DE102011015252A1 - Cleaning lance and method for cleaning engines - Google Patents

Abstract

The invention relates to a lance for cleaning components of a gas turbine, with a supply for cleaning medium and outlet openings (11, 19) for cleaning medium arranged in an end region of the lance (1). According to the invention it is provided that it has at least two outlet openings for cleaning medium which allow cleaning medium to exit in two diametrically opposite jet segments (3, 4) pointing radially outward from the axis of the lance. The invention also relates to a cleaning method using this lance.

Description

The invention relates to a lance for the cleaning of components of a gas turbine, in particular components of a jet engine of an aircraft, according to the preamble of claim 1. The invention further relates to a method for the purification of such components using a lance according to the invention.

Aircraft jet engines have in known manner 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 release some of their thermal and mechanical energy, which is used to drive the compressor stages. Today jet engines of commercial airliners have predominantly a so-called turbofan, which is arranged upstream of the compressor stages and usually has a considerably larger diameter than the compressor stages. The turbofan is also powered by the turbine stages and allows a significant portion of the air passing through the engine as a so-called secondary air flow to bypass the compressor stages, combustor and turbine stages. By such a side stream, the efficiency of an engine can be significantly increased and also provided for improved noise reduction of the engine.

Contamination of an aircraft jet engine can lead to a reduction in efficiency, resulting in increased fuel consumption and thus increased environmental impact. 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 of the combustion chamber. These contaminants form a coating on the air-flowed parts of an aircraft engine and affect the surface quality. This affects the thermodynamic efficiency of the engine. In this case, in particular, the blades in the compressor stages are mentioned whose pollution has a significant impact on the efficiency of the entire engine.

To eliminate impurities is known to clean an engine with a cleaning liquid, usually hot water. From the WO 2005/120953 An arrangement is known in which a plurality of cleaning nozzles upstream of the turbofan or the compressor stages are arranged. The cleaning fluid is then sprayed into the engine. The engine can thereby rotate in the so-called dry-cranking, ie the blades of the engine rotate without burning kerosene in the combustion chamber. The cleaning fluid introduced into the engine is intended to wash away soiling from the surfaces of the engine components.

Alternatively to the use of water as a cleaning medium, the use of coal dust is known. The pulverized coal, like the water, is introduced through nozzles into the engine and removes contaminants from surfaces due to abrasive effects. However, the coal dust also attacks the surface of the engine parts, 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 remain unwanted remains of the cleaning material in the engine.

Out WO 2009/132847 A1 It is known to clean jet engines of an aircraft with solid carbon dioxide (snow or pellets) as a cleaning medium.

The invention is based on the object to provide a lance and a method of the type mentioned, or allow a handling technically simple and effective cleaning of components of a gas turbine or a jet engine.

In a lance according to the invention is provided that it has at least two outlet openings for cleaning medium, the cleaning medium in two radially outwardly from the axis of the lance facing outward, diametrically opposite Strahlsegementen emerge.

• a) Einführen der Lanze von einer Radialseite her in den zu reinigenden Bereich der Komponente, so dass die einander diametral gegenüber liegenden Strahlsegmente jeweils im wesentlichen in eine Axialrichtung der Komponente weisen,
• b) Zufuhr von Reinigungsmedium und Reinigen der von den Strahlsegmenten überstrichenen Komponenten.

The process according to the invention uses a lance according to the invention and has the following steps:

• a) introducing the lance from a radial side into the region of the component to be cleaned such that the diametrically opposite beam segments each point essentially in an axial direction of the component,
• b) Supply of cleaning medium and cleaning of swept by the beam segments components.

First, some terms used in the invention are explained.

A lance according to the invention is an elongated device which usually has outlet openings for cleaning medium in one end region. As a rule, it has in the second end region a supply or a connection for cleaning medium, for example one Connection for a supply hose of the cleaning medium. It may be formed hollow inside to allow a flow of cleaning medium from the supply to the outlet openings. According to the invention, it has at least two outlet openings which allow the cleaning medium to emerge in two jet segments pointing radially outward from the axis of the lance and diametrically opposite one another. The term beam segment designates that spatial region which is swept over by the cleaning medium emerging from the corresponding opening during operation of the lance. Such a beam segment may for example have the shape of a cone. According to the invention, the beam segments extend radially outward from the axis of the lance. This means that the main direction of each beam segment is approximately radially away from the axis of the lance. The beam direction of the segments is therefore not in the direction of the axis of the lance, but is transverse to it. The two beam segments are diametrically opposite each other. This means in the context of the invention that it is possible to run in the region of the outlet openings an imaginary straight line perpendicular through the axis of the lance, which runs straight through both diametrically opposite beam segments. In other words, this claim feature thus means that the two beam segments point in mutually opposite directions pointing away from each other, so that simultaneous operation in these two spatial directions is possible during operation of the lance.

When cleaning a jet engine it comes to maintain or for the improvement of the efficiency in particular to an effective cleaning of Schaufein (blades) of the compressor and turbine stages of the so-called core engine, ie that area of the engine through which the actual combustion air or The combustion gases flow. In the operation of the engine pollute in particular those areas of the blades, which can not be cleaned or insufficiently cleaned by the usual in the prior art introduction of cleaning medium (usually from the suction side of the engine ago). On the one hand, these are the blade surfaces directed downstream in the direction of flow of the engine and, on the other hand, those blade surfaces which are shaded by adjacent blades in the axial direction of the engine and, therefore, are difficult to reach by cleaning medium. In the high-pressure compressor of a jet engine, soils such as sand deposits are located mainly in the region of the trailing edge of each compressor blade viewed in the direction of rotation of the compressor. This trailing edge is often shadowed in the axial direction of the engine by the leading edge of the adjacent blade and is therefore difficult to clean. Such shading is particularly problematic when a cleaning according to the invention with solid carbon dioxide (dry ice) takes place, since dry ice is usually sublimated on first encounter with a surface and thus (unlike a liquid at room temperature cleaning medium such as water) not of such Bounce surface and therefore can have no secondary cleaning effects on hidden surfaces.

According to the invention, it is provided that the lance does not radiate, as usual in the prior art, substantially in the longitudinal or axial direction of the lance, but in two diametrically opposite directions radially to the axis of the lance. In carrying out the method according to the invention, this lance is guided from the radial side of the engine or its component to be cleaned forth in the region to be cleaned of the component, so that the diametrically opposite beam segments each have substantially in an axial direction of this component. In other words, the lance is introduced from the side into the component to be cleaned and emits in operation cleaning medium in the axial direction of the component to be cleaned both forward and backward (upstream and downstream), so that, for example, the downstream surfaces of blades directly be charged with cleaning medium.

The insertion of the lance can according to the invention in particular by testing and / or maintenance openings, in particular Boroskopöffnungen take place. These openings allow access to the areas to be cleaned radially from the side. The insertion of the lance is preferably carried out in each case between two compressor stages or turbine stages.

During operation of the lance, one jet segment is then directed to the pressure side of the upstream stage and the other jet segment to the suction side of the downstream stage. It may be preferred according to the invention to introduce a lance successively or more lances simultaneously into a plurality of openings located at an axial height of the engine component in order to allow a good cleaning over the entire circumference of the engine component. Alternatively or additionally, it is possible to slowly rotate a rotating engine component past the lance. The entire scope of this engine component is covered.

For a good cleaning effect, it is preferable if the cleaning jet impinges perpendicular to the surface to be cleaned or this Vertical as far as possible is approximated. It may therefore be necessary to adapt the size and exit angle of the outlet openings of the lance according to the invention to the component to be cleaned or the engine to be cleaned, since in particular the angle of attack and the shape (for example convex or concave) of the blades can vary. According to the invention, it may be preferred that each beam segment in the circumferential direction of the lance has an opening angle of 30 to 110 °, preferably 40 to 100 °, more preferably 50 to 90 °, more preferably 60 to 90 °. This opening angle is the angle range seen in the circumferential direction of the lance, which is actually swept by the corresponding jet segment with cleaning medium in operation.

As already explained above, the two beam segments in diametrically opposite directions. If the direction or the angle 0 ° is assigned to a straight line pointing radially away from the longitudinal axis of the lance, the first beam segment can start in the circumferential direction of the lance between 150 and 180 ° and end between 210 and 260 °. This first beam segment thus points away from the hypothetical line. The second beam segment can start in the circumferential direction of the lance between 320 and 140 ° and end between 50 and 70 °. This second beam segment thus includes this hypothetical straight line pointing in the direction of 0 °. The main direction and the opening angle of each jet segment can be adapted to the conditions of an engine to be cleaned. In the context of the invention, it is possible to provide, for example, for the cleaning of the various compressor stages adapted lances whose length, radius and beam segments are designed so that after insertion into the associated opening (eg Boroskopöffnung) the blades (blades) of the upstream and irradiated downstream of the lance position at an angle which is as close as possible to 90 °, since then the best cleaning effect occurs.

The length of a lance can be adapted to the inside radius of the engine area to be cleaned. The term length here refers to the free region of the lance projecting from the borescope opening into the interior of the engine. In the context of the invention, this length can be, for example, between 50 and 500 mm, preferably 60 and 300 mm.

The diameter of a lance according to the invention is adapted to the diameter of the bore through which the lance is inserted into the engine interior. It can for example be between 5 and 20 mm, preferably 10 mm. The lance may have a means for fixing in the associated opening of the engine. For fixing in a Boroskopöffnung the lance may for example have a thread and be screwed into the corresponding opening.

According to the invention, it is possible for each jet segment to be fed by two or more outlet openings spaced axially from one another. In this way it is possible to increase the extent of each beam segment in the longitudinal direction of the lance. This enlargement of the extension in the longitudinal direction of the lance means in the context of the method according to the invention that a larger area of the radius of the component to be cleaned can be cleaned simultaneously, without the lance having to be displaced in the radial direction of the component. If the extent of the jet segment in the longitudinal direction of the lance is less than the radial extent of the region of the engine component to be cleaned, a complete cleaning may require the lance to be pushed back and forth in the radial direction of the component.

According to the invention, it is particularly preferred if solid carbon dioxide is used as the cleaning medium. These may be pellets or carbon dioxide snow. The carbon dioxide snow can be generated in situ by the escape of liquid carbon dioxide from the outlet openings of the lance.

The solid carbon dioxide may be provided in a supply device in the form of pellets which are sprayed from the exit opening by means of a propellant gas. It is also possible to provide liquid carbon dioxide as a precursor of the cleaning medium in the supply device. The liquid carbon dioxide solidifies at the exit from the outlet opening at least partially and forms a solid component in the form of carbon dioxide flakes or carbon dioxide snow. When using carbon dioxide pellets, it is preferred that the deflection of the pellets from the axial direction of the lance (in which they are fed into the lance and passed therethrough) by a continuous, no or little discontinuities curvature occurs. Such a continuous deflection avoids that the pellets bounce in the region of the deflection, for example, and sublimate completely or substantially before they leave the lance. In the context of the invention, it is preferably provided in a lance provided for cleaning with carbon dioxide pellets that the supply for cleaning medium has at least two supply pipes which are curved in the end region of the lance away from the axial direction of the lance in the radial direction and have outlet openings pointing in at least two radial directions , The curvature of these two or more feed tubes from the axial direction in the intended (radial) discharge direction is preferably carried out continuously and with the largest possible radius of curvature. It is understood that this radius of curvature is limited by the available diameter of the lance. This embodiment of the invention allows a "gentle" deflection of the pellets from the feed direction (axial direction) in the intended discharge direction, without the pellets already sublimate to significant parts in this deflection.

Liquid carbon dioxide comes into contact with ambient air, in which it z. B. exits through a nozzle, so a part immediately assumes the gas form. Another part of the carbon dioxide gets stuck in the form of flakes. This is due to the fact that the part of the carbon dioxide passing from the liquid to the gaseous state binds a great deal of heat, which is removed from the remaining liquid part, as a result of which the temperature of the carbon dioxide drops to the point at which the carbon dioxide solidifies. The solid carbon dioxide is thus obtained as white, snow-like flakes, which last quite a long time in the air, regardless of the temperature of the air. Because of the poor conductivity for heat and the very low temperature of the solid carbon dioxide, only a very slow sublimation takes place. The gaseous escaping from the flakes carbon dioxide forms a protective layer around the flakes, which usually prevents direct contact with the solid flakes.

Pellets can be produced in a so-called pelletizer from liquid CO ₂ and are well storable. It can be provided that the supply device already conveys prefabricated pellets with the aid of a propellant gas to the nozzle device. However, it is also possible that the supply device has a device for forming carbon dioxide pellets from liquid carbon dioxide, and conveys these with a propellant gas to the outlet opening. In both cases, the solid carbon dioxide exits the outlet openings and enters the engine to be cleaned.

In the context of the process according to the invention, the throughput of cleaning medium carbon dioxide can be, for example, between 10 and 100 kg / h, preferably 20 and 80 kg / h. When using pellets, a throughput of 40-60 kg / h may be preferred. The throughput is adapted to the lance used (length, number and size of the outlet openings) and the respective cleaning task.

Compared to water, carbon dioxide as a cleaning medium offers the advantage that it can be used at any outside temperature, ie. H. even at temperatures below 5 ° C. That's why it can be used year-round. In addition, the carbon dioxide flakes sublime completely after some time, so that there are no residues in the engine. Due to the mentioned protective layer by the gas escaping from the flakes, the carbon dioxide flakes also not abrasive, such. B. the already known cleaning medium coal dust. Rather, the cleaning effect is essentially due to thermal effects to conditions. Due to the induced by the carbon dioxide flakes heat-cold voltages, the impurities are detached from the surfaces of the engine parts. The detached dirt is blown either at a possible dry-cranking by the then existing air flow from the engine, but at the latest when starting the engine for the first time after cleaning with carbon dioxide.

In the context of the method according to the invention, the components to be cleaned are preferably selected from the group consisting of high-pressure compressor, high-pressure turbine and low-pressure turbine of a jet engine.

An embodiment of the invention will be explained below with reference to the drawing. Show:

1a : Schematically an axial section through a lance according to the invention in the region of the outlet openings;

1b : Schematically a radial section through a lance according to the invention in the region of the outlet openings;

2 : Schematically, the positioning of a lance according to the invention in the range of different stages of a high-pressure compressor of a jet engine;

3 FIG. 2 schematically shows a section through an embodiment of a lance according to the invention; FIG.

4 schematically shows the exit region of a lance, in which a separate deflection of the cleaning medium from the axial to the radial direction takes place in two separate curved tubes.

1a and 1b schematically show an axial or radial section of a lance according to the invention in the region of the outlet openings for cleaning medium. Into the lance body 1 is a coordinate system for illustrative purposes 2 can be illustrated with its help, in which directions relative to the circumference of the lance body 1 Cleaning medium from the outlet openings 19 can escape. It can be seen that the two schematically illustrated beam segments 3 and 4 in each other roughly diametrically facing opposite directions. Relative to the 0 ° axis of the coordinate system 2 extends the opening angle of the jet segment 3 of about 330-60 ° and the opening angle of the diametrically opposed jet segment 4 from 160-220 °. For the purpose of deflecting the axially through the lance body 1 flowing cleaning medium towards the outlet openings 19 points the lance in the area of these outlet openings 19 a deflecting body 16 on, its baffles 17 Redirect impinging cleaning medium in the radial direction and out of the outlet openings 19 let escape. The baffles 17 may for example have the shape of a cone tip. Opposing baffles may, for example, include between them an angle of 80-130 °, as in FIG 18 indicated.

2 schematically shows the inventive method using the example of cleaning a high-pressure compressor of a jet engine. The figure shows a section of the sequence of rotor and stator segments of this high-pressure compressor. The rotating rotor segments have rotor blades 7 (Blades), the stator segments have rigid vanes 6 (Vanes) up. The arrow 5 points in the direction of the longitudinal axis of the compressor. In the area of the stator segments Boroskopöffnungen are arranged, which are usually used for visual inspection of the state of the compressor. Through these openings, a horoscope can be introduced and the state of the visible environment can be inspected. By slowly rotating the compressor (dry-cranking), it is possible to pass adjacent rotor segments on the borescope to a certain extent and to check the condition of this rotor segment and the associated blades over the entire circumference.

The inventive method uses these openings to cleaning lances 1 from the radial side of the compressor to effectively clean all stages of the compressor directly. One recognizes in 2 that the lance 1 the shape is introduced into the region of a stator segment that the beam segment 3 the concave surfaces of the blades 7 of the upstream adjacent rotor segment sweeps and impinges on these surfaces at an angle near the vertical. The beam segment 4 is directed downstream and impinges on the convex blade surfaces of the blades 7 of the downstream rotor segment. During the cleaning process, the rotor can be slowly rotated so that the cleaning medium sweeps over all rotor blades. As in 2 can detect lances in the region of each stator segment between two rotor segments 1 be introduced for cleaning the respective adjacent stator segments. In the context of the method according to the invention, such a purification of several stages can be carried out either sequentially, ie one or optionally several lances 1 are successively introduced into the respective openings, or such cleaning can be done in parallel by a plurality of lances 1 is simultaneously positioned through corresponding openings.

3 schematically shows a longitudinal section through a lance according to the invention. The lance 1 has a lance body 8th on, whose connection end 9 for connection to a generator of carbon dioxide (liquid) is provided. A lance holder with a thread 10 is for attaching the lance 1 formed by screwing into a Boroskopöffnung. In the body 8th are radially directed outlet openings 11 provided by the carbon dioxide escape. can. If the interior of the lance body 8th fed with liquid carbon dioxide, it exits the openings 11 firmly as carbon dioxide snow.

4 schematically shows another embodiment of a lance according to the invention, which is provided for cleaning with carbon dioxide pellets. The lance body 8th branches into two feed pipes 12 and 13 that are in the area of the exit end 14 the lance having a radius of curvature R are curved from the axial to the radial direction. The main exit direction of the pellets from the tube 13 is at 15 indicated, α is an example of an opening angle (half angle), which can take the exiting pellets. The diameter d of the two tubes 12 . 13 together is sized so that it is less than or equal to the available diameter D of the opening through which the lance is inserted.

The invention enables a simple, quick and thorough cleaning of components of a jet engine, without this having to be disassembled or disassembled (On Wing cleaning).

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2005/120953 [0004]
• WO 2009/132847 A1 [0006]

Claims (13)

Lance for cleaning components of a gas turbine, with a supply for cleaning medium and in one end of the lance ( 1 ) arranged outlet openings for cleaning medium, characterized in that they at least two outlet openings ( 11 . 19 ) for cleaning medium, the cleaning medium in two radially from the axis of the lance outwardly facing, diametrically opposite Strahlsegementen ( 3 . 4 ). Lance according to claim 1, characterized in that each beam segment ( 3 . 4 ) in the circumferential direction of the lance an opening angle of 30 to 110 °, preferably 40 to 100 °, more preferably 50 to 90 °, more preferably 60 to 90 °. Lance according to claim 2, characterized in that the first beam segment ( 4 ) starts in the circumferential direction of the lance between 150 and 180 ° and ends between 210 and 260 °. Lance according to claim 2 or 3, characterized in that the second beam segment ( 3 ) starts in the circumferential direction of the lance between 320 and 340 ° and ends between 50 and 70 °. Lance according to one of claims 1 to 4, characterized in that the supply for cleaning medium at least two supply pipes ( 12 . 13 ), which are curved in the end region of the lance away from the axial direction of the lance in the radial direction and have in at least two radial directions pointing outlet openings. Lance according to one of claims 1 to 4, characterized in that each beam segment ( 3 . 4 ) of two or more axially spaced outlet openings ( 11 ) is fed. Lance according to one of claims 1 to 6, characterized in that it is designed for insertion through inspection and / or maintenance openings, in particular Boroskopöffnungen the gas turbine. A method for cleaning components of a gas turbine using a lance according to any one of claims 1 to 7, comprising the steps of: a) inserting the lance ( 1 ) from a radial side in the region to be cleaned of the component, so that the diametrically opposite beam segments ( 3 . 4 ) each have substantially in an axial direction of the component, b) supply of cleaning medium and cleaning the swept over by the beam segments components. A method according to claim 8, characterized in that the components to be cleaned are selected from the group consisting of high pressure compressor, high pressure turbine and low pressure turbine of a jet engine Method according to claim 8 or 9, characterized in that the lance ( 1 ) is introduced through inspection and / or maintenance openings, in particular Boroskopöffnungen. Method according to one of claims 8 to 10, characterized in that solid carbon dioxide is used as the cleaning medium. Method according to one of claims 8 to 11, characterized in that the cleaning lance ( 1 ) is displaced during cleaning in the radial direction of the component. Method according to one of claims 8 to 12, characterized in that during cleaning a jet segment ( 3 ) upstream surfaces of the component and another beam segment ( 4 ) sweeps downstream surfaces of the component.

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