Patent Application
20210062674
This application claims priority to German Patent Application DE102019123240.6 filed Aug. 29, 2019, the entirety of which is incorporated by reference herein.
The present disclosure relates to a measuring device for an aircraft engine having the features of Claim 1, to an aircraft engine having the features of Claim 13 and to a measuring method for an aircraft engine having the features of Claim 14.
Aircraft engines are complex devices, the operation of which requires a multiplicity of sensors for gathering measurement values. One example of a sensor system of this type is described in US 2008/291964 A1.
Measurements with sensors, for example for a temperature, can be undertaken in cavities (referred to below as measuring space) in the interior of the aircraft engine, the measurements frequently being made difficult due to leakage flows, i.e. fluid, for example gas or air, unintentionally entering from cavities which are arranged as necessitated by the design and through which the sensor is guided. This distorts the measurement values and ultimately makes control of the aircraft engine difficult. However, an Engine Health Management, which requires a measurement value recording for longer periods, is also adversely affected as a result.
It is therefore the object to create devices and methods permitting measurements which are more accurate.
Use is made here of at least one probe device for measuring a physical and/or chemical state in at least one measuring space within the aircraft engine, wherein the at least one measuring space is fluidically connected to a cavity. A leakage flow can flow from said cavity into the measuring space during the operation of the aircraft engine.
At least one air-conducting device is designed and configured here to have a fluidic coupling, via which a gas flow (generally an air flow or else a liquid) can be removed from the at least one cavity to a pressure sink. A pressure sink here is a region in or else outside the aircraft engine, in which a lower pressure prevails at the respective point in time than in the cavity. This pressure difference permits air to be sucked out of the cavity. The suction here should as far as possible be undertaken in such a manner that there is an at least sufficient equal pressure gradient between the measuring space and the cavity such that the leakage flow does not flow to the measuring space, but rather to the pressure sink.
It is possible here that, for example, the air-conducting device as a fluidic connection has a duct and/or an opening in a wall between the cavity and the pressure sink. An outward flow can therefore take place in a controlled manner.
The at least one probe device which is used in the measuring device can have a sensor for temperature, pressure, particles and/or a chemical composition. All of these parameters can play a role individually or in combination in the monitoring and control of the aircraft engine.
In one embodiment, the at least one measuring space is arranged in a static part of the aircraft engine, i.e. it is not located in a component rotating with the drive.
In one embodiment, the at least one measuring space is arranged in a vane of a turbine and/or of a compressor of the aircraft engine. The temperature is monitored at least in some vanes, and therefore it is expedient to minimize leakage flows. The vane here can be in particular the first static vane of a low-pressure turbine in the flow direction.
It is also possible for the at least one measuring space to be designed as an annular space between two turbine stages and/or compressor stages. Alternatively or additionally, a bearing can be arranged in the at least one measuring space. The monitoring of temperatures in the vicinity of bearings may be expedient in order to prevent damage to the bearings. The same is true of embodiments in which the at least one measuring space is part of a rotating seal, in particular of a labyrinth seal. Temperatures are monitored here in order to establish whether the seal is still functioning.
Furthermore, in one embodiment, the at least one measuring space can be arranged in an engine nacelle of the aircraft engine.
In principle, the at least one measuring space and/or the cavity can be part of the secondary air supply system of the aircraft engine, in particular of an internal cooling and blockage air system.
The object is also addressed by the subject matter of claims 13 and 14.
Embodiments will now be described by way of example, with reference to the figures, in which:
Before embodiments of a measuring device are described, first of all the basic design of an aircraft engine 10 is described.
During operation, the core air flow A is accelerated and compressed by the low-pressure compressor 14 and directed into the high-pressure compressor 15, where further compression takes place. The compressed air expelled from the high-pressure compressor 15 is directed into the combustion device 16, where it is mixed with fuel and the mixture is combusted. The resulting hot combustion products then propagate through the high-pressure and the low-pressure turbines 17, 19 and thereby drive said turbines, before they are expelled through the nozzle 20 to provide a certain propulsive thrust. The high-pressure turbine 17 drives the high-pressure compressor 15 by means of a suitable connection shaft 27. The fan 23 generally provides the major part of the propulsive thrust. The epicyclic planetary transmission 30 is a reduction gear.
It is noted that the terms “low-pressure turbine” and “low-pressure compressor” as used herein may be taken to mean the lowest-pressure turbine stage and lowest-pressure compressor stage (i.e. not including the fan 23) respectively, and/or the turbine and compressor stages that are connected together by the connecting shaft 26 with the lowest rotational speed in the engine (i.e. not including the transmission output shaft that drives the fan 23). In some documents, the “low-pressure turbine” and the “low-pressure compressor” referred to herein may alternatively be known as the “intermediate-pressure turbine” and “intermediate-pressure compressor”. Where such alternative nomenclature is used, the fan 23 can be referred to as a first, or lowest-pressure, compression stage.
This form of an aircraft engine 10, which is also referred to as a transmission fan engine, is illustrated here merely by way of example since the embodiments for the measuring device are basically usable even in aircraft engines 10 without a transmission 30.
In an aircraft engine 10, measurements are undertaken here at different locations for different purposes, with, for example, a probe device 100 serving to measure a temperature in a measuring space 110.
In the embodiment illustrated, the vane 102 is approached by an air flow B (still has to be added in the drawing) which is branched off from the core air flow A. Above the duct for the core air flow A, a bearing device 105 for the pivotably designed vane 102 is arranged in an adjacent cavity 120. Since, however, the vane 102 does not rotate with the drive, i.e. does not rotate about the main axis of rotation 9, the vane can be understood as being a static component.
The cavity 120 here is a type of annular space in the aircraft engine 10 that is filled with air or through which air of the secondary air supply system flows.
The secondary air supply system is that part of the air conduction in an aircraft engine 10 which does not serve directly for the propulsion. In other embodiments, the cavity 120 can be a sealed space or a duct through which air flows. In each case, the cavity 120 is fluidically connected to the measuring space 110, i.e. a gas (air) can flow from the cavity 120 into the measuring space 110 (leakage).
In the illustration according to
The air-conducting device 101 here is a duct which produces the fluidic connection to the region with a lower pressure than in the cavity 110. Thus, for example, the bypass duct 22 (not illustrated here) can serve as a pressure sink D. A lower pressure prevails in the region of the pressure sink D than in the cavity 120, and therefore a leakage flow L into the measuring space 110 is prevented. Typically, regions in the aircraft engine 10 that are exposed to a small pressure increase within the engine and to a high flow velocity are suitable as pressure sinks D since the local pressure there is the lowest, according to Bernouilli's principle. It is also possible to use a region which is exposed to atmospheric pressure in flight as a pressure sink D.
In principle, the measuring space 110 may also be of a more complex form than illustrated here.
The vane 102 here is basically comparable to that illustrated in
However, here too, a leakage flow L enters from the cavity 120 into the measuring space 110 in the interior of the vane 102 during operation. The measurement results of the measuring probe 100 are distorted as a result.
In the embodiment illustrated, the core air flow A has a substantially higher temperature than in the cavity 120 lying radially outside the vane 102.
If the leakage flow L with said lower temperature now flows into the measuring space 110 of the vane 102, the temperature especially in the inflow region in the vicinity of the probe device 100 is reduced, and therefore sensors of the probe device 100 measure too low a temperature. A possible overheating of the additional air from the core air flow A into the vane 102 thus cannot be detected.
By contrast, the vane 102 in the embodiment according to
In principle, it would be possible for a leakage flow L (not illustrated here) to be able to flow from the adjacent cavity 120 lying axially upstream into the measuring space 110.
In order to prevent (or at least to minimize) the leakage flow L, an air-conducting device 101 is provided which produces a fluidic connection from the cavity 120 to the pressure sink D. The air-conducting device 101 leads radially outwards through the vane 102. An air flow G can therefore be removed from the cavity 120 in order as far as possible to prevent a leakage into the measuring space 110.
An analogous embodiment could also be used in conjunction with a measuring space 110 in which a seal is arranged instead of a bearing 103.
A probe device 100 is arranged between the vanes 102, 102a, said probe device measuring the temperature (and/or the pressure) between the vanes 102, 102a. The probe device 100 projects in the radial direction into the measuring space 110.
The measuring space 110 is at least partially surrounded by a cavity 120 from which air could flow into the measuring space, i.e. both cavity and measuring space are fluidically connected to each other.
In the region of the passage of the probe device through the walls of the measuring space 110 and of the cavity 120, ducts are arranged in the form of the air-conducting device 105, through which the air can be sucked out of the cavity 120 by means of a fluidic connection to the pressure sink D. The pressure sink D lies radially further outside the cavity 120 and is connected, for example, to the bypass duct 22 or to the exterior (not illustrated here), wherein a lower pressure prevails at these locations than in the cavity 120.
The embodiments illustrated here comprise probe devices 100 which have sensors for temperature measurements. However, it is also possible to use other sensors which, for example, measure the pressure, a pressure difference, particles (for example in smoke) and/or a chemical composition (for example within the scope of the combustion). All of these measurements are directed towards the measuring conditions in the measuring space 110 being distorted as little as possible.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 123 240.6 | Aug 2019 | DE | national |
