EP3189934B1 - Device for cleaning a jet engine - Google Patents

Description

The invention relates to a device and an arrangement for cleaning an aircraft jet engine.

Aircraft jet engines have one or more compressor stages, a combustion chamber and one or more turbine stages. In the turbine stages, the hot combustion gases from the combustion chamber give off part of their thermal and mechanical energy, which is used to drive the compressor stages. Jet engines of commercial airliners today predominantly have what is known as a turbofan, which is arranged upstream of the compressor stages and generally has a considerably larger diameter than the compressor stages. The turbofan is also driven by the turbine stages and lets a considerable part of the air flowing through the engine as a whole flow past the compressor stages, the combustion chamber and the turbine stages as a so-called secondary air flow. Such a bypass flow can significantly increase the efficiency of an engine and also improve the noise insulation of the engine.

Contamination of an aircraft jet engine can lead to a reduction in efficiency, which results in increased fuel consumption and thus increased environmental pollution. The pollution can be caused, for example, by insects, dust, salt spray or other environmental pollution. Parts of the engine can be contaminated by combustion residues from the combustion chamber. These contaminants form a coating on the parts of an aircraft engine through which air flows and impair the surface quality. This affects the thermodynamic efficiency of the engine. Particular mention should be made of the blades in the compressor stages, the contamination of which has a significant influence on the efficiency of the entire engine.

To remove contamination, it is known to clean an engine with a cleaning fluid, usually hot water. From the WO 2005/120953 an arrangement is known in which a plurality of cleaning nozzles are arranged upstream of the turbofan or the compressor stages. The cleaning fluid is then sprayed into the engine. The engine can rotate in so-called dry cranking, ie the blades of the engine rotate without kerosene being burned in the combustion chamber. The cleaning fluid introduced into the engine is intended to wash off dirt from the surfaces of the engine components.

As an alternative to the use of water as a cleaning medium, the use of coal dust is known. Like water, the coal dust is fed into the engine through nozzles and removes contamination from surfaces due to abrasive effects. However, the surface of the engine parts is also attacked by the coal dust, which is why a cleaning medium such as coal dust is not suitable for the regular cleaning of aircraft engines. In addition, when cleaning with coal dust, undesired residues of the cleaning material remain in the engine.

WO 2009/132847 A1 discloses an apparatus and a method for cleaning jet engines using solid carbon dioxide as the cleaning medium. The U.S. 7,445,677 describes the features of the preamble of claim 1 and discloses a device for cleaning jet engines which can be attached to the shaft of a jet engine.

The invention is based on the object of creating a device and an arrangement which enable aircraft engines to be cleaned in an improved manner.

This object is achieved by a nozzle device according to claim 1 and an arrangement according to claim 11. Advantageous developments result from the dependent claims.

The application also relates to a method for cleaning a jet engine with a cleaning medium that contains solids. The solids are introduced into the engine by means of a carrier gas through at least one nozzle. The cleaning medium thus comprises at least one carrier gas and solids, preferably exclusively carrier gas and solids. A carrier gas is a medium which is gaseous at the application temperature, preferably compressed air can be used. The solids can be solids stable at the application temperature such as plastic beads, glass beads or coal dust. However, preference is given to using thermolabile solids such as solid carbon dioxide and / or ice (water ice).

The claimed process parameters enable effective cleaning, in particular of the compressor or compressor of an engine. The cleaning medium follows the flow in the compressor and achieves a cleaning effect in all stages of the compressor, especially in the rearmost stages. In particular, it is achieved that thermolabile solids such as carbon dioxide or ice in particular do not give up all the kinetic energy and / or sublime or melt in the front stages of the compressor. Instead, the parameters only give the solids a basic impulse that feeds them into the engine. The solid matter is then carried along by the gas flow in the engine and thus also conveyed to the rearmost compressor stages. The pressure of the carrier gas is therefore 1 to 5 bar, preferably 2 to 4 bar. A particularly preferred pressure is 3 bar.

In order to enable the desired entrainment of the solids by the air flow in the compressor without the solids hitting the inner or outer compressor wall prematurely, the exit direction of the nozzle (this term denotes the main exit direction) should extend as far into the compressor as possible without this exit direction or its imaginary axis touches the walls of the compressor. To this end it is provided that the outlet of the at least one nozzle is arranged at a radial distance from the axis of rotation of the engine which corresponds to 0.5 to 1.2 times, preferably 0.5 to 1 times the radius of the upstream inlet opening of the first compressor stage. The outlet is therefore closer to the outer compressor wall in the radial direction than to the axis of rotation of the engine or compressor. The main exit direction of the nozzle is directed obliquely inwards towards the axis of rotation of the engine and forms an angle of 10 to 30 °, preferably 12 to 25 °, more preferably 16 to 19 ° with this axis.

The combination of these process parameters allows an effective cleaning of the compressor (core engine) of jet engines over their entire length, in particular also in the rear stages in the direction of flow.

A particularly preferred compressor geometry has a curved flow channel, with a convex curvature of the flow channel arranged radially inwardly in the flow direction and a convex curvature of the flow channel arranged radially outwardly arranged behind it in the flow direction. The term radially inwardly arranged convex curvature in the front in the flow direction denotes an inward curvature of the flow channel in the direction of the axis of rotation of the jet engine and the term of the radially outwardly arranged convex curvature arranged behind it in the flow direction refers to an outward curvature of the flow channel. In a compressor geometry that is particularly preferred for them In an advantageous variant of the method, the main exit direction of the at least one nozzle can preferably enclose an angle with the axis of rotation of the engine which is between β and α; where β is the angle between the axis of rotation of the engine and a first straight line, which runs as a tangent to the radially inwardly arranged convex curvature of the flow channel of the compressor in the flow direction and to the radially outwardly arranged convex curvature of the flow channel arranged behind it in the flow direction; and where α is the angle between the axis of rotation of the engine and a second straight line which runs as a tangent to the radially outer edge of the inlet of the compressor (compressor) and to the radially inner convex curvature of the flow channel arranged behind it in the flow direction. Furthermore, the outlet of the at least one nozzle can preferably be arranged at a radial distance from the axis of rotation of the engine that lies between the radial distances of the intersection points of the first and second straight lines with the radial plane in which the outlet of the at least one nozzle is arranged. The term radial plane denotes a plane arranged perpendicular to the axis of rotation.

The solids are preferably selected from the group consisting of solid carbon dioxide and water ice. Solid carbon dioxide is particularly preferred. Carbon dioxide and / or water ice can particularly preferably be used in the form of pellets. It is also possible to use water ice as crushed ice.

Pellets can be produced from liquid CO ₂ in a so-called pelletiser and are easy to store. Provision can be made for a supply device to convey prefabricated pellets to the nozzle device with the aid of the carrier gas. It is also possible, however, for the supply device to have a device to produce solid carbon dioxide pellets or solid carbon dioxide snow from liquid carbon dioxide and to convey them to the nozzle device with the carrier gas. In both cases, the solid carbon dioxide emerges from the nozzles of the nozzle device and reaches the engine to be cleaned. In the document "Carbon Dioxide Blasting Operations" of the US armed forces, the technology for the production of CO ₂ pellets is described. Pellets are obtained, for example, by compressing solid CO ₂ (for example flakes) in a pelletiser or the like. The production of ice pellets (water ice) is familiar to the person skilled in the art and does not require any further explanation here.

In a variant of the method, the cleaning medium can have solid carbon dioxide and water ice in a mass ratio of 5: 1 to 1: 5, preferably 1: 2 to 2: 1. Basically it is already known ( WO 2012/123098 A1 ) to provide a mixture of pellets made of carbon dioxide and ice as a solid abrasive for cleaning surfaces. It has been shown, however, that this mixture can be used in a particularly advantageous manner for cleaning jet engines, since the greater part of the solid carbon dioxide already sublimes in the front area of the compressor and cleans it on the one hand through the kinetic energy of the collision and through thermal effects . Due to the heat-cold tension induced by the carbon dioxide, impurities are removed from peeled off the surfaces of the engine parts. The ice added in the mixture has a higher hardness and longer shelf life than solid carbon dioxide. As a result, on the one hand, it improves the mechanical cleaning effect through the kinetic energy of the impact and is better able to penetrate the compressor as a whole up to the rear stages and also develop a cleaning effect there. The mixture used causes, on the one hand, a largely complete and uniform cleaning of all stages of the compressor and, on the other hand, only introduces comparatively small amounts of water into the engine. This introduced water is generally transported away from the engine for the most part by the carrier gas used (preferably air) or by the air stream flowing through the engine during dry cranking.

The mean size of the pellets used is preferably in the range 1 to 10 mm, preferably it can be about 3 mm. If elongated pellets are used, their length can be, for example, 3 to 6 mm, the dimension transverse to the longitudinal extension, for example, about 3 mm. The solids with a mass flow rate of 100 to 2000 kg / h, more preferably 200 to 1500 kg / h, more preferably 350 to 2000 kg / h, more preferably 400 to 2000 kg / h, more preferably 350 to 1200 kg / h are preferred , more preferably 400 to 1200 kg / h, more preferably 100 to 600 kg / h, more preferably 200 to 500 kg / h, more preferably 350 to 450 kg / h. The duration of the cleaning process (pure blasting time without breaks) is preferably 1 to 15 minutes, more preferably 2 to 10 minutes min, more preferably 4 to 8 min. Thus, for example, 1.5 to 200 kg, preferably 35 to 200 kg, more preferably 40 to 200 kg, more preferably 40 to 120 kg, more preferably 1.5 to 50 kg can be used during a cleaning process , more preferably 3 to 35 kg, more preferably 7 to 25 kg of solids are introduced into the engine.

The nozzle or nozzles are preferably flat jet nozzles, for example flat jet nozzles with an opening angle of 1 °.

The dry cranking or rotation of the jet engine during the cleaning process is preferably carried out at a fan speed of 50 to 500 min ^-1 , preferably 100 to 300 min ^-1 , more preferably 120 to 250 min ^-1 . A fan speed of between 150 and 250 min ^-1 is particularly preferred. The cleaning can also take place when the engine is idling. The speed is then preferably 500 to 1500 min ^-1 .

The subject of the invention is a nozzle device with at least one nozzle which is designed for introducing cleaning medium containing solids into a jet engine, which has means for the rotationally fixed connection to the shaft of the turbo fan of a jet engine, and which has a rotary coupling to which a line connection can be connected .

A basic idea of the invention is that the lines for the cleaning medium from the rotary coupling to the outlet of the nozzle have transition angles or angles of curvature that are as gentle and not too large as possible, in order to enable the solids to be conveyed with as little friction as possible using the carrier gas. In the invention, the use of flexible hoses that can be dismantled enables the solids to be guided in a sufficiently gently curved manner. On the other hand, the hoses ensure that the nozzle device is sufficiently small for storage and transport and not too bulky; in particular, the hoses can preferably be dismantled and transported or stored separately for transport and storage.

A line connection connects the nozzle device with a supply device, this supply device makes the cleaning medium available (for example in tanks) and can be provided with operating and drive devices, pumps, energy storage devices or the like be. It is preferably designed as a mobile, in particular a mobile unit.

The nozzle device has one or more nozzles. It is particularly preferred if the nozzle device has at least two nozzles.

Due to the non-rotatable connection with the shaft, the nozzle device can rotate with dry cranking, i.e. when the engine is slowly cranked without injection of kerosene.

The term rotary coupling between the nozzle device and the line connection is to be understood functionally and refers to any device that is suitable for producing a sufficiently stable, preferably pressure-resistant and tight connection between the stationary part of the line connection and the nozzle device rotating with the fan. The purpose of the rotary coupling is to guide the cleaning medium from the stationary supply device into the rotating nozzle device and then to let it emerge from the nozzles.

The rotary coupling is preferably located in the front area of the nozzle device, ie in that area which, in the assembled state, points upstream, ie away from the inlet of the jet engine. The outlet opening of the nozzles is accordingly provided in the axial end region of the nozzle device pointing away therefrom, that is to say in the downstream end region in the assembled state. This arrangement makes it possible to either insert the nozzles through the spaces between the blades when they are mounted on the shaft of the fan of a turbofan engine, so that they are arranged directly in front of the first compressor stage, or at least to be aligned in such a way that they spray directly onto the first compressor stage through the spaces between the blades of the turbofan.

The outlet of the rotary coupling on the nozzle side is preferably located diametrically opposite the inlet. The inlet preferably points in the axial direction and upstream, that is to say in the direction from which, in the assembled state of the nozzle device on an engine, the flow of the engine takes place. The diametrically opposite outlet then also takes place downstream in the axial direction. In this way, the cleaning medium undergoes no or at most a slight change in the direction of flow within the rotary coupling, so that there is no undesirable friction of the solids due to bends or too narrow bends in the lines.

In the nozzle device according to the invention, the nozzle or the nozzles are generally arranged in the radially outer region, while the rotary coupling is usually arranged in the axis of rotation or axis of rotation. In order to enable the cleaning medium to be guided through lines or flexible hoses with slight curvatures, it is advantageous if the rotary coupling, which usually represents the upstream axial end of the nozzle device, is provided by the means for the rotationally fixed connection to the turbo fan shaft, which is usually represent the downstream end of the nozzle device according to the invention, has a sufficiently large axial distance, which allows or facilitates guidance of the lines from the rotary coupling to the nozzles with sufficiently large radii of curvature. According to the invention, the axial distance between the rotary coupling and the said means for the rotationally fixed connection to the shaft of the turbofan is 0.2 to 2 m. This distance can preferably be 0.5 to 2 m, more preferably 0.75 to 1.25 m. Furthermore, the guidance of the cleaning medium from the inlet of the at least one nozzle to the nozzle outlet can be designed essentially in a straight line. The cleaning medium is therefore not deflected between the inlet and outlet within the actual nozzle.

It can be provided that the nozzle device is attached to the turbofan in such a way that its nozzles point through between the blades of the turbofan. This enables targeted cleaning of the compressor stages and then the combustion chamber or turbine stages. The nozzles that rotate during dry cranking cover the first compressor stage evenly over the entire circumference. The cleaning medium is not adversely affected by the turbofan arranged in front of it in the direction of flow, and the direction of spraying of the cleaning medium can thus be adapted to the angle of incidence of the blades of the first compressor stage.

The mass distribution of the nozzle device is preferably rotationally symmetrical about its axis of rotation. In this way, when the nozzle device rotates with it, no significant additional imbalance is introduced. For this purpose, the rotary coupling is preferably seated essentially centrally on the axis of rotation of the device according to the invention in the assembled state. The nozzle device preferably has at least two or more nozzles, which are preferably rotationally symmetrical are distributed around the axis of rotation. The nozzles are preferably designed as flat jet nozzles, which can preferably have an opening angle of 1 °, for example.

According to the invention, the radial distance of the nozzle outlet from the axis of rotation of the engine and thus also the nozzle device can be, for example, 200 to 800 mm, more preferably 400 to 750 mm, more preferably 600 to 700 mm, more preferably 200 to 400 mm, more preferably 230 to 300 mm , more preferably 260 to 280 mm. These values depend on the engine to be cleaned and can vary accordingly. The preferred distance of 260 to 280 mm is suitable, for example, for cleaning the core engine of a CF6-50 engine. The preferred distance of 600 to 700 mm is suitable, for example, for cleaning the core engine of a CF6-80 engine. When the nozzle device is installed, the nozzle outlet is then located in the area of the radially outer edge of the compressor inlet.

The jet plane or main exit direction of the nozzle (s) is preferably directed obliquely inward to the axis of rotation of the engine and forms an angle of 10 to 30 °, preferably 12 to 25 °, more preferably 16 to 19 ° with this axis. The stated values can vary depending on the engine to be cleaned and should be selected so that the main outlet direction of the nozzle (or its imaginary extension) protrudes as far into the compressor as possible without touching the inside or outside walls of the compressor.

In a preferred embodiment, the jet plane or main exit direction of the nozzle (s) can preferably enclose an angle between β and α with the axis of rotation of the engine; where β is the angle between the axis of rotation of the engine and a first one Straight line which runs as a tangent to the radially inwardly arranged convex curvature of the flow channel of the compressor, which is at the front in the flow direction and to the radially outwardly arranged convex curvature of the flow channel arranged behind it in the flow direction; and where α is the angle between the axis of rotation of the engine and a second straight line which runs as a tangent to the radially outer edge of the inlet of the compressor (compressor) and to the radially inner convex curvature of the flow channel arranged behind it in the flow direction.

The means for the rotationally fixed connection to the shaft of the turbofan of the jet engine preferably comprise fastening means for fastening to the turbofan blades, such as, for example, suitably designed hooks with which the nozzle device can be hooked onto the trailing edges (the downstream edges) of the turbofan's blades.

For the rotationally fixed fixing with the shaft of the turbofan, the nozzle device can have a device for essentially positively fitting onto the shaft hub of the fan. Turbofan engines usually have a conically curved hub on the upstream end of the turbofan's shaft, which is intended to improve the flow behavior of the air. The corresponding means for a non-rotatable connection can be placed on this hub. “Essentially form-fitting” in this context means that the shape of the shaft hub is used for the intended positioning of the nozzle device and for fixing it in the desired position. It does not mean, that the entire surface of the shaft hub must be enclosed in a form-fitting manner.

For example, the device can have one or more ring parts with which it can be placed on the shaft hub. In the case of a plurality of ring parts, these have a different diameter which is adapted to the diameter of the shaft hub in the corresponding areas. For example, two axially spaced rings of different diameters can be provided with which the nozzle device is positioned and centered on the shaft hub.

Tension ropes can preferably be provided for further fixation. For example, the nozzle device can be centered on the shaft hub of the fan by means of the ring parts and then tensioned with tensioning cables that are fixed to the rear edge of the turbo fan blades. According to the invention, spring devices can be provided for pretensioning the tensioning cables so that the nozzle device is pressed against the shaft hub with a defined force. The tension ropes are preferably fastened (for example by means of hooks) to the turbo fan blades, preferably to their rear edge.

A supply device for the cleaning medium preferably has storage tanks for the components of the cleaning medium and at least one pump for pressurizing the nozzle device with the cleaning medium. A carrier gas, preferably air, is used. The carrier gas can be pretreated, for example it can be dried so that it absorbs and discharges as large a proportion as possible of the water introduced into the engine can. It can be provided that the carrier gas is cooled so that ice pellets and / or carbon dioxide pellets are as stable as possible in the carrier gas flow. Alternatively, however, it is also possible to heat the carrier gas stream, for example to about 80.degree. This initially seems absurd for carbon dioxide pellets, for example, since it reduces the stability of the pellets. However, the invention has recognized that the warm carrier gas flow supplies the inside of the engine with thermal energy which compensates for the cooling caused by the cleaning medium. This prevents the solid carbon dioxide from being able to develop an insufficient cleaning effect due to excessive cooling (due to the insufficient temperature difference). This can also prevent the water remaining inside the engine from freezing solid if water ice is used as the cleaning medium. Since the carrier gas only acts on the cold pellets for a very short period of time before they can develop their cleaning effect, the influence of the heated carrier gas on the pellets is negligible or negligible.

The invention also relates to an arrangement comprising a jet engine and a nozzle device according to the invention. The arrangement is characterized in that the nozzle device is arranged such that its nozzle (s) is / are directed towards the inlet of the jet engine.

The jet plane or main exit direction of the nozzle (s) is preferably directed obliquely inward to the axis of rotation of the engine and forms an angle of 10 to 30 °, preferably 12 to 25 °, more preferably 16 to 19 ° with this axis.

The outlet of the at least one nozzle is preferably arranged at a radial distance from the axis of rotation of the engine which corresponds to 0.5 to 1.2 times, preferably 0.5 to 1 times the radius of the upstream inlet opening of the first compressor stage. The outlet is therefore closer to the outer compressor wall in the radial direction than to the axis of rotation of the engine or compressor.

In a preferred embodiment, the main outlet direction of the nozzle (s) can enclose an angle with the axis of rotation of the engine which lies between β and α; where β is the angle between the axis of rotation of the engine and a first straight line, which runs as a tangent to the radially inwardly arranged convex curvature of the flow channel of the compressor in the flow direction and to the radially outwardly arranged convex curvature of the flow channel arranged behind it in the flow direction; and where α is the angle between the axis of rotation of the engine and a second straight line which runs as a tangent to the radially outer edge of the inlet of the compressor (compressor) and to the radially inner convex curvature of the flow channel arranged behind it in the flow direction. Furthermore, the outlet of the at least one nozzle can preferably be arranged at a radial distance from the axis of rotation of the engine that lies between the radial distances of the intersection points of the first and second straight lines with the radial plane in which the outlet of the at least one nozzle is arranged.

It can preferably be provided that the nozzle device is rotationally fixed to the shaft of the fan of the jet engine is connected, the axes of rotation of the fan of the jet engine and the nozzle device are arranged essentially concentrically, the nozzles of the nozzle device have a radial distance from the common axis of rotation of the jet engine and the device, which is 0.5 to 1.2 times, preferably 0. 5 to 1 times the radius of the first compressor stage, and the outlet openings of the nozzles are arranged in the axial direction behind the plane of the turbofan and / or the nozzles are arranged in the spaces between the turbofan blades and / or are aligned with the spaces between the turbofan blades, so that the nozzle jets essentially can pass unhindered through the plane of the turbofan.

Fig. 1

eine erste Ansicht einer erfindungsgemäßen Düseneinrichtung;

Fig. 2

eine zweite Ansicht einer erfindungsgemäßen Düseneinrichtung;

Fig. 3

eine Ansicht einer besonders bevorzugten Kompressorgeometrie.

An exemplary embodiment of the invention is explained below with reference to the drawings. Show in it:

Fig. 1

a first view of a nozzle device according to the invention;

Fig. 2

a second view of a nozzle device according to the invention;

Fig. 3

a view of a particularly preferred compressor geometry.

The nozzle device has two ring elements 101, 102, with the aid of which the nozzle device is placed on a shaft hub of the turbofan of a jet engine. In the attached state, the ring elements 101, 102 enclose the shaft hub essentially in a form-fitting manner. To the details of the connection of the nozzle device to a shaft hub is on the WO 2009/132847 A1 referenced. The two ring elements 101, 102 are connected to one another by radial struts 104. At the upstream tip of the nozzle device (in relation to the direction of flow of the engine) there is a rotary coupling denoted as a whole by 105, which has an inlet 110. The rotary coupling 105 can alternatively be designed separately from the branching with the pressure connections 106 and, for example, be connected to it by a short piece of hose, the flexibility of which helps compensate for possible axial deviations during assembly. From this rotary coupling 105 two pressure connections 106 extending axially downstream extend. Two pressure hoses 108 can be connected to the pressure connections 106 (in FIG Fig. 1 For the sake of clarity, only one pressure hose 108 is shown), the other end of which is connected to the inlet of the flat jet nozzles 107. The length and flexibility of these pressure hoses 108 is dimensioned such that, in the assembled state, they are designed in the curvatures so that they allow the blasting medium to be conveyed without interference. Due to the large radii of curvature, solids and in particular pellets can be transported with little friction from the inlet of the rotary coupling 105 to the nozzle outlet 109 of the flat jet nozzles 107. The two flat jet nozzles 107 are thus fed with cleaning medium.

The axial distance between the rotary coupling 105 and the outlet openings 109 of the nozzles 107 is approximately 1.2 m in the exemplary embodiment. This distance is sufficient for the pressure hoses 108 to reach the inlets of the nozzles 107 without excessive curvatures of these pressure hoses 108 with the outlets 106 the rotary coupling 105 can connect. The radial distance between the nozzle outlet 109 and the axis of rotation is approximately 270 mm in the exemplary embodiment. It is designed for cleaning a CF6-50 engine. The main exit direction of the nozzles 107 (this essentially corresponds to their longitudinal axis) forms an angle of 18 ° with the axis of rotation of the nozzle device.

The nozzle device is attached to the shaft hub of a turbofan by means of tension ropes, as detailed in WO 2009/132847 A1 described.

To clean a jet engine, the nozzle device is placed on the shaft hub of the turbofan and fixed to the turbofan's blades. The engine is set in rotation (dry-cranking). The flat jet nozzles 107 are fed with cleaning medium from a supply device (not shown) via the rotary coupling 105 and the pressure hoses 108. This cleaning medium sweeps the inlet of the first compressor stage over its entire circumference and thus carries out the cleaning.

Figure 3 shows the schematic section of an engine with a particularly preferred compressor geometry. A turbo fan blade 301 and the downstream inlet 303 of the compressor 304 relative to the axis of rotation 308 of the engine are shown. The inlet 303 has an edge 305 arranged radially on the outside. In the direction of flow behind the edge 305, a radially inwardly arranged convex curvature 306 of the flow channel 302 of the compressor is arranged. This is an inward curve in the direction of the axis of rotation 308 of the engine. Behind the curve 306 in the direction of flow a radially outwardly arranged convex curvature 307 of the flow channel 302. The main exit direction of the nozzle (s) (in Fig. 3 not shown) can preferably enclose an angle with the axis of rotation 308 of the engine which lies between the angles β and α; where β is the angle between the axis of rotation 308 of the engine and a first straight line 310, which is a tangent to the radially inwardly arranged convex curvature 306 (at point B ₁ ) of the flow channel of the compressor and to the one behind it in the direction of flow, radially outwardly arranged convex curvature 307 (at point B ₂ ) of the flow channel 302 runs; and where α is the angle between the axis of rotation 308 of the engine and a second straight line 311, which is arranged as a tangent to the radially outer edge 305 of the inlet 303 of the compressor 304 (at point P) and to that arranged radially inward in the flow direction convex curvature 306 (at point A) of the flow channel. Furthermore, the outlet of a nozzle (not shown) can be arranged at a radial distance from the axis of rotation 308 of the engine, which is between the radial distances (x _min , x _max ) of the points of intersection (x ₂ , x ₁ ) of the first and second straight lines with that radial plane 309, in which the nozzle outlet (in Fig. 3 not shown) is arranged.

Claims (15)

1. Nozzle installation having at least one nozzle, which is configured for introducing a cleaning medium containing solids into a jet engine, which has means (101, 102, 104) for connecting in a rotationally fixed manner to the shaft of the turbofan of a jet engine, and which has a rotary coupling (105) to which a line connection is able to be connected, wherein the connection of the nozzle-proximal outlet (106) of the rotary coupling (105) to the inlet of the at least one nozzle (107) is established by means of a flexible hose (108), characterized in that the rotary coupling (105) is spaced apart from the means (101, 102, 104) for the rotationally fixed connection to the shaft of the turbofan of a jet engine by 0.2 to 2 m, wherein curvatures present in the flexible hose (108) are configured such that a solid can follow a flow through the flexible hose (108) without hindrance and does not precipitate or sublimate on walls of the flexible hose (108) by virtue of excessively tight curvature radii.
2. Nozzle installation according to Claim 1, characterized in that the nozzle-proximal outlet (106) of the rotary coupling (105) lies diametrically opposite the inlet (110).
3. Nozzle installation according to one of Claims 1 to 2, characterized in that the rotary coupling is spaced apart from the means for the rotationally fixed connection to the shaft of the turbofan of a jet engine by 0.5 to 2 m, preferably 0.75 to 1.25 m.
4. Nozzle installation according to one of Claims 1 to 3, characterized in that the routing of the cleaning medium from the inlet of the at least one nozzle to the nozzle exit is configured so as to be substantially rectilinear.
5. Nozzle installation according to one of Claims 1 to 4, characterized in that said nozzle installation is configured for introducing the cleaning medium into the compressor stages of the jet engine.
6. Nozzle installation according to one of Claims 1 to 5, characterized in that said nozzle installation has at least one nozzle (107).
7. Nozzle installation according to one of Claims 1 to 6, characterized in that said nozzle installation has flat-spray nozzles.
8. Nozzle installation according to one of Claims 1 to 7, characterized in that the radial spacing of the nozzle exit from the rotation axis of the engine is 200 to 800 mm, preferably 400 to 750 mm, furthermore preferably 600 to 700 mm, furthermore preferably 200 to 400 mm, preferably 230 to 300 mm, furthermore preferably 260 to 280 mm.
9. Nozzle installation according to one of Claims 1 to 8, characterized in that the plane of the spray conjointly with the rotation axis of the jet engine encloses an angle which is preferably 10 to 30°, furthermore preferably 12 to 25°, furthermore preferably 16 to 19°.
10. Nozzle installation according to one of Claims 1 to 9, characterized by the following features:

    the plane of the spray conjointly with the rotation axis of the jet engine encloses an angle which is between β and α; wherein

    β is the angle between the rotation axis of the engine and a first straight line which runs as a tangent on that convex curvature of the flow duct of the compressor that in the flow direction is at the front and is disposed so as to be radially inward, and on that convex curvature of the flow duct that in the flow direction is disposed behind the former and so as to be radially outward;

    α is the angle between the rotation axis of the engine and a second straight line which runs as a tangent on that periphery of the inlet of the compressor that is disposed so as to be radially outward, and on that convex curvature of the flow duct that in the flow direction is disposed behind the former and so as to be radially inward.
11. Assembly of a jet engine and a nozzle installation according to one of Claims 1 to 10, characterized in that the nozzle installation is disposed such that the nozzle(s) (107) thereof is/are directed toward the inlet of the jet engine such that the cleaning medium can make its way into the jet engine.
12. Assembly according to Claim 11, characterized in that the main exit direction of the at least one nozzle (107) in relation to the rotation axis of the jet engine encloses an angle of 10 to 30°, preferably of 15 to 25°, furthermore preferably of 16 to 19°.
13. Assembly according to Claim 11 or 12, characterized in that the exit of the at least one nozzle (107) is disposed at a radial spacing from the rotation axis of the engine which corresponds to 0.5 to 1.2 times, preferably to 0.5 to 1 times, the radius of the entry opening of the first compressor stage that is directed upstream.
14. Assembly according to one of Claims 11 to 13, characterized by the following features:

    the main exit direction of the at least one nozzle (107) in relation to the rotation axis of the jet engine encloses an angle which is between β and α;
    wherein

    β is the angle between the rotation axis of the engine and a first straight line which runs as a tangent on that convex curvature of the flow duct of the compressor that in the flow direction is at the front and is disposed so as to be radially inward, and on that convex curvature of the flow duct that in the flow direction is disposed behind the former and so as to be radially outward;

    α is the angle between the rotation axis of the engine and a second straight line which runs as a tangent on that periphery of the inlet of the compressor that is disposed so as to be radially outward, and on that convex curvature of the flow duct that in the flow direction is disposed behind the former and so as to be radially inward;

    the exit (109) of the at least one nozzle (107) is disposed at a radial spacing from the rotation axis of the engine which lies between the radial spacings of the intersection points of the first and the second straight line with that radial plane in which the exit (109) is disposed.
15. Assembly according to one of Claims 11 to 14, characterized by the following features:

    a) the nozzle installation is connected in rotationally fixed manner to the shaft of the turbofan of the jet engine;

    b) the rotation axes of the turbofan of the jet engine and of the nozzle installation are disposed so as to be substantially concentric;

    c) the nozzles (107) of the nozzle installation have a radial spacing from the common rotation axis of the jet engine and of the nozzle installation that corresponds to 0.5 to 1.2 times, preferably to 0.5 to 1 times, the radius of the entry opening of the first compressor stage;

    d) the exit openings (109) of the nozzles (107) in the axial direction are disposed behind the plane of the turbofan, and/or the nozzles (107) are disposed in the intermediate spaces of the blades of the turbofan and/or directed toward intermediate spaces of the blades of the turbofan such that the nozzle jets may pass through the plane of the turbofan substantially without hindrance.

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