Gas turbine engine

1 . A gas turbine engine comprising:

a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the compressor section having a high pressure compressor defining a high pressure compressor exit area (A HPCExit ) in square inches and the turbine section having a drive turbine defining a drive turbine exit area (A DTExit ) in square inches, the turbomachine further comprising a drive turbine shaft coupled to the drive turbine;

wherein the gas turbine engine defines a maximum exhaust gas temperature (EGT) in degrees Celsius, a maximum drive turbine shaft torque (T OUT ) in Newton meters, and a corrected specific power (CSP) in Newtons squared times degrees Celsius over meters squared, wherein the corrected specific power is determined as follows:

(

T

OUT

A

DTExit

)

2

*

EGT

A

HPCExit

*

1

⁢

0

-

1

⁢

1

;

wherein CSP is greater than 0.0001194×EGT 2 −0.103×EGT+22.14 and less than 0.0003294×EGT 2 −0.306×EGT+77.91;

wherein EGT is greater than 525 degrees Celsius and less than 1250 degrees Celsius; and

wherein the compressor section comprises a centrifugal compressor stage having an impeller and a deswirler assembly.

2 . The gas turbine engine of claim 1 , further including a service tube, and wherein the deswirler assembly includes:

an outer portion with an inner wall and an outer wall defining a portion of an air flowpath; and

a deswirler vane disposed in the air flowpath and extending between the inner and outer walls, wherein the service tube extends through the deswirler vane.

3 . The gas turbine engine of claim 2 , further including:

a bearing to rotatably support the drive turbine shaft; and

a sump housing surrounding at least a portion of the drive turbine shaft and the bearing and defining a sump with oil, wherein the service tube fluidly couples the sump to an exterior of the gas turbine engine.

4 . The gas turbine engine of claim 2 , wherein the service tube is one of a plurality of service tubes, wherein the desirler vane is part of a second set of deswirler vanes of the deswirler assembly, and wherein the deswirler assembly further includes a first set of deswirler vanes, the second set of deswirler vanes being thicker than the first set of deswirler vanes, and each deswirler vane of the second set of deswirler vanes having a hollow interior to accommodate a respective service tube of the plurality of service tubes.

5 . The gas turbine engine of claim 4 , wherein one of the second set of deswirler vanes is disposed between two of the first set of deswirler vanes.

6 . The gas turbine engine of claim 2 , wherein the deswirler vane is airfoil shaped.

7 . The gas turbine engine of claim 2 , further including a heat shield disposed around at least a portion of the service tube.

8 . The gas turbine engine of claim 7 , wherein the heat shield is separated from the service tube by an air gap.

9 . A gas turbine engine comprising:

a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the compressor section having a high pressure compressor defining a high pressure compressor exit area (A HPCExit ) in square inches and the turbine section having a drive turbine defining a drive turbine exit area (A DTExit ) in square inches, the turbomachine further comprising a drive turbine shaft coupled to the drive turbine and defining an overall pressure ratio greater than 14:1 and less than or equal to 22:1;

wherein the gas turbine engine defines a maximum exhaust gas temperature (EGT) greater than 600 degrees Celsius and less than 1000 degrees Celsius, an output power of at least 550 horsepower and up to 2,000 horsepower when operated at a rated speed, a maximum drive turbine shaft torque (T OUT ) in Newton meters, and a corrected specific power (CSP) in Newtons squared times degrees Celsius over meters squared, wherein CSP is greater than 3.3 and less than 101 and is determined as follows:

(

T

OUT

A

DTExit

)

2

*

EGT

A

HPCExit

*

1

⁢

0

-

1

⁢

1

;

and

wherein the compressor section comprises a centrifugal compressor stage having an impeller and a deswirler assembly.

10 . The gas turbine engine of claim 9 , further including a service tube, and wherein the deswirler assembly includes:

an outer portion with an inner wall and an outer wall defining a portion of an air flowpath; and

a deswirler vane disposed in the air flowpath and extending between the inner and outer walls, wherein the service tube extends through the deswirler vane.

11 . The gas turbine engine of claim 10 , further including:

a bearing to rotatably support the drive turbine shaft; and

a sump housing surrounding at least a portion of the drive turbine shaft and the bearing and defining a sump with oil, wherein the service tube fluidly couples the sump to an exterior of the gas turbine engine.

12 . The gas turbine engine of claim 10 , wherein the service tube is one of a plurality of service tubes, wherein the desirler vane is part of a second set of deswirler vanes of the deswirler assembly, and wherein the deswirler assembly further includes a first set of deswirler vanes, the second set of deswirler vanes being thicker than the first set of deswirler vanes, and each deswirler vane of the second set of deswirler vanes having a hollow interior to accommodate a respective service tube of the plurality of service tubes.

13 . The gas turbine engine of claim 12 , wherein one of the second set of deswirler vanes is disposed between two of the first set of deswirler vanes.

14 . The gas turbine engine of claim 10 , wherein the deswirler vane is airfoil shaped.

15 . The gas turbine engine of claim 10 , further including a heat shield disposed around at least a portion of the service tube.

16 . The gas turbine engine of claim 15 , wherein the heat shield is separated from the service tube by an air gap.

17 . A method of operating a gas turbine engine, comprising:

operating the gas turbine engine at a takeoff power level, wherein operating the gas turbine engine at the takeoff power level comprises driving a propeller of a propeller assembly across a propeller shaft of the propeller assembly, the gas turbine engine further comprising a turbomachine with a high pressure compressor defining a high pressure compressor exit area (A HPCExit ) in square inches and a drive turbine defining a drive turbine exit area (A DTExit ) in square inches, the gas turbine engine defining a maximum exhaust gas temperature (EGT) in degrees Celsius, a maximum drive turbine shaft torque (T OUT ) in Newton meters, and a corrected specific power in Newtons squared times degrees Celsius over meters squared;

wherein the corrected specific power (CSP) is determined as follows:

(

T

OUT

A

DTExit

)

2

*

EGT

A

HPCExit

*

1

⁢

0

-

1

⁢

1

;

wherein CSP is greater than 0.0001194×EGT 2 −0.103×EGT+22.14 and less than 0.0003294×EGT 2 −0.306×EGT+77.91;

wherein EGT is greater than 525 degrees Celsius and less than 1250 degrees Celsius; and

wherein the gas turbine engine comprises a centrifugal compressor stage having an impeller and a deswirler assembly.

18 . The method of claim 17 , wherein the gas turbine engine includes a service tube, and wherein the deswirler assembly includes:

an outer portion with an inner wall and an outer wall defining a portion of an air flowpath; and

a deswirler vane disposed in the air flowpath and extending between the inner and outer walls, wherein the service tube extends through the deswirler vane.

19 . The method of claim 18 , wherein the gas turbine engine includes:

a bearing to rotatably support the drive turbine shaft; and

a sump housing surrounding at least a portion of the drive turbine shaft and the bearing and defining a sump with oil, wherein the service tube fluidly couples the sump to an exterior of the gas turbine engine.

20 . The method of claim 18 , wherein the gas turbine engine includes a heat shield disposed around at least a portion of the service tube.