Gas turbine

A gas turbine comprising:

• a housing in which combustion gas flows;
• a rotor section rotatably installed in the housing;
• and
• a turbine blade configured to rotate the rotor section by receiving a rotational force from the combustion gas and to be cooled by a cooling fluid flowing in a cooling path, the turbine blade including
• a tip side provided with a plurality of tip cooling holes through which a portion of the cooling fluid in the cooling path is discharged from the turbine blade,
• an inclined surface (S1, S2) for facilitating formation of the plurality of tip cooling holes, and
• a squealer rib extending centrifugally from the tip side of the turbine blade, between an end surface of the turbine blade and a suction surface of the turbine blade,
• wherein the tip side of the turbine blade includes an inclined surface (S1) formed between the end surface of the turbine blade and the pressure surface of the turbine blade, such that the surface is inclined with respect to each of the end surface and the pressure surface,
• wherein the cooling path of the turbine blade includes a first inner wall formed opposite to an outer portion of the pressure surface of the turbine blade, a second inner wall formed opposite to an outer portion of the suction surface of the turbine blade to be parallel to the first inner wall, and a third inner wall that is substantially perpendicular to the first and second inner walls and connects the first and second walls at a radially outer end of the cooling path,
• wherein the plurality of tip cooling holes include:
• a first tip cooling hole formed in a pressure surface of the turbine blade to communicate with the first inner wall of the cooling path at a first communication point along the first inner wall, the first tip cooling hole extending through the turbine blade from the cooling path to the inclined surface (S1), and
• a second tip cooling hole formed in the squealer rib to communicate with the third inner wall of the cooling path at a second communication point along the second inner wall,
• wherein the first tip cooling hole forms an air curtain with a cooling fluid discharged from the first tip cooling hole, so that leakage gas flowing from the pressure surface of the turbine blade to the suction surface of the turbine blade through a tip gap between the tip side of the turbine blade and an inner circumferential surface of the housing can be reduced,
• wherein the second tip cooling hole forms an air curtain with a cooling fluid discharged from the second tip cooling hole, the second tip cooling hole having an outlet that faces the inner circumferential surface of the housing and is disposed downstream from an outlet of the first tip cooling hole so that leakage gas flowing from the pressure surface of the turbine blade to the suction surface of the turbine blade through the tip gap can be further reduced,
• wherein the first and third inner walls communicate with each other at a first perpendicular junction, the first perpendicular junction including a first surface portion of the first inner wall and a second surface portion of the third inner wall, the first surface portion including a flat surface extending from the first perpendicular junction to the first communication point, and
• wherein the second and third inner walls communicate with each other at a second perpendicular junction, the second perpendicular junction including a third surface portion of the second inner wall and a fourth surface portion of the third inner wall, the fourth surface portion including a flat surface extending from the second perpendicular junction to the second communication point.

A gas turbine comprising:

• a housing in which combustion gas flows;
• a rotor section rotatably installed in the housing;
• and
• a turbine blade configured to rotate the rotor section by receiving a rotational force from the combustion gas and to be cooled by a cooling fluid flowing in a cooling path, the turbine blade including a tip side provided with a plurality of tip cooling holes through which a portion of the cooling fluid in the cooling path is discharged from the turbine blade,
• wherein the cooling path of the turbine blade includes a first inner wall formed opposite to an outer portion of the pressure surface of the turbine blade, a second inner wall formed opposite to an outer portion of the suction surface of the turbine blade to be parallel to the first inner wall, and a third inner wall that is substantially perpendicular to the first and second inner walls and connects the first and second walls at a radially outer end of the cooling path,
• wherein the plurality of tip cooling holes include:
• a first tip cooling hole (514a) formed in a squealer rib to communicate with the first inner wall of the cooling path at a first communication point along the first inner wall, and
• a second tip cooling hole (514b) formed in a suction surface of the turbine blade to communicate with the third inner wall of the cooling path at a second communication point along the second inner wall;
• wherein the tip side of the turbine blade includes:
• the squealer rib (516) protruding centrifugally from the tip side of the turbine blade, between an end surface of the turbine blade and the suction surface of the turbine blade, and
• a first inclined surface (S1) formed between the end surface and the pressure surface, such that the first inclined surface is inclined with respect to each of the end surface and the pressure surface;
• wherein the squealer rib includes:
• an upper rib surface (516c) that is spaced apart from the end surface of the turbine blade,
• an outer rib surface (516b) that extends continuously relative to the suction surface of the turbine blade,
• an inner rib surface (516a) forming a back surface of the outer rib surface, and
• a second inclined surface (S2) inclined with respect to each of the end surface and the upper rib surface,
• wherein the first tip cooling hole forms an air curtain with a cooling fluid discharged from the first tip cooling hole, so that leakage gas flowing from the pressure surface of the turbine blade to the suction surface of the turbine blade through a tip gap between the tip side of the turbine blade and an inner circumferential surface of the housing can be reduced,
• wherein the second tip cooling hole forms an air curtain with a cooling fluid discharged from the second tip cooling hole, the second tip cooling hole having an outlet that faces the inner circumferential surface of the housing and is disposed downstream from an outlet of the first tip cooling hole so that leakage gas flowing from the pressure surface of the turbine blade to the suction surface of the turbine blade through the tip gap can be further reduced,
• wherein the first and third inner walls communicate with each other at a first perpendicular junction, the first perpendicular junction including a first surface portion of the first inner wall and a second surface portion of the third inner wall, the first surface portion including a flat surface extending from the first perpendicular junction to the first communication point, and
• wherein the second and third inner walls communicate with each other at a second perpendicular junction, the second perpendicular junction including a third surface portion of the second inner wall and a fourth surface portion of the third inner wall, the fourth surface portion including a flat surface extending from the second perpendicular junction to the second communication point.