Patent Grant
10753212
This application claims priority to Korean Patent Application No. 10-2017-0106634, filed on Aug. 23, 2017, the disclosure of which is incorporated herein by reference in its entirety.
Exemplary embodiments of the present disclosure relate to a turbine blade configured to rotate a turbine using pressure generated when high-temperature and high-pressure gas is discharged, and a turbine and a gas turbine having the same.
A turbine is a machine which generates rotating force from impulsive force or reaction force using the flow of compressive fluid such as steam or gas. The turbine is classified into a steam turbine using steam, a gas turbine using high-temperature combustion gas, and so forth.
The gas turbine chiefly includes a compressor, a combustor, and a turbine. The compressor includes an air inlet into which air is introduced, and a plurality of compressor vanes and a plurality of compressor blades which are alternately provided in a compressor casing.
The combustor is configured to supply fuel into air compressed by the compressor and ignite the fuel mixture using a burner, thus generating high-temperature and high-pressure combustion gas.
The turbine includes a plurality of turbine vanes and a plurality of turbine blades which are alternately arranged in a turbine casing. Furthermore, a rotor is disposed passing through central portions of the compressor, the combustor, the turbine, and an exhaust chamber.
Opposite ends of the rotor are rotatably supported by bearings. A plurality of disks are fixed to the rotor, and the blades are coupled to the corresponding disks, respectively. A driving shaft of a generator or the like is coupled to an end of the rotor that is adjacent to the exhaust chamber.
The gas turbine does not have a reciprocating component such as a piston of a four-stroke engine. Therefore, mutual friction parts such as a piston-and-cylinder are not present, so that there are advantages in that there is little consumption of lubricant, the amplitude of vibration is markedly reduced unlike a reciprocating machine having high-amplitude characteristics, and high-speed driving is possible.
A brief description of the operation of the gas turbine is as follows. Air compressed by the compressor is mixed with fuel, the fuel mixture is combusted to generate high-temperature combustion gas, and the generated combustion gas is discharged to the turbine. The discharged combustion gas passes through the turbine vanes and the turbine blades and generates rotating force, by which the rotor is rotated.
Here, each turbine blade includes a root coupled to a turbine rotor disk, a turbine blade part or airfoil with which high-temperature combustion gas collides, and a platform connected between the root and the airfoil. In addition, an angel wing extends outward from each of opposite sides of the platform so as to seal space between the airfoil and the turbine rotor disk.
In the turbine blade according to a conventional technique, the root, the airfoil, the platform, and the angel wings are integrally formed through a casting process. However, there is a problem in that the castability reduces due to the angel wings that protrude sideways from the root. Particularly, since the angel wings are integrally formed with the root by casting, it is difficult to adjust a clearance between the airfoil and the turbine rotor disk such that the space between the airfoil and the turbine rotor disk is reliably sealed by the angel wings when the turbine blade is mounted to the turbine rotor disk. In addition, if an angel wing is damaged, the entirety of the turbine blade must be replaced with a new one. Hence, the maintenance cost is increased.
A technique related to the conventional turbine blade was proposed in Korean Utility Model Registration No. 10-0901905 (Jun. 10, 2009).
Various embodiments of the present disclosure are directed to a turbine blade capable of improving the castability and adjusting a clearance between an airfoil and a turbine rotor disk such that space between the airfoil and the turbine rotor disk can be reliably sealed, and a turbine and a gas turbine having the same.
In accordance with one aspect of the present disclosure, there is provide a turbine blade installed on a rotor disk of a turbine and configured to rotate the turbine by a force of flowing gas. The turbine blade may include a root configured to be coupled to the rotor disk; a platform integrally formed with an upper portion of the root, the platform having opposite sides respectively extending in an axial direction of the rotor disk; an airfoil integrally formed with an upper portion of the platform; and an angel wing configured to be removably coupled to each of the opposite sides of the platform. When coupled, the angel wing may protrude from the platform in the axial direction. The angel wing may include a distal end that is bent toward the airfoil.
In accordance with another aspect of the present disclosure, there is provided a turbine configured to pass combustion gas supplied from a combustor to generate a driving force. The turbine may include a housing; and a turbine section disposed in the housing, the turbine section including a plurality of turbine rotor disks, and a plurality of turbine blades coupled to an outer surface of each of the plurality of turbine rotor disks. Each turbine blade is consistent with the above turbine blade.
In accordance with another aspect of the present disclosure, a gas turbine may include a compressor configured to draw in air and compress the air; a combustor configured to generate combustion gas by combusting fuel and the compressed air; and the above turbine.
The turbine blade may further include a coupling protrusion formed on a first end of the angel wing; and a coupling recess corresponding to the coupling protrusion formed in each of the opposite sides of the platform. The coupling protrusion may include an insert guide and a locking arm extending from the insert guide, and the coupling recess may include an insert guide slot configured to receive the insert guide of the coupling protrusion, and a locking arm slot configured to receive the locking arm of the coupling protrusion.
The locking arm slot may be disposed between a first end of the insert guide slot and a second end of the insert guide slot based on a longitudinal direction of the insert guide slot and slantly extend toward the inside of the platform. The locking arm slot may be disposed between the first end of the insert guide slot and the second end of the insert guide slot based on the longitudinal direction of the insert guide slot and extend upward toward the inside of the platform and/or downward toward the inside of the platform.
The locking arm may extend from the insert guide of the coupling protrusion in at least one direction of a first direction parallel to a radial direction of the rotor disk and a second direction opposite to the first direction. The first direction may be upward with respect to the insert guide inserted in the insert guide slot, and the second direction may be downward with respect to the insert guide inserted in the insert guide slot. Further, the locking arm may have a polygonal cross-sectional shape, and may extend from the insert guide at a slant relative to a longitudinal direction of the insert guide.
In a turbine blade, a turbine and a gas turbine having the same according to the present disclosure, an angel wing is removably coupled to each of opposite sides of a platform by a coupling protrusion and a coupling recess that correspond to each other. Consequently, an operation of integrally forming the platform, a root, and an airfoil through a casting process is facilitated. Furthermore, by replacement and installation of each angel wing on the platform, a clearance between the airfoil and the turbine rotor disk may be adjusted so that space between the airfoil and the turbine rotor disk is reliably sealed.
The above and other objects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Hereinafter, embodiments of a turbine in accordance with the present disclosure will be described with reference to the accompanying drawings.
Referring to
Based on a flow direction of air, the compressor section 110 is disposed at an upstream side of the housing 102, and a turbine section 120 is disposed at a downstream side. In addition, a torque tube 130 which is a torque transmission unit for transmitting rotational torque generated from the turbine section 120 to the compressor section 110 is disposed between the compressor section 110 and the turbine section 120.
The compressor section 110 is provided with a plurality (e.g., fourteen sheets) of compressor rotor disks 140. The compressor rotor disks 140 are coupled by a tie rod 150 such that they are not spaced apart from each other in an axial direction.
In detail, the compressor rotor disks 140 are arranged along the axial direction of the tie rod 150 passing through respective approximately central portions of the compressor rotor disks 140. Here, facing surfaces of neighboring compressor rotor disks 140 are compressed onto each other by the tie rod 150, whereby the compressor rotor disks 140 cannot rotate relative to each other.
A plurality of compressor blades 144 are radially coupled to an outer circumferential surface of each compressor rotor disk 140. Each of the compressor blades 144 includes a root 146 by which the compressor blade 144 is coupled to the compressor rotor disk 140.
Vanes (not shown) fixed to the housing 102 are disposed between the compressor rotor disks 140. The vanes are fixed not to be rotated unlike the compressor rotor disks 140. Each vane functions to align the flow of compressed air that has passed through the compressor blades 144 of the compressor rotor disk 140 disposed at an upstream side, and guide the compressed air to the compressor blades 144 of the compressor rotor disk 140 disposed at a downstream side.
A coupling scheme of the root 146 is classified into a tangential type and an axial type. This may be selected depending on a needed structure of the gas turbine to be used, and may be embodied in a well-known dovetail or fir-tree type structure. In some cases, the compressor blade 144 may be coupled to the compressor rotor disk 140 by using a separate coupling device, e.g., a fastener such as a key or a bolt, other than the above-mentioned coupling scheme.
The tie rod 150 is disposed passing through central portions of the plurality of compressor rotor disks 140. One end of the tie rod 150 is coupled to the compressor rotor disk 140 that is disposed at the most upstream side, and the other end thereof is fixed in the torque tube 130.
The shape of the tie rod 150 is not limited to the shape proposed in
Although not shown, a vane functioning as a guide vane may be installed in the compressor of the gas turbine at a position following the diffuser so as to adjust a flow angle of fluid to a designed flow angle, the fluid entering an entrance of the combustor after the pressure of the fluid has been increased. This vane is referred to as a deswirler.
The combustor 104 mixes introduced compressed air with fuel, combusts the fuel mixture to generate high-temperature and high-pressure combustion gas having high energy, and increases, through an isobaric combustion process, the temperature of the combustion gas to a heat resistant limit temperature at which the parts of the combustor and the turbine can endure.
A combustion system of the gas turbine may include a plurality of combustors 104 arranged in a casing formed in a cell shape. Each of the combustors 104 includes a burner including a fuel injection nozzle, etc., a combustor liner forming a combustion chamber, and a transition piece serving as a connector between the combustor and the turbine.
In detail, the liner provides a combustion space in which fuel discharged from the fuel injection nozzle is mixed with compressed air supplied from the compressor and then combusted. The liner may include a flame tube for providing the combustion space in which the fuel mixed with air is combusted, and a flow sleeve for forming an annular space enclosing the flame tube. The fuel injection nozzle is coupled to a front end of the liner, and an ignition plug is coupled to a sidewall of the liner.
The transition piece is connected to a rear end of the liner so as to transfer combustion gas combusted by the ignition plug toward the turbine. An outer wall of the transition piece is cooled by compressed air supplied from the compressor so as to prevent the transition piece from being damaged by high-temperature combustion gas.
To this end, the transition piece has cooling holes through which air can be injected into an internal space of the transition piece. Compressed air cools a main body in the transition piece through the cooling holes and then flows toward the liner.
The cooling air that has cooled the transition piece may flow through the annular space of the liner. Compressed air may be provided as cooling air from the outside of the flow sleeve through cooling holes provided in the flow sleeve, and collide with an outer wall of the liner.
On the one hand, high-temperature and high-pressure combustion gas that has come out of the combustor is supplied into the above-described turbine section 120. The supplied high-temperature and high-pressure combustion gas expands and collides with an impeller of the turbine so that reaction force is generated in the turbine, thus inducing rotational torque. The obtained rotational torque is transmitted to the compressor section 110 via the torque tube. Power that exceeds power needed to drive the compressor is used to drive the generator, etc.
The turbine section 120 basically has a structure similar to that of the compressor section 110. In detail, the turbine section 120 includes a plurality of turbine rotor disks 180 similar to the compressor rotor disks 140 of the compressor section 110. Each turbine rotor disk 180 also includes a plurality of turbine blades 184 which are radially disposed. Each turbine blade 184 may also be coupled to the turbine rotor disk 180 in a dovetail coupling manner or the like. In addition, vanes 185 fixed to the housing 101 of the turbine section 120 are provided between the turbine blades 184 of the turbine rotor disks 180 so as to guide the flow direction of combustion gas that passes through the turbine blades 184.
Referring to
According to an embodiment of the present disclosure, the turbine blade 184 includes a root 184 configured to be coupled to the turbine rotor disk 180; a platform 184a integrally formed with an upper portion of the root 184; an airfoil 184c integrally formed with an upper portion of the platform 184a; and a pair of angel wings configured to be removably coupled to the platform 184, which has opposite sides respectively extending in the axial direction of the turbine rotor disk 180.
As shown in
The root 184b is provided under a lower surface of the platform 184a. The root 184b has a so-called axial-type structure, such that the root 184b is inserted into the coupling slot 180a of the turbine rotor disk 180 along the axial direction of the turbine rotor disk 180. The root 184b has is a corrugated surface having a fir-tree shape or similar configuration corresponding to the configuration of the coupling slot 180a. Here, the coupling structure of the root 184b is not limited to a fir-tree shape, and may be formed to have a dovetail structure.
The airfoil 184c is provided on an upper surface of the platform 184a and is formed to have an optimized profile according to specifications of the gas turbine. That is, the airfoil 184c includes a leading edge disposed on the upstream side of the turbine blade 184, with respect to the combustion gas flow direction, and a trailing edge disposed on the downstream side.
Here, unlike the compressor blade 144 of the compressor section 110, the turbine blade 184 of the turbine section 120 comes into direct contact with high-temperature and high-pressure combustion gas. Since combustion gas has a high temperature reaching 1700° C., a cooling method is required. To this end, the gas turbine includes a cooling passage through which compressed air drawn from the compressor section 110 is supplied to the turbine blades 184 of the turbine section 120. The cooling passage may include one or both of an external passage extending outside the housing 101 and an internal passage extending through the interior of the rotor disk. As shown in
Furthermore, each of the pair of angel wings 184e is coupled to the axially arranged opposite sides of the platform 184a in such a way that the angel wings 184e protrude outward in opposite side directions of the platform 184a. The angel wings 184e function to seal space between the airfoil 184c and the turbine rotor disk 180 so that high-temperature and high-pressure combustion gas colliding with the airfoil 184c can be prevented from being drawn into the turbine rotor disk 180.
The angel wings 184e are respectively coupled to the opposite side surfaces of the platform 184a. Here, the angel wings 184e may be provided in a single- or multi-stage structure on the respective opposite side surfaces of the platform 184a. In the case where the angel wings 184e may be provided in the multi-stage structure on the respective opposite side surfaces of the platform 184a, the sealing between the airfoil 184c and the turbine rotor disk 180 may be more reliably embodied.
A first end, i.e., a first side, of each angel wing 184e that is coupled to the platform 184a is removably coupled to a corresponding one of the opposite side surfaces of the platform 184a. As such, in the case where the angel wings 184e are removably coupled to the respective opposite side surfaces of the platform 184a, a process of integrally casting the platform 184a, the root 184b, and the airfoil 184c that are parts of the turbine blade 184 other than the angel wings 184e may be facilitated. Furthermore, the structure capable of removably coupling the angel wings 184e to the respective opposite side surfaces of the platform 184a makes it possible to replace the angel wings 184e with other ones such that a clearance between the airfoil 184c and the turbine rotor disk 180 is reduced. Here, a second side edge 184f of each angel wing 184e may be a distal end that is bent toward the airfoil 184c, i.e., radially upward, but it is not limited thereto, and, for example, it may have a planar shape.
Each angel wing 184e and the platform 184a may be removably coupled to each other by a coupling protrusion 190 and a coupling recess 200 which are coupled correspondingly to each other. In other words, the coupling protrusion 190 is provided on the first side edge of the angel wing 184e. The coupling recess 200 is formed in each of the opposite side surfaces of the platform 184a. Here, the coupling recess 200 is formed extending from a front surface of the platform 184a to a rear surface so as to allow the coupling protrusion 190 from being inserted and coupled into the coupling recess 200 from the front or rear surface of the platform 184a in a sliding manner.
The coupling recess 200 includes an insert guide slot 200a which is depressed from each of the opposite side surfaces of the platform 184a toward an inside of the platform 184a, and a locking arm slot 200b which extends, based on a longitudinal direction of the insert guide slot 200a, from an inner end of the insert guide slot 200a toward the inside of the platform 184a.
The coupling protrusion 190 includes an insert guide 190a which extends from the first side edge of the angel wing 184e and is inserted correspondingly into the insert guide slot 200a, and a locking arm 190b which extends from an end of the insert guide 190a and is inserted correspondingly into the locking arm slot 200b.
Here, the locking arm slot 200b of the coupling recess 200 extends from the inner end of the insert guide slot 200a, i.e., a first longitudinal end of the insert guide slot 200a, at a predetermined inclined angle based on the longitudinal direction of the insert guide slot 200a. Therefore, after the locking arm 190b of the coupling protrusion 190 is inserted correspondingly into the locking arm slot 200b, the coupled state can be maintained such that the angel wing 184e is prevented from being undesirably removed in the opposite side directions of the platform 184a. Here, although it is preferable that the locking arm slot 200b be extended perpendicular to the first longitudinal end of the insert guide slot 200a based on the longitudinal direction of the insert guide slot 200a, the present disclosure is not limited thereto. For example, the locking arm slot 200b may be inclined at various angles from the first longitudinal end of the insert guide slot 200a. In this case, the locking arm 190b of the coupling protrusion 190 slantly extends from the end of the insert guide 190a. In other words, the locking arm 190b extends from the end of the insert guide 190a at a predetermined inclined angle based on the longitudinal direction of the insert guide 190a so that the locking arm 190b can be inserted correspondingly into the locking arm slot 200b.
Referring to
Alternatively, as shown in
As a further alternative, as shown in
That is, referring to
Alternatively, referring to
As a further alternative, referring to
Here, although each of the locking arm slot 200b and the locking arm 190a is illustrated as having a polygonal cross-sectional shape, the present disclosure is not limited thereto. For example, each of the locking arm slot 200b and the locking arm 190a may have a semi-circular or circular cross-sectional shape such that, when the locking coupling is embodied by the locking arm 190a and the locking arm slot 200b, reliable fastening force can be transmitted from the inside of the platform 184a.
As described above, in the turbine blade, the turbine and the gas turbine having the same in accordance with the embodiments of the present disclosure, the angel wings 184e are removably coupled to the respective opposite sides of the platform 184a by the coupling protrusion 190 and the coupling recess 200 that correspond to each other. Consequently, an operation of integrally forming the platform 184a, the root 184b, and the airfoil 184c through a casting process is facilitated. Furthermore, by replacement and installation of each angel wing 184e on the platform 184a, a clearance between the airfoil 184c and the turbine rotor disk 180 may be adjusted so that space between the airfoil 184c and the turbine rotor disk 180 is reliably sealed.
While the present disclosure has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the disclosure as defined in the following claims.
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