TURBINE BLADE

Abstract

Turbine blade comprising: a cooling channel (512) having a partition wall (511) dividing an interior region of the turbine blade (510); and an inlet channel (520) extending from a root portion (510a) of the turbine blade (510) to a platform portion (510b) of the turbine blade (510) and configured to supply cooling air to the cooling channel (512), wherein the inlet channel (520) includes an inclined part (521) having a diameter that decreases from the root part (510a) to the platform part (510b), wherein the inlet channel (520) includes a guide web (521a) projecting into the inlet channel (520) to allow the cooling air moving in the flow direction to form swirls, and wherein a length of the guide web (521a) projecting from the inclined part (521) into the inlet channel (520) increases in the flow direction of the cooling air.

Description

This application claims priority to Korean Patent Application No. 10-2018-0117156 filed on Oct. 1, 2018.BACKGROUNDField of InterestApparatuses and methods consistent with example embodiments relate to a turbine blade, and more particularly, to a turbine blade having an internal structure that has been improved to minimize loss of cooling air to be supplied to a cooling passage.Description of Related ArtA gas turbine is an internal combustion engine that mixes air compressed in a compressor with fuel for combustion, and rotates a turbine using high-temperature and high-pressure combustion gas generated by the combustion.The turbine has a configuration in which a plurality of turbine rotor disks each having a plurality of turbine blades on its outer circumferential surface are arranged in a multistage structure to pass high-temperature and high-pressure combustion gas through the turbine blades.However, since the temperature of an outlet of a combustion device gradually increases according to an increase in the size and efficiency of gas turbines, a turbine blade cooling unit has been employed to allow the turbine blades to resist high-temperature combustion gas.For example, a configuration has been widely known in which a predetermined cooling passage through which cooling air can flow is provided in a turbine blade, and compressed air supplied from a compressor rotor flows through the cooling passage to use the compressed air as cooling air.The gas turbine includes a compressor, a combustor, a turbine, and a rotor. The compressor includes a plurality of compressor vanes and a plurality of compressor blades arranged alternately.The combustion device is configured to supply fuel to air compressed by the compressor and ignite the fuel mixture using a burner, thereby generating high-temperature and high-pressure combustion gas.The turbine includes a plurality of turbine blades and a plurality of turbine blades arranged in an alternating fashion. The rotor is configured to pass through central portions of the compressor, the combustor, and the turbine. Opposite ends of the rotor are rotatably supported by bearings, and one of its ends is coupled to a drive shaft of a generator.The rotor includes a plurality of compressor rotor disks coupled to the compressor blades, a plurality of turbine disks coupled to the turbine blades, and a torque tube configured to transmit a rotational force from the turbine disks to the compressor disks.In the gas turbine, air compressed by the compressor is mixed with fuel and burned in the combustor, and is then converted into high-temperature combustion gas, which is discharged to the turbine. The discharged combustion gas passes through the turbine blades and generates a rotational force to rotate the rotor.The gas turbine does not have a reciprocating component such as a piston in a four stroke engine. Since the gas turbine does not have mutual friction parts such as a piston and a cylinder, there are advantages in that there is little consumption of lubricant, an amplitude of vibration as a characteristic of a piston engine is significantly reduced, and high-speed operation is possible.In the conventional gas turbine, a root part is formed in a lower portion of the turbine blade, and an inlet part into which cooling air is sucked is formed in the root part. In the turbine blade, a cooling passage is formed through which cooling air flows along an inner region divided by a partition wall.The inlet duct has a hollow cylindrical shape with a constant diameter, and is problematic in that a flow loss occurs when cooling air passes through a platform. In the conventional turbine blade, because cooling air is sucked into the cooling passage through the inlet passage, when a flow loss occurs in the inlet passage, the cooling efficiency of the turbine blade is lowered.US 2007 / 0 140 848 A1 describes a turbine engine component, for example a turbine blade, which has an airfoil section and a plurality of cooling channels within the airfoil section, wherein each of the cooling channels has an inlet for a cooling fluid.US 2017 / 0 009 590 A1 relates to an orifice member which can be inserted into a recess formed at an outer opening of a channel in a turbine stator or rotor blade, the channel being adapted to direct a cooling fluid through the blade.US 2016 / 0 237 833 A1 relates to a turbine blade having an airfoil and a pine tree root.US 2002 / 0 119 046 A1 relates to an improved fastening configuration for the air inlet of a turbine blade.US 2014 / 0 161 625 A1 relates to systems and apparatus configured to cool turbine components in a turbine by passing a cooling stream through the turbine component via a variable diameter cooling passage.EP 2 899 370 A1 relates to a turbine blade which comprises a cooling duct through which cooling air is conducted, and a swirl section which is provided at an inlet of the cooling duct in order to generate a swirling flow in the cooling air.SUMMARYAspects of one or more exemplary embodiments provide a turbine blade that can solve problems occurring due to a loss of flow rate by improving a structure of an inner inlet channel of a root part into which cooling air is drawn.Aspects of one or more example embodiments provide a turbine blade that may supply cooling air into a cooling passage such that the flow of cooling air through the cooling passage may remain stable.Additional aspects are set forth in part in the description that follows, and in part will become apparent from the description, or may be learned by operation of the exemplary embodiments.The object is achieved by the features of the independent claim. Preferred embodiments are given in the dependent claims.According to an aspect of an exemplary embodiment, there is provided a turbine blade including: a cooling passage configured to be defined by a partition wall partitioning an inner region of the turbine blade; and an inlet passage extending from a root part of the turbine blade to a platform part of the turbine blade and configured to supply cooling air to the cooling passage, wherein an inclined part having a diameter decreasing from the root part to the platform part may be formed in the inlet passage.The turbine blade may further include a leading edge formed on a front side of the turbine blade such that the leading edge first comes into contact with hot gas, and a trailing edge formed on a back side of the turbine blade. The inlet duct may include a first inlet duct formed on the basis of the partition wall on one side in a cross-sectional view of the root part and a second inlet duct formed on the other side of the partition wall.The intake passage may include a single first intake passage and a plurality of second intake passages.The second inlet duct may extend in a transverse direction over a length greater than a length of the first inlet duct.The plurality of second inlet passages may have different sizes.The inlet duct may have a width (W) extending in a horizontal direction and a length (L) extending in a vertical direction, and the width (W) may be greater than the length (L).The inclined part may be inclined at an angle of 45° or less.A guide land protruding outward is provided at the inclined part to allow the cooling air to form vortices while moving in a flow direction.The guide rib may be spirally wound along an inner surface of the inclined part. An opening hole open to the cooling passage may be formed in the guide land.The opening hole may have a nozzle shape having a diameter decreasing toward the cooling passage.A length to which the guide land protrudes from the inclined part increases in the flow direction of the cooling air.According to an aspect of another exemplary embodiment, there is provided a turbine blade including: a cooling passage configured to be defined by a partition wall partitioning an inner region of the turbine blade; an inlet passage extending from a root part of the turbine blade to a platform part of the turbine blade and configured to supply cooling air to the cooling passage; and an inclined part configured to be provided inside such that its diameter decreases from the root part to the platform part, wherein a guide land is formed on the inclined part to allow the cooling air to form vortices while moving in a flow direction, and a land may be provided on the platform part to guide a flow direction of cooling air having passed through the inlet passage.The web may extend outward in a linear shape over a predetermined length in a radial direction of the turbine blade.The web may extend outward in a radial direction of the turbine blade in a curved shape over a predetermined length.The web may include a first web extending a predetermined length and a second web disposed adjacent the first web, the first web and the second web having different extension lengths.The first web can run in a straight line to the cooling channel and the second web can run obliquely to the separating wall.The inlet duct may include a first inlet duct formed based on the partition wall on one side in a cross-sectional view of the root part and a second inlet duct formed based on the partition wall on the other side, wherein each of the first inlet duct and the second inlet duct may include a single inlet duct.The first inlet channel and the second inlet channel may have different sizes.The web may include a plurality of webs each disposed at a position facing each other on an inner bottom side and an inner top side of the cooling channel.BRIEF DESCRIPTION OF THE DRAWINGSThe above and other aspects will be more fully understood from the following description of the exemplary embodiments with reference to the accompanying drawings, in which: FIG. 1 is a sectional view illustrating a turbine apparatus provided with turbine blades according to an exemplary embodiment; FIG. 2 is a sectional view illustrating a turbine blade according to a first exemplary embodiment; FIG. 3 is a diagram illustrating an inlet passage provided in the turbine blade according to the first exemplary embodiment; FIGS. 4 to 6 are diagrams illustrating various examples of the intake passage according to the first exemplary embodiment; FIGS. 7 and 8 are diagrams illustrating examples of a guide land provided in the intake passage according to the first exemplary embodiment; FIG. 9 is a diagram illustrating an inlet passage provided in a turbine blade according to a second exemplary embodiment; FIG. 10 is a diagram illustrating a cross section of an intake passage according to the second exemplary embodiment; FIGS. 11 to 13 are diagrams illustrating various examples of a land according to the second exemplary embodiment; and FIG. 14 is a diagram illustrating another example of an inlet passage provided in the turbine blade according to the second exemplary embodiment.DETAILED DESCRIPTIONVarious changes may be made to the embodiment of the disclosure, and various types of embodiments may be present. Thus, certain embodiments are illustrated in the drawings and embodiments will be described in detail in the specification. However, it should be noted that the various embodiments are not intended to limit the scope of the disclosure to a particular embodiment, but should be interpreted as including all changes, equivalents, or alternatives to the embodiments included in the concepts and technical scopes disclosed herein. Meanwhile, detailed explanation is omitted if it is determined that in describing the embodiments, detailed explanation of related known technologies would unnecessarily obscure the gist of the disclosure.Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings. In order to clearly illustrate the disclosure in the drawings, some of the elements that are not essential to complete understanding may be omitted, and like reference numerals refer to like elements throughout the specification.The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the scope of the disclosure. As used herein, the singular forms "a," "an," and "the / s" are intended to include the plural forms as well, unless the context clearly indicates the opposite. Further, the terms "comprises," "includes," or "have / own" are intended to mean that such features, ranges, integers, steps, operations, elements, components, and / or a combination thereof are in specification, not to preclude the presence or possibility of adding one or more other features, ranges, integers, steps, operations, elements, components, and / or combinations thereof.Further, the terms such as "first", "second", etc. may be used to describe various elements, but these elements are not intended to be limited by these terms. These terms are used only to distinguish one element from another element. The use of such ordinal numbers is not to be construed as limiting the meaning of the term. For example, the components associated with such an ordinal number should not be limited in the order of use, arrangement order, or the like. If necessary, any ordinal number may be used interchangeably.In addition, the following embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. The drawings are not necessarily to scale, and in some cases, circumstances may have been exaggerated to clearly illustrate features of the example embodiments.FIG. 1 is a sectional view illustrating a turbine apparatus provided with turbine blades according to an exemplary embodiment. FIG. 2 is a sectional view illustrating a turbine blade according to a first exemplary embodiment. FIG. 3 is a diagram illustrating an inlet passage provided in the turbine blade according to the first exemplary embodiment.Referring to FIGS. 1 to 3, a gas turbine may include a casing 100, a rotor 600, a compressor 200, a combustion device 400, a turbine, a generator, and a diffuser. The rotor 600 is rotatably provided in the housing 100. The compressor 200 may receive a rotational force from the rotor 600 and compress air drawn into the housing 100. The combustor 400 may mix fuel with air compressed by the compressor 200 and ignite the fuel mixture to generate combustion gas. The turbine 500 may obtain a rotational force from the combustion gas generated by the combustion device 400 and rotate the rotor 600 using the rotational force. The generator may be interlocked with the rotor 600 to generate electricity. The diffuser may exhaust combustion gas that has passed through the turbine 500.The housing 100 may include a compressor housing 110 housing the compressor 200, a combustor housing 120 housing the combustor 400, and a turbine housing 130 housing the turbine 500.The compressor housing 110, the combustor housing 120, and the turbine housing 130 are sequentially arranged in the configuration order on the assumption that a fluid flows from left to right.The rotor 600 may include a compressor disc 610 housed in the compressor housing 110, a turbine disc 630 housed in the turbine housing 130, and a torsion tube 620 housed in the combustor housing 120 to couple the compressor disc 610 and the turbine disc 630.In addition, the rotor 600 may include a pull rod 640 and a mounting nut 650 provided to couple the compressor disc 610, the torque tube 620, and the turbine disc 630.A plurality of compressor disks 610 are arranged in an axial direction of the rotor 600. In other words, the compressor disks 610 form a multistage structure.Each of the compressor disks 610 has a disk shape and has, in its outer circumferential surface, a compressor disk slot into which a compressor blade 210 is coupled.The compressor disc slot may have a firtree shape to prevent the compressor blade 210 from being undesirably removed from the compressor disc slot in a radial rotational direction of the rotor 600.The compressor disc 610 and the compressor blade 210 are coupled together in a tangential type or an axial type scheme. In the exemplary embodiment, the axial type scheme is used.A plurality of compressor disk slots may be formed radially and arranged in a circumferential direction of the compressor disk 610. Each of the compressor disk slots may extend in a rotational axis direction.Turbine disc 630 may be formed in a manner similar to that of compressor disc 610. A plurality of turbine disks 630 may be arranged in the axial direction of the rotor 600 and have a multistage structure.Each of the turbine disks 630 has a disk shape and includes, in its outer circumferential surface, a turbine disk slot into which a turbine blade 510 is coupled.The torsion tube 620 may be a torque transfer element configured to transfer the rotational force of the turbine disks 630 to the compressor disks 610. One end of the torsion tube 620 may be coupled to one of the plurality of compressor disks 610 disposed at the most downstream end with respect to an air flow direction. The other end of the torsion tube 620 may be coupled to one of the plurality of turbine disks 630 disposed at the most upstream end with respect to a combustion gas flow direction.A protrusion may be provided at each end of the torsion tube 620. A recess to engage the corresponding protrusion may be formed in both the associated compressor disc 610 and the associated turbine disc 630 such that the torsion tube 620 may be prevented from rotating relative to the compressor disc 610 or the turbine disc 630.The torsion tube 620 may have a hollow cylindrical shape to allow air supplied from the compressor 200 to flow into the turbine 500 via the torsion tube. The torsion tube 620 may be formed to resist deformation, distortion, etc., and configured to be easily assembled or disassembled to facilitate maintenance.The tie rod 640 may be provided to pass through the plurality of compressor disks 610, the torsion tube 620, and the plurality of turbine disks 630. One end of the pull rod 640 may be coupled into one of the plurality of compressor disks 610 disposed at the most upstream end with respect to the airflow direction. The other end of the tie rod 640 may protrude in a direction opposite to the compressor 200 based on one of the plurality of turbine disks 630 disposed at the most downstream end with respect to the combustion gas flow direction, and may be coupled to the fixing nut 650.The fixing nut 650 may press the turbine disk 630 disposed at the most downstream end toward the compressor 200 to reduce a distance between the compressor disk 610 disposed at the most upstream end and the turbine disk 630 disposed at the most downstream end. In this case, the plurality of compressor disks 610, the torsion tube 620, and the plurality of turbine disks 630 may be compressed in the axial direction of the rotor 600.Therefore, the plurality of compressor disks 610, the torsion tube 620, and the plurality of turbine disks 630 can be prevented from moving in the axial direction or rotating relative to each other.FIG. 1 illustrates a case where the single tie rod 640 is provided to pass through central portions of the plurality of compressor disks 610, the torsion tube 620, and the plurality of turbine disks 630, however, it should be understood that this is merely an example and other example embodiments are not limited thereto.For example, separate tie rods 640 may be provided in each of the compressor 200 and the turbine 200, multiple tie rods 640 may be arranged in the circumferential direction, or a combination thereof is also possible.According to this configuration, opposite ends of the rotor 600 may be rotatably supported by bearings, and one end thereof may be coupled to a drive shaft of the generator. The compressor 200 may include the compressor blade 210 rotating with the rotor 600 and a compressor blade 220 fixed in the housing 100 and configured to direct the flow of air to be drawn into the compressor blade 210.A plurality of compressor blades 210 may form a multistage structure in the axial direction of the rotor 600. The plurality of compressor blades 210 may be provided in each stage and may be radially formed and oriented in a rotational direction of the rotor 600.Each compressor blade 210 may include a planar compressor blade platform portion, a compressor blade root portion, and a compressor blade portion. The compressor blade root part extends from the compressor blade platform part to a central side of the rotor 600 with respect to the radial rotation direction of the rotor 600. The compressor blade part extends from the compressor blade platform part to a centrifugal side of the rotor 600 with respect to the radial rotation direction of the rotor 600.The compressor blade platform portion may be in contact with an adjacent compressor blade platform portion and may act to maintain a distance between the adjacent compressor blade portions.The compressor blade root part has an axial type shape inserted into the compressor disk slot in the axial direction of the rotor 600.The compressor blade root portion may have a firtree shape corresponding to the compressor disk slot.A size of the compressor disk slot is larger than that of the compressor blade root portion to enable coupling of the compressor blade root portion to the compressor disk slot. In the coupled state, a clearance may be formed between the compressor blade root portion and the compressor disc slot.The compressor airfoil portion is formed to have an optimized profile according to specifications of the turbine device. The compressor airfoil part includes a compressor airfoil leading edge disposed on an upstream side with respect to the airflow direction such that air is incident on the leading edge, and a compressor airfoil trailing edge disposed on a downstream side with respect to the airflow direction such that air exits the trailing edge.A plurality of compressor blades 220 may form a multistage structure in the axial direction of the rotor 600.The compressor blades 220 and the compressor blades 210 are arranged alternately in the air flow direction. A plurality of compressor blades 220 are provided in each stage, formed radially, and arranged in the rotational direction of the rotor 600.Each compressor blade 220 may include a compressor blade platform part formed in an annular shape in the rotational direction of the rotor 600 and a compressor blade part extending from the compressor blade platform part in the radial rotational direction of the rotor 600.The combustor 400 is configured to mix air supplied from the compressor 200 with fuel and combust the fuel mixture to generate high-temperature and high-pressure combustion gas having high energy and raise the temperature of the combustion gas to a heat resistance limit value within which the combustor 400 and the turbine 500 can resist the heat in an isobaric combustion process.The turbine 500 is configured in a manner similar to that of the compressor 200, and includes the turbine blade 510 that rotates together with the rotor 600 and a turbine blade 530 that is fixed in the casing 100 and is configured to direct the flow of combustion gas to be sucked into the turbine blade 510.A plurality of turbine blades 510 may form a multistage structure in the axial direction of the rotor 600. A plurality of turbine blades 510 are provided in each stage, are radially formed, and are arranged in the rotational direction of the rotor 600.Each of the turbine blades 510 may include a cooling passage 512 and 514 defined by a partition wall 511 partitioning an inner region of the turbine blade 510, and an inlet passage 520 extending from a root part 510 aof the turbine blade 510 to a platform part 510 bto supply cooling air into the cooling passage 512 and 514. An inclined part 521, the diameter of which decreases from the root part 510 ato the platform part 510 b, is formed in the inlet duct 520.In the exemplary embodiment, the structure of the inlet duct 520 through which cooling air is supplied to the cooling duct 512 and 514 is improved, whereby a flow loss of the cooling air supplied to the cooling duct 512 and 514 can be minimized.Because the inlet duct 520 has a cross section that extends in a nozzle shape in a flow direction of the cooling air, the cooling air can be reliably supplied to the cooling duct 512 and 514 without a pressure decrease.The turbine blade 510 may further include a leading edge 510 cthat first comes into contact with hot gas and is formed in a front side of the turbine blade 510, and a trailing edge 510 dformed in a back side of the turbine blade 510. The inlet duct 520 may include a first inlet duct 522 formed based on the partition wall 511 on one side in a cross-sectional view of the root part 510 aand a second inlet duct 524 formed based on the partition wall 511 on the other side.For example, a first inlet channel 522 may be formed and a plurality of second inlet channels 524 may be formed. The number of first and second inlet passages 522 or 524 may be changed depending on the internal structure or arrangement of the turbine blade 510.It should be understood that the number of first or second inlet passages 522 or 524 is not limited thereto and may be increased or changed to supply cooling air to an area or position required to cool the turbine blade 510.Although the second inlet passage 524 has a transverse length greater than that of the first inlet passage 522, this may also be changed depending on the internal structure or arrangement of the turbine blade 510.The second inlet channel 524 corresponds to the back of the turbine blade 510. The temperature distribution of the back surface of the turbine blade 510 may be changed depending on the position due to a round surface shape of the turbine blade 510.In the turbine blade 510, it is most preferable that cooling air supplied for internal cooling is stably supplied with a minimized flow rate or pressure fluctuation. In the exemplary embodiment, to this end, the second inlet duct 524 extends a transverse length that is greater than that of the first inlet duct 522.Therefore, cooling air drawn into the turbine blade 510 through the second inlet duct 524 can be supplied without a decrease in flow rate under conditions of minimized pressure fluctuation, and the cooling efficiency of the turbine blade 510 can be improved.The first inlet duct 522 supplies cooling air to a position adjacent to the leading edge 510 cof the turbine blade 510, and the second inlet duct 524 supplies cooling air to a region between the partition wall 511 and the trailing edge 510 d.FIGS. 4 to 6 are diagrams illustrating various examples of the intake passage according to the first exemplary embodiment.Referring to FIGS. 4 to 6, when the first intake passage 522 is divided into a plurality of parts, the plurality of parts have different sizes. The turbine blade 510 has a complex internal structure, and regions that need cooling vary depending on the position. Therefore, compared to a structure having a single first inlet duct in a structure having a plurality of first inlet ducts, cooling air can be easily supplied to positions that need cooling.FIGS. 4 to 6 illustrate cases where two first intake passages 522 are provided, but it is to be understood that this is merely an example and other example embodiments are not limited thereto. The number of first inlet passages 522 may be changed, and their positions may also be changed.For example, the first and second intake ports 522 and 524 may be arranged such that their opening sizes increase from the first intake port 522 to the second intake port 524, or vice versa.FIGS. 7 and 8 are diagrams illustrating examples of a guide land provided in the intake passage according to the first exemplary embodiment.Referring to FIG. 7, the inlet duct 520 is formed such that a width W extending in a horizontal direction is greater than a length L extending in a vertical direction.In this case, supply of a large amount of cooling air in the air flow direction can be enabled. That is, as the length L extending in the vertical direction is increased, vortices may occur due to friction with an inner surface of the intake passage. Therefore, it is preferable that the width W extending in the horizontal direction is longer than the length L. Although the width W and the length L of the inlet duct 520 have been described as having predetermined values, the width W and the length L may be changed depending on specifications of the turbine blade 510.The inclined part 521 is inclined at an angle of 45° or less. The angle corresponds to an angle capable of facilitating the flow direction of cooling air to a certain position and minimizing occurrence of vortices due to large angular variation.The inclined part 521 has a bilaterally symmetrical structure and is inclined at the same angle on opposite sides thereof. Therefore, cooling air can be reliably moved in a direction indicated by the arrow without being focused on a certain position.The inclined part 521 may include a guide rib 521 athat protrudes outward to allow the cooling air to form vortices while moving in the flow direction.The guide land 521 ais spirally wound around an inner surface of the inlet duct 520 at a portion corresponding to the inclined part 521. Therefore, a part of the flow of cooling air forms a flow of cooling air moving along the inner surface of the inclined part 521, and the further flow of cooling air forms a flow of cooling air moving along a central portion of the inlet duct 520 indicated by the arrow.When cooling air moves in a spiral shape, a rotational force is generated, thereby forming a flow of cooling air coming into contact with the inner surface of the inclined part 521. Moreover, since cooling air can move on the inclined part 521 without being separated from the inclined part 521, the flow stability of cooling air can be improved.The guide land 521 amay include an opening hole 521 bopened to the cooling passage 512. The opening hole 521 bhas a nozzle shape whose diameter decreases toward the cooling passage 512. Therefore, the velocity and pressure of the cooling air that has passed through the opening hole 521 bincreases.The velocity of the cooling air flowing through the inlet duct 520 decreases from the center of the width W to the inclined part 521. Thus, if the velocity of the cooling air at the inclined part 521 increases through the opening hole 521 b, a swirling phenomenon due to separation of the flow can be minimized.Therefore, when cooling air is supplied to the cooling passage 512 via the inlet passage 520, the cooling air can move without a decrease in speed or a large decrease in pressure.A single opening hole 521 bor a plurality of opening holes 521 bmay be formed. The direction in which the opening hole 521 bis opened may be the same as that of the foregoing.Referring to FIG. 8, a guide rib 521 amay be formed such that the length L to which the guide rib 521 aprotrudes from the inclined part 521 increases in the direction in which the cooling air moves.If the length L to which the guide land 521 aprotrudes from the inclined part 521 increases in the flow direction of the cooling air, the cooling air can move to the cooling passage 512 without separation of the flow in the portion corresponding to the inclined part 521 or a decrease in the speed or pressure.In the inlet duct 520, the guide rib 521 aprotrudes in a manner different from that of the exemplary embodiment of FIG. 7, such that a phenomenon in which the flow rate of cooling air decreases from the center of the inlet duct 520 in the width direction (W direction) to the inclined part 521 can be minimized.Moreover, because the protruding length of the guide land 521 aincreases so as to change the flow of cooling air and to be guided so as to be more stable, cooling air can be easily supplied to a specific position that needs to be cooled more urgent. Therefore, the cooling efficiency can be improved.FIG. 9 is a diagram illustrating an inlet passage provided in a turbine blade according to a second exemplary embodiment. FIG. 10 is a diagram illustrating a cross section of an intake passage according to the second exemplary embodiment.Referring to FIGS. 9 and 10, the turbine blade 510 may include a cooling passage 512 and 514, an inlet passage 520, and an inclined part 521. The cooling passage 512 and 514 is defined by a partition 511 partitioning an interior region of the turbine blade 510. The inlet duct 520 extends from a root part 510 aof the turbine blade 510 to a platform part 510 band is configured to supply cooling air to the cooling duct 512 and 514. The inclined part 521 is formed inside so that its diameter decreases from the root part 510 ato the platform part 510 b. The inclined part 521 is provided with a guide land on an inner surface of the inclined part 521 to allow the cooling air to form vortices while moving in a flow direction. A land 900 is provided on the platform part 510 bto guide the flow direction of the cooling air that has passed through the inlet duct 520.In the second exemplary embodiment, the fin 900 is provided in the platform part 510 bto guide the movement of cooling air that has passed through the inlet duct 520 once more reliably.In the turbine blade 510, cooling air that has passed through the inlet duct 520 is drawn into the cooling duct 512 and 514 defined by the partition 511. As the cooling air flows along the cooling passage 512 and 514 and then moves toward the trailing edge 510 d, the cooling air cools the turbine blade 510.In the second exemplary embodiment, before the cooling air is supplied to the cooling passage 512 and 514, the flow direction, the velocity, and the pressure of the cooling air are additionally adjusted, whereby the cooling efficiency depending on the position of the turbine blade 510 can be improved.For this purpose, the land 900 extends outward in a rectilinear shape over a predetermined length in a radial direction of the turbine blade 510.It is understood that the number of ridges 900 is not limited to FIG. 9 and may be changed. The length and width of each web 900 may also be varied. Moreover, the ridges 900 may be provided at positions facing each other on an inner bottom surface 510 eand on an inner top surface 510 fof the platform part 510 b.For example, if the fins 900 are disposed facing each other, the flow of cooling air is directed along the fins 900 regardless of the position in the platform portion 510 b.Therefore, cooling air reliably moves to the cooling passage 512 and 514 without a decrease in speed or a loss in flow rate.FIGS. 11 to 13 are diagrams illustrating various examples of a land according to the second exemplary embodiment.Referring to FIG. 11, the land 900 extends outward in a curved shape over a predetermined length in the radial direction of the turbine blade 510.Because the curvature and shape of the land 900 can be changed in various ways, the flow stability of cooling air can be secured and variation in the flow rate and pressure of cooling air can be minimized.Referring to FIG. 12, the web 900 may include a first web 910 extending over a predetermined length and a second web 920 disposed adjacent to the first web 910. The first land 910 and the second land 920 have different lengths.It should be understood that the lengths of the first and second webs 910 and 920 are not limited to FIG. 12 and may be changed in various ways.The lengths over which the first land 910 and the second land 920 extend are determined in consideration of an internal temperature distribution of the cooling passage 512 and 514. The first land 910 and the second land 920 may direct the flow of cooling air into the platform portion 510 b, thereby ensuring the flow stability of cooling air and minimizing a loss of hydraulic pressure.Referring to FIG. 13, the first land 910 may be straight to the cooling passage 512 and the second land 920 may be oblique to the partition wall 511.The first fin 910 guides the flow of cooling air in the 12 o'clock direction and the second fin 920 guides the flow of cooling air to the partition 511. Thus, the flow of cooling air can be efficiently directed to certain positions, thereby improving the cooling efficiency of the turbine blade 510.FIG. 14 is a diagram illustrating another example of an inlet passage provided in the turbine blade according to the second exemplary embodiment.Referring to FIG. 14, the inlet duct 520 may include a first inlet duct 522 formed based on the partition wall 511 on one side in a cross-sectional view of the root part 510 aand a second inlet duct 524 formed based on the partition wall 511 on the other side. Here, a single first inlet passage 522 and a single second inlet passage 524 are formed to improve convenience in manufacturing, ensure a stable flow rate, and improve cooling efficiency of the turbine blade 510.The first inlet passage 522 and the second inlet passage 524 may have different sizes. Therefore, cooling air can be reliably supplied to a region having a high flow rate.Therefore, cooling air can be efficiently supplied to a portion of the turbine blade 510 that requires cooling to permeate.One or more example embodiments may provide a turbine blade in which an inlet channel is formed in a root part such that a flow loss in a platform part is reduced, whereby the flow stability in the turbine blade may be improved.Moreover, one or more example embodiments may provide a turbine blade having an inlet passage that may minimize loss of a flow rate and a hydraulic pressure of cooling air supplied to the inside of the turbine blade, such that the efficiency of cooling the turbine blade may be improved.

Claims

A turbine blade, comprising: a cooling passage (512) having a partition (511) dividing an interior region of the turbine blade (510); and an inlet duct (520) extending from a root part (510a) of the turbine blade (510) to a platform part (510b) of the turbine blade (510) and configured to supply cooling air to the cooling duct (512), wherein the inlet duct (520) includes an inclined part (521) having a diameter decreasing from the root part (510a) to the platform part (510b), wherein the inlet duct (520) includes a guide land (521a) protruding into the inlet duct (520) to allow the cooling air moving in the flow direction to form vortices, and wherein a length of the guide land (521a) protruding from the inclined part (521) into the inlet duct (520) increases in the flow direction of the cooling air.The turbine blade of claim 1, wherein the turbine blade (510) further comprises: a leading edge (510c) formed on an end face of the turbine blade (510) such that the leading edge (S10c) first comes into contact with hot gas; and a trailing edge (510d) formed on a back face of the turbine blade (510).The turbine blade according to claim 1 or 2, wherein the inlet channel (520) comprises: a first inlet channel (522) formed on one side of the partition wall (511) in a cross-sectional view of the root part (510a); and a second inlet channel (524) formed on the other side of the partition wall (511).The turbine blade of claims 1 to 3, wherein the inlet duct (520) comprises a single first inlet duct (522) and a plurality of second inlet ducts (524), or the inlet duct (520) comprises a single first inlet duct (522) and a single second inlet duct (524).The turbine blade of claim 4, wherein the plurality of second inlet passages (524) are of different sizes.The turbine blade according to claim 1 to 5, wherein the inclined part (521) is inclined at an angle of 45° or less.The turbine blade according to claim 1 to 6, wherein the guide land (521a) is spirally wound along an inner surface of the inclined part (521).The turbine blade according to claim 7, wherein an opening hole (521b) open to the cooling passage (512) is formed in the guide land (521a), and the opening hole (521b) has a nozzle shape having a diameter decreasing toward the cooling passage (512).The turbine blade according to any one of the preceding claims, wherein a web (900) is provided on the platform part (S10b) to guide a flow direction of cooling air that has passed through the inlet duct (520).Turbine blade according to Claim 9, wherein the web (900) has a rectilinear and / or a curved shape.The turbine blade of claim 9 or 10, wherein the web (900) comprises: a first web (910) extending a predetermined length; and a second web (920) disposed adjacent to the first web (910), wherein the first web (910) and the second web (920) have different extension lengths.The turbine blade of claim 11, wherein the first land (910) is straight to the cooling passage (512) and the second land (920) is oblique to the partition wall (511).

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