Gas turbine airfoil trailing edge corner

1. A gas turbine airfoil comprising:

a pressure sidewall and a suction sidewall joined along respective leading and trailing edges and extending radially outward from a root to a tip;

a trailing edge corner defining an intersection of the trailing edge and the tip; the trailing edge corner comprising:

a metering hole receiving a cooling fluid flow from an interior fluid flow channel of the airfoil and discharging a metered flow;

a dispersion cavity receiving the metered flow and discharging a dispersed flow, the dispersion cavity having a cross sectional area greater than a cross sectionnal area of the metering hole, said dispersion cavity being defined by a pair of spaced apart ribs extending in a flow direction of the dispersed flow, by the suction sidewall spanning between the ribs on one side of the cavity, and by the pressure sidewall on an opposed side of the cavity;

an open flow channel receiving the dispersed flow and conducting the dispersed flow to a periphery of the airfoil, the open flow channel controlling mixing of the cooling fluid flow with a process gas flowing around an exterior of the airfoil.

2. The gas turbine airfoil of claim 1 , further comprising the open flow channel defined by the pair of spaced apart ribs extending from the dispersion cavity in a flow direction of the dispersed flow and by the suction sidewall spanning between the ribs on the one side of the flow channel.

3. The gas turbine airfoil of claim 1 , wherein the pair of ribs extend at an oblique angle away from a radial axis of the airfoil.

4. The gas turbine airfoil of claim 3 , wherein the oblique angle is between 30 and 60 degrees.

5. The gas turbine airfoil of claim 1 , wherein a ratio of the cross sectional area of the dispersion cavity and the cross sectional area of the metering hole is selected to produce a desired dispersion of the metered flow into the cavity.

6. The gas turbine airfoil of claim 5 , wherein the ratio is from two to five.

7. A gas turbine comprising the airfoil of claim 1 .

8. A method of cooling a trailing edge corner of a gas turbine airfoil comprising:

disposing a cooling fluid flow conduit between an interior of the airfoil and an exterior of the airfoil proximate the trailing edge corner;

providing a metering hole at an inlet of the conduit for receiving a cooling fluid flow;

expanding the cooling fluid flow from the metering hole into a first region of the conduit, the first region having a cross sectional area greater than a cross sectional area of the metering hole;

confining the cooling fluid flow in the first region by a pair of spaced apart ribs extending in a flow direction of the dispersed flow, by a suction sidewall spanning between the ribs on one side of the region, and by a pressure sidewall on an opposite side of the region;

directing the cooling fluid flow into an open channel in a second region of the conduit downstream of the first region to control mixing of the cooling fluid flow with a process gas flowing around the exterior of the airfoil.

9. The method of claim 8 , further comprising confining the fluid flow between the two spaced apart ribs extending from the first region and by the suction sidewall of the airfoil spanning between the ribs on one side of the open channel so that a surface of the flow opposite the suction sidewall is exposed to the process gas flowing around a pressure sidewall of the airfoil.

10. The method of claim 9 , further comprising selecting a rib geometry to achieve a rigidity of the trailing edge corner effective to control vibration of the trailing edge corner during turbine operation.

11. The method of claim 10 , wherein the rib geometry is selected from the group consisting of a cross-sectional area of the rib, a length of the rib, and a spacing between adjacent ribs.

12. The method of claim 8 , further comprising selecting a ratio of the cross sectional area of the first region and the cross sectional area of the metering hole to produce a desired dispersion of the cooling fluid flow into the first region.

13. The method of claim 12 , wherein the ratio is from two to five.

14. The method of claim 8 , further comprising orienting the conduit at an oblique angle to an axis of the airfoil.

15. The method of claim 14 , wherein the oblique angle is between 30 and 60 degrees.