Heat transfer coefficients in a compressor case for improved tip clearance control system

1. A compressor case to blade tip clearance system comprising:

a rotor having blades with tips,

the case including an inner case comprising at least one surface feature fluidly coupled to a distribution manifold disposed in a cooling air passageway, said at least one surface feature configured to interact with the cooling air, and

a tip clearance located between the tips and the inner case; wherein said tip clearance is maintained responsive to a flow of the cooling air over said at least one surface feature;

a collection manifold fluidly coupled to the distribution manifold fluidly coupled to said inner case comprising the at least one surface feature;

a valve fluidly coupled between said collection manifold and said distribution manifold, said valve configured to control said flow of cooling air over said at least one surface feature;

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 case;

instrumentation and controls operatively coupled to the controller, wherein said instrumentation comprises sensors selected from the group consisting of temperature sensor, pressure sensor, flow rate sensor and altitude sensor.

2. The compressor case to blade tip clearance system according to claim 1 , wherein said air is directed to cool said inner case comprising the at least one surface feature and cause a contraction of the inner case and reduce the tip clearance.

3. A gas turbine engine compressor having a tip clearance control system comprising:

an inner case having a cooling air passageway configured to direct cooling air through said compressor;

at least one surface feature formed in a surface of a component in said inner case, said at least one surface feature configured to contact the cooling air;

at least one blade having a blade tip;

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

a collection manifold fluidly coupled to a distribution manifold fluidly coupled to the cooling air passageway of said inner case comprising the at least one surface feature, wherein said collection manifold and said distribution manifold are configured to direct the cooling air to said at least one surface feature to manage said tip clearance;

a valve fluidly coupled between said collection manifold and said distribution manifold, said valve configured to control the cooling air over said at least one surface feature;

a controller coupled to said valve, said controller configured to actuate said valve to control the cooling air flow velocity to change the tip clearance by changing the temperature of the at least one surface feature;

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; and

an insert coupled to said distribution manifold, said insert selected from the group consisting of a convergent passageway, a divergent passageway, a nozzle and a diffuser.

4. The gas turbine engine compressor according to claim 3 , wherein said at least one surface feature is configured to interrupt lamellar flow boundaries along a surface of the cooling air passageway and cause mixing of the cooling air.

5. The gas turbine engine compressor according to claim 3 , wherein said distribution manifold is selected from the group consisting of a nozzle and a diffuser.

6. A process for maintaining a tip clearance of a compressor by use of a tip clearance control system comprising:

configuring at least a portion of an inner case of the compressor with at least one surface feature;

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 at least one surface feature;

directing cooling air from said collection manifold to said distribution manifold to said at least one surface feature; fluidly coupling a valve between said collection manifold and said distribution manifold,

controlling said valve to control the cooling air directed to said at least one surface feature; and

utilizing said distribution manifold to at least one of increase the cooling air velocity or decrease the cooling air velocity proximate the at least one surface feature;

coupling a controller to said valve,

configuring said controller to actuate said valve to control the cooling air flow rate to change the tip clearance by changing the temperature of the casing proximate the at least one surface feature;

coupling instrumentation and controls to the controller;

configuring said instrumentation and controls to activate said controller responsive to gas turbine engine information;

sensing parameters and characteristics of the gas turbine engine with said instrumentation; and

changing the tip clearance responsive to heat transfer between said case proximate the at least one surface feature and said cooling air.

7. The process of claim 6 , wherein said air cools said at least one surface feature.

8. The process of claim 6 , further comprising:

installing an insert proximate said at least one surface feature;

modifying the velocity of the cooling air proximate the at least one surface feature with said insert configured as at least one of convergent flow area or divergent flow area.

9. The process of claim 6 , wherein 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.

10. The process of claim 6 , wherein said instrumentation comprises sensors selected from the group consisting of temperature sensor, pressure sensor, flow rate sensor and altitude sensor.

11. The process of claim 6 , wherein said controls include at least one of programs, signals, communications links, and engine operational data.

12. The process of claim 6 , further comprising:

operating said valve with said controller based on a predetermined schedule derived from engine operational data.

13. The compressor case to blade tip clearance system according to claim 1 , wherein said controller is configured to operate said valve based on a predetermined schedule derived from engine operational data.