Turbine airfoil with de-coupled platform

A turbine airfoil comprising:

• a root;
• an airfoil portion having a pressure side and a suction side;
• a platform extending from the airfoil portion;
• the root, the airfoil portion and the platform are a single piece;
• and,
• a thin slot formed in the airfoil between the platform and the airfoil portion, the thin slot reducing a stiffness between the platform and the airfoil to uncouple the platform from the airfoil portion to reduce stresses due to thermal gradients, the thin slot opening onto the platform surface and having a bottom that does not pass through the platform;
• and,
• the thin slot having a width of from about 0.25 mm to about 1 mm.

A turbine airfoil comprising:

• a root;
• an airfoil portion having a pressure side and a suction side;
• a platform extending from the airfoil portion;
• the root, the airfoil portion and the platform are a single piece;
• and,
• a thin slot formed in the airfoil between the platform and the airfoil portion, the thin slot reducing a stiffness between the platform and the airfoil to uncouple the platform from the airfoil portion to reduce stresses due to thermal gradients, the thin slot opening onto the platform surface and having a bottom that does not pass through the platform;
• and,
• the slot has a depth from about one to two times the thickness of the platform.

A turbine airfoil comprising:

• a root;
• an airfoil portion having a pressure side and a suction side;
• a platform extending from the airfoil portion;
• the root, the airfoil portion and the platform are a single piece;
• a thin slot formed in the airfoil between the platform and the airfoil portion, the thin slot reducing a stiffness between the platform and the airfoil to uncouple the platform from the airfoil portion to reduce stresses due to thermal gradients, the thin slot opening onto the platform surface and having a bottom that does not pass through the platform;
• a metering hole fluidly connecting the thin slot with a dead rim cavity formed below the platform for supplying a cooling fluid into the slot;
• and,
• an exit area of the slot is from about 3 to 5 times the size of the exit area of the metering hole.

A turbine airfoil comprising:

• a root;
• an airfoil portion having a pressure side and a suction side;
• a platform extending from the airfoil portion;
• the root, the airfoil portion and the platform are a single piece;
• and,
• a thin slot formed in the airfoil between the platform and the airfoil portion, the thin slot reducing a stiffness between the platform and the airfoil to uncouple the platform from the airfoil portion to reduce stresses due to thermal gradients, the thin slot opening onto the platform surface and having a bottom that does not pass through the platform;
• and,
• a row of separated thin slots extending along the platform from the leading edge to the trailing edge, each separated thin slot having a metering hole fluidly connecting the thin slot with a dead rim cavity formed below the platform for supplying a cooling fluid into the thin slot.

A turbine airfoil comprising:

• a root;
• an airfoil portion having a pressure side and a suction side;
• a platform extending from the airfoil portion;
• the root, the airfoil portion and the platform are a single piece;
• and,
• a thin slot formed in the airfoil between the platform and the airfoil portion, the thin slot reducing a stiffness between the platform and the airfoil to uncouple the platform from the airfoil portion to reduce stresses due to thermal gradients, the thin slot opening onto the platform surface and having a bottom that does not pass through the platform;
• the slot is a thin continuous slot that extends along the platform surface from the leading edge to the trailing edge;
• and,
• a plurality of metering holes fluidly connecting the thin continuous slot with a dead rim cavity formed below the platform for supplying a cooling fluid into the slot.