CONDENSATION IRRADIATION SYSTEM

Abstract

A condensation irradiation system is disclosed comprising an electromagnetic radiation emitter mounted on a locating structure, the locating structure being arranged in use to position the radiation emitter so as radiation emitted therefrom travels through a condensation detection region adjacent an upstream side of a gas turbine engine fan.

Claims

1. A condensation irradiation system comprising an electromagnetic radiation emitter mounted on a locating structure, the locating structure being arranged in use to position the radiation emitter so as radiation emitted therefrom travels through a condensation detection region adjacent an upstream side of a gas turbine engine fan.

2. A condensation irradiation system according to claim 1 where the detection region is a space bounded by planes that are substantially parallel with the fan plane.

3. A condensation irradiation system according to claim 1 where the emitted electromagnetic radiation may pass through the detection region travelling in a direction substantially parallel to the fan plane.

4. A condensation irradiation system according to claim 1 where the system comprises the fan.

5. A condensation irradiation system according to claim 1 where the detection region is downstream of a radial plane passing through a tip of a nose cone of the fan.

6. A condensation irradiation system according to claim 1 where the system further comprises a camera oriented so as at least part of the detection region is within its field of view.

7. A condensation irradiation system according to claim 6 where the camera is positioned outside of an axial projection of the fan.

8. A condensation irradiation system according to claim 6 where the electromagnetic radiation emitter emits monochromatic radiation and the camera is arranged to detect only the wavelength emitted.

9. A condensation irradiation system according to claim 6 where at least two of the cameras are provided and all parts of the detection region are in the field of view of at least one of the cameras.

10. A condensation irradiation system according to claim 1 comprising a fan test rig comprising the locating structure.

11. A condensation irradiation system according to claim 1 comprising a gas turbine engine comprising the locating structure.

12. A condensation irradiation system according to claim 1 where the electromagnetic radiation emitter is a laser.

13. A condensation irradiation system according to claim 1 comprising a lens system arranged to convert the emitted radiation into a substantially planar sheet for passage across the detection region.

14. A condensation irradiation system according to claim 1 where at least two of the electromagnetic radiation emitters are provided.

15. A method of detecting condensation occurring within a detection region adjacent an upstream side of a gas turbine engine fan, the method comprising irradiating the detection region with electromagnetic radiation and detecting electromagnetic radiation backscattered on any condensation present.

Description

[0028] Embodiments will now be described by way of example only, with reference to the Figures, in which:

[0029] FIG. 1 is a sectional side view of a gas turbine engine;

[0030] FIG. 2 is a side view of an embodiment of the invention;

[0031] FIG. 3 is a front view of an embodiment of the invention.

[0032] With reference to FIG. 1, a gas turbine engine is generally indicated at 10, having a principal and rotational axis 11. The engine 10 comprises, in axial flow series, an air intake 12, a propulsive fan 13, an intermediate pressure compressor 14, a high-pressure compressor 15, combustion equipment 16, a high-pressure turbine 17, an intermediate pressure turbine 18, a low-pressure turbine 19 and an exhaust nozzle 20. A nacelle 21 generally surrounds the engine 10 and defines both the intake 12 and the exhaust nozzle 20.

[0033] The gas turbine engine 10 works in the conventional manner so that air entering the intake 12 is accelerated by the fan 13 to produce two air flows: a first air flow into the intermediate pressure compressor 14 and a second air flow which passes through a bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 14 compresses the air flow directed into it before delivering that air to the high pressure compressor 15 where further compression takes place.

[0034] The compressed air exhausted from the high-pressure compressor 15 is directed into the combustion equipment 16 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 17, 18, 19 before being exhausted through the nozzle 20 to provide additional propulsive thrust. The high 17, intermediate 18 and low 19 pressure turbines drive respectively the high pressure compressor 15, intermediate pressure compressor 14 and fan 13, each by suitable interconnecting shaft.

[0035] Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. By way of example such engines may have an alternative number of interconnecting shafts (e.g. two) and/or an alternative number of compressors and/or turbines. Further the engine may comprise a gearbox provided in the drive train from a turbine to a compressor and/or fan.

[0036] Referring now to FIGS. 2 and 3 a condensation irradiation system is generally shown at 30. The condensation irradiation system comprises a gas turbine engine 32 shown within a test cell 34. The gas turbine engine 32 is a turbofan engine and therefore has a fan 36. The fan 36 defines a fan plane that passes through the tip 38 of each fan blade 40. The fan 36 has a spinner 42 at its centre and is surrounded by an intake duct which is itself surrounded by a nacelle 44. The intake duct forms part of a locating structure which locates four electromagnetic radiation emitters 46 with respect to the fan 36. The electromagnetic radiation emitters 46 are evenly distributed circumferentially about the intake duct and positioned so as to all lie in an emitter plane, upstream of the fan 36 and parallel to the fan plane. Depending on the embodiment the emitters 46 may be intrinsically provided as part of the intake duct or may alternatively be retrofitted for operation within the test cell 34. Associated with each electromagnetic radiation emitter 46 is a lens of a lens system (not shown).

[0037] Adjacent and upstream of the fan 36 and bounded by the intake duct is a condensation detection region generally provided at 48. The detection region 48 is further bounded on an upstream side by a spinner tip plane parallel to the fan plane and passing through a tip 50 of the spinner 42 and on the downstream side by the fan plane. The condensation detection region 48 is therefore cylindrical in shape and the emitter plane divides the cylinder into two equal sized smaller cylinders.

[0038] The condensation irradiation system 30 further comprises a pair of cameras 52. The cameras 52 are positioned upstream of the fan 36 and detection region 48, beyond the upstream extent of the nacelle 44. The cameras 52 are also positioned outside of an axial projection of the fan 36 and of the intake duct. The cameras 52 are therefore out of a main airflow 54 drawn into the fan 36. The cameras 52 are positioned opposite each other and are directed with their fields of view towards the detection region 48. The whole of the detection region 48 is within the combined fields of view of the cameras 52. In this embodiment the cameras 52 are mounted to the walls of the test cell 34 and are therefore mounted separately to the locating structure. In other embodiments however (especially where the cameras 52 are provided embedded within the nacelle or where the fan is mounted via a fan test rig rather than by a whole engine) the cameras 52 may be mounted on the locating structure.

[0039] In use of the condensation irradiation system 30, the gas turbine engine 32 is placed into the test cell 34. The engine 32 is secured in a predetermined position and orientation with respect to the test cell 34 and the cameras 52 before it is started. Each electromagnetic radiation emitter 46 emits a constant beam of monochromatic laser light. Each beam is shaped by the lens associated with each emitter 46 into a substantially planar sheet 56 which passes across the detection region 48. The planar sheets 56 pass through the detection region 48 travelling in a direction substantially parallel to the fan plane. The planar sheets 56 form a near complete detection net across the intake duct.

[0040] The cameras 52 film the detection region 48 and are sensitive only to the wavelength of the laser light emitted by the emitters 46. The cameras 52 film consistently throughout the engine 32 run and transmit data pertaining to the captured images to an image processor (not shown) via a data transmitter. The processor utilises image processing software stored on a memory to analyse the images (e.g. filtering to remove noise and searching for evidence of condensation 58). If the image processing reveals that condensation is present an alarm to this effect is triggered by the processor and is shown on a user display. The data recorded by the cameras 52 is also stored in the memory for optional subsequent analysis. The filming, transmission, image processing, alarm display and data storage steps occur in real-time whilst the engine 32 is running.

[0041] In the event that condensation 58 occurs within the detection region 48, laser light of a sheet 56 may irradiate droplets within the condensation and may be scattered in the direction of one or other of the cameras 52. At least one of the cameras 52 may capture this light and trigger the issuing of the alarm.

[0042] As will be appreciated, in some embodiment the image processor may also map the condensation present in terms of its distribution at a particular time or over a period of time. The latter in particular may offer improved understanding of the development and evolution of the condensation. Additionally, in areas of the detection region filmed by at least two cameras, mapping may be performed in three dimensions, as facilitated by the stereoscopic view provided by the cameras. Maps may be displayed on the user display and/or recorded in the memory.

[0043] The triggering of the alarm and/or analysis of the maps may give rise to termination of the engine run and/or the application of condensation compensation factors applied to other test data (e.g. pressure ratio across the fan and fan inlet temperature). collected during the engine run Additionally or alternatively such data may be used to better understand the ambient and/or engine operating conditions which can be expected to give rise to condensation formation, and may be used to set conditions which must be met before future engine runs are undertaken.

[0044] It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. By way of example it may be that the gas turbine engine and/or test cell are replaced with a fan test rig that may for instance comprise a frame as the locating structure on which may be mounted the emitters and optionally the cameras and/or fan. Such a rig may also be provided with an intake duct. By way of further example, other embodiments may be implemented in the context of an in service engine and not therefore in a specific test environment. In this case it may be that the camera(s) are integrated into the intake duct. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.