Air regulation for film cooling and emission control of combustion gas structure

1. A gas turbine engine compressed air flow control arrangement, comprising:

a combustion gas structure comprising an acceleration geometry configured to receive combustion gas from a can combustor and accelerate the combustion gas to a speed appropriate for delivery onto a first row of turbine blades, the combustion gas structure defining a straight combustion flow path and disposed in a plenum that receives compressed air from a compressor;

a film cooling hole disposed through the combustion gas structure at a location within or downstream of the acceleration geometry;

a sleeve surrounding at least a portion of the combustion gas structure comprising the film cooling hole and defining a volume between the combustion gas structure and the sleeve; and

an adjustable flow control system comprising a valve disposed in a cooling air flow path between the plenum and the volume, the valve configured to adjust a flow volume through the cooling air flow path.

2. The arrangement of claim 1 , wherein the adjustable flow control system comprises a butterfly valve configured to adjust the flow volume.

3. The arrangement of claim 1 , comprising an impingement structure within the volume configured to provide an impingement cooling flow onto the combustion gas structure.

4. The arrangement of claim 1 , wherein any compressed air entering the volume enters through the flow control system, and the volume is otherwise sealed.

5. The arrangement of claim 1 , wherein flow control system comprises a fail-safe configured to always allow a minimum flow of compressed air.

6. The arrangement of claim 1 , wherein a film generated by the film cooling covers an entire circumference of a hot surface adjacent the combustion gas.

7. A gas turbine engine compressed air flow control arrangement, comprising:

a sleeve configured to separate compressed air in a plenum from a structure configured to guide combustion gas in a combustion flow path from a combustor to a first row of turbine blades, wherein the sleeve and combustion gas structure define a volume there between; and

an adjustable flow regulation system configured to adjust a cooling air flow path between the plenum and the volume;

wherein the combustion gas structure is configured to receive the combustion gas from a can combustor and comprises a plurality of film cooling holes effective to provide symmetric film cooling of a hot surface of the combustion gas structure using a flow of compressed air flowing through the adjustable flow regulation system,

wherein the adjustable flow regulation system comprises at least a first position wherein a flow volume of compressed air through the cooling air flow path is sufficient to cool the combustion gas structure, and at least a second position that provides a greater flow volume further effective to reduce emissions.

8. The arrangement of claim 7 , further comprising an impingement structure disposed in the volume and comprising an impingement hole configured to provide impingement cooling to a cool surface of the combustion gas structure.

9. The arrangement of claim 7 , further comprising a sensor configured to provide information regarding a temperature of the combustion gas structure.

10. The arrangement of claim 7 , wherein the combustion gas structure comprises an acceleration geometry configured to accelerate the combustion gas to a speed appropriate for delivery onto a first row of turbine blades, and wherein the film cooling hole is disposed within or downstream of the acceleration geometry.

11. The arrangement of claim 7 , wherein the flow regulation system is unable to completely prevent flow there through.

12. The arrangement of claim 7 , further comprising a controller system configured to control the flow regulation system to adjust a flow of bypass compressed air, effective to control formation of NOx and/or CO.

13. The arrangement of claim 7 , wherein all compressed air entering the volume enters through the flow regulation system.

14. The arrangement of claim 7 , wherein the volume is otherwise sealed.

15. A gas turbine engine comprising the arrangement of claim 7 .

16. A gas turbine engine compressed air flow control arrangement, comprising:

a combustion gas structure defining a combustion gas flow path, the combustion gas structure comprising an acceleration geometry configured to receive combustion gas from a can combustor and accelerate the combustion gas to a speed appropriate for delivery onto a first row of turbine blades;

a sleeve configured to separate compressed air in a plenum from the combustion gas structure, wherein the sleeve and the combustion gas structure define a volume there between;

a cooling air flow path between the plenum and the volume, the cooling air flow path comprising an adjustable flow regulation system configured to adjust the flow volume, wherein the adjustable flow regulation system comprises at least a first position wherein the cooling air flow path provides a flow volume of compressed air sufficient to cool the combustion gas structure, and at least a second position that provides a greater flow volume further effective to reduce emissions; and

further comprising an impingement structure disposed in the volume and configured to provide impingement cooling to a cool surface of the combustion gas structure.

17. The arrangement of claim 16 , wherein in the first position the adjustable flow regulation system provides a pressure drop in the compressed air from a first pressure in the plenum to a second pressure, wherein the cool surface is characterized by a plurality of pockets and a plurality of impingement holes for each pocket.