Airfoil, turbine blade including the airfoil, and gas turbine including the turbine blade

1 . An airfoil comprising:

a suction side having an outwardly convex surface;

a pressure side having a concave surface toward the suction side;

a leading edge connecting the suction side and the pressure side and defining a front end of the airfoil;

a trailing edge connecting the suction side and the pressure side and defining a rear end of the airfoil;

a cooling flow passage configured to guide cooling fluid, introduced from a lower portion of the suction side and the pressure side, to one or more flow channels respectively at the suction side and the pressure side, and to discharge the cooling fluid to a region rearward of the trailing edge;

a flow guide part provided in each of the one or more flow channels and forming a cooling space; and

a plurality of cooling fluid spray holes formed in the flow guide part and configured to spray the cooling fluid supplied into the one or more flow channels to the suction side and the pressure side, each forming an inner surface of the cooling space,

wherein a plurality of flow guides protruding toward the cooling space are provided on one surface of the flow guide part,

a plurality of impingement holes, each in communication with a corresponding one of the plurality of cooling fluid spray boles, are formed respectively in the plurality of flow guides,

a circumferential surface of each of the plurality of flow guides has a circular shape, and each of the plurality of cooling fluid spray holes is disposed at a center of a corresponding flow guide of the plurality of flow guides, and

each of the plurality of flow guides protrudes obliquely from its circumferential surface toward a center where a corresponding impingement hole is formed.

2 . The airfoil of claim 1 , further comprising a plurality of heat transfer fins provided on the one surface of the flow guide part and connecting the flow guide part to the suction side or to the pressure side.

3 . The airfoil of claim 2 , wherein the plurality of heat transfer fins are arranged on the one surface of the flow guide part so as to be positioned at top, bottom, left, and right locations around each cooling fluid spray hole,

outer circumferential surfaces of the plurality of heat transfer fins are disposed on the circumferential surface of each of the plurality of flow guides, and

a distance between an outlet of each cooling fluid spray hole and the suction side or the pressure side is greater than 0.5 times and less than 1.5 times a diameter of a corresponding one of the plurality of cooling fluid spray holes.

4 . The airfoil of claim 1 , wherein the cooling flow passage comprises:

a first cooling flow passage configured to guide the cooling fluid, introduced from the lower portion of the pressure side at the leading edge, to the one or more flow channels formed at the pressure side, and then discharge the cooling fluid toward the region rearward of the trailing edge; and

a second cooling flow passage configured to divide the cooling fluid introduced from the lower portion of the suction side to the one or more flow channels formed at the suction side, merge the divided cooling fluid, and then discharge the cooling fluid toward the region rearward of the trailing edge.

5 . The airfoil of claim 4 , wherein the first cooling flow passage comprises:

a first inlet extending downward from the lower portion of the pressure side at the leading edge and configured to receive the cooling fluid;

a 1-1 flow channel configured to guide the cooling fluid introduced into the first inlet toward an airfoil tip;

a 1-2 flow channel formed adjacent to the 1-1 flow channel and configured to guide the cooling fluid toward a root portion of the airfoil;

a 1-3 flow channel formed adjacent to the 1-2 flow channel and configured to guide the cooling fluid toward the airfoil tip;

a 1-1 turning channel extending toward the trailing edge from an upper end of the 1-1 flow channel;

a 1-2 turning channel extending toward the trailing edge from a lower end of the 1-2 flow channel;

a 1-3 turning channel extending toward the trailing edge from an upper end of the 1-3 flow channel; and

a first discharge channel configured to discharge the cooling fluid flowing through the 1-3 flow channel to an outside of the airfoil, and

the second cooling flow passage comprises:

a 2-1 inlet and a 2-2 inlet extending downward from the lower portion of the suction side and configured to receive the cooling fluid;

a 2-1 flow channel and a 2-3 flow channel configured to respectively guide the cooling fluid introduced into the 2-1 inlet and the 2-2 inlet toward the airfoil tip;

a 2-2 flow channel and a 2-4 flow channel formed adjacent to the 2-1 flow channel and the 2-3 flow channel, respectively, and configured to guide the cooling fluid toward the root portion of the airfoil;

a 2-1 turning channel extending toward the trailing edge from an upper end of the 2-1 flow channel; and

a 2-2 turning channel extending toward the leading edge from an upper end of the 2-3 flow channel.

6 . The airfoil of claim 5 , wherein a communication hole that is in communication with a central cavity is formed at a lower end of each of the 2-2 flow channel and the 2-4 flow channel, the central cavity being formed in an area defined by a cavity at the leading edge, cavities at the pressure side, and cavities at the suction side,

the cooling fluid flowing through the 2-2 flow channel and the 2-4 flow channel merges within the central cavity through the communication holes,

the second cooling flow passage further comprises a second discharge channel configured to discharge the cooling fluid in the central cavity to the outside of the airfoil, and

a connecting hole that is in communication with the second discharge channel is formed on a side at the trailing edge of the central cavity.

7 . A turbine blade mounted on a turbine rotor disk and rotated by high-pressure combustion gas, the turbine blade comprising:

a root portion coupled to the turbine rotor disk; and

an airfoil coupled to the root portion, and having a cooling flow passage comprising a first cooling flow passage and a second cooling flow passage formed in the airfoil,

wherein the airfoil comprises:

a suction side having an outwardly convex surface;

a pressure side having a concave surface toward the suction side;

a leading edge connecting the suction side and the pressure side and defining a front end of the airfoil;

a trailing edge connecting the suction side and the pressure side and defining a rear end of the airfoil;

the cooling flow passage configured to guide cooling fluid introduced from a lower portion of the suction side and the pressure side, to one or more flow channels respectively at the suction side and the pressure side, and then discharge the cooling fluid to a region rearward of the trailing edge;

a flow guide part provided in each of the one or more flow channels and forming a cooling space; and

a plurality of cooling fluid spray holes formed in the flow guide part and configured to spray the cooling fluid supplied into the one or more flow channels to the suction side and the pressure side, each forming an inner surface of the cooling space,

wherein a plurality of flow guides protruding toward the cooling space are provided on one surface of the flow guide part,

a plurality of impingement holes, each in communication with a corresponding one of the plurality of cooling fluid spray holes, are formed respectively in the plurality of flow guides,

a circumferential surface of each of the plurality of flow guides has a circular shape, and each of the plurality of cooling fluid spray holes is disposed at a center of a corresponding flow guide of the plurality of flow guides, and

each of the plurality of flow guides protrudes obliquely from its circumferential surface toward a center where a corresponding impingement hole is formed.

8 . The turbine blade of claim 7 , further comprising a plurality of heat transfer fins provided on the one surface of the flow guide part and connecting the flow guide part to the suction side or to the pressure side.

9 . The turbine blade of claim 8 , wherein the plurality of heat transfer fins are arranged on the one surface of the flow guide part so as to be positioned at top, bottom, left, and right locations around each cooling fluid spray hole,

outer circumferential surfaces of the plurality of heat transfer fins are disposed on the circumferential surface of each of the plurality of flow guides, and

a distance between an outlet of each cooling fluid spray hole and the suction side or the pressure side is greater than 0.5 times and less than 1.5 times a diameter of a corresponding one of the plurality of cooling fluid spray holes.

10 . The turbine blade of claim 7 , wherein the cooling flow passage comprises:

the first cooling flow passage configured to guide the cooling fluid, introduced from the lower portion of the pressure side at the leading edge, to the one or more flow channels formed at the pressure side, and then discharge the cooling fluid toward the region rearward of the trailing edge; and

the second cooling flow passage configured to divide the cooling fluid introduced from the lower portion of the suction side to the one or more flow channels formed at the suction side, merge the divided cooling fluid, and then discharge the cooling fluid toward the region rearward of the trailing edge.

11 . The turbine blade of claim 10 , wherein the first cooling flow passage comprises:

a first inlet extending downward from the lower portion of the pressure side at the leading edge and configured to receive the cooling fluid;

a 1-1 flow channel configured to guide the cooling fluid introduced into the first inlet toward an airfoil tip;

a 1-2 flow channel formed adjacent to the 1-1 flow channel and configured to guide the cooling fluid toward the root portion of the airfoil;

a 1-3 flow channel formed adjacent to the 1-2 flow channel and configured to guide the cooling fluid toward the airfoil tip;

a 1-1 turning channel extending toward the trailing edge from an upper end of the 1-1 flow channel; and

a 1-2 turning channel extending toward the trailing edge from a lower end of the 1-2 flow channel;

a 1-3 turning channel extending toward the trailing edge from an upper end of the 1-3 flow channel; and

a first discharge channel configured to discharge the cooling fluid flowing through the 1-3 flow channel to an outside of the airfoil, and

the second cooling flow passage comprises:

a 2-1 inlet and a 2-2 inlet extending downward from the lower portion of the suction side and configured to receive the cooling fluid;

a 2-1 flow channel and a 2-3 flow channel configured to respectively guide the cooling fluid introduced into the 2-1 inlet and the 2-2 inlet toward the airfoil tip;

a 2-2 flow channel and a 2-4 flow channel formed adjacent to the 2-1 flow channel and the 2-3 flow channel, respectively, and configured to guide the cooling fluid toward the root portion of the airfoil;

a 2-1 turning channel extending toward the trailing edge from an upper end of the 2-1 flow channel; and

a 2-2 turning channel extending toward the leading edge from an upper end of the 2-3 flow channel.

12 . The turbine blade of claim 11 , wherein a communication hole that is in communication with a central cavity is formed at a lower end of each of the 2-2 flow channel and the 2-4 flow channel, the central cavity being formed in an area defined by a cavity at the leading edge, cavities at the pressure side, and cavities at the suction side,

the cooling fluid flowing through the 2-2 flow channel and the 2-4 flow channel merges within the central cavity through the communication holes,

the second cooling flow passage further comprises a second discharge channel configured to discharge the cooling fluid in the central cavity to the outside of the airfoil, and

a connecting hole that is in communication with the second discharge channel is formed on a side at the trailing edge of the central cavity.

13 . A gas turbine comprising:

a compressor configured to compress intake air;

a combustor configured to mix compressed air from the compressor with fuel and burn the mixture; and

a turbine configured to generate power using combustion gas from the combustor, and comprising turbine vanes configured to guide the combustion gas on a combustion gas path along which the combustion gas flows and turbine blades that are rotated by the combustion gas on the combustion gas path,

wherein the turbine blade comprises an airfoil having a cooling flow passage comprising a first cooling flow passage and a second cooling flow passage formed in the airfoil,

wherein the airfoil comprises:

a suction side having an outwardly convex surface;

a pressure side having a concave surface toward the suction side;

a leading edge connecting the suction side and the pressure side and defining a front end of the airfoil;

a trailing edge connecting the suction side and the pressure side and defining a rear end of the airfoil;

the cooling flow passage configured to guide cooling fluid introduced from a lower portion of the suction side and the pressure side, to one or more flow channels respectively at the suction side and the pressure side, and to discharge the cooling fluid to a region rearward of the trailing edge;

a flow guide part provided in each of the one or more flow channels and forming a cooling space; and

a plurality of cooling fluid spray holes formed in the flow guide part and configured to spray the cooling fluid supplied into the one or more flow channels to the suction side and the pressure side, each forming an inner surface of the cooling space,

wherein a plurality of flow guides protruding toward the cooling space are pr vided on one surface of the flow guide part,

a plurality of impingement holes, each in communication with a corresponding one of the plurality of cooling fluid spray boles, are formed respectively in the plurality of flow guides,

a circumferential surface of each of the plurality of flow guides has a circular shape, and each of the plurality of cooling fluid spray holes is disposed at a center of a corresponding flow guide of the plurality of flow guides, and

each of the plurality of flow guides protrudes obliquely from its circumferential surface toward a center where a corresponding impingement hole is formed.

14 . The gas turbine of claim 13 , further comprising a plurality of heat transfer fins provided on the one surface of the flow guide part and connecting the flow guide part to the suction side or to the pressure side,

wherein the plurality of heat transfer fins are arranged on the one surface of the flow guide part so as to be positioned at top, bottom, left, and right locations around each cooling fluid spray hole,

outer circumferential surfaces of the plurality of heat transfer fins are disposed on the circumferential surface of each of the plurality of flow guides, and

a distance between an outlet of each cooling fluid spray hole and the suction side or the pressure side is greater than 0.5 times and less than 1.5 times a diameter of a corresponding one of the plurality of cooling fluid spray holes.

15 . The gas turbine of claim 13 , wherein the cooling flow passage comprises:

a first cooling flow passage configured to guide the cooling fluid, introduced from the lower portion of the pressure side at the leading edge, to the one or more flow channels formed at the pressure side, and then discharge the cooling fluid toward the region rearward of the trailing edge; and

a second cooling flow passage configured to divide the cooling fluid introduced from the lower portion of the suction side to the one or more flow channels formed at the suction side, merge the divided cooling fluid, and then discharge the cooling fluid toward the region rearward of the trailing edge.

16 . The gas turbine of claim 15 , wherein the first cooling flow passage comprises:

a first inlet extending downward from the lower portion of the pressure side at the leading edge and configured to receive the cooling fluid;

a 1-1 flow channel configured to guide the cooling fluid introduced into the first inlet toward an airfoil tip;

a 1-2 flow channel formed adjacent to the 1-1 flow channel and configured to guide the cooling fluid toward the root portion of the airfoil;

a 1-3 flow channel formed adjacent to the 1-2 flow channel and configured to guide the cooling fluid toward the airfoil tip;

a 1-1 turning channel extending toward the trailing edge from an upper end of the 1-1 flow channel; and

a 1-2 turning channel extending toward the trailing edge from a lower end of the 1-2 flow channel;

a 1-3 turning channel extending toward the trailing edge from an upper end of the 1-3 flow channel; and

a first discharge channel configured to discharge the cooling fluid flowing through the 1-3 flow channel to an outside of the airfoil, and

the second cooling flow passage comprises:

a 2-1 inlet and a 2-2 inlet extending downward from the lower portion of the suction side and configured to receive the cooling fluid;

a 2-1 flow channel and a 2-3 flow channel configured to respectively guide the cooling fluid introduced into the 2-1 inlet and the 2-2 inlet toward the airfoil tip;

a 2-2 flow channel and a 2-4 flow channel formed adjacent to the 2-1 flow channel and the 2-3 flow channel, respectively, and configured to guide the cooling fluid toward the root portion of the airfoil;

a 2-1 turning channel extending toward the trailing edge from an upper end of the 2-1 flow channel; and

a 2-2 turning channel extending toward the leading edge from an upper end of the 2-3 flow channel.

17 . The gas turbine of claim 16 , wherein a communication hole that is in communication with a central cavity is formed at a lower end of each of the 2-2 flow channel and the 2-4 flow channel, the central cavity being formed in an area defined by a cavity at the leading edge, cavities at the pressure side, and cavities at the suction side,

the cooling fluid flowing through the 2-2 flow channel and the 2-4 flow channel merges within the central cavity through the communication holes,

the second cooling flow passage further comprises a second discharge channel configured to discharge the cooling fluid in the central cavity to the outside of the airfoil, and

a connecting hole that is in communication with the second discharge channel is formed on a side at the trailing edge of the central cavity.