GB2534166A

GB2534166A - Pressure sensor system

Info

Publication number: GB2534166A
Application number: GB1500604.2A
Authority: GB
Inventors: Goulds Roberts; R Lace Brian; Peace Richard
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 2015-01-15
Filing date: 2015-01-15
Publication date: 2016-07-20
Also published as: GB201500604D0

Abstract

Pressure of a combustor in a gas turbine engine is measured to identify rumble. A conduit 31extends from a first end 32, connected to an opening in the combustor component, to a closed second end 33. A pressure sensor 34 is mounted to a sidewall of the tube 31 or in a cavity (42) of a mounting block (40) connecting with a further internal cavity (41) connecting to the conduit 31. The pipe 31 may be coiled 35.

Description

PRESSURE SENSOR SYSTEM

The present disclosure relates to a pressure sensor system that may be used within a gas turbine engine. In particular, the pressure sensor system may be used to obtain pressure signals corresponding to the pressure within a component of a gas turbine engine, for example the combustor.

When a gas turbine engine is run at low power and/or in engines designed to use low emissions burners, combustor rumble may occur. This condition is an instability in the combustion process. It may potentially lead to violent pressure variations, which can damage surrounding components through vibration. It may also create a great deal of noise that may be alarming to passengers and ground crew of aircraft in which the gas turbine engine is mounted.

High frequency pressure fluctuations may be indicative of the initiation of combustor rumble. Accordingly, it is desirable to be able to detect the high frequency pressure fluctuations such that potential combustor rumble may be detected before it occurs or becomes significant. This may permit the operation of a gas turbine engine closer to the condition at which combustor rumble may become possible, enabling the engine to be run at lower power, reducing fuel usage and reducing emissions. It is therefore desirable to provide a pressure sensor system with improved capability for detecting pressure signals from components within a gas turbine engine.

According to an aspect, there is provided a pressure sensor system for obtaining a pressure signal corresponding to the pressure in a component of a gas turbine engine, comprising a conduit, extending from a first end to a second end, and a pressure sensor, configured to output a pressure signal. The first end of the conduit is configured to be connected to an opening in the component of the gas turbine engine. The pressure sensor has a sensor surface and the pressure signal output by the pressure sensor corresponds to the pressure exerted on the sensor surface. The pressure sensor is mounted to a sidewall of the conduit between the first end and the second end of the conduit, such that the sensor surface is in fluid contact with the internal volume of the conduit.

According to an aspect, the conduit may be elongate and the pressure sensor may be mounted closer to the first end of the conduit than to the second end of the conduit.

In an arrangement, the pressure sensor may be mounted much closer to the first end of the conduit than to the second end of the conduit. For example, the length of the conduit between the location at which the pressure sensor is mounted and the second end may be relatively long, for example at least 100 times the width of the conduit, optionally at least 1,000 times the width of the conduit, optionally at least 10,000 times the width of the conduit. For example, the conduit may have an internal diameter of approximately 1 to 3mm and the length of the conduit between the location at which the pressure sensor is mounted and the second end of the conduit may be at least 10m, optionally approximately 20m or longer.

According to an aspect, at least a portion of the conduit may be flexible and at least a portion of the conduit between the location at which the pressure sensor is mounted and the second end of the conduit may be coiled.

According to an aspect, at least one connector may be provided to secure the coiled portion of the conduit within the gas turbine engine. In such an arrangement, each connector may secure multiple turns of the conduit within the coiled portion of the conduit.

According to an aspect, the conduit may be configured such that there are no discontinuous changes of the cross-sectional area of the conduit between the first end and the location at which the pressure sensor is mounted and between said location and the second end of the conduit. In an arrangement, the cross-section of the conduit may be constant between the first end and a location at which the pressure sensor is mounted and between said location and the second end of the conduit.

According to an aspect, the sensor surface may be configured to have a shape matching the shape of the sidewall of the conduit at the location at which the pressure sensor is mounted. In such an arrangement, the internal surface of the conduit may be continuous at the location at which the pressure sensor is mounted.

According to an aspect, the cross-section of the sensor surface may be the same size or smaller than the cross-section of the conduit at the location at which the pressure is mounted.

According to an aspect, the conduit may comprise a mounting block, configured to receive the pressure sensor. The mounting block may include first and second cavities that intersect. The first cavity may extend between first and second ends that are connected to respective adjoining sections of the conduit, extending to the first and second ends of the conduit. The cross-section of the first cavity may be the same as the cross-section of the adjoining sections of the conduit at the point at which they are connected. The second cavity may have the same cross-section as the sensor surface of the pressure sensor and may be configured such that the pressure sensor can be mounted within the second cavity.

According to an aspect, the mounting block may be configured such that the sensor surface of the pressure sensor mounted within the second cavity is located abutting a side of the first cavity at the intersection between the first and second cavity.

According to an aspect, the second cavity may be configured to taper from the side of the first cavity at which the sensor service is located to the opposition side of the first cavity such that the cross-section of the second cavity reduces across the region in which the first and second cavities intersect. Such an arrangement may be useful in arrangement in which the cross-section of the sensor surface is larger than the cross-section of the conduit.

According to an aspect, there is provided a gas turbine engine including a pressure sensor system according to the present disclosure.

According to an aspect, the conduit of the pressure sensor system may be connected to an opening in the combustor.

According to an aspect, an analyser may be provided that is configured to detect the occurrence of combustor rumble within a combustor based on an analysis of the pressure signal from the pressure sensor within the pressure sensor system.

Examples of the disclosure will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Figure 1 shows a gas turbine engine which may comprise a pressure sensor system according to an aspect of the disclosure; Figure 2 depicts a pressure sensor system; Figure 3 depicts, in cross-section a mounting block that may be used within a pressure sensor system according to the present disclosure; and Figures 4 and 5 depict an alternative arrangement of a mounting block that may be used in an arrangement according to the present disclosure, in cross-section across the conduit of the pressure sensor system and along the length of the conduit of the pressure sensor system, respectively.

With reference to Figure 1, a ducted fan gas turbine engine generally indicated at 10 has a principal and rotational axis X-X. The engine 10 comprises, in axial flow series, an air intake 11, a compressive fan 12 (which may also be referred to as a low pressure compressor), an intermediate pressure compressor 13, a high-pressure compressor 14, combustion equipment 15, a high-pressure turbine 16, an intermediate pressure turbine 17, a low-pressure turbine 18 and a core exhaust nozzle 19. The engine also has a bypass duct 22 and a bypass exhaust nozzle 23.

The gas turbine engine 10 works in a conventional manner so that the air entering the intake 11 is accelerated by the fan 12 to produce two air flows; a first air flow A into the intermediate pressure compressor 13 and a second air flow B which passes through the bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 13 compresses the air flow A directed into it before delivering that air to the high pressure compressor 14 where further compression takes place. The compressed air exhausted from the high-pressure compressor 14 is directed into the combustion equipment 15 where it is mixed with fuel and the mixture combusted. The resulting hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 16, 17 and 18 before being exhausted through the nozzle 19 to provide additional propulsive thrust. The high, intermediate and low-pressure turbines 16, 17, 18 respectively drive the high and intermediate pressure compressors, 14, 13 and the fan 12 by suitable interconnecting shafts.

Figure 2 depicts schematically an arrangement of a pressure sensor system according to the present disclosure. The pressure sensor system may be configured to be connected to a component 30, such as a combustor within a gas turbine engine, in order to obtain a pressure signal corresponding to the pressure within the component 30. The pressure signal may have frequency components that correspond to the frequency components of the pressure fluctuations that may occur within the component 30. The pressure sensor system may be used with a gas turbine engine such as that described above or other arrangements of gas turbine engines.

As shown in Figure 2, the pressure sensor system of the present disclosure includes a conduit 31 that may also be referred to as a sense line. The conduit 31 may extend from a first end 32 that is connected to an opening in the component 30 such that the internal volume of the conduit 31 is in fluid contact with an internal volume of the component 30. Consequently, pressure variations within the component 30 may result in pressure variations within the conduit 31. The conduit 31 extends to a second end 33, which is closed. As described further below, the conduit 31 may be elongate and relatively long. A pressure sensor 34 is mounted to the conduit 31 between the first and second ends 32, 33.

The pressure sensor 34 may be mounted to a sidewall of the conduit 31 such that a sensor surface of the sensor 34 is in fluid contact with the internal volume of the conduit 31. In such an arrangement, the pressure sensor 34 may be mounted to the conduit 31 in such a way that there is minimal interference on pressure waves travelling from the first end 32 to the second end 33 of the conduit 31. At the same time, the pressure sensor 34 may output a pressure signal that corresponds to the pressure exerted on the sensor surface, which in turn corresponds to the pressure within the component 30.

The arrangement discussed above contrasts with previously known pressure sensor systems used within gas turbine engines, in which the pressure sensor may be mounted at the end of a conduit connected to, for example, a combustor. In such a previously known arrangement, a positive pressure wave travelling from the component to the sensor, would be reflected back along the conduit to the component. On return to the component, at which there is an opening into the component, the positive pressure wave would be reflected again, this time as a negative pressure wave, back towards the sensor. This negative pressure wave may interfere with the signal at the sensor. Accordingly, it is now appreciated that, in the previously known arrangements, the real pressure signal may be masked by the dynamics of the conduit and/or sensor geometry.

In the present arrangement, as a positive pressure wave passes the pressure sensor 34 it is not reflected but continues to the second end 33 of the conduit 31, which is closed. Although the positive pressure wave may be reflected as a positive pressure wave by the second end 33 of the conduit, by the time it returns to the pressure sensor 34 a first time and is subsequently reflected as a negative pressure wave by the opening in the component 30 and returns to the pressure sensor 34 a second time, the pressure wave is dissipated, reducing the interference with the original signal.

According to an aspect, the pressure sensor 34 may be mounted closer to the first end 32 of the conduit 31 than the second end 33. This may ensure that the power of the original signal is significantly stronger than the noise generated by the reflections.

According to an aspect of the present disclosure, the length of the conduit 31 between the location at which the pressure sensor 34 is mounted to the conduit 31 and the second end 33 of the conduit 31 may be maximised. It should be appreciated that, in general, the longer this section of the conduit 31, the more the reflected pressure waves may be dissipated before reaching the pressure sensor 34, reducing the interference with the original signal. However, a balance may be required between the desirability of a long conduit 31 and the practicality of including such a long conduit 31 within a gas turbine engine.

According to an aspect of the disclosure, the length of the conduit 31 between the location at which the pressure sensor 34 is mounted and the second end 33 may be at least 100 times the width of the conduit, optionally at least 1,000 times the width of the conduit, optionally at least 10,000 times the width of the conduit. For example, the conduit may have an internal diameter of between approximately 1 and 3mm. In that case, the length of the conduit 31 between the pressure sensor 34 and the second end 33 may be at least lm, possibly at least 10m and possibility 20m or more.

According to an aspect, as schematically depicted in Figure 2, a portion of the conduit 31 may be arranged in a coil 35. This may make it easier to contain a long conduit 31 within a gas turbine engine without interfering with other components of the gas turbine engine. Alternatively or additionally, this may assist in securing the conduit 31 within the gas turbine engine. In particular, a plurality of connectors may be provided to secure the conduit 31 within the gas turbine engine. At least one of the connectors may be configured to secure the coiled portion 35 of the conduit 31. In such an arrangement, each of the connectors may be configured to secure multiple turns of the conduit 31 within the coiled portion 35 of the conduit. In such an arrangement, fewer connectors overall may be required in order to suitably secure the conduit 31 within the gas turbine engine.

The conduit 31, or at least the coiled portion 35, may be formed from, for example, stainless steel or a nickel alloy. Tubes formed of such materials may be formed into the coil cold and provide sufficient mechanical strength that, when restrained by suitable connectors as described above, it retains the coiled form when under pressure in use. The exemplary materials may also be capable of operation under the relatively high temperatures that may be experienced within a gas turbine engine.

In order to minimise the possibility of gas pressure wave reflections, the pressure sensor system may be configured in order to minimise changes in the cross-sectional area of the volume through which the pressure waves pass. According to an aspect, the conduit may be configured such that there are no discontinuous changes in the cross-sectional area of the conduit 31 between the first end 32 of the conduit and the location at which the pressure sensor 34 is mounted and between that location and the second end 33 of the conduit 31. Optionally, the cross-section of the conduit 31 may be constant along those sections of the conduit.

As discussed above, it is desirable to minimise reflections of the pressure wave along the conduit 31 at the point at which it passes the sensor 34. According to an aspect, the pressure sensor 34 may be configured such that the sensor surface of the pressure sensor 34 has a shape matching the shape of the sidewall of the conduit 31 at the location at which the pressure sensor 34 is mounted. In such an arrangement, the sensor surface of the pressure sensor 34 may be set within the sidewall of the conduit 31 in such a way that the combined surface of the sidewall of the conduit the sensor surface of the pressure sensor 34 is continuous. In such an arrangement, the internal volume may have a constant cross-sectional area with no sharp edges, minimising pressure wave reflections. In an arrangement, the internal volume of the conduit 31 may have a circular cross-section, in which case the sensor surface of the pressure sensor 34 may be curved to match the curvature of the sidewall of the conduit 31.

According to an aspect, the pressure sensor system may incorporate a pressure sensor 34 having a sensor surface that does not match the shape of the conduit 31. This may be necessary due to the requirement to use a standard or semi-standard pressure sensor 34, for example for cost reasons. In that case, arrangements such as those discussed below using a mounting block it may be used in order that the pressure sensor 34 be mounted to the conduit 31 such that the sensor surface is as flush as possible with the sidewall of the conduit 31 and/or in order to minimise any interference with the pressure signal that may be caused by, for example, reflections. In either case, the pressure sensor system according to the present disclosure may be configured such that the cross-section of the sensor surface of the pressure sensor 34 is similar in size to, or smaller than, the cross-section of the conduit 31 at the location at which the pressure sensor 34 is mounted. Such an arrangement may make it easier to minimise changes in the cross-sectional area of the volume within the conduit 31 at the point at which the pressure sensor 34 is mounted and/or minimise the requirement for abrupt changes.

Figures 3, 4 and 5 depict arrangements of a mounting block 40 that may be used to mount a pressure sensor 34 to a conduit 31 where the shape of the sensor surface 43 does not match the shape of the sidewall of the conduit 31. In the arrangements shown, the conduit 31 may have a circular cross-section, namely a curved sidewall whereas the sensor surface 43 of the pressure sensor 34 may be flat. It should be appreciated, however, that with suitable modifications similar arrangements may be used for other shapes of conduit 31 and/or sensor surfaces 43.

Figure 3 depicts an arrangement in which the cross-sectional area of the sensor surface 43 of the pressure sensor 34 is similar to the cross-sectional area of the conduit 31, although in the arrangement shown it is slightly larger.

Figures 4 and 5 depict an arrangement in which the cross-sectional area of the sensor surface 43 of the pressure sensor 34 is significantly larger than the cross-section of the conduit 31. This may be necessitated by the requirement to use a particular pressure sensor 34, as discussed above. Figure 4 depicts the arrangement in a cross-section across the conduit 31 while Figure 5 depicts a cross-section along the conduit 31.

In both the arrangement of Figure 3 and the arrangement of Figures 4 and 5, a mounting block 40 is provided to mount the pressure sensor 34 to the conduit 31. The mounting block 40 includes first and second intersecting cavities 41, 42. The first cavity 41 may be connected at either end of the first cavity to adjoining sections of the conduit 31. The first cavity 41 may be configured such that it has the same cross-section as the adjoining sections of conduit 31 at the location at which the pressure sensor 34 is to be mounted. In such an arrangement, there may be no change in cross-sectional area in passing from either section of the conduit 31 to the first cavity 41.

The second cavity 42 may be configured to receive the pressure sensor 34 and to secure it to the mounting block 40. The second cavity 42 may have the same cross-section as the sensor surface 43 of the pressure sensor 34 at the point of intersection between the first and second cavities 41, 42. In an arrangement, the pressure sensor 34 may be mounted within the second cavity such that the sensor surface 43 is located at the intersection between the first and second cavities 41, 42.

According to an aspect, the second cavity 42 may be configured to taper from a first side 45 of the first cavity 41, namely the side at which the sensor surface 43 of the pressure sensor 34 is located, to a second side 46 of the first cavity 41, that is on the opposite side of the first cavity 41 from the first side 45. As shown most clearly in Figures 4 and 5, this may result in a tapered section 47 of the second cavity 42, providing a relatively gentle change in cross-sectional area in order to minimise pressure wave reflections and/or interferences. It should be appreciated that the Figures are schematic representations of the arrangements of the mounting block 40. Accordingly, any sharp edges shown in the Figures may, in reality, be smoothed.

According to an aspect, the pressure sensor 34 may be connected to an analyser that is configured to analyse the pressure signals provided by the pressure sensor 34. In particular, the analyser may be configured to identify the initiation or occurrence of combustor rumble if the pressure sensor system is connected to a combustor within a gas turbine engine. For example, the analyser may be configured to detect frequency signatures that are characteristic of combustor rumble. This may enable action to be taken to prevent and/or reduce combustor rumble before damage is caused to components and/or before it becomes noticeable to passengers and/or crew.

Claims

CLAIMS1 A pressure sensor system for obtaining a pressure signal corresponding to the pressure in a component (30) of a gas turbine engine, comprising: a conduit (31) extending from a first end (32) to a second end (33), the first end configured to be connected to an opening in the component (30); and a pressure sensor (34) configured to output a pressure signal; wherein the pressure sensor (34) has a sensor surface and the pressure signal output by the pressure sensor corresponds to the pressure exerted on the sensor surface; and the pressure sensor (34) is mounted to a sidewall of the conduit (31) between the first end (32) and second end (33) of the conduit such that the sensor surface is in fluid contact with the internal volume of the conduit.
2. A pressure sensor system according to claim 1, wherein the conduit (31) is elongate and the pressure sensor (34) is mounted closer to the first end (32) of the conduit than to the second end (33) of the conduit.
3. A pressure sensor system according to claim 1 or 2, wherein the length of the conduit (31) between the location at which the pressure sensor (34) is mounted and the second end (33) of the conduit is at least 100 times the width of the conduit, optionally at least 1,000 times the width of the conduit, optionally at least 10,000 times the width of the conduit.
4. A pressure sensor system according to any one of the preceding claims, wherein at least a portion (35) of the conduit between the location at which the pressure sensor (34) is mounted and the second end (33) of the conduit is coiled.
5. A pressure sensor system according to claim 4, further comprising at least one connector, configured to secure the coiled portion (35) of the conduit (31) within the gas turbine engine, wherein each said connector secures multiple turns of the conduit within the coiled portion of the conduit.
6. A pressure sensor system according to any one of the preceding claims, wherein the cross-sectional area of the conduit (31) has no discontinuous changes between the first end (32) and the location at which the pressure sensor (34) is mounted and between said location and the second end (33).
7. A pressure sensor system according to any one of the preceding claims, wherein the cross-section of the conduit (31) is constant between the first end (32) and the location at which the pressure sensor (34) is mounted and between said location and the second end (33).
8. A pressure sensor according to any of the preceding claims, wherein the sensor surface is configured to have a shape matching the shape of the sidewall of the conduit (31) at the location at which the pressure sensor (34) is mounted such that the internal surface of the conduit (31) is continuous at the location at which the pressure sensor (34) is mounted.
9. A pressure sensor according to any of the preceding claims, wherein the cross-section of the sensor surface is the same size or smaller than the cross-section of the conduit (31) at the location at which the pressure sensor (34) is mounted.
10. A pressure sensor system according to any one of the preceding claims, wherein the conduit (31) comprises a mounting block (40), configured to receive the pressure sensor and having first and second intersecting cavities (41,42); the first cavity (41) is connected at either end to adjoining sections of the conduit (31) and has the same cross-section as those sections of the conduit; the second cavity (42) has the same cross-section as the sensor surface (43) of the pressure sensor (34) at the point at which the first and second cavities (41,42) intersect; and the pressure sensor (34) is mounted within the second cavity (42).
11. A pressure sensor system according to claim 10, wherein the mounting block (40) is configured such that the sensor surface (43) of the pressure sensor (34) mounted within the second cavity (42) is located abutting a side of the first cavity (41), at the intersection between the first and second cavity.
12. A pressure sensor system according to claim 11, wherein the second cavity (42) is configured to taper from the side (45) of the first cavity (41) at which the sensor surface (43) is located to a second side (46) of the first cavity (41), opposite the first side (45).
13. A pressure sensor system according to any one of the preceding claims, further comprising an analyser, configured such that, if the pressure sensor system is connected to a combustor in a gas turbine engine, the analyser can detect the initiation or occurrence of combustor rumble within the combustor from the pressure signal.
14. A gas turbine engine, comprising a pressure sensor system according to any one of the preceding claims.
15. A gas turbine engine according to claim 14, wherein the conduit of the pressure sensor system is connected to an opening in the combustor.
16. A pressure sensor system for a gas turbine engine substantially as hereinbefore described with reference to the accompanying drawings.
17. A gas turbine engine substantially as hereinbefore described with reference to the accompanying drawings.