Turbine blade, and turbine and gas turbine including the same

A turbine comprising:

• a rotor disk configured to be rotatable;
• and
• a plurality of turbine blades installed on the rotor disk,
• wherein each of the turbine blade comprises an airfoil having a blade shape and including a suction side formed in a convex shape and a pressure side formed in a concave shape, a platform coupled to a lower portion of the airfoil, and a root member protruding downward from the platform and coupled to the rotor disk, and
• wherein the platform comprises:
• a plurality of inlets through which air is drawn into the platform;
• a plurality of outlets through which the air is discharged from the platform;
• and
• a cooling passage connecting the inlets to the outlets and including a plurality of dispersion spaces, a width in each dispersion spaces increasing from the inlet to the outlet, and a narrow space formed between the dispersion spaces and having a width less than a width of each dispersion spaces.

A gas turbine comprising:

• a compressor configured to compress air drawn thereinto from an outside;
• a combustor configured to mix fuel with air compressed by the compressor and combust a mixture of the fuel and the compressed air;
• and
• a turbine including a plurality of turbine blades configured to be rotated by combustion gas discharged from the combustor,
• wherein each of the turbine blade comprises an airfoil having a blade shape and including a suction side formed in a convex shape and a pressure side formed in a concave shape, a platform coupled to a lower portion of the airfoil, and a root member protruding downward from the platform and coupled to the rotor disk, and
• wherein the platform comprises:
• a plurality of inlets through which air is drawn into the platform;
• a plurality of outlets through which the air is discharged from the platform;
• and
• a cooling passage connecting the inlets to the outlets and including a plurality of dispersion spaces, a width in each dispersion spaces increasing from the inlet to the outlet, and a narrow space formed between the dispersion spaces and having a width less than a width of each dispersion spaces.