Turbofan with gear-driven compressor and fan-driven core

Patent metadata

Field	Value
Publication number	US-9003808-B2
Application number	US-201113287446-A
Country	US
Kind code	B2
Filing date	Nov 2, 2011
Priority date	Nov 2, 2011
Publication date	Apr 14, 2015
Grant date	Apr 14, 2015

Abstract

A gas turbine engine comprises an outer engine case, a combustor, a high pressure spool and a low pressure spool. The combustor is disposed within the outer engine case. The high pressure spool is configured for rotation coaxially with the combustor. The low pressure spool is configured for rotation coaxially with the high pressure spool. The low pressure spool is configured to rotate at speeds faster than that of the high pressure spool during operation of the gas turbine engine. In one embodiment, the low pressure spool includes a gear system configured to rotate a low pressure compressor faster than a low pressure turbine. In another embodiment, the high pressure spool rotates outward of the combustor within the outer engine case. In another embodiment, the high pressure spool includes a drum having radially inward projecting blades and vanes and radially outward projecting fan blades.

First claim

The invention claimed is:

1. A gas turbine engine comprising:
an outer engine case;
an inner engine case coupled to the outer case radially inward of the outer engine case;
a combustor disposed between the outer engine case and the inner engine case;
a high pressure spool having an annular drum configured for rotation within the outer engine case; wherein the annular drum has an axially-extending portion configured for rotation outward of the combustor; and
a low pressure spool having a drive shaft configured for rotation inward of the inner engine case.

2. The gas turbine engine of claim 1 wherein the drive shaft rotates at speeds faster than that of the annular drum during operation of the gas turbine engine.

3. The gas turbine engine of claim 2 wherein the low pressure spool comprises:
a low pressure turbine blade array extending from the drive shaft;
a low pressure compressor blade array extending from a stub shaft; and
a gear system coupling the drive shaft to the stub shaft and configured so that the stub shaft rotates at speeds faster than that of the drive shaft during operation of the gas turbine engine.

4. The gas turbine engine of claim 1 wherein the high pressure spool further comprises:
a plurality of compressor blades extending radially inward from a rotor and disposed upstream of the combustor, wherein the rotor is disposed radially inward from the axially-extending portion of the annular drum; and
a plurality of turbine blades extending radially inward from the annular drum downstream of the combustor, wherein the annular drum extends axially between the outer engine case and the inner engine case.

5. The gas turbine engine of claim 4 wherein the high pressure spool further comprises:
a fan stage driven by the high pressure spool between the outer engine case and the inner engine case, the fan stage comprising a plurality of fan blades extending radially outwardly from the annular drum.

6. The gas turbine engine of claim 5 and further comprising:
a plurality of compressor vanes extending radially outward from the inner engine case to engage the plurality of compressor blades and form a high pressure compressor;
a plurality of turbine vanes extending radially outward from the inner engine case to engage the plurality of turbine blades and form a high pressure turbine; and
a plurality of fan vanes extending radially inward from the outer engine case to engage the plurality of fan blades.

7. The gas turbine engine of claim 4 wherein the inner engine case comprises:
a forward duct;
an aft duct;
a support strut connecting the forward duct to the aft duct so that the aft duct is radially inward of the forward duct;
a forward strut connecting the forward duct to the outer engine case;
an aft strut connecting the aft duct to the outer engine case;
a plurality of low pressure compressor vanes extending radially inward from the forward duct;
a plurality of high pressure compressor vanes extending radially outward from the aft duct;
a plurality of high pressure turbine vanes extending radially outward from the aft duct;
a first bearing coupled to the forward duct; and
a second bearing coupled to the aft duct;
wherein the high pressure spool is disposed axially between the forward strut and the aft strut on the first and second bearings.

8. The gas turbine engine of claim 7 wherein the inner engine case further comprises:
an elbow joining the forward duct to the first bearing and the forward strut;
an inlet guide vane extending radially inward from the forward duct; and
a nose extending from the inlet guide vane.

9. The gas turbine engine of claim 1 wherein the low pressure spool further comprises:
a gear system coupled to the drive shaft, wherein the drive shaft extends axially within the inner engine case;
a stub shaft coupled to the gear system;
a plurality of turbine blades extending radially outward from the drive shaft downstream of the combustor; and
a plurality of compressor blades extending radially outward from the stub shaft upstream of the combustor.

10. The gas turbine engine of claim 9 and further comprising:
a plurality of turbine vanes extending radially inward from the outer engine case to engage the plurality of turbine blades and form a low pressure turbine; and
a plurality of compressor vanes extending radially inward from the inner engine case to engage the plurality of compressor blades and to form a low pressure compressor.

11. The gas turbine engine of claim 9 wherein:
the gear system comprises a planetary gear system that increases a rotational speed of the plurality of compressor blades over a rotational speed of the plurality of turbine blades.

12. The gas turbine engine of claim 9 wherein the outer engine case comprises:
an annular outer duct extending from an upstream end to a downstream end;
a plurality of vanes extending radially inward from the annular outer duct;
first and second struts extending radially inward from the annular outer duct downstream of the plurality of vanes;
an annular inner duct coupled to the annular outer duct via the first and second struts to form a bypass duct;
a plurality of vanes extending radially inward from the annular inner duct;
an aft strut extending radially inward from the annular outer duct;
an aft bearing coupled to the aft strut;
a forward strut extending radially inward form the annular outer duct; and
a forward bearing coupled to the forward strut;
wherein the aft bearing and the forward bearing support the low pressure spool within the inner engine case.

13. The gas turbine engine of claim 1 and wherein the high pressure spool further comprises:
a high pressure turbine blade array;
a high pressure compressor blade array, wherein the annular drum connects the high pressure turbine blade array and the high pressure compressor blade array; and
a fan stage extending from the annular drum.

14. The gas turbine engine of claim 1 wherein the low pressure spool further comprises:
a low pressure turbine blade array;
a low pressure compressor blade array;
a stub shaft extending from the low pressure compressor blade array; and
a planetary gear system coupling the drive shaft to the stub shaft.

15. A turbofan engine comprising:
a combustor for producing gas;
a high pressure turbine configured to be rotationally driven by the gas;
a high pressure compressor;
a high spool shaft coupling the high pressure turbine to the high pressure compressor;
a low pressure turbine configured to be rotationally driven by the gas leaving the high pressure turbine;
a low spool shaft coupled to the low pressure turbine;
a low pressure compressor;
a gear system coupling the low pressure compressor to the low spool shaft; and
a fan stage driven by the high spool shaft.

16. The turbofan engine of claim 15 wherein the gear system comprises:
a ring gear anchored to a non-rotating component of the turbofan engine;
a gear carrier configured to be driven by the low pressure turbine;
a plurality of planet gears mounted to the gear carrier; and
a sun gear disposed within the plurality of planet gears so as to drive the low pressure compressor at a speed higher than that of the high pressure turbine.

17. The turbofan engine of claim 15 wherein the high spool shaft comprises:
an annular drum comprising a forward end and an aft end; and
a cone section extending from the forward end of the annular drum;
a plurality of fan blades extending radially outward from the cone section;
a compressor disk extending radia

Assignees

• Kupratis Daniel B
• United Technologies Corp

Inventors

• Kupratis Daniel B

Classifications

• Y02T50/671

  Cross-Sectional Technologies · mapped topic

• F02K3/077

  the plant being of the multiple flow type, i.e. having three or more flows · CPC title

• F02K3/04 Primary

  the plant including ducted fans, i.e. fans with high volume, low pressure outputs, for augmenting the jet thrust, e.g. of double-flow type · CPC title

• F02K3/06

  with front fan · CPC title

• F02C3/107

  with two or more rotors connected by power transmission · CPC title