Turbine blade and gas turbine including the same

Abstract

To provide a turbine blade improved in cooling efficiency and a gas turbine including the same.SOLUTION: An airfoil includes: a suction surface that protrudes forming a curved surface that bulges outward; a pressure surface that forms a curved surface recessed toward the suction surface side; a leading edge that connects the suction surface and the pressure surface and is formed at a front end of the connection; a trailing edge that connects the suction surface and the pressure surface and is formed at a rear end of the connection; a first cooling passage that causes a first cooling fluid flowing in from a lower part of the leading edge to flow into a first serpentine passage, which is formed on the pressure surface side, and then causes the first cooling fluid to discharge behind the trailing edge; a second cooling passage that causes a second cooling fluid flowing in from the lower part of the suction surface to a second serpentine passage, which is formed on the suction surface side, and then causes the second cooling fluid to discharge behind the trailing edge; and a plurality of cooling pins that are formed on the inner peripheral surfaces of the first cooling passage and the second cooling passage perpendicular to the pressure surface and the suction surface to an opposite surface.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a turbine blade and a gas turbine including the same.

Background Art

[0002] A turbine is a mechanical device that obtains rotational force by impulse force or reaction force using the flow of a compressible fluid such as steam or gas, and includes a steam turbine using steam and a gas turbine using high-temperature combustion gas.

[0003] Among these, a gas turbine mainly includes a compressor, a combustor, and a turbine. The compressor is provided with an air inlet for introducing air, and a plurality of compressor vanes and compressor blades are alternately arranged in a compressor casing.

[0004] The combustor supplies fuel to the compressed air compressed by the compressor and ignites it with a burner, thereby generating high-temperature and high-pressure combustion gas.

[0005] The turbine has a plurality of turbine vanes and turbine blades alternately arranged in a turbine casing. Also, a rotor is arranged so as to penetrate the central portions of the compressor, the combustor, the turbine, and the exhaust chamber.

[0006] Both ends of the rotor are rotatably supported by bearings. A plurality of disks are fixed to the rotor, and respective blades are connected thereto. At the same time, a drive shaft such as a generator is connected to the end on the exhaust chamber side.

[0007] Such a gas turbine does not have a reciprocating mechanism like a piston of a four-stroke engine, so there is no mutual friction part like a piston-cylinder, the consumption of lubricating oil is extremely small, the amplitude, which is a characteristic of a reciprocating machine, is significantly reduced, and it has the merit of enabling high-speed movement.

[0008] Briefly explaining the operation of a gas turbine, high-temperature combustion gas is produced by mixing compressed air compressed by a compressor with fuel and burning it. The combustion gas thus produced is injected onto the turbine side. The injected combustion gas generates a rotational force while passing through the turbine vanes and turbine blades, thereby rotating the rotor.

Summary of the Invention

Problems to be Solved by the Invention

[0009] An object of the present invention is to provide a turbine blade with improved cooling efficiency and a gas turbine including the same.

Means for Solving the Problems

[0010] A turbine blade of the present invention for achieving the above object is a turbine blade mounted on a turbine rotor disk and rotated by high-pressure combustion gas. The turbine blade includes a root portion coupled to the turbine rotor disk at a lower portion, and an airfoil integrally formed on an upper side of the root portion and having a cooling flow path formed therein. Here, the airfoil has a suction surface protruding with a curved surface bulging outward, a pressure surface having a curved surface recessed and sunken on the suction surface side, a leading edge formed at a tip by connecting the suction surface and the pressure surface, a trailing edge formed at a rear end by connecting the suction surface and the pressure surface, a first cooling flow path for flowing a first cooling fluid flowing in from a lower portion of the leading edge to a first meandering flow path formed on the pressure surface side and then discharging it behind the trailing edge, a second cooling flow path for flowing a second cooling fluid flowing in from a lower portion of the suction surface to a second meandering flow path formed on the suction surface side and then discharging it behind the trailing edge, and a plurality of cooling pins formed perpendicular to the pressure surface and the suction surface up to the opposite surface on an inner peripheral surface of the first cooling flow path and the second cooling flow path.

[0011] The first cooling flow path is formed to extend downward from the lower part of the leading edge, and includes a first inlet through which the first cooling fluid flows in, a first-1 flow channel that causes the first cooling fluid flowing into the first inlet to flow in the direction of the airfoil tip, a first-2 flow channel that is formed adjacent to the first-1 flow channel and causes the first cooling fluid to flow in the direction of the root portion, and a first-3 flow channel that is formed adjacent to the first-2 flow channel and causes the first cooling fluid to flow in the direction of the airfoil tip.

[0012] The first cooling flow path may further include a first-1 turning channel formed to extend from the upper end of the first-1 flow channel toward the trailing edge side, and a first-2 turning channel extending from the lower end of the first-2 flow channel toward the trailing edge side.

[0013] The first cooling flow path may further include a first-3 turning channel formed to extend from the upper end of the first-3 flow channel toward the trailing edge side, and a first discharge channel that discharges the first cooling fluid flowing through the first-3 flow channel to the outside.

[0014] The plurality of cooling pins may be arranged at predetermined intervals in the first-2 flow channel and the first-3 flow channel.

[0015] The plurality of cooling pins may be formed in a frustum of a square pyramid shape and arranged such that the bottom surface with a larger area is connected to the pressure surface side.

[0016] The second cooling flow path is formed to extend downward from the suction surface side, and includes a second-1 inlet and a second-2 inlet through which the second cooling fluid flows in, a second-1 flow channel and a second-3 flow channel that cause the second cooling fluid flowing into the second-1 inlet and the second-2 inlet to flow in the direction of the airfoil tip, and a second-2 flow channel and a second-4 flow channel that are formed adjacent to the second-1 flow channel and the second-3 flow channel and cause the second cooling fluid to flow in the direction of the root portion.

[0017] The second cooling flow path may further include a second - 1 turning channel extending from the upper end of the second - 1 flow channel toward the trailing edge side and a second - 2 turning channel extending from the upper end of the second - 3 flow channel toward the leading edge side.

[0018] Communication ports are formed at the lower ends of the second - 2 flow channel and the second - 4 flow channel respectively, communicating with a central cavity formed between a cavity on the leading edge side, a cavity on the pressure surface side, and a cavity on the suction surface side. The second cooling fluid flowing through the second - 2 flow channel and the second - 4 flow channel can merge in the central cavity through the communication ports.

[0019] The second cooling flow path may further include a second discharge channel for discharging the second cooling fluid in the central cavity to the outside, and a connection port communicating with the second discharge channel may be formed on a side surface of the central cavity on the trailing edge side.

[0020] The plurality of cooling pins may be arranged at predetermined intervals in the second - 2 flow channel, the second - 3 flow channel, and the second - 4 flow channel.

[0021] The plurality of cooling pins may be formed in a frustum - shaped pyramid, and arranged such that the bottom surface with a larger area is connected to the suction surface side.

[0022] A gas turbine according to an embodiment of the present invention includes a compressor that compresses incoming air, a combustor that mixes and burns the compressed air from the compressor and fuel, a turbine vane that generates power with the combustion gas from the combustor and guides the combustion gas on a combustion gas path through which the combustion gas passes, and a turbine blade that rotates by the combustion gas on the combustion gas path. Here, the turbine blade includes an airfoil in which a cooling flow path is formed inside, and the airfoil has a suction surface that protrudes with a curved surface bulging outward, a pressure surface that is recessed and sunken on the suction surface side with a curved surface, a leading edge that connects the suction surface and the pressure surface and is formed at the tip, a trailing edge that connects the suction surface and the pressure surface and is formed at the rear end, a first cooling flow path that allows a first cooling fluid flowing in from below the leading edge to flow into a first meandering flow path formed on the pressure surface side and then discharges it behind the trailing edge, a second cooling flow path that allows a second cooling fluid flowing in from below the suction surface to flow into a second meandering flow path formed on the suction surface side and then discharges it behind the trailing edge, and a plurality of cooling pins formed perpendicular to the pressure surface and the suction surface up to the opposite surface on the inner peripheral surfaces of the first cooling flow path and the second cooling flow path.

[0023] The first cooling flow path may include a first inlet that extends downward from below the leading edge and into which the first cooling fluid flows, a first-1 flow channel that allows the first cooling fluid flowing into the first inlet to flow in the airfoil tip direction, a first-2 flow channel that is formed adjacent to the first-1 flow channel and allows the first cooling fluid to flow in the root portion direction, and a first-3 flow channel that is formed adjacent to the first-2 flow channel and allows the first cooling fluid to flow in the airfoil tip direction.

[0024] The first cooling flow path may further include a first-1 turning channel that extends from the upper end of the first-1 flow channel toward the trailing edge side and a first-2 turning channel that extends from the lower end of the first-2 flow channel toward the trailing edge side.

[0025] The first cooling flow path may further include a first to third turning channel extending from the upper ends of the first to third flow channels toward the trailing edge side, and a first discharge channel for discharging the first cooling fluid flowing through the first to third flow channels to the outside.

[0026] The plurality of cooling pins may be arranged at predetermined intervals in the first to second flow channels and the first to third flow channels.

[0027] The plurality of cooling pins may be formed in a frustum of a square pyramid shape and arranged such that the bottom surface with a larger area is connected to the pressure surface side.

[0028] The second cooling flow path is formed to extend downward from the suction surface side, and includes a second to first inlet and a second to second inlet through which the second cooling fluid flows in, and a second to first flow channel and a second to third flow channel for flowing the second cooling fluid flowing into the second to first inlet and the second to second inlet in the airfoil tip direction, and a second to second flow channel and a second to fourth flow channel that are formed adjacent to the second to first flow channel and the second to third flow channel and for flowing the second cooling fluid in the root portion direction.

[0029] The second cooling flow path may further include a second to first turning channel extending from the upper end of the second to first flow channel toward the trailing edge side, and a second to second turning channel extending from the upper end of the second to third flow channel toward the leading edge side.

[0030] Communication ports are formed at the lower ends of the second to second flow channel and the second to fourth flow channel respectively, communicating with a central cavity formed between a leading edge side cavity, a pressure surface side cavity, and a suction surface side cavity, and the second cooling fluid flowing through the second to second flow channel and the second to fourth flow channel can merge in the central cavity through the communication ports.

[0031] The second cooling channel further includes a second discharge channel for discharging the second cooling fluid in the central cavity to the outside, and a connection port communicating with the second discharge channel may be formed on a side surface of the trailing edge side of the central cavity.

[0032] The plurality of cooling pins may be arranged at predetermined intervals in the second-2 flow channel, the second-3 flow channel, and the second-4 flow channel.

[0033] The plurality of cooling pins may be formed in a frustum of a square pyramid shape and arranged such that a bottom surface with a larger area is connected to the suction surface side.

Advantages of the Invention

[0034] According to the turbine blade of the present invention and the gas turbine including the same, by providing a plurality of columnar cooling pins that gradually become thicker toward one side in the first cooling channel for cooling the leading edge and the pressure surface, and the second cooling channel for cooling the trailing edge and the suction surface, the cooling performance of the airfoil can be improved.

Brief Description of the Drawings

[0035]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14A

Figure 14B

Figure 15

Figure 16

DETAILED DESCRIPTION OF THE INVENTION

[0036] The present invention can have various embodiments with various modifications, and specific embodiments will be illustrated and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that all modifications, equivalents, or alternatives included in the spirit and technical scope of the present invention are included.

[0037] The terms used in the present invention are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present invention, terms such as "including" or "having" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should be understood that the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof is not precluded in advance.

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. At this time, it should be noted that in the accompanying drawings, the same components are represented by the same reference numerals as much as possible. In addition, detailed descriptions of known functions and configurations that may obscure the gist of the present invention are omitted. For the same reason, some components in the accompanying drawings are exaggerated, omitted, or shown schematically.

[0039] FIG. 1 is a view showing the inside of a gas turbine according to an embodiment of the present invention, and FIG. 2 is a partially cut-away sectional view of the gas turbine of FIG. 1.

[0040] As shown in FIGS. 1 and 2, a gas turbine 1 according to an embodiment of the present invention includes a compressor 10, a combustor 20, and a turbine 30. The compressor 10 serves to compress the incoming air to a high pressure and transmit the compressed air to the combustor side. The compressor 10 includes a plurality of compressor blades provided radially, and a part of the power generated from the rotation of the turbine 30 is received to rotate the compressor blades, and the air is moved toward the combustor 20 while being compressed by the rotation of the blades. The size and installation angle of the blades may vary depending on the installation position.

[0041] The air compressed by the compressor 10 moves to the combustor 20, mixes with fuel through a plurality of annularly arranged combustion chambers and a fuel nozzle module, and burns. The high-temperature combustion gas generated by combustion is discharged to the turbine 30, and the turbine rotates by the combustion gas.

[0042] The turbine 30 is arranged in multiple stages via a center tie rod 400 that axially couples the turbine rotor disk 300. The turbine rotor disk 300 includes a plurality of turbine blades 100 arranged radially. The turbine blade 100 can be coupled to the turbine rotor disk 300 by a method such as a double tail. At the same time, turbine vanes 200 fixed to the housing are also provided between the turbine blades 100 to guide the flow direction of the combustion gas passing through the turbine blades 100.

[0043] As shown in FIG. 2, in the turbine 30, n turbine vanes 200 and n turbine blades 100 may be alternately arranged along the axial direction of the gas turbine 1. The high-temperature combustion gas passes through the turbine vanes 200 and the turbine blades 100 along the axial direction, and rotates the turbine blades 100.

[0044] The airfoil according to an embodiment of the present invention may be an airfoil applied to the turbine blade 100. Further, the technical idea described in this specification is not limited to gas turbines, and is applicable to devices provided with airfoils such as steam turbines.

[0045] FIG. 3 is a perspective view showing a turbine blade including an airfoil according to an embodiment of the present invention.

[0046] The turbine blade 100 is mounted on the turbine rotor disk 300 to cause the turbine to rotate by high-pressure combustion gas. On the lower side, a root portion 110 coupled to the turbine rotor disk 300 is formed. On the upper side of the root portion 110, an airfoil 1000 that rotates by gas pressure is integrally coupled so that the turbine rotates by the pressure difference between the front and rear surfaces of the airfoil 1000.

[0047] On the outer surface of the root portion 110, a shank and a platform protruding outward are formed to ensure firm fixation. In the root portion 110, an inlet 111 through which cooling fluid flows into the airfoil 1000 is formed. The cooling fluid is part of the compressed air compressed by the compressor 10 or the air supplied by compressing outside air, and is supplied from the compressor 10 to the root portion 110 of the turbine blade 100, and can cool the turbine blade 100 while flowing into the airfoil 1000 through the inlet 111. Alternatively, the cooling fluid can be supplied from the compressor 10 to the root portion 110 through an internal flow path (not shown) connected to the turbine 30, and can cool the turbine blade 100 while flowing into the airfoil 1000 through the inlet 111.

[0048] On the front surface where the combustion gas flows into the airfoil 1000, a suction side (1002) that forms a curved surface protruding outward is formed, and on the rear surface, a pressure side (1001) that forms a curved surface recessed and sunken on the suction side 1002 side is formed, so that a smooth gas flow is achieved while maximizing the pressure difference between the front and rear of the airfoil 1000.

[0049] The airfoil 1000 includes a leading edge (1003, leading edge) and a trailing edge (1004, trailing edge) which are both ends where the pressure surface 1001 and the suction surface 1002 are in contact. The leading edge 1003 means the tip that faces the fluid flowing in the airfoil 1000, and the trailing edge 1004 means the rear end of the airfoil 1000. Also, the direction from the root part toward the airfoil tip (1006, tip) is referred to as the span direction.

[0050] The airfoil 1000 can include a plurality of cooling holes 1005 formed through the suction surface 1002 or the pressure surface 1001. While the cooling fluid is being injected through the cooling holes 1005, it can act like an air curtain on the outer surface of the airfoil and cool the outer surface of the airfoil 1000 in a so-called film cooling method. On the other hand, cooling holes 1005 may not be formed on the leading edge 1003 side.

[0051] FIG. 4 is a perspective view of the inside of the airfoil according to an embodiment of the present invention as viewed from the pressure surface side, and FIG. 5 is a perspective view of the inside of the airfoil according to an embodiment of the present invention as viewed from the suction surface side.

[0052] Referring to FIGS. 4 and 5, the airfoil 1000 includes a first cooling flow path 1100 and a second cooling flow path 1200 through which the cooling fluid flows inside. While the cooling fluid flows through the first and second cooling flow paths 1100 and 1200, it collides with the inner walls of the first and second cooling flow paths 1100 and 1200 to absorb the heat of the airfoil 1000 and cool it.

[0053] The first cooling flow path 1100 allows the cooling fluid that has flowed in from the lower part of the leading edge 1003 to flow into a meandering flow path (1120 - 1180, see FIGS. 6 and 7) formed on the pressure surface 1001 side, and then discharges it behind the trailing edge 1004.

[0054] The second cooling flow path 1200 divides the cooling fluid flowing in from the lower part of the suction surface 1002 and makes it flow separately into a plurality of serpentine channels (1221 to 1251, 1222 to 1252, see Fig. 8) formed on the suction surface 1002 side. After the separately flowing cooling fluid merges at the lower part of the serpentine channels, it is discharged behind the trailing edge 1004.

[0055] In the following description, the serpentine channels 1120 to 1180 on the pressure surface 1001 side that form the first cooling flow path 1100 are referred to as the first serpentine channels, and the cooling fluid flowing into the first serpentine channels is referred to as the first cooling fluid. Similarly, the serpentine channels 1221 to 1251, 1222 to 1252 on the suction surface 1002 side that form the second cooling flow path 1200 are referred to as the second serpentine channels, and the cooling fluid flowing into the second serpentine channels is referred to as the second cooling fluid. And the serpentine channels can mean a flow channel formed in a meandering shape, where the fluid flows from the lower part to the upper part, then moves to an adjacent channel and repeats flowing from the upper part to the lower part.

[0056] As will be described later, a plurality of cooling pins 1500 may be formed on the inner peripheral surfaces of the first cooling flow path 1100 and the second cooling flow path 1200 so as to be connected from one side surface to the opposite surface perpendicular to the pressure surface 1001 and the suction surface 1002.

[0057] The plurality of cooling pins 1500 may be formed in the shape of columns or pins that are integrally connected from one side surface to the opposite surface inside the first cooling flow path 1100 and the second cooling flow path 1200. Therefore, the cooling pins can be said to be pin-shaped cooling fins. The plurality of cooling pins 1500 may be arranged in a plurality of rows and columns, and the cooling pins in n + 1 rows may be arranged so as to be staggered with each other instead of being arranged in a column with the cooling pins in n rows.

[0058] Figs. 6 and 7 are perspective views showing the first cooling flow path formed inside the airfoil according to an embodiment of the present invention. Fig. 6 is the first cooling flow path 1100 viewed from the pressure surface 1001 side, and Fig. 7 is the first cooling flow path 1100 viewed from the suction surface 1002 side.

[0059] Referring to FIGS. 6 and 7, the first cooling channel 1100 can include a first inlet 1110, a first-1 flow channel 1120, a first-1 turning channel 1130, a first-2 flow channel 1140, a first-2 turning channel 1150, a first-3 flow channel 1160, a first-3 turning channel 1170, and a first discharge channel 1180. Of course, the number of the flow channels and the turning channels is illustrative, and the number of the channels is not limited thereto.

[0060] The first inlet 1110 is formed to extend downward by a predetermined length from the lower part of the leading edge 1003. Specifically, it is connected to the cavity on the leading edge 1003 side and extends downward. The cavity on the leading edge 1003 side may be substantially the first-1 flow channel (see 1120 in FIG. 10). At least a part of the cooling fluid flowing into the inlet 111 formed in the root part 110 can flow into the first inlet 1110. The cooling fluid flowing into the first inlet 1110 is the first cooling fluid.

[0061] The first-1 flow channel 1120 communicates with the first inlet 1110 and allows the first cooling fluid flowing into the first inlet 1110 to flow in the direction of the airfoil tip 1006. The first-1 flow channel 1120 may be substantially the cavity on the leading edge 1003 side.

[0062] At the upper end of the first-1 flow channel 1120, a first-1 turning channel 1130 extending toward the trailing edge 1004 is formed, and the first-1 turning channel 1130 moves the first cooling fluid flowing through the first-1 flow channel 1120 to the first-2 flow channel 1140. The first-2 flow channel 1140 allows the first cooling fluid to flow in the direction of the root part 110.

[0063] At the lower end of the first to second flow channels 1140, first to second turning channels 1150 extending toward the trailing edge 1004 side are formed. The first to second turning channels 1150 move the first cooling fluid flowing through the first to second flow channels 1140 to the first to third flow channels 1160. The first to third flow channels 1160 allow the first cooling fluid to flow from the root portion 110 in the direction of the airfoil tip 1006.

[0064] At the upper end of the first to third flow channels 1160, first to third turning channels 1170 extending toward the trailing edge 1004 side are formed. The first to third turning channels 1170 move the first cooling fluid flowing through the first to third flow channels 1160 to the first discharge channel 1180. The first cooling fluid is discharged to the outside of the airfoil 1000 through the first discharge channel 1180. A plurality of discharge holes (not shown) for discharging the first cooling fluid may be formed in the first discharge channel 1180.

[0065] The first to first flow channels 1120 are formed on the leading edge 1003 side, and the channels 1130 to 1180 directly or indirectly connected to the first to first flow channels 1120 are formed on the pressure surface 1001 side. By forming one first serpentine flow path with the channels 1120 to 1180, the flow time of the first cooling fluid can be increased and the cooling efficiency can be improved. In particular, the first cooling fluid flowing through the first cooling flow path 1100 can effectively cool the leading edge 1003, the pressure surface 1001, and the airfoil tip on the pressure surface side.

[0066] As shown in FIG. 6, a plurality of cooling pins 1500 may be arranged at predetermined intervals in the first to second flow channels 1140 and the first to third flow channels 1160. At this time, no cooling pins are formed in the first to first flow channels 1120, but the present invention is not limited thereto, and a plurality of cooling pins may also be formed in the first to first flow channels 1120.

[0067] As described below, the plurality of cooling pins 1500 may be formed in a frustum of a square pyramid shape and arranged such that the bottom surface with a large area is connected to the pressure surface 1001 side. Since the first cooling channel 1100 is arranged close to the pressure surface 1001 of the airfoil 1000, this is to enable the first cooling fluid to quickly cool the side wall on the pressure surface side of the airfoil 1000.

[0068] FIG. 8 and FIG. 9 are perspective views showing a second cooling channel formed inside an airfoil according to an embodiment of the present invention. FIG. 8 shows the second cooling channel 1200 viewed from the pressure surface 1001 side, and FIG. 9 shows the second cooling channel 1200 viewed from the suction surface 1002 side.

[0069] Referring to FIGS. 8 and 9, the second cooling channel 1200 can include a second-1 inlet 1211, a second-1 flow channel 1221, a second-1 turning channel 1231, a second-2 flow channel 1241, a second-2 inlet 1212, a second-3 flow channel 1222, a second-2 turning channel 1232, a second-4 flow channel 1242, and a second discharge channel 1260.

[0070] The second-1 inlet 1211, the second-1 flow channel 1221, the second-1 turning channel 1231, and the second-2 flow channel 1241 can form a second-1 meandering flow channel, and the second-2 inlet 1212, the second-3 flow channel 1222, the second-2 turning channel 1232, and the second-4 flow channel 1242 can form a second-2 meandering flow channel. Of course, the number of flow channels, turning channels, and meandering flow channels is an example, and the number of channels and meandering flow channels is not limited thereto.

[0071] The second-1 inlet 1211 and the second-2 inlet 1212 are formed to extend downward by a predetermined length from the suction surface 1002 side. The second-1 inlet 1211 may be formed on the leading edge 1003 side, and the second-2 inlet 1212 may be formed on the side of the second-1 inlet 1211 in the trailing edge 1004 direction.

[0072] At least a part of the cooling fluid flowing into the inlet 111 formed in the root portion 110 can flow into the second-1 inlet 1211, and at least a part can also flow into the second-2 inlet 1212. The cooling fluid flowing into the second inlets 1211 and 1212 is the second cooling fluid.

[0073] The second-1 flow channel 1221 communicates with the second-1 inlet 1211 and causes the second cooling fluid flowing into the second-1 inlet 1211 to flow in the direction of the airfoil tip 1006.

[0074] At the upper end of the second-1 flow channel 1221, a second-1 turning channel 1231 extending toward the trailing edge 1004 is formed. The second-1 turning channel 1231 moves the second cooling fluid flowing through the second-1 flow channel 1221 to the second-2 flow channel 1241. The second-2 flow channel 1241 causes the second cooling fluid to flow in the direction of the root portion 110.

[0075] The second-3 flow channel 1222 communicates with the second-2 inlet 1212 and causes the second cooling fluid flowing into the second-2 inlet 1212 to flow in the direction of the airfoil tip 1006.

[0076] At the upper end of the second-3 flow channel 1222, a second-2 turning channel 1232 extending toward the leading edge 1003 is formed. The second-2 turning channel 1232 moves the second cooling fluid flowing through the second-3 flow channel 1222 to the second-4 flow channel 1242. The second-4 flow channel 1242 causes the second cooling fluid to flow in the direction of the root portion 110.

[0077] FIG. 10 is a cross-sectional view looking down from the A-A line in FIG. 3.

[0078] On each side surface of the lower end portions of the second - second flow channel 1241 and the second - fourth flow channel 1242, communication ports 1251 and 1252 communicating with the central cavity (1300, see FIG. 10) are formed. The communication ports 1251 and 1252 are formed on the side surfaces on the central cavity 1300 side. Of course, the communication ports 1251 and 1252 do not necessarily have to be formed on the side surfaces.

[0079] The central cavity 1300 is a flow space formed between the cavity 1120 on the leading - edge side, the cavities 1140 and 1160 on the pressure - side, and the cavities 1221, 1241, 1242, and 1222 on the suction - side. The second cooling fluid flowing through the second - second flow channel 1241 and the second - fourth flow channel 1242 merges within the central cavity 1300 through the communication ports 1251 and 1252.

[0080] The second discharge channel 1260 is formed to extend at substantially the same height as the height of the central cavity 1300 and communicate with a connection port (1301, see FIG. 5) formed on the side surface on the trailing - edge side of the central cavity 1300. And in a predetermined region on the trailing - edge side of the second discharge channel 1260, a plurality of discharge holes 1261 for discharging the second cooling fluid may be formed in a matrix.

[0081] By forming at least two or more meandering flow paths on the suction - surface 1002 side in the second - first flow channel 1221, the second - second flow channel 1241, the second - third flow channel 1222, and the second - fourth flow channel 1242, the flow time of the second cooling fluid can be increased and the cooling efficiency can be improved. In particular, the second cooling fluid flowing through the second cooling channel 1200 can effectively cool the trailing - edge 1004, the suction - surface 1002, and the air - foil tip on the suction - side.

[0082] As shown in FIG. 9, a plurality of cooling pins 1500 may be arranged at predetermined intervals in the second - second flow channel 1241, the second - third flow channel 1222, and the second - fourth flow channel 1242. At this time, although no cooling pins are formed in the second - first flow channel 1221, it is not limited thereto, and a plurality of cooling pins may also be formed in the second - first flow channel 1221.

[0083] As will be described later, the plurality of cooling pins 1500 may be formed in a frustum - of - square - pyramid shape and arranged such that the bottom surface with a larger area is connected to the suction surface 1002 side. Since the second cooling channel 1200 is arranged close to the suction surface 1002 of the airfoil 1000, this is to enable the second cooling fluid to quickly cool the side wall on the suction surface side of the airfoil 1000.

[0084] Next, referring to FIG. 11, an airfoil according to a modified example of the present invention will be described. FIG. 11 is a perspective view showing a second cooling channel formed inside the airfoil according to the modified example of the present invention.

[0085] The airfoil according to the modified example of the present invention includes a first cooling channel 1100 and a second cooling channel 1200. Compared with the above - described embodiment, only a part of the configuration of the second cooling channel 1200 is different, and the remaining configurations are substantially the same. Therefore, repeated descriptions will be omitted, and for convenience of explanation, the same or corresponding configurations will be denoted by the same reference numerals and described.

[0086] Referring to FIG. 11, different from the above - described embodiment, in the second cooling channel 1200, the second - first inlet 1211 and the second - second inlet 1212 are formed close to each other. As a result, the second - first flow channel 1221 and the second - third flow channel 1222 are also formed close to each other. The second - first turning channel 1231 extends from the upper end of the second - first flow channel 1221 toward the leading edge 1003 side, and the second - second turning channel 1232 extends from the upper end of the second - third flow channel 1222 toward the trailing edge 1004 side and is formed.

[0087] In the above-described embodiment, the cooling fluid flowing into the inlet 111 formed in the root portion 110 branches and flows into the first inlet 1110, the second-1 inlet 1211, and the second-2 inlet 1212. However, the second-1 inlet 1211 and the second-2 inlet 1212 are relatively far apart from each other, and the first inlet 1110 and the second-1 inlet 1211 are adjacent to each other. Therefore, even if more cooling fluid flows into the first inlet 1110 side, it may be possible.

[0088] On the other hand, in this modified example, by forming the second-1 inlet 1211 and the second-2 inlet 1212 close to each other, it is possible to partially prevent the second cooling fluid that should flow into the second inlet 1211, 1212 side from flowing into the first inlet 1110 side.

[0089] As shown in FIG. 11, the plurality of cooling pins 1500 may be arranged at predetermined intervals in the second-1 flow channel 1221, the second-2 flow channel 1241, the second-3 flow channel 1222, and the second-4 flow channel 1242. At this time, the plurality of cooling pins 1500 may be arranged so as to form a plurality of rows and columns, and the cooling pins in the n + 1 row may be arranged so as to be staggered from the cooling pins in the n row without being arranged in the same column.

[0090] As will be described later, the plurality of cooling pins 1500 may be formed in a frustum of a square pyramid shape and arranged such that the bottom surface with a large area is connected to the suction surface 1002 side. Since the second cooling channel 1200 is arranged close to the suction surface 1002 of the airfoil 1000, this is to enable the second cooling fluid to quickly cool the side wall on the suction surface side of the airfoil 1000.

[0091] FIG. 12 is a perspective view of the inside of an airfoil according to another embodiment of the present invention as viewed from the pressure surface side, and FIG. 13 is a perspective view of the inside of an airfoil according to another embodiment of the present invention as viewed from the suction surface side.

[0092] The airfoil 1000 according to another embodiment of the present invention has a similar form of the first cooling channel 1100 compared to the above-described embodiment. In particular, the form of the second cooling channel 1200 is formed differently.

[0093] Specifically, as shown in FIG. 12, the first cooling channel 1100, similar to the above-described embodiment, can include a first inlet 1110, a first-1 flow channel 1120, a first-1 turning channel 1130, a first-2 flow channel 1140, a first-2 turning channel 1150, a first-3 flow channel 1160, a first-3 turning channel 1170, and a first discharge channel 1180. A plurality of cooling pins 1500 may be integrally formed in a columnar shape in the first-2 flow channel 1140 and the first-3 flow channel 1160.

[0094] On the other hand, the second cooling channel 1200 can include a second inlet 1210, a second-1 flow channel 1221, a second-1 turning channel 1231, a second-2 flow channel 1241, and a second discharge channel 1260. That is, in the previous embodiment, the second cooling channel 1200 is composed of two inlets, four flow channels, two turning channels, and one discharge channel. However, the second cooling channel 1200 of this embodiment may be composed of one inlet, two flow channels, one turning channel, and one discharge channel.

[0095] A communication port 1250 communicating with the central cavity (1300, see FIG. 10) may be formed on the lower end side surface of the second-2 flow channel 1241. The communication port 1250 may be formed on the side surface on the central cavity 1300 side.

[0096] A plurality of cooling pins 1500 may be integrally formed in a columnar shape in the second-1 flow channel 1221 and the second-2 flow channel 1241. At this time, the plurality of cooling pins 1500 may be arranged in a plurality of rows and columns, and the cooling pins in n + 1 rows may be arranged so as to be staggered from the cooling pins in n rows instead of being arranged in a column.

[0097] As described below, the plurality of cooling pins 1500 may be formed in a frustum of a square pyramid shape and arranged such that the bottom surface with a large area is connected to the suction surface 1002 side. Since the second cooling channel 1200 is arranged close to the suction surface 1002 of the airfoil 1000, it is to enable the second cooling fluid to quickly cool the side wall on the suction surface side of the airfoil 1000.

[0098] An airfoil and a turbine blade in which a plurality of flow channels and a plurality of columnar cooling pins are integrally formed may be formed from a mold fabricated using a ceramic core that constitutes the space around the flow channels and the cooling pins. After molding the ceramic core that constitutes the space around the flow channels and the cooling pins, the turbine blade may be cast with the ceramic core inserted into the mold of the turbine blade, and then the ceramic core inserted into the airfoil may be removed with chemicals to fabricate the turbine blade.

[0099] FIG. 14A is a perspective view showing the form of one cooling pin, FIG. 14B is a cross-sectional view showing air flowing around a plurality of cooling pins, FIG. 15 is a diagram showing the temperature distribution of the air flowing around a plurality of cooling pins, and FIG. 16 is a graph showing a comparison of the cooling effects of circular pins and frustum of a square pyramid-shaped pins.

[0100] As shown in FIG. 14A, each cooling pin 1500 may be formed in a frustum of a square pyramid shape. In particular, the upper end surface of the cooling pin 1500 may be formed as a square with a side length of a, and the lower end surface of the cooling pin 1500 may be formed as a square with a side length of b. In this case, the average of a and b may be defined as D, and the height of the cooling pin 1500 may be defined as H. b is formed larger than a, and the end portion having a large area is arranged on the outer side of the airfoil, that is, on the pressure surface or the suction surface side.

[0101] The shape of the cooling pin 1500 was diversified by changing the dimensions of a, b, and H, and the cooling effect due to the flow of air was experimented.

[0102] For example, the length a of the upper side is 16 or 12, the length b of the lower side is 24 or 28, and the height H is one of 32, 24, 26, 8 mm. The cooling pins 1500 can be formed and the cooling effects can be compared by simulation. Also, the inflow velocity Vinlet of the cooling air is one of 7.8, 19.5, 27.2 m / s, and the experiment can be conducted under one of the boundary conditions where the Reynolds number ReDpin is 10000, 25000, 35000. In this case, H / D can have a value of 0.4 to 1.6. And when the distance between the cooling pins is S, the cooling performance is the best when S / D is set to about 2.5. Also, the angle between the bottom surface and the side surface of the frustum-shaped cooling pin may be formed at 40 to 80 degrees.

[0103] FIG. 15 shows the flow and temperature distribution of the cooling air flowing around the upper end surface and the bottom surface of the frustum-shaped cooling pin.

[0104] The lower end surface with a large area of the cooling pin is arranged to be connected to the outer inner peripheral surface in each flow channel, and the upper end surface with a small area is arranged to be connected to the inner inner peripheral surface in each flow channel. Since the combustion gas flows around the outer surface of the airfoil, by arranging the lower end surface with a large area of the frustum-shaped cooling pin on the pressure surface and the suction surface side of the outer wall, the outer wall of the airfoil can be cooled more effectively.

[0105] The graph in FIG. 16 shows a comparison of the cooling performance of the circular cooling pin and the upper end surface and the bottom surface of the frustum-shaped cooling pin.

[0106] Here, the distance S between the cooling pins is set such that S / D is 2.5, the aspect ratio is 3.5, and the Reynolds number ReDh is set to 87500.

[0107] The graph in FIG. 16 shows the area-averaged Nu / Nu0 values for each of the seven rows of cooling pins for the circular cooling pin and the upper end surface and the bottom surface of the frustum-shaped cooling pin.

[0108] The Nusselt number (Nu) indicates the ratio of convective heat transfer to conductive heat transfer at the surface of an object. It can be seen that for all seven rows of cooling pins, the cooling performance of the bottom surface of the frustum-shaped cooling pins is the best, the upper surface of the frustum-shaped cooling pins is slightly lower than that, and the cooling performance of the circular cooling pins is the worst.

[0109] For the circular cooling pins and the upper and lower surfaces of the frustum-shaped cooling pins, the average value of the area-averaged Nu / Nu0 values can be calculated for each of the seven rows of cooling pins.

[0110] Looking at the average value of the area-averaged Nu / Nu0 values, compared with the circular cooling pins, the upper surface of the frustum-shaped cooling pins can have a value about 13% larger, and the bottom surface of the frustum-shaped cooling pins can have a value about 20% larger. Thus, it can be seen that the frustum-shaped cooling pins have much better cooling performance than the circular cooling pins.

[0111] According to the present invention, by forming a plurality of flow channels inside the airfoil and forming a plurality of frustum-shaped cooling pins in each flow channel, the cooling performance of the airfoil can be improved.

[0112] As described above, an embodiment of the present invention has been explained. However, those with ordinary knowledge in the relevant technical field can make various modifications and changes to the present invention by adding, changing, deleting, or adding components, etc., without departing from the idea of the present invention described in the claims, and this is also included within the scope of the rights of the present invention.

Explanation of Reference Numerals

[0113] 1: Gas turbine, 10: Compressor 20: Combustor, 30: Turbine 100: Turbine blade 110: Root part, 111: Inlet 200: Turbine vane, 300: Turbine rotor disk 400: Center tie rod 1000: Airfoil, 1001: Pressure surface 1002: Suction surface, 1003: Leading edge 1004: Trailing edge, 1005: Cooling hole 1006: Airfoil tip 1100: First cooling flow path, 1110: First inlet 1120: First - 1 flow channel, 1130: First - 1 turning channel 1140: First - 2 flow channel, 1150: First - 2 turning channel 1160: First - 3 flow channel, 1170: First - 3 turning channel 1180: First discharge channel 1200: Second cooling flow path, 1210: Second inlet 1211: Second - 1 inlet, 1221: Second - 1 flow channel 1231: Second - 1 turning channel, 1241: Second - 2 flow channel 1212: Second - 2 inlet, 1222: Second - 3 flow channel 1232: Second - 2 turning channel, 1242: Second - 4 flow channel 1250, 1251, 1252: Communication ports, 1260: Second discharge channel 1261: Discharge hole 1300: Central cavity, 1301: Connection port 1500: Cooling pin a: Length of the upper - surface corner, b: Length of the lower - surface corner D: Average width of the pin, H: Height of the pin

Claims

1. A turbine blade mounted on a turbine rotor disk and rotated by high-pressure combustion gas, wherein the turbine blade includes a root portion coupled to the turbine rotor disk at a lower portion thereof, and an airfoil integrally formed on an upper side of the root portion and having a cooling flow path formed therein, wherein the airfoil has a suction surface that protrudes with a curved surface bulging outward, a pressure surface that forms a curved surface recessed and sunken on the suction surface side, a leading edge that connects the suction surface and the pressure surface and is formed at a tip, a trailing edge that connects the suction surface and the pressure surface and is formed at a rear end, a first cooling flow path that allows a first cooling fluid flowing in from a lower portion of the leading edge to flow into a first serpentine flow path formed on the pressure surface side and then discharges the fluid behind the trailing edge, a second cooling flow path that allows a second cooling fluid flowing in from a lower portion of the suction surface to flow into a second serpentine flow path formed on the suction surface side and then discharges the fluid behind the trailing edge, and a plurality of cooling pins formed on an inner peripheral surface of the first cooling flow path and the second cooling flow path perpendicular to the pressure surface and the suction surface up to an opposite surface.

2. The first cooling flow path is formed to extend downward from a lower portion of the leading edge, and includes a first inlet through which the first cooling fluid flows in, a first-1 flow channel that allows the first cooling fluid flowing into the first inlet to flow in the airfoil tip direction, a first-2 flow channel that is formed adjacent to the first-1 flow channel and allows the first cooling fluid to flow in the root portion direction, and a first-3 flow channel that is formed adjacent to the first-2 flow channel and allows the first cooling fluid to flow in the airfoil tip direction. The turbine blade according to claim 1, characterized in that it includes the above.

3. The first cooling flow path further includes a first-1 turning channel that is formed to extend from an upper end of the first-1 flow channel toward the trailing edge side, and a first-2 turning channel that extends from a lower end of the first-2 flow channel toward the trailing edge side. The turbine blade according to claim 2, characterized in that it includes the above.

4. The first cooling flow path further includes a first-3 turning channel that is formed to extend from an upper end of the first-3 flow channel toward the trailing edge side, The turbine blade according to claim 3, further comprising a first discharge channel for discharging the first cooling fluid flowing through the first to third flow channels to the outside.

5. The turbine blade according to any one of claims 2 to 4, wherein the plurality of cooling pins are arranged at predetermined intervals with respect to each other in the first to second flow channels and the first to third flow channels.

6. The plurality of cooling pins are formed in a frustum of a square pyramid shape, The turbine blade according to claim 5, wherein the bottom surface having a large area is arranged to be connected to the pressure surface side.

7. The second cooling flow path, is formed to extend downward from the suction surface side, and includes a second-1 inlet and a second-2 inlet into which the second cooling fluid flows, a second-1 flow channel and a second-3 flow channel for flowing the second cooling fluid flowing into the second-1 inlet and the second-2 inlet in the airfoil tip direction, The turbine blade according to claim 1, further comprising a second-2 flow channel and a second-4 flow channel that are formed adjacent to the second-1 flow channel and the second-3 flow channel and that flow the second cooling fluid in the root portion direction.

8. The second cooling flow path, includes a second-1 turning channel formed to extend from the upper end of the second-1 flow channel toward the trailing edge side, The turbine blade according to claim 7, further comprising a second-2 turning channel formed to extend from the upper end of the second-3 flow channel toward the leading edge side.

9. At each of the lower end portions of the second-2 flow channel and the second-4 flow channel, a communication port is formed that communicates with a central cavity formed between a cavity on the leading edge side, a cavity on the pressure surface side, and a cavity on the suction surface side, The turbine blade according to claim 8, wherein the second cooling fluid flowing through the second-2 flow channel and the second-4 flow channel merges in the central cavity through the communication port.

10. The second cooling flow path further includes a second discharge channel for discharging the second cooling fluid in the central cavity to the outside, The turbine blade according to claim 9, wherein a connection port that communicates with the second discharge channel is formed on a side surface of the central cavity on the trailing edge side.

11. The plurality of cooling pins are arranged at a predetermined interval from each other in the second - 2 flow channel, the second - 3 flow channel, and the second - 4 flow channel, the turbine blade according to claim 7, characterized in that.

12. The plurality of cooling pins are formed in a frustum of a square pyramid shape, The turbine blade according to claim 11, characterized in that the bottom surface with a large area is arranged to be connected to the suction surface side.

13. A compressor that compresses the incoming air, a combustor that mixes and burns the compressed air and fuel from the compressor, a turbine vane that generates power with the combustion gas from the combustor and guides the combustion gas on the combustion gas path through which the combustion gas passes, and a turbine blade that rotates by the combustion gas on the combustion gas path, a turbine including, The turbine blade includes an airfoil in which a cooling flow path is formed inside, The airfoil is, A suction surface that protrudes with a curved surface bulging outward, A pressure surface that forms a curved surface recessed and sunken on the suction surface side, A leading edge that connects the suction surface and the pressure surface and is formed at the tip, A trailing edge that connects the suction surface and the pressure surface and is formed at the rear end, A first cooling flow path that allows the first cooling fluid flowing in from the lower part of the leading edge to flow into the first meandering flow path formed on the pressure surface side and then discharges it behind the trailing edge, A second cooling flow path that allows the second cooling fluid flowing in from the lower part of the suction surface to flow into the second meandering flow path formed on the suction surface side and then discharges it behind the trailing edge, A gas turbine including a plurality of cooling pins formed perpendicular to the pressure surface and the suction surface up to the opposite surface on the inner peripheral surfaces of the first cooling flow path and the second cooling flow path.

14. The first cooling flow path is, Extended downward from the lower part of the leading edge, a first inlet through which the first cooling fluid flows in, A first - 1 flow channel that allows the first cooling fluid flowing into the first inlet to flow in the airfoil tip direction, A first - 2 flow channel formed adjacent to the first - 1 flow channel and allowing the first cooling fluid to flow in the root part direction, The gas turbine according to claim 13, characterized in that it includes a first - 3 flow channel formed adjacent to the first - 2 flow channel and allowing the first cooling fluid to flow in the airfoil tip direction.

15. The first cooling flow path is, A first-1 turning channel extending from the upper end of the first-1 flow channel toward the trailing edge side; The gas turbine according to claim 14, further comprising a first-2 turning channel extending from the lower end of the first-2 flow channel toward the trailing edge side. **Claim 16** The first cooling flow path is A first-3 turning channel extending from the upper end of the first-3 flow channel toward the trailing edge side; The gas turbine according to claim 15, further comprising a first discharge channel for discharging the first cooling fluid flowing through the first-3 flow channel to the outside. **Claim 17** The gas turbine according to any one of claims 14 to 16, wherein the plurality of cooling pins are arranged at predetermined intervals in the first-2 flow channel and the first-3 flow channel. **Claim 18** The plurality of cooling pins are formed in a frustum of a square pyramid shape, The gas turbine according to claim 17, wherein the bottom surface with a larger area is arranged to be connected to the pressure surface side. **Claim 19** The second cooling flow path is A second-1 inlet and a second-2 inlet extending downward from the suction surface side and into which the second cooling fluid flows; A second-1 flow channel and a second-3 flow channel for flowing the second cooling fluid flowing into the second-1 inlet and the second-2 inlet in the airfoil tip direction; The gas turbine according to claim 13, further comprising a second-2 flow channel and a second-4 flow channel formed adjacent to the second-1 flow channel and the second-3 flow channel and for flowing the second cooling fluid in the root portion direction. **Claim 20** The second cooling flow path is A second-1 turning channel extending from the upper end of the second-1 flow channel toward the trailing edge side; The gas turbine according to claim 19, further comprising a second-2 turning channel extending from the upper end of the second-3 flow channel toward the leading edge side. **Claim 21** At each of the lower end portions of the second-2 flow channel and the second-4 flow channel, A communication port is formed to communicate with a central cavity formed between a cavity on the leading edge side, a cavity on the pressure surface side, and a cavity on the suction surface side. The second cooling fluid flowing through the second - 2 flow channel and the second - 4 flow channel merges in the central cavity through the communication port, the gas turbine according to claim 20, characterized in that.

22. The second cooling flow path further includes a second discharge channel for discharging the second cooling fluid in the central cavity to the outside. On the side surface of the trailing edge side of the central cavity, a connection port communicating with the second discharge channel is formed, the gas turbine according to claim 21, characterized in that.

23. The plurality of cooling pins are arranged at predetermined intervals with respect to each other in the second - 2 flow channel, the second - 3 flow channel, and the second - 4 flow channel, the gas turbine according to claim 19, characterized in that.

24. The plurality of cooling pins are formed in a frustum - shaped pyramid. The gas turbine according to claim 23, characterized in that the bottom surface with a large area is arranged to be connected to the suction surface side.

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