EP2012965A1

EP2012965A1 - Gas turbine component and method for machining gas turbine components during production or reconditioning of said gas turbine components

Info

Publication number: EP2012965A1
Application number: EP07721962A
Authority: EP
Inventors: Reinhold Meier
Original assignee: MTU Aero Engines GmbH
Current assignee: MTU Aero Engines AG
Priority date: 2006-03-09
Filing date: 2007-02-27
Publication date: 2009-01-14
Also published as: US20090274550A1; CA2644094A1; US7841084B2; WO2007101423A1; DE102006010927A1

Abstract

The invention relates to the problem that during diverse machining steps of application to the production or reconditioning of internally cooled gas turbine blades (1), an undesired effect may be had on sections of the gas turbine blade and proposes, as an improvement, to inject the cavity (14) of the gas turbine blades (1) before the machining steps with a plastic material (22) which can be removed without trace, such as polystyrol, which can be subsequently removed again, in particular by heat.

Description

Gas turbine component and method for processing gas turbine components in the production or repair of these gas turbine components

The invention relates to a gas turbine component and to a method for processing gas turbine components in the context of the manufacture or repair of these gas turbine components.

Gas turbine components which have an inner cavity-referred to below as the first inner cavity-are already known. An example of such a design is a blade, such as a blade or blade of a gas turbine or an aircraft engine, which is provided for cooling purposes with an addressed first inner cavity. Such a first inner cavity, which may also be formed as a channel or arrangement of a plurality of cooperating channels or as a chamber or chamber system and / or one or more undercuts (or undercuts), may in this case with holes or slots in combination stand, so that the overall arrangement of the inner cavity and the holes or slots allows air to flow through the blade. Such blades are also referred to as internally cooled or internally air cooled blades.

In the manufacture or repair of such blades, a plurality of processing steps are typically carried out in each case. For example, it may be provided that one of the processing steps carried out during the production is a "pouring" in the blade, the first inner cavity being formed as part of this casting process. The first inner cavity can also be formed in other ways. Holes or cooling holes or slots or cooling slots are usually introduced after the formation of an addressed first cavity. This may be such that cooling holes are introduced by means of a mechanical machining method, such as drilling, which extend from the outer surface of the blade to the first cavity. Another possibility is to introduce such holes or slots by means of a laser. While a mechanical drilling of such cooling holes can be ensured in a relatively simple manner,

i that during drilling of the bore formed in this case opposite boundary portion of the first cavity is not affected or damaged, this is much more difficult when laser drilling. While in the mechanical drilling by controlling the drilling depth an impairment of the mentioned opposite wall portion can be avoided in a simple manner, there is the not insignificant danger during laser drilling that the laser radiation causes undesirable changes on the opposite wall portion of the cavity boundary.

The area of action on which this laser arc is acted upon or the area of action of the laser is thus not only in the area of the laser bore but also on the wall section of the boundary wall of the first cavity opposite the laser bore. It would be desirable, however, that impairments or changes in this opposite wall section could be avoided or reduced.

The problem that is acted in the context of manufacturing or repair of gas turbine components in the context of processing steps or by means of a Bearbeitungswerkszeugs on areas of the component or gas turbine component in which such action is undesirable, however, is not only in the mentioned laser drilling.

This problem can also occur, for example, in the coating of gas turbine components - be it within the scope of the manufacturing process or as part of a repair. If, for example, an internally air-cooled blade is at least partially stripped and then coated again during repair work, there is a risk that the cooling air holes may become clogged or their cross-sectional areas at least reduced during this coating.

In this case also, in one processing step, namely the coating, (inter alia), an area of the component or of the blade is acted upon, in which a corresponding action is undesirable. The invention is based on the object, a method for processing, in particular internal or internal air cooled, gas turbine components, which processing takes place in the production or repair of these gas turbine components to create, with the risk of undesirable or damaging effects in the context of Processing steps on the gas turbine component is reduced or even avoided.

According to the invention, a method according to claim 1 is proposed. An inventive gas turbine component is the subject of claim 9. Preferred embodiments are the subject of the dependent claims.

According to the invention, therefore, a method for processing, in particular internal or internal air-cooled, gas turbine components in the production or repair of these gas turbine components is proposed in which initially provided with at least a first inner cavity component is provided and then at least a first processing step on this Component is performed. In order to limit the area of action given to the component, which is acted upon in the first processing step, plastic material is introduced into the first cavity before the at least one first processing step is carried out. This plastic material is removed after the first processing steps or from the first cavity again. As mentioned, a method for machining gas turbine components is proposed; In this connection, it should be noted that the gas turbine component to be machined does not need to be a finished gas turbine component or a partially finished or serviceable gas turbine component, preferably a gas turbine blade, and more preferably internally cooled or gas turbine scoop. The gas turbine blade may be configured, for example, as a vane or blade of a turbine or a compressor of an aircraft engine.

The plastic material is injected in an advantageous design or applied in a liquid or viscous state. In a particularly expedient design is provided that the plastic material is injected or the first cavity is sprayed with plastic material, particularly preferably completely.

The first cavity may be, for example, an opening or opening extending into the interior of the gas turbine component or a channel or an arrangement of a plurality of interacting channels or a chamber or a chamber system, or may be formed by the same. The first cavity may also be a bore, in particular laser bore or cooling (air) bore, be. In a particularly advantageous embodiment, it is provided that the first cavity forms a kind of channel from which laser holes or cooling holes extend to the outer surface of these gas turbine blades in the finished state of the gas turbine blade. Such a channel formed as the first cavity may, for example, extend oblong; For example, it may be curved or meandering or otherwise. The first cavity may, for example, have one or more undercuts or undercuts or undercuts. In an advantageous embodiment, the first cavity has been produced in the context of a Geißprozesses.

The first cavity or first channel has in an advantageous embodiment at its one end to an outwardly open opening or main opening and is substantially closed at its other end.

In a particularly expedient embodiment, it is provided that the or a first processing step is carried out by means of a laser. This first processing step may be, for example, laser drilling. With such a laser drilling through holes or cooling holes can be introduced into the gas turbine component or the blade. Such cooling holes can be introduced so that connect the addressed first cavity or first channel with the outer surface of the blade.

The addressed plastic material may therefore be previously introduced into the first cavity or channel so that it is at least (also) positioned in the first cavity so that it in imaginary extension of the laser holes or cooling holes to be produced is positioned so that it shields the opposite wall portion of the channel or first cavity.

The plastic material is in a particularly preferred embodiment, a substantially residue-free removable plastic material. In a particularly advantageous design, the plastic material is polystyrene.

It can be provided in a development of the method according to the invention, in which previously mentioned cooling bores are produced by means of laser drilling, that after the laser drilling the blade root is clamped in a holding device with good thermal conductivity or in copper jaws. This holding direction or these copper jaws, for example, can be designed such that they have an oxygen or air pressure supply. The blade can be designed so that the first channel or the first cavity in the region of the blade root is open to the outside or forms a main opening, wherein the oxygen or Druckluftzufuhrung is connected to this open area or this main opening, so that oxygen or compressed air can be introduced there, in particular to - eg in combination with a flow measurement or the like - to carry out a quality control. For such a quality control, in which it is checked in particular whether the laser or cooling openings are dimensioned in the desired manner, a measuring device can be provided.

To remove the plastic material or polystyrene, it may be provided that an induction coil or induction mat is placed around the blade and the blade or the cavity or the blade channels are hereby heated, and preferably simultaneously flooded with oxygen or atmospheric oxygen. The heating can be carried out, for example, at a temperature which is in the range between 400 ° C and 800 ° C, preferably in the range of 400 ° C to 600 ⁰ C, and is more preferably at about 500 ⁰ C. The above-mentioned temperature values are especially suitable when the plastic material is polystyrene. The polystyrene burns or evaporates essentially without residue. It can further be provided that the blade is then cooled or rapidly cooled. This can for example be such that rapid cooling takes place via the copper jaws or the holding device whose material preferably has good thermal conductivity. The rapid cooling can be carried out, for example, with additional air or additional water, in particular air or water, which is or to the copper jaws or to the holding device whose material preferably has a good thermal conductivity is performed. This may, for example, be such as to allow the blades to be relatively quickly cooled down so that they can be gripped by hand, thereby reducing throughput times in the gas turbine blade manufacturing process.

It can be provided that even before the filling of the first cavity with plastic material, one or several holes or openings are introduced in such a way that they connect the outer surface of the blade with the cavity addressed. Such holes or openings may, for example, be arranged at the end of the cavity facing away from the mentioned main opening. Through these previously introduced holes or openings, which can also be produced for example by means of laser drilling, can be achieved or ensured that when filling with plastic not a (substantially closed) air-filled space forms, which forms an air cushion and thus the Penetration of plastic into the appropriate section is prevented; when filling with plastic so the air can escape via the above-mentioned holes or openings.

It should be noted that the terms "first" and "second" processing step have been chosen in particular for the identification or distinctness of the processing steps, wherein the second processing step takes place after the first processing step in an advantageous design, provided preferred developments have both of these processing steps. Before the first or between the first and the second processing step but also one or more further processing steps can be performed. The gas turbine component or the blade is preferably made of a metallic or metal-containing material and / or of a material which cobalt and / or nickel - in particular as a base material or as a matrix material - and is optionally coated or provided with a coating and / or is alitiert; Other materials, and in particular materials which are proposed in the prior art for gas turbine components, in particular gas turbine blades, can be used as material for the gas turbine component or the blade.

For carrying out the method or for processing, in particular in the context of production or maintenance of the gas turbine component, in particular a blade, for example, a device may be used which is designed as follows and for which the applicant reserves the right to protection combined or integrated mold, comprising: a laser, a holding device for holding the gas turbine component, which is designed in particular in the manner mentioned above, a spray device for spraying plastic material, in particular for spraying polystyrene, a heater for removing the plastic material, in particular as an induction coil or induction mat or, if appropriate, one or more of the following devices: an electronic control device for controlling the method for processing the gas turbine component, a device for stripping the gas turbine component, ie e is optionally the laser, a measuring device for measuring or checking of the processing results generated by the method or for measuring one or more characteristics of the gas turbine component. It may be further provided that an oxygen or Luftdruckzuführungseiiirichtung is provided, which is optionally combined in the manner mentioned above with the holding device.

Below, exemplary embodiments of the invention will be explained in more detail with reference to the figures, without the invention being restricted thereby. Showing:

1 and FIG. 2 shows an exemplary gas turbine blade according to the invention in schematic representation, wherein FIG. 1 shows a flow profile in FIG. 1 Shovel shown coarsely schematically and with reference to this Fig. An exemplary erfmdungsgemäßes method is explained.

In FIGS. 1 and 2, a blade 1 of a gas turbine or an aircraft engine is shown. This blade 1 is designed here as a blade, as a turbine blade. In further embodiments, for which the following embodiments in particular may apply, however, such a blade may also be designed as a guide vane of a gas turbine or an aircraft engine, or as a guide or moving blade of a compressor of a gas turbine or an aircraft engine.

The blade 1 has an airfoil 10 and a blade root 12. Furthermore, the blade 1 has a first inner cavity 14 or a first inner chamber or a first inner channel 14, whose wall or boundary in FIGS. 1 and 2 is delimited by the (dashed) lines 14a. This first inner cavity 14 may be provided with undercuts or undercuts or undercuts. The first inner cavity 14 opens in the region of the blade root 12 to the outside. The corresponding (main) opening 20 provided there at the area of the blade root 12 is here positioned so that it is located radially inside or in the radially inward-arranged region of the blade 1 in the case of a blade 1 mounted in an aircraft engine with respect to the turbine rotational axis. According to a gas turbine component according to the invention, which is in particular a blade 1, it is provided that the first inner channel 14 or the first cavity 14 is filled with a residue-free removable plastic material, which is polystyrene here. This may be such that the first cavity 14 is substantially completely filled with the addressed polystyrene.

The blade 1 shown in FIGS. 1 and 2 further includes a plurality of first openings 16 and a plurality of second openings 18. The openings 16, 18 extend from the outer surface 21 of the blade 1 to the first inner cavity 14, in the region of the airfoil 10. The first openings 16 are here as holes, namely laser holes, designed, and may also be referred to as cooling holes become. The second openings 18 are designed here slit-shaped, but may alternatively be (laser) holes or the like.

The first inner cavity 14 is further connected to the blade outer via a main opening 20 of the first inner cavity 14, which, as already mentioned, is arranged here in the region of the blade root 12. The first inner cavity 14 is therefore connected to the exterior of the blade 1 only via the main opening 20 and, with respect to its cross-section, relatively smaller openings 16, 18 arranged in the region of the airfoil. The thus formed channel arrangement or cavity arrangement is used in the operation of the cooling or air cooling. Relatively cold air can be introduced into the blade 1 via the main opening 20 in relation to the ambient temperature of the blade 1, which then exits via the openings 16, 18. The "relatively" cold air may, for example, be in the range of 700 ^° C., which is relatively low compared to the temperatures caused by the combustion gases of an aircraft engine in the area adjoining the combustion chamber.

It should be noted that the addressed polystyrene in sections is symbolically indicated by the cross-hatched areas 22 in sections.

An inventive method can proceed in an exemplary embodiment as follows.

First, a blade 1 provided with a first inner cavity 14 is provided. This blade 1 can be, for example, as illustrated in FIGS. 1 and 2 or explained with reference to this figure, although initially the openings 16, 18 are not provided.

Subsequently, for example by means of a laser, second openings 18 are created, which connect the outside of the blade 1 with the first inner cavity 14, as can also be clearly seen in FIG. 2, where the flow profile or a section through the airfoil 10 is shown is. For example, as shown in FIGS. 1 and 2, the openings 18 can be positioned in the region of the outlet edge 24 of the blade 1, namely in particular there on the pressure side 26. As mentioned, the openings 18 may also have a different shape than the shape prescribed here.

Subsequently, polystyrene 22 is injected into the hollow chamber 14 or the hollow chamber 14 is sprayed with polystyrene 22, which can be done via the second openings 18 and / or via the main opening 20. Depending on whether it takes place via the main opening 20 or the second openings 18, it is ensured by the respective other openings 20, 18 that no compressed air cushion is built up, which could prevent complete infestation of the chamber 14 with polystyrene 22.

Subsequently, the first holes or cooling holes 16 are now generated by means of a laser. The holes 16 can therefore also be referred to as laser holes. These cooling holes 16 are arranged in the design according to FIGS. 1 and 2 in the region of the leading edge 28 of the blade 1. Characterized in that the first inner cavity 14 is filled with polystyrene 22, is prevented when laser drilling the opposite in the extension of these resulting holes 16 wall portion, the component of the first cavity 14 bounding wall 14a, by the laser radiation in an undesirable manner is impaired. This is schematically indicated in FIG. 2 for one of the holes 16, where denoted by the reference numeral 30 is a laser head, denoted by the reference numeral 32 laser radiation, and by the reference numeral 34 an addressed opposite wall portion. As can be clearly seen there, the opposite wall section 34 is shielded by means of the polystyrene 22 and thus prevents the laser radiation 32 from undesirably acting on this opposite wall section 34 or changing the surface or material properties of this wall section 34, in particular remaining permanent.

It can be provided that the laser radiation 32 or whose intensity is tuned or adjusted so that by means of the polystyrene 22 sufficiently secured prevents acts during laser drilling or by the laser radiation 32 on the (opposite) wall portion 34. It may be the case that the serstrahlung radiation 32 acts on the polystyrene 22 and this optionally partially evaporated or acted upon this.

When all of the holes 16 have been formed by the laser in the aforementioned manner, the polystyrene 22 is subsequently removed again. This is done so that the polystyrene 22 is heated or heated, thereby burning or evaporating. The corresponding heating of the polystyrene 22 may, for example - as shown schematically in Fig. 1 - carried out by means of an induction coil 36. It can further be provided that for the clamping of the blade root 12 copper jaws 38 are provided, in which the blade root 12 is clamped. Such copper jaws 38 may have, as roughly indicated schematically in FIG. 1, an oxygen or air pressure supply or supply device 40, which may be connected to the main opening 20. It should be noted that instead of the mentioned induction coil 36, an induction mat or another suitable heating device may be provided. The coil 36 or mat is placed around the blade and optionally the blade root 12. By means of the heating device or induction coil 36, the blade channels or their interior are heated to about 500 ° C and simultaneously flooded via the oxygen or air pressure supply means 40 with oxygen or atmospheric oxygen. The polystyrene burns or evaporates essentially without residue. Essentially, this produces only water (H ₂ O) and carbon dioxide (CO ₂ ). Furthermore, it can be provided that rapid cooling takes place via the copper jaws 38 additionally with air or water.

It may be provided that after removing the polystyrene 22 again polystyrene 22 is injected, and this time so that not only the first cavity 14 is sprayed with polystyrene 22, but also or alternatively the openings 16, 18. This allows at a subsequent coating process, which can also be referred to as a second processing step, to coat the surface of the blade 1, without thereby coating material penetrates into the openings 16, 18 and changes their cross-sectional area or even leads to blockages in the region of these openings 16, 18. After the corresponding coating process by which, for example, a hot-temperature-resistant layer or a corrosion-temperature-resistant layer or the like is formed. is brought, the polystyrene 22 can be removed in the aforementioned manner again. It should be noted that the aforementioned second injection with polystyrene 22 can take place via openings 16 and / or 18 and / or via the main opening 20. It should be noted, furthermore, that the removal of polystyrene 22 in the embodiment described above by heating or heating, and inductive takes place. Instead, however, other removal methods may be provided, for example chemical.

As the exemplary embodiment shows, this makes it possible in a simple manner to limit the area of action of tools or the area of action given in the course of processing steps by means of the polystyrene 22 or a corresponding plastic, it being noted that the injection molding of polystyrene fast, clean and inexpensive to carry out. The burning or evaporation of polystyrene is also residue-free, fast, inexpensive and environmentally friendly feasible.

Claims

claims

1. A method for processing gas turbine components (1) in the context of the manufacture or repair of these gas turbine components (I) ₅ with the following

5 steps:

- Providing a provided with at least a first cavity (14) gas turbine component (1);

Performing at least a first processing step on the gas turbine component (1); LO, characterized in that for limiting the on the gas turbine component (1) given Einwirkbereich acted upon in the first processing step, prior to performing the at least one first processing step plastic material (22) in this first holster (14) introduced, in particular injected, is , And that this L 5 plastic material (22) after the first or the first processing steps from the first cavity (14) is removed again.

2. The method according to claim 1, characterized in that the or a first processing step is a laser drilling, in particular a laser drilling,

20 by means of which through holes (16) in predetermined portions (28) of the first cavity (14) bounding wall (14 a) are introduced, extending from the outer surface (21) of the gas turbine component (1) to the first cavity (14).

25 3. The method according to claim 2, characterized in that the plastic material

(22) in such a way in the first cavity (14) introduced, in particular injected, or in the first cavity (14) is positioned, that between the respective laser bore (16) and the imaginary extension of these laser drill pipe (16) opposite wall portion (34) forming part of

3 o the first cavity (14) limiting wall (14 a), plastic material (22) for shielding this opposite wall portion (34) during laser drilling is.

4. The method according to any one of claims 2 and 3, characterized in that the gas turbine component (1) is processed after the first processing step in at least one second processing step, and that for limiting the on the

Plastic material (22) in at least one, in particular all, of the laser holes (16) and / or in the first cavity (14) and / or before the performing of this at least one second processing step gas turbine component given Einwirkbereichs acted on in the second processing step is introduced into the main opening (20) of the first cavity (14) and that the

.0 ses plastic material (22) after the or the second processing steps is removed again.

5. The method according to claim 4, characterized in that before the first processing step in the first cavity (14) introduced plastic material

.5 (22) is removed prior to introducing plastic material (22) into the laser holes (16) and / or into the first cavity (14) and / or into the main opening (20) of the first cavity (14).

6. The method according to any one of claims 4 and 5, characterized in that the

o is at least a second processing step is a coating process, wherein by means of this coating method, the outer surface (21) of the gas turbine component (1) is partially or completely coated, and wherein by means of the at least one laser bore (16) introduced plastic material (22) the penetration of Coating material in this laser bore (16) prevented

»5 will.

7. The method according to any one of the preceding claims, characterized in that the plastic material (22) is removed thermally.

8. Method according to one of the preceding claims, characterized in that the plastic material (22) is polystyrene (22). Gas turbine component having an inner cavity (14), characterized in that said inner cavity (14) is filled with a non-solid state or injected and residue-free removable plastic material (22), in particular polystyrene (22), in particular completely or partially.

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