Negative thermal expansion compressor case for improved tip clearance

1. A compressor with negative coefficient of thermal expansion case material comprising:

a rotor having blades with tips,

the case including an inner case comprising a negative coefficient of thermal expansion material, wherein said negative coefficient of thermal expansion case material is configured as a case support ring configured to produce a symmetric response to the case, such that heating said ring contracts said case, and

a tip clearance located between the tips and the inner case; wherein said tip clearance is maintained responsive to a flow of air over said negative coefficient of thermal expansion material.

2. The compressor with negative coefficient of thermal expansion case material according to claim 1 , wherein said air is configured to warm said inner case comprising the negative coefficient of thermal expansion and cause a contraction of the inner case and reduce the tip clearance.

3. The compressor with negative coefficient of thermal expansion case material according to claim 1 further comprising:

a collection manifold fluidly coupled to a distribution manifold fluidly coupled to said inner case comprising the negative coefficient of thermal expansion.

4. The compressor with negative coefficient of thermal expansion case material according to claim 3 , further comprising:

a valve fluidly coupled between said collection manifold and said distribution manifold, said valve configured to control said flow of air over said negative coefficient of thermal expansion material.

5. The compressor with negative coefficient of thermal expansion case material according to claim 4 , further comprising:

a controller coupled to said valve, said controller configured to actuate said valve to control the air flow rate to change the tip clearance by changing the temperature of the negative coefficient of thermal expansion case material.

6. The compressor with negative coefficient of thermal expansion case material according to claim 1 , wherein said air is selected from the group consisting of compressor cooling air, combustor air and turbine air.

7. A gas turbine engine compressor having a tip clearance responsive to a negative coefficient of thermal expansion material comprising:

an inner case having a negative coefficient of thermal expansion material;

at least one blade having a blade tip;

the tip clearance located between said inner case and said blade tip; and

a collection manifold fluidly coupled to a distribution manifold fluidly coupled to said inner case comprising the negative coefficient of thermal expansion material, wherein said negative coefficient of thermal expansion material comprises a case support ring, wherein said collection manifold and said distribution manifold are configured to direct air to said negative coefficient of thermal expansion material and change said tip clearance such that heating said case support ring contracts said inner case.

8. The gas turbine engine compressor according to claim 7 , further comprising:

a valve fluidly coupled between said collection manifold and said distribution manifold, said valve configured to control a flow of air over said negative coefficient of thermal expansion material.

9. The gas turbine engine compressor according to claim 8 , further comprising:

a controller coupled to said valve, said controller configured to actuate said valve to control the air flow rate to change the tip clearance by changing the temperature of the negative coefficient of thermal expansion material.

10. The gas turbine engine compressor according to claim 9 , further comprising:

instrumentation and controls coupled to the controller, said instrumentation and controls configured to activate said controller responsive to gas turbine engine information, said gas turbine engine information comprises real time information from the gas turbine engine, said real time information selected from the group consisting of temperature, dimensions and operational mode.

11. The gas turbine engine compressor according to claim 7 , wherein said air is selected from the group consisting of compressor cooling air, combustor air and turbine air.

12. A process for maintaining a tip clearance of a compressor by use of a negative coefficient of thermal expansion material comprising:

configuring at least a portion of an inner case of the compressor with the negative coefficient of thermal expansion material;

at least one compressor blade having a blade tip;

the tip clearance located between said inner case and said blade tip;

fluidly coupling a collection manifold to a distribution manifold within the compressor;

fluidly coupling said distribution manifold to said inner case comprising the negative coefficient of thermal expansion material, wherein said negative coefficient of thermal expansion material comprises a case support ring;

directing air from said collection manifold to said distribution manifold to said negative coefficient of thermal expansion material, wherein said air heats said case support ring to contract said inner case; and

changing the tip clearance responsive to heat transfer between said negative coefficient of thermal expansion material and said air.

13. The process of claim 12 , further comprising:

fluidly coupling a valve between said collection manifold and said distribution manifold, and

controlling said valve to control the air directed to said negative coefficient of thermal expansion material.

14. The process of claim 13 , further comprising:

coupling a controller to said valve,

configuring said controller to actuate said valve to control the air flow rate to change the tip clearance by changing the temperature of the negative coefficient of thermal expansion material.

15. The process of claim 14 , further comprising:

coupling instrumentation and controls to the controller;

configuring said instrumentation and controls to activate said controller responsive to gas turbine engine information, said gas turbine engine information comprises real time information from the gas turbine engine, said real time information selected from the group consisting of temperature, dimensions and operational mode.

16. The process of claim 12 , wherein said air is selected from the group consisting of compressor cooling air, combustor air and turbine air.