Gas turbine engine and turbine arrangement

Patent metadata

Field	Value
Publication number	US-2019309681-A1
Application number	US-201916352014-A
Country	US
Kind code	A1
Filing date	Mar 13, 2019
Priority date	Apr 9, 2018
Publication date	Oct 10, 2019
Grant date	—

Abstract

A turbine arrangement for gas turbine engine, the arrangement comprising a high pressure turbine mounted on a high pressure shaft and a low pressure turbine mounted on a low pressure shaft, wherein the high pressure turbine comprises a single stage turbine rotor configured to rotate in a first direction, and wherein the low pressure turbine comprises three or more rotors (19a, b, c) configured to rotate in a second direction opposite to the first direction. The low pressure turbine is closely coupled to the high pressure turbine with no stator vanes provided between the two.

First claim

1 . A turbine arrangement for a gas turbine engine, the arrangement comprising a high pressure turbine mounted on a high pressure shaft and a low pressure turbine mounted on a low pressure shaft, wherein the high pressure turbine comprises a single stage turbine rotor configured to rotate in a first direction, and wherein the low pressure turbine comprises three or more rotors configured to rotate in a second direction opposite to the first direction.

2 . A turbine arrangement according to claim 1 wherein a space extends between the low pressure turbine and the high pressure turbine, the space being statorless.

3 . A turbine arrangement or a geared turbine engine according to claim 2 wherein the low pressure turbine has first, second and third rotor stages, and wherein the first rotor stage is positioned upstream of the second and third rotor stages, the first rotor stage being mounted to the low pressure shaft by a first drive arm.

4 . A turbine arrangement according to claim 3 wherein the first drive arm circumferentially surrounds a downstream end of the high pressure shaft.

5 . A turbine arrangement according to claim 4 , wherein the first drive arm defines an annular space into which projects the rear end of the high pressure shaft.

6 . A turbine arrangement according to claim 5 , wherein a bearing is provided between the rear end of the high pressure shaft and the first drive arm.

7 . A turbine arrangement according to claim 3 wherein the second and third rotor stages of the low pressure turbine are mounted to the low pressure shaft by one or more further drive arms independent of the first drive arm.

8 . A turbine arrangement according to claim 3 wherein the first and second rotor stages of the low pressure turbine are mounted on a first drive arm and the third and subsequent rotor stages of the low pressure turbine are mounted on a second drive arm.

9 . A turbine arrangement according to claim 8 wherein a single bearing is positioned axially adjacent the second rotor stage of the low pressure turbine.

10 . A turbine arrangement according to claim 2 wherein the low pressure shaft is carried by two bearings comprising an upstream bearing and a downstream bearing; wherein the upstream bearing is axially adjacent the second low pressure turbine rotor stage; and wherein the downstream bearing is axially adjacent the third low pressure turbine rotor stage.

11 . A turbine arrangement according to claim 2 wherein the high pressure turbine is configured to have an exit flow angle in the range from 20 to 50 degrees, or from 30-40 degrees.

12 . A geared turbine engine comprising a power gearbox, a high pressure turbine mounted on a high pressure shaft and a low pressure turbine mounted on a low pressure shaft, wherein the high pressure turbine comprises a single stage turbine rotor configured to rotate in a first direction, and the low pressure turbine is configured to rotate in a second direction opposite to the first direction.

13 . A geared turbine engine according to claim 12 wherein the low pressure shaft is arranged to input power to the power gearbox and the power gearbox drives a propulsion fan.

14 . A geared turbine engine according to claim 13 wherein the low pressure turbine is separated from the high pressure turbine by a statorless gas flow path; wherein a space extends between the low pressure turbine and the high pressure turbine, the space being statorless.

15 . A a geared turbine engine according to claim 14 wherein the low pressure turbine has first, second and third rotor stages, and wherein the first rotor stage is positioned upstream of the second and third rotor stages, the first rotor stage being mounted to the low pressure shaft by a first drive arm.

16 . A geared turbine engine according to claim 15 wherein the first drive arm circumferentially surrounds a downstream end of the high pressure shaft; and wherein the first drive arm defines an annular space into which projects the rear end of the high pressure shaft.

17 . A geared turbine engine according to claim 15 wherein the second and third rotor stages of the low pressure turbine are mounted to the low pressure shaft by one or more further drive arms independent of the first drive arm; and wherein the first and second rotor stages of the low pressure turbine are mounted on a first drive arm; and wherein the third and subsequent rotor stages of the low pressure turbine are mounted on a second drive arm.

18 . A geared turbine engine according to claim 14 wherein the low pressure shaft is carried by a single bearing; wherein the single bearing is positioned axially adjacent the second rotor stage of the low pressure turbine.

19 . A geared turbine engine according to claim 14 wherein the low pressure shaft is carried by two bearings comprising an upstream bearing and a downstream bearing; wherein the upstream bearing is axially adjacent the second low pressure turbine rotor stage; wherein the downstream bearing is axially adjacent the third low pressure turbine rotor stage.

20 . A geared turbine engine according to claim 14 wherein the gearbox is coupled to drive a propulsion fan and the engine is adapted to produce a maximum net thrust as herein defined of at least any of the following: 160 kN, 170 kN, 180 kN, 190 kN, 200 kN, 250 kN, 300 kN, 350 kN, 400 kN, 450 kN, 500 kN, or 550 kN.

Assignees

• Rolls Royce Plc

Inventors

• Townes Roderick M
• Sadler Keith C

Classifications

• F02C9/16

  Control of working fluid flow (F02C9/48 takes precedence; control of air-intake flow F02C7/057) · CPC title

• F02C7/268

  Starting drives for the rotor {, acting directly on the rotor of the gas turbine to be started} · CPC title

• F02C3/10

  with another turbine driving an output shaft but not driving the compressor · CPC title

• F05D2260/40311

  of the epicyclical, planetary or differential type · CPC title

• F02K3/06

  with front fan · CPC title