Method for cleaning an internal region of a turbomachine by injecting water

Abstract

The invention relates to a method for cleaning an internal region (1) of a turbomachine (3), the method comprising the following steps: - inserting a tool (5) into an endoscopy port (7) of the turbomachine (3), wherein the tool (5) comprises an injection nozzle (17) for injecting a mixture (21) comprising water in the liquid state or in the vapour state, preferably in the vapour state; - arranging the injection nozzle (17) of the mixture (21) opposite an internal region (1) to be cleaned of the turbomachine (3); - injecting the mixture (21) through the injection nozzle (17) onto the internal region (1) to be cleaned; and - removing the tool (5) from the endoscopy port (7).

Description

[0001] DESCRIPTION

[0002] TITLE: Method for cleaning an internal area of ​​a turbomachine by water injection

[0003] technical field

[0004] The invention relates to a method for cleaning an internal area of ​​a turbomachine, such as for example a turbojet or an aircraft turboprop.

[0005] In particular, the present invention relates to the cleaning of an area of ​​a distributor blade or a moving blade of a low pressure turbine of the turbomachine.

[0006] More specifically, cleaning helps to remove oxidation from cracks and fissures in an area to facilitate its inspection.

[0007] Previous techniques

[0008] A turbomachine typically comprises, from upstream to downstream in the direction of gas flow, a blower, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, and a low-pressure turbine.

[0009] The low-pressure turbine typically has several stages, each stage comprising a bladed rotor wheel and a ring of distributors located downstream of the bladed wheel. The distributor consists of an inner radial platform and an outer radial platform connected by blades.

[0010] During maintenance operations, damage to various areas of the turbomachine is checked, either visually or using instruments. Areas external to the turbomachine are easily accessible from the outside, while internal areas require the insertion of an endoscope through a dedicated endoscopic port. The endoscope allows visualization of areas inside the turbomachine, particularly for checking the condition of the distributors or the moving blades of the low-pressure turbine. Defects can thus be detected, caused, for example, by environmental exposure, contact between parts, wear, or debris.

[0011] These defects significantly reduce the lifespan of parts and can lead to premature removal of turbomachinery when they are complex to resolve.

[0012] The defects most often take the form of cracks and fissures regularly found in turbomachinery.

[0013] There is a crack repair method called "boroblending" which involves removing material to prevent the initiation and potential propagation of cracks. However, this method has limitations because there are areas where this removal would reduce the part's lifespan, necessitating repair or replacement.

[0014] Furthermore, detecting and identifying cracks and their dimensions is sometimes difficult, particularly during endoscopic inspections. This is mostly due to the presence of dust, sand, or oxidation that accumulates at the bottom of the cracks and on the surface, making inspection hazardous and ineffective. Other, more costly operations, such as dye penetrant testing, must then be implemented to properly inspect the turbomachine. However, in many cases, the presence of contaminants at the bottom of cracks and fissures also prevents the proper execution of dye penetrant testing.

[0015] The invention is not limited to the context of cleaning areas of the low-pressure turbine. Indeed, the invention can be applied to the maintenance of any internal part located, for example, in the aerodynamic duct of the turbomachine.

[0016] Description of the invention

[0017] The present invention aims to overcome the aforementioned drawbacks and provide a method for removing dust, sand, oxidation, and pollutants from the components of turbomachinery. The present invention relates to a method for cleaning an internal area of ​​a turbomachine, the method comprising the following steps:

[0018] - A step of inserting a tool into an endoscopy port of the turbomachine, said tool comprising an injection nozzle for a mixture comprising water in liquid or vapor state, preferably in vapor state.

[0019] - A step of positioning the mixture injection nozzle in relation to an internal area of ​​the turbomachine to be cleaned;

[0020] - A step of injecting the mixture through the injection nozzle onto the internal area to be cleaned; and

[0021] - A step of removing the tooling from said endoscopy orifice.

[0022] Thus, water cleaning allows for the cleaning and stripping of surfaces, as well as cracks and crevices in hard-to-reach areas, without damaging the turbomachine's components. Cleaning and deoxidizing these crevices also makes them easier to detect during endoscopic inspection and to determine their dimensions more readily. In particular, nickel oxides and coked oil can be removed using this process, as well as corrosion, soot, dust, and sand.

[0023] Furthermore, the presence of water prevents dust generation, unlike dry stripping. The mixture also requires no reagents or solvents and is environmentally friendly.

[0024] Advantageously, the water included in the mixture is demineralized water.

[0025] In a particular implementation method, the injection step is carried out with a mixture pressure between 0.1 and 0.8 MPa, preferably between 0.4 and 0.6 MPa.

[0026] In a more specific implementation method, the injection step is carried out at a mixture temperature between 120°C and 175°C, preferably between 130°C and 160°C, with the water in the mixture in a vapor state. Advantageously, the mixture comprises particles with a size distribution between 50 and 500 microns, preferably between 125 and 255 microns.

[0027] Advantageously, the particles have a hardness between 2 and 5 on the Mohs scale, preferably between 2.5 and 3.5.

[0028] In one implementation mode, the particles have a density between 1.3 and 1.7 g / cm3, preferably between 1.4 and 1.5 g / cm3.

[0029] In one implementation method, the process further includes a step of checking the internal area by dye penetrant testing after the tooling removal step.

[0030] Preferably, the procedure includes an endoscopic step by inserting an endoscope into the endoscopic orifice and visualizing the internal area before and / or during and / or after any of the steps of the cleaning procedure.

[0031] In particular, the internal area to be cleaned is an area of ​​a distributor blade or a moving blade of a low-pressure turbine of the turbomachine

[0032] Brief description of the drawings

[0033] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0034] [Fig 1] is a schematic view of the different stages of the cleaning process of an internal area of ​​a turbomachine according to the invention; and

[0035] [Fig 2] is a schematic cross-sectional view of a turbomachine surface on which a deposit has formed and is cleaned using tooling to implement the process according to the invention.

[0036] Detailed description of at least one embodiment The different steps implemented by the cleaning process of an internal zone 1 of a turbomachine 3 have been schematically represented in Figure 1.

[0037] Furthermore, a schematic cross-sectional view of an internal zone 1 of a turbomachine 3 and a tooling 5 enabling the implementation of the process have been represented in Figure 2.

[0038] The internal zone 1 to be cleaned is for example an area of ​​a distributor blade or of a moving blade of a low pressure turbine of the turbomachine 3. The internal zone 1 is therefore located inside the housing of the turbomachine 3 and is only accessible through endoscopy ports 7 previously formed in the housing.

[0039] In particular, Figure 2 illustrates a surface 9 of the turbomachine 3 on which a deposit 11 has formed and which needs to be cleaned, in other words removed, by implementing the present method. The deposit 11 includes, for example, dust, sand, corrosion, oxidation, for example nickel oxide, soot, or even coked oil. The surface 9 is, for example, a surface 9 including a crevice 13 that needs to be cleaned.

[0040] For the implementation of said process, a first step 15 is carried out of insertion of the tooling 5 into an endoscopy orifice 7 of the turbomachine 3. For this purpose, the tooling 5 must be sufficiently thin, for example of a size similar to an endoscope used in aeronautics.

[0041] The tooling 5 includes an injection nozzle 17 and an injection channel 19 connecting said injection nozzle 17 to a pump and a reservoir (not shown) containing a mixture 21 intended to be injected onto the internal zone 1 via the injection nozzle 17. The injection nozzle 17 has, for example, an outlet section of the mixture 21 with a diameter between 1 and 10 millimeters, preferably between 1 and 5 millimeters.

[0042] Thus, a step 23 is then carried out of positioning the injection nozzle 17 of the mixture 21 in relation to the internal area 1 to be cleaned of the turbomachine 3. Then, a step 25 is carried out of injecting the mixture 21 by the injection nozzle 17 onto the internal area 1 to be cleaned.

[0043] Preferably, the injection of mixture 21 is direct from the injection nozzle 17 towards the internal zone 1, without being deflected by any obstacle. For example, the injection nozzle 17 is positioned less than five centimeters from the internal zone 1 to be cleaned for the implementation of step 25, which involves injecting mixture 21.

[0044] Mixture 21 comprises water in either a liquid or vapor state. For water in a liquid state, mixture 21 will be described as cold, while for water in a vapor state, mixture 21 will be described as hot.

[0045] To make injection step 25 more effective in cleaning the internal zone 1, pressure injection is preferably applied, for example with a mixture pressure between 0.1 and 0.8 MPa, more preferably between 0.4 and 0.6 MPa. However, excessively high pressure is undesirable to avoid damaging the internal zone 1 and the metal constituting the surface 9 to be cleaned.

[0046] Preferably, mixture 21 includes water in vapor form because this hot mixture is faster than a cold mixture for cleaning the internal area 1.

[0047] In the latter case, injection step 25 can be carried out at a mixture temperature between 120°C and 175°C, preferably between 130°C and 160°C, these temperatures being obtained with pressure injection as described previously.

[0048] Preferably, the water included in mixture 21 is demineralized water, allowing to avoid the deposition of impurities or limescale inside the turbomachine 3.

[0049] In order to increase the abrasiveness of the mixture 21, it is possible to add particles 27 with a particle size between 50 and 500 microns, preferably between 125 and 255 microns.

[0050] The particles 27 are, for example, mineral grains, such as sand grains, so the implementation of the process according to the invention is wet blasting or steam blasting. Thanks to the water, no particles 27 become embedded in the internal zone 1, and the cleaning finish is finer than dry blasting, forming a satin surface with a polished effect.

[0051] In particular, the Arithmetic Mean Roughness, denoted Ra, of the surface 9 after cleaning is between 4 and 7 micrometers.

[0052] Preferably, the particles 27 have a hardness between 2 and 5 on the Mohs scale, preferably between 2.5 and 3.5.

[0053] Advantageously, particles 27 have a density between 1.3 and 1.7 g / cm3, preferably between 1.4 and 1.5 g / cm3.

[0054] Finally, step 29 is performed of removing the tooling 5 from the endoscopy orifice 7 once the internal area 1 has been cleaned.

[0055] Optionally, a step 31 of checking the internal zone 1 by dye penetrant testing is then carried out after step 29 of removing the tooling 5.

[0056] Dye penetrant testing involves applying a colored or fluorescent liquid to the internal area 1 so that the liquid penetrates potential cracks 13. After surface washing of the internal area 1 and drying, a developing product is applied to the internal area 1 so that the presence of cracks 13 and their dimensions can be easily identified, for example by ultraviolet vision, or with an endoscope in the visible range.

[0057] In addition to the steps previously described, the procedure further includes an endoscopic step 33 by inserting an endoscope into the endoscopic orifice 7.

[0058] This step 33 allows visualization of the internal zone 1 before, during, and / or after any of the cleaning procedure steps. The endoscope can be inserted into the endoscopic port 7 at the same time as the instrument 5, or before, or after, once the cleaning has been completed. Visualization of the internal zone 1 with the endoscope allows identification of cracks 13 and determination of their dimensions.

[0059] In addition to the steps previously described, the process further includes a step 35 of repairing the cracks, according to a process known to the person skilled in the art such as for example the application of a soldering paste.

Claims

DEMANDS 1. A method for cleaning an internal area (1) of a turbomachine (3), characterized in that it comprises the following steps: - An insertion step (15) of a tool (5) into an endoscopy port (7) of the turbomachine (3), said tool (5) comprising an injection nozzle (17) of a mixture (21) comprising water in liquid or vapor form; - A positioning step (23) of the injection nozzle (17) of the mixture (21) opposite an internal area (1) to be cleaned of the turbomachine (3); - An injection step (25) of the mixture (21) through the injection nozzle (17) onto the internal area (1) to be cleaned, the injection step (25) being carried out with a pressure of the mixture (21) between 0.1 and 0.8 MPa, preferably between 0.4 and 0.6 MPa, and at a temperature of the mixture (21) between 120°C and 175°C, preferably between 130°C and 160°C, the water included in the mixture (21) being in the vapor state; and - A step of removing (29) the tooling (5) from said endoscopy orifice (7).

2. A method according to claim 1, wherein the water included in the mixture (21) is demineralized water.

3. A process according to any one of claims 1 and 2, wherein the mixture (21) comprises particles (27) with a particle size between 50 and 500 microns, preferably between 125 and 255 microns.

4. A method according to claim 3, wherein the particles (27) have a hardness between 2 and 5 on the Mohs scale, preferably between 2.5 and 3.

5.

5. A method according to any one of claims 3 and 4, wherein the particles (27) have a density of between 1.3 and 1.7 g / cm³ 3 , preferably between 1.4 and 1.5 g / cm³ 3 .

6. A method according to any one of claims 1 to 5, further comprising a step (31) of checking the internal area (1) by dye penetrant testing after the step (29) of removing the tooling (5).

7. A method according to any one of claims 1 to 6, comprising an endoscopic step (33) by inserting an endoscope into the endoscopic orifice (7) and visualizing the internal area (1) before and / or during and / or after any of the steps of the cleaning method.

8. A method according to any one of claims 1 to 7, wherein the internal area (1) to be cleaned is an area of ​​a distributor blade or of a moving blade of a low-pressure turbine of the turbomachine (3).

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