the blade back side are mounted.

  For example, when the airfoil forming member 20 is a metal material, the airfoil side airfoil forming member 20a and the blade backside airfoil forming member 20b are attached to the airfoil metal core 12b. There is a method of welding the member 20 or the like.

  According to the present embodiment, the airfoil forming member 20 made of the same metal material as the wing metal core 12b is welded in a wide region of the wing metal core 12b, and therefore compared to the structures of the first to third embodiments. There is an advantage that the adhesive strength is increased.

  Finally, a fifth embodiment of the present invention will be described.

  FIG. 9 is a diagram showing a fifth embodiment of the present invention. Here, about the structure equivalent to the structure demonstrated previously in the 1st-4th Example, the same code | symbol is attached | subjected and description is abbreviate | omitted, and a different location from the Example demonstrated previously is demonstrated.

  In FIG. 9, as in the first to fourth embodiments, the metal core 12 and the high-tensile sheet 11 are bonded and bonded, and the airfoil forming portion 14 or 20 or the embedded member 19 is mounted thereon. It has become.

  Here, the difference from the configurations of the first to fourth embodiments is that the erosion shield 17 is attached to the front edge of the wing.

  The erosion shield 17 plays a role of preventing droplets existing in the steam from colliding with the blade leading edge and eroding. As the material, a stellite-based metal material that is less susceptible to erosion than the metal material used for the metal core 12 is used.

  As the method for attaching the erosion shield 17, when the airfoil forming portion 14 or 20 at the leading edge of the blade is a metal material, a method of welding the airfoil forming portion 14 or 20 and the erosion shield 17 is used. When the airfoil forming part 14 or 20 is made of a non-metallic material, the airfoil forming part 14 or 20 and the erosion shield 17 are bonded and bonded, and the erosion shield 17, the metal core 12 a and the wing lower part 13 are welded. .

  According to the present embodiment, since the leading edge of the airfoil forming portion 14 or 20 can be protected by the erosion shield 17, the blades are added to the droplets in the steam as compared with the configurations of the first to fourth embodiments. There is an advantage that it is hard to be eroded.

  As mentioned above, although the Example of this invention was described, this invention is not limited to an above-described Example, Various modifications are included. In short, there is no problem if the structure is such that a high-strength sheet made of a non-metallic material is used for a part of the shroud cover, which is a metallic material, so that the shroud cover can be reduced in weight and the reduction in cover strength due to weight reduction can be suppressed.

  In the embodiments of the present invention, the final stage of the steam turbine has been described as an example. However, the present invention is not limited to the final stage of the steam turbine. For example, a stage or a gas turbine before the final stage of the steam turbine is used. The same effect can be obtained with the compressor blades.

1 wing part 2 shroud cover 3 tie boss 4 platform 5 wing root part 6 disk part 7 disk part groove 8 shroud cover rotation direction 9 ventral side protrusion part 10 back side protrusion part 11 high tension sheet 12a cover part metal core 12b wing part metal core 12c Latch part metal core 13 Wing lower part 14 Airfoil forming member 15 Airfoil forming member and lower part boundary 16 Latching hole 17 Erosion shield 18 Thinning part 19 Embedding member 20 Airfoil forming member

Claims (7)

A wing portion formed of a metal base material and having a twisted portion;
A shroud cover that is integrally formed at the tip of the wing portion with the same metallic base material as the wing portion, and that has contact portions that contact the shroud covers of adjacent blades due to centrifugal force during rotation at both circumferential ends. A rotor blade of an axial-flow turbomachine comprising a portion,
Each of the wing part and the shroud cover part is formed by bonding with a high-tensile sheet made of a nonmetallic material having a specific gravity smaller than that of the metal base material,
A moving blade of an axial-flow turbomachine characterized in that an airfoil forming member is provided on the high-tension sheet of the blade to form a blade shape. A rotor blade for an axial-flow turbomachine according to claim 1,
The shroud cover portion includes a core portion made of a metal base material and a high-tensile sheet portion bonded to the surface of the core portion, and the contact portions provided at both ends in the circumferential direction are made of a metal base material. A moving blade of an axial-flow turbomachine characterized by being formed. A rotor blade for an axial-flow turbomachine according to claim 1 or 2,
The moving blade of an axial-flow turbomachine characterized in that the wing portion has a hooking means for hooking the high tension sheet on the wing portion. A rotor blade for an axial-flow turbomachine according to claim 1 or 2,
The wing portion has a thinned portion on the wing wall surface on which the high tension sheet is installed,
The blade of the axial-flow turbomachine, wherein the airfoil forming member is a member that is embedded in the thinned portion to form a blade wall surface. A rotor blade of an axial-flow turbomachine according to any one of claims 1 to 4,
The blade of the axial-flow turbomachine, wherein the airfoil forming member is formed of laminated high tension sheets. A rotor blade for an axial-flow turbomachine according to any one of claims 1 to 5,
The high-tension sheet is a reinforcing fiber sheet using carbon fibers.   A steam turbine comprising the rotor blade of the axial-flow turbomachine according to any one of claims 1 to 6 in a final stage of a low-pressure turbine.