Convergent-divergent nozzle

Patent metadata

Field	Value
Publication number	US-2016305368-A1
Application number	US-201615079797-A
Country	US
Kind code	A1
Filing date	Mar 24, 2016
Priority date	Apr 17, 2015
Publication date	Oct 20, 2016
Grant date	—

Abstract

A convergent-divergent nozzle arranged to convey fluid from an upstream zone to a downstream zone via a throat aperture, wherein the nozzle includes an assembly movable to vary the size of the throat aperture of the nozzle, thereby regulating the flow of fluid to the downstream zone.

First claim

1 . A gas turbine engine comprising an upstream zone and a downstream zone, wherein:
the downstream zone is a fire-critical zone that requires a predetermined flow rate of ventilation fluid during use; a convergent-divergent nozzle is provided between the upstream zone and the downstream zone, and is arranged to convey fluid from the upstream zone to the downstream zone via a throat aperture; and the nozzle includes an assembly movable to vary the size of the throat aperture of the nozzle, thereby regulating the flow of ventilation fluid to the downstream zone.

2 . A gas turbine engine according to claim 1 wherein the movable assembly includes at least one member formed of a shape memory alloy.

3 . A gas turbine engine according to claim 2 wherein the movable assembly is movable between a first position in which the convergent-divergent nozzle presents a first throat aperture through which the fluid is able to flow, and a second position in which the convergent-divergent presents a second throat aperture through which the fluid is able to flow, the first and second throat apertures being of respectively different sizes.

4 . A gas turbine engine according to claim 3 wherein the at least one member is configured such that heating the at least one member above a predetermined temperature causes the movable assembly to adopt the first position.

5 . A gas turbine engine according to claim 4 , wherein the at least one member is arranged to be heated by passing an electric current through the at least one member.

6 . A gas turbine engine according to claim 4 , wherein the at least one member is heatable by one or more heater elements controllable to heat the at least one member above the predetermined temperature.

7 . A gas turbine engine according to claim 4 wherein the at least one member is configured such that cooling, or maintaining, the at least one member below the predetermined temperature causes the movable assembly to adopt the second position.

8 . A gas turbine engine according to claim 3 wherein the movable assembly includes a spring member, arranged to urge the movable assembly to resile to the second position.

9 . A gas turbine engine according to claim 8 wherein the spring member is provided in the form of a spring sheet.

10 . A gas turbine engine according to claim 3 wherein the at least one member is provided in the form of a sheet member.

11 . A gas turbine engine according to claim 10 , wherein the spring member is provided in the form of a spring sheet, and
the spring member and the sheet member are provided as a laminate sub-assembly.

12 . A gas turbine engine according to claim 9 , wherein the at least one member is provided in the form of a wire spanning a concave portion of the spring sheet to be capable of causing the movable assembly to adopt the first position in response to being heated above the predetermined temperature.

13 . A gas turbine engine according to claim 3 , wherein in the first position the convergent-divergent nozzle presents a relatively small throat aperture through which the fluid is able to flow, and in the second position the convergent-divergent presents a relatively large throat aperture through which the fluid is able to flow.

14 . A gas turbine engine according to claim 3 , wherein in the first position the convergent-divergent nozzle presents a relatively large throat aperture through which the fluid is able to flow, and in the second position the convergent-divergent presents a relatively small throat aperture through which the fluid is able to flow.

Assignees

• Rolls Royce Plc

Inventors

• Hussain Zahid M

Classifications

• F02K1/06

  Varying effective area of jet pipe or nozzle (by using fluid jets to influence the jet flow F02K1/30) · CPC title

• F05D2250/324

  divergent · CPC title

• B64D37/32

  Safety measures not otherwise provided for, e.g. preventing explosive conditions · CPC title

• F02K1/08

  by axially moving or transversely deforming an internal member, e.g. the exhaust cone · CPC title

• F02C9/18

  by bleeding, bypassing or acting on variable working fluid interconnections between turbines or compressors or their stages {(F02C3/113 takes precedence)} · CPC title