Blade with improved cooling performance and gas turbine having the same

A blade, comprising:

• a body part;
• an injection hole comprising a communication part connected to an internal flow passage formed inside the body part;
• and an extension connecting the communication part and a surface of the blade to each other and having a width gradually increasing from the communication part to the surface of the blade and configured to inject a cooling fluid to the surface of the blade;
• an injection guide means disposed in the extension and configured to uniformly inject the cooling fluid in an expanding manner so as to form a cooling film on the surface of the blade, and
• a center line passing through a central axis of the injection hole;
• wherein the injection guide means comprises:
• a first partition wall extending along the center line from an inside of the extension to the surface of the blade and comprising two sides, each facing an inner wall of the extension;
• and
• a second partition wall on each of the two sides of the first partition and forming a pair, each extending from the inside of the extension to the surface of the blade and disposed between the first partition wall and the inner wall of the extension,
• wherein a first distance is defined as a distance from the first partition wall to the second partition wall, and a second distance is defined as a distance from the second partition wall to the inner extension wall, both measured at the surface of the blade,
• wherein the first distance is smaller than the second distance.