Intercooled cooling air heat exchanger arrangement

1. A method of providing cooling air to a gas turbine engine, the method comprising:

cooling a bleed air flow in a first cooling stage to produce a cooled bleed air flow, the bleed air flow provided from a bleed port of a compressor of a compressor section of the gas turbine engine;

passing the cooled bleed air flow from the first cooling stage to a pump;

increasing a pressure of the cooled bleed air flow in the pump to produce a pressurized cooled bleed air flow;

receiving the pressurized cooled bleed air flow from the pump in a second cooling stage;

cooling the pressurized cooled bleed air flow in the second cooling stage to produce an intercooled cooling air, wherein the first cooling stage and the second cooling stage are arranged with one another to define a series relationship;

mixing the intercooled cooling air from the second cooling stage with another source of bleed air to provide the cooling air; and

providing the cooling air to a port located downstream of a combustor section of the gas turbine engine and located at an intake of a turbine section of the gas turbine engine, wherein a first duct wall is configured to isolate a main bypass stream from a secondary bypass stream between a compressor section and a turbine section of the gas turbine engine, and a second duct wall is configured to isolate the secondary bypass stream from a third bypass stream between the compressor section and the turbine section of the gas turbine engine, wherein the third bypass stream is defined between the second duct wall and a casing of the gas turbine engine, the first and second duct walls extend from the compressor section to the turbine section, and the first cooling stage and the second cooling stage are in fluid communication with an air stream of the secondary bypass stream to perform the cooling.

2. An assembly for a gas turbine engine, the assembly comprising:

a casing;

a compressor section comprising a compressor;

a turbine section;

a first duct wall configured to isolate a main bypass stream from a secondary bypass stream between the compressor section and the turbine section;

a second duct wall configured to isolate the secondary bypass stream from a third bypass stream between the compressor section and the turbine section, wherein the third bypass stream is defined between the second duct wall and the casing, and the first and second duct walls extend from the compressor section to the turbine section;

a plurality of cooling stages in fluid communication with an air stream of the secondary bypass stream utilized by the plurality of cooling stages for cooling,

wherein a first cooling stage of the plurality of cooling stages is fluidly coupled to a bleed port of the compressor to receive bleed air and cool the bleed air with the air stream to produce a cool bleed air; and

a pump fluidly coupled to the first cooling stage to receive the cool bleed air and increase a pressure of the cool bleed air to produce a pressurized cool bleed air,

wherein a second cooling stage of the plurality of cooling stages is fluidly coupled to the pump to receive the pressurized cool bleed air and cool the pressurized cool bleed air to produce an intercooled cooling air, the first cooling stage and the second cooling stage being arranged with one another in a series relationship, and

wherein the second cooling stage provides the intercooled cooling air to a port located at an intake of the turbine section.

3. The assembly of claim 2 , wherein the bleed port comprises a port at a low pressure location of the compressor.

4. The assembly of claim 2 , wherein the bleed port comprises a port at a mid-pressure location of the compressor.

5. The assembly of claim 2 , wherein the cooling by the first cooling stage offsets the pressurizing by the pump.

6. The assembly of claim 2 , wherein the pressurized cool bleed air has a pressure greater than a pressure of the cool bleed air.

7. The assembly of claim 2 , wherein the intercooled cooling air produced by the second cooling stage is mixed with a second bleed air sourced from a second bleed port of the compressor.

8. The assembly of claim 7 , wherein the second bleed port comprises a port at a high pressure location of the compressor.

9. The assembly of claim 7 , wherein the intercooled cooling air and the second bleed air are mixed upstream of the turbine section.

10. The assembly of claim 2 , wherein the plurality of cooling stages is upstream of the combustor section.

11. The assembly of claim 2 , wherein the plurality of cooling stages is aligned on the second duct wall.

12. The assembly of claim 2 , wherein the pump is configured to be powered by a gearbox utilizing a second bleed air from the compressor.

13. The assembly of claim 2 , wherein the first cooling stage and the second cooling stage of the plurality of cooling stages are in a cross stream configuration such that the first cooling stage and the second cooling stage are both within the secondary bypass stream and the third bypass stream of the gas turbine engine to permit a combination of the secondary bypass stream and the third bypass stream to act as a heat sink for the bleed air from the bleed port.

14. A gas turbine engine, comprising:

a compressor section;

a combustor section;

a turbine section; and

an intercooled cooling system comprising:

a first duct wall configured to isolate a main bypass stream from a secondary bypass stream between the compressor section and the turbine section of the gas turbine engine;

a second duct wall configured to isolate the secondary bypass stream from a third bypass stream between the compressor section and the turbine section of the gas turbine engine, wherein the third bypass stream is defined between the second duct wall and a casing of the gas turbine engine, and the first and second duct walls extend from the compressor section to the turbine section;

a plurality of cooling stages in fluid communication with an air stream of the secondary bypass stream utilized by the plurality of cooling stages for cooling,

wherein a first cooling stage of the plurality of cooling stages is fluidly coupled to a bleed port of a compressor of the compressor section to receive bleed air and cool the bleed air with the air stream to produce a cool bleed air; and

a pump fluidly coupled to the first cooling stage to receive the cool bleed air and increase a pressure of the cool bleed air to produce a pressurized cool bleed air,

wherein a second cooling stage of the plurality of cooling stages is fluidly coupled to the pump to receive the pressurized cool bleed air and cool the pressurized cool bleed air to produce an intercooled cooling air,

wherein the second cooling stage provides the intercooled cooling air to a port located downstream of the combustor section and located at an intake of the turbine section and wherein the first cooling stage and the second cooling stage are arranged with one another to define a series relationship.

15. The gas turbine engine of claim 14 , wherein the pump is configured to be powered by a gearbox utilizing a second bleed air from the compressor.

16. The gas turbine engine of claim 14 , wherein the first cooling stage and the second cooling stage of the plurality of cooling stages are in a cross stream configuration such that the first cooling stage and the second cooling stage are both within the secondary bypass stream and the third bypass stream of the gas turbine engine to permit a combination of the secondary bypass stream and the third bypass stream to act as a heat sink for the bleed air from the bleed port.