REVERSE-FLOW CORE GAS TURBINE ENGINE WITH A PULSE DETONATION SYSTEM

• US 20150377125A1
• Filed: 01/29/2013
• Published: 12/31/2015
• Est. Priority Date: 01/29/2013
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Kupratis, Daniel B., Moon, Francis R
• Granted Patent: US 10,094,279 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02C 3/107 with two or more rotors connected by power transmission
• CPC Class Codes: F02C 3/14 characterised by the arrangement of the combustion chamber in the plant combustion chambers per se F23R; F02C3/205 takes precedence
• CPC Class Codes: F02C 5/02 characterised by the arrangement of the combustion chamber in the chamber in the plant combustion chambers per se F23R
• CPC Class Codes: F02C 7/06 Arrangements of bearings bearings F16C; Lubricating of turbo machines F01D25/18; of machines or engines in general F01M
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F02K 3/06 with front fan
• CPC Class Codes: F02K 3/11 by means of burners or combustion chambers
• CPC Class Codes: F05D 2250/31 according to the direction of their main axis or their axis of rotation
• CPC Class Codes: F05D 2250/311 the axes being in line
• CPC Class Codes: F05D 2260/16 Fluid modulation at a certain frequency
• CPC Class Codes: F23G 7/065 using gaseous or liquid fuel
• CPC Class Codes: F23R 7/00 Intermittent or explosive combustion chambers

Abstract

The engine (10) includes a low spool (16) disposed aft of an air inlet (12) and a high spool (34) disposed aft of the low spool (16). An intake reverse-duct (44) is disposed radially outward of the high spool (34) and reverses direction of low pressure compressed air from the low spool (16) into a forward-flow high pressure compressor (40) of the high spool (34). A discharge reverse-manifold (48) directs flow of an exhaust gas stream (50} from a forward-flow low pressure turbine (20) into a rearward-flow direction and into at least one pulse detonation firing tube (54). An annular bypass air duct (72) directs cooling air along the engine (10)—The at least, one firing tube is positioned radially outward of the high spool (34), overlies the high spool (34) and is also positioned within the bypass air duct (72).

Claims

1. A reverse-flow core gas turbine engine having an air inlet and an engine exhaust aft of the air inlet, the engine comprising:

a. a low spool disposed aft of the air inlet including a rearward-flow low pressure compressor, and a forward-flow low pressure turbine disposed aft of the rearward-flow low pressure compressor;

b. a high spool disposed aft of the low spool, the high spool including a forward-flow high pressure turbine disposed aft of the forward-flow low pressure turbine, a combustor disposed aft of the forward-flow high pressure turbine, and a forward-flow high pressure compressor disposed aft of the combustor;

c. an intake reverse-duct disposed radially outward of the high spool for directing output of the rearward-flow low pressure compressor to the forward-flow high pressure compressor so that the output reverses from rearward-flow to forward-flow to pass through the high spool;

d. a discharge reverse-manifold disposed forward of the high spool and radially outward of the intake reverse-duct for receiving an exhaust gas stream from the forward-flow low pressure turbine and for directing the exhaust gas stream from forward-flow to rearward-flow toward the engine exhaust;

e. a pulse detonation system including at least one pulse detonation firing tube secured in fluid communication With the reverse discharge-duct, the at least one pulse detonation firing tube positioned to be radially outward of and to overlie the high spool so that a portion of the pulse detonation firing tube intersects an axis that is perpendicular to an engine center line and which axis passes through the high spool; and

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f. the at least one pulse detonation firing tube being configured to mix the exhaust gas stream with fuel so that the mixed fuel and exhaust gas stream pulse detonates as the mixed fuel and exhaust gas stream pass through the firing tube toward the engine exhaust.

2. The reverse-flow core gas turbine engine of claim 1, further comprising a plurality of pulse detonation firing tubes, wherein each of the plurality of firing tubes is positioned about an equal distance from adjacent firing tubes, and wherein the plurality of firing tubes are positioned to surround the high spool of the engine.

3. The reverse-flow core gas turbine engine of claim 2 wherein the plurality of pulse detonation firing tubes includes between about eleven and about twenty-two firing tubes.

4. The reverse-flow core gas turbine engine of claim 1, wherein the engine further comprises an annular bypass duct surrounding and extending radially outward of the low spool, and the high spool that directs bypass air from the air inlet to the exhaust of the engine, and wherein the one or more pulse detonation firing tubes are positioned within the annular bypass duct and exposed to cooling air passing through the bypass duct.

5. The reverse-flow core gas turbine engine of claim 1, further comprising a plurality of pulse detonation firing tubes and wherein the plurality of firing tubes comprise constant volume combustor tubes.

6. The reverse-flow core gas turbine engine of claim 1, further comprising a plurality of groups of adjacent pulse detonation firing tubes, each of the plurality of groups of adjacent firing tubes being positioned so that each group is about an equal distance from a closest group of firing tubes, and the groups of adjacent pulse detonation firing tubes being positioned to surround the high spool of the engine.

7. A reverse-flow core gas turbine engine having an air inlet and an engine exhaust aft of the air inlet, the engine comprising:

a. a low spool disposed aft of the air inlet including a rearward-flow low pressure compressor, a forward-flow low pressure turbine disposed aft of the rearward-flow low pressure compressor and a low pressure shaft secured between the low pressure turbine and the low pressure compressor;

b. a high spool disposed aft of the low spool, the high spool including a forward-flow high pressure turbine disposed aft of the forward-flow low pressure turbine, a combustor disposed aft of the forward-flow high pressure turbine, a forward-flow high pressure compressor disposed aft of the combustor, and a high pressure shaft secured between the high pressure turbine and the high pressure compressor;

c. an intake reverse-duct disposed radially outward of the high spool for directing output of the rearward-flow low pressure compressor to the forward-flow high pressure compressor so that the output reverses from rearward-flow to forward-flow to pass through the high spool;

d. a discharge reverse-manifold disposed forward of the high spool and radially outward of the intake reverse-duct for receiving an exhaust gas stream from the forward-flow low pressure turbine and for directing the exhaust gas stream from forward-flow to rearward-flow toward the engine exhaust;

e. a pulse detonation system including at least one pulse detonation firing tube secured in fluid communication with the reverse discharge-duct, the at least one pulse detonation firing tube positioned to be radially outward of and to overlie the high spool so that a portion of the pulse detonation firing tube intersects an axis that is perpendicular to an engine center line and which axis passes through the high spool;

f. the at least one pulse detonation firing tube being configured to mix the exhaust gas stream with fuel so that the mixed fuel and exhaust gas stream pulse detonates as the mixed fuel and exhaust gas stream pass through the firing tube toward the engine exhaust; and

g. wherein flow through the engine extends sequentially through the rearward-flow low pressure compressor in a downstream direction, through the intake reverse-duct to the forward-flow high pressure compressor, the combustor, the forward-flow high pressure turbine and the forward-flow low pressure turbine in a forward direction, and through the discharge reverse-manifold to a rearward direction through the at least one pulse detonation firing tube.

8. The reverse-flow core gas turbine engine of claim 7, further comprising a plurality of pulse detonation firing tubes, wherein each of the plurality of firing tubes is positioned about an equal distance from adjacent firing tubes, and wherein the plurality of firing tubes are positioned to surround the high spool of the engine.

9. The reverse-flow core gas turbine engine of claim 8, wherein the engine further comprises an annular bypass duct surrounding and extending radially outward of the low spool and the high spool that directs bypass air from the air inlet to the exhaust of the engine, and wherein the one or more pulse detonation firing tubes are positioned within the annular bypass duct and exposed to cooling air passing through the bypass duct.

10. The reverse-flow core gas turbine engine of claim 7, wherein the one or more pulse detonation firing tubes comprise pulse detonation shock tubes.

11. A method of operating a reverse-flow gas turbine engine, the method comprising:

a. directing flow of inlet air through an air inlet of the engine;

b. then, compressing the air in a downstream direction through a rearward-flow low pressure compressor of a low spool of the engine;

c. then, directing flow of the compressed air through an intake reverse-duct, and then into a forward-flow high pressure compressor, then combusting the compressed air by directing the compressed air with fuel through a combustor, then directing a combusted gas stream from the combustor and through a forward-flow high pressure turbine of a high spool, and then through a forward-flow low pressure turbine in a forward direction;

c. then, directing the exhaust gas stream from the forward-flow low pressure turbine through a discharge reverse-manifold and then in a rearward direction through at least one pulse detonation firing tube overlying the high spool; and

,

d. mixing the exhaust gas stream with fuel within the at least one pulse detonation firing tube and pulse detonating the mixed fuel and exhaust gas stream at least one within the at least one pulse detonation firing tube.

12. A method of operating the reverse-flow gas turbine engine of claim 11, further comprising directing a flow of bypass air through a bypass duct and positioning the at least one pulse detonation firing tube within the bypass duct.

13. A method of operating the reverse-flow gas turbine engine of claim 11, further comprising directing the exhaust gas stream from the forward-flow low pressure turbine through a plurality of pulse detonation firing tubes positioned about an equal distance from adjacent firing tubes and positioned to surround the high spool of the engine.

14. A method of operating the reverse-flow gas turbine engine of claim 11, further comprising directing the exhaust gas stream from the forward-flow low pressure turbine through a plurality of groups of adjacent pulse detonation firing tubes positioned so that each group is about an equal distance from a closest group of firing tubes, and positioned to surround the high spool of the engine.

15. A method of operating the reverse-flow gas turbine engine of claim 11, wherein the step of directing the exhaust gas stream through at least one pulse detonation firing tube overlying the high spool further comprises generating shock waves within the at least one pulse detonation firing tube.