EP1507957B1 - Coolable component and method for the production of a through-opening in a coolable component - Google Patents

Description

Technical application

The present invention relates to a coolable Component according to the preamble of claim 1. Sie continues to specify a procedure, a Passage opening for a cooling medium, in one to manufacture inventive component.

In the field of turbomachines, in particular gas turbines in power generation plants or in aviation, will increase the Performance increasingly higher turbine inlet temperatures of the hot gas aimed and realized. These However, higher temperatures pose a problem for the Integrity of the high-temperature-loaded Turbine components, in particular the Turbine blades, dar. The inlet temperatures of the first turbine stage exceed in modern Gas turbines already the melting point of Blade material. To avoid damage to the Turbine blades due to these high operating temperatures is a cooling of the blade components over inside the blade extending cooling channels carried out.

A well-known cooling method for the cooling of Gas turbine blades is the internal, convective Cooling. In this cooling technique, as shown in FIG. 1 is shown schematically, cooling air through the Rotor shaft introduced into the blade root and from there in extending within the airfoil cooling channels in which they heat the turbine blade receives. The heated cooling air is finally by suitably arranged holes and Slots blown out of the turbine blade. In Combination with this convective cooling will be in usually the so-called impact cooling as well as the film cooling used. In the impact cooling bounces the Cooling air through small through holes on the Inside the wall of the turbine blade while in film cooling via small through holes to the outer surface of the turbine blade passes and forms a thin film of cooling air there. The Cooling air for the cooling of the turbine blade comes in usually from the compressor stage, part of which branched off compressed air and for cooling in the respective components of the turbomachine to be cooled to be led.

Adequate and reliable cooling of Components of a turbomachine provides a essential aspect for their operation dar. Modern High temperature gas turbines require to achieve a high efficiency a sophisticated cooling system, in particular for cooling the highly loaded Turbine blades. In the operation of such a cooling system However, a turbomachine can cause problems with a blockage of the cooling channels or cooling air holes due to dirt or dust particles, from the atmosphere or from upstream of the cooling channels located components of the turbomachine come can and introduced with the cooling medium in the cooling channels become. A blockage of individual cooling channels or cooling holes can not anymore due to one maintained minimum mass flow of cooling medium to a significant local temperature load to Cooling component lead to their damage.

State of the art

There are numerous measures to avoid the Blockage of cooling air holes in turbomachinery. So it is for avoidance or reduction the risk of clogging, for example, dust collectors, such as cyclones, within the To arrange cooling circuit, the dirt or dust particles separate from the cooling medium. In these dust collectors vortexes are generated in the cooling medium, through the dust and dirt particles due to their inertia separated from the cooling medium and a separate Dust discharge opening removed from the cooling medium become.

The use of such a dust collector in A form of axial cyclone is, for example, DE 198 34 376 A1. The of the compressor stage incoming cooling air is here before entering the first vane of the turbine stage through the axial cyclone directed. In the axial cyclone is a swirl generator formed, a vortex in the cooling air generated due to which the slower dust and Dirt particles on the wall of the axial cyclone hit and fall off from there. At the bottom of the cyclone they are deducted via corresponding discharge channels.

In another technique, partly in Combination with dust collectors is used in the cooling channels within the turbine blade special dust discharge openings provided from which larger dust or dirt particles due to their Lethargy escape. An example of the arrangement such Staubaustragsöffnungen in the cooling channels is for example the US-A-4820122 refer.

Despite the measures implemented so far However, it can not be completely ruled out that Dust or dirt particles in the cooling channels of the cooling component to the narrow passages for the cooling medium and get these passages clog.

Presentation of the invention

The object of the present invention is It is to specify a coolable component which the Disadvantages of the prior art is able to avoid and a special embodiment of a passage opening indicate for the cooling medium, the one less susceptibility to such blockage by dust or dirt particles, as well as a for producing such a passage opening in a coolable component suitable manufacturing process.

The task is with the passage opening according to Claim 1 and with the method for manufacturing a passage opening according to claim 20 solved. Advantageous embodiments of Passage opening and the manufacturing process are Subject of the dependent claims or can be taken from the subsequent description and the Refer to exemplary embodiments.

A coolable component according to the invention has a passage opening for a cooling medium, which first in a known manner by a first Opening of a first opening cross-section in one formed a component consisting of a first material is. The core of the invention is in the first opening to arrange an insert which the Opening cross section of the passage bore on a reduced second passage cross-section. It is in general, the second opening cross-section of Setpoint of the opening cross section. Between the insert and the basic material of the component, expediently on the Interface between the insert and the interior of the first opening, it becomes a thermally unstable Connection made when crossing a limit temperature dissolves. The thermally unstable Connection can be made by the material the insert, for example, a Bondcoat- and / or TBC material, directly into the first opening is introduced, and there adheres, with the adhesive force temperature dependent between the two materials varies, and when the limit temperature is exceeded for the safe seat of the insert in the first Opening necessary value falls below. Another Possibility is a thermally unstable Material, such as an adhesive or a solder, which high temperature softens and the connection does not is able to maintain, for the production of Connection in particular in a joint gap between Use and component to use. Furthermore, the Insert also used with excess in the opening be such that a press fit arises, wherein Instability of the connection in a simple manner by appropriate choice of the thermal Expansion coefficients of the material of the component and the material of the insert is achieved.

Preferably, the thermally unstable exist Connection and / or use of a material that oxidized in the cooling medium and its oxides in the vaporize desired temperature, in particular the oxides formed are oxides from the series chromium oxide, Molybdenum oxide and tungsten oxide are.

The thermally unstable compound can also made of a material that is at the desired Temperature exceeds its melting point, where in particular the thermally unstable compound metals from the series Ag, Cu, Au, Al, Zn, Cd, In, Tl, Ge, Sn, Pb, Sb, and Bi individually or in conjunction with each other contains.

Furthermore, it is conceivable that the thermal unstable connection wood-metal, soft solder, brazing alloy like e.g. Brass solder, nickel silver solder, silver solder, Al-Si solder, B-Cu55ZnAg, or nickel-based solder with silicon alone and / or with boron, or that contains the thermal unstable connection glass solder, especially lead-rich Glass, composite solder with codierite additive, or solder glass, contains.

It is also conceivable that the thermal unstable connection and / or use of one Material exist because of the transgression of his Creep failure fails, the material in particular, an Ag-Cu-Zn solder or an austenitic one Steel is.

Likewise, the thermally unstable compound and / or the insert are made of a material that fails because of exceeding the softening temperature, wherein the material is in particular a self-flowing NiCrFeSiB corrosion protection layer is.

Finally, it is conceivable that the thermally unstable connection and / or the insert consist of a material which has a low coefficient of thermal expansion and fails in thermal overload due to the stresses occurring and its brittleness. Preferably, the material is a ceramic, in particular SiN ₄ , or unstabilized or partially stabilized ZrO ₂ , or a glass.

A suitable method, a passage opening for a cooling medium according to the invention in a To introduce coolable component is, first a first opening with a first opening cross-section into the component, for example, to drill. In a next step, for example, becomes Bondcoat and / or a TBC material so applied, that the opening is substantially closed. Finally, in the introduced for closing Material the flow opening with the second Opening cross section are incorporated.

The operation of the invention is now the following: The component is heated by at least one side brought in. Through coolant passages escaping cooling medium takes heat out of the component on. The second opening cross section in the use of a Passage opening is sized so that in the normal undisturbed operation a minimum required Coolant mass flow flows through this opening, the is sufficient to the material temperature in the immediate vicinity of the passage below to keep the limit temperature.

A blockage of the second opening cross-section through a dust or dirt particles leads to a Reduction of the coolant mass flow under the Minimum required mass. This increases the Temperature at the cooling point and / or the pressure drop over the insert in the passage opening. At the Exceeding the limit temperature becomes the thermal unstable connection solved, so that the use finally together with the clogging particle the passage opening dissolves and this again for the Flow of the cooling medium releases. After this Event remains with the first Öffungsquerschnitt a slightly larger opening cross section than the Nominal cross-section, the further cooling of the corresponding However, the location of the component is ensured.

As suitable materials for use can used for example in gas turbine technology Bonders, TBC materials (Thermal Barrier Coating) or paint test materials used become. Of course, others, these having temperature-dependent properties Materials that are also specific to this Application can be developed used become.

The mechanism used to release the insert The drilling leads to different physical Properties are based. So, for example the melting point of the second one chosen for use Material of the limit temperature correspond. The second Material can reach the limit temperature too so under mechanical tension that it is shatters above this temperature. Essential in This embodiment is in any case that the Connection between the insert and the bore above the limit temperature triggers, so the use along with the clogging particle from the bore is discharged. This is not always a case increased pressure drop at the bore required. It Rather, it can be used in normal operation without constipation sufficient pressure drop on the insert.

In a further embodiment, the Temperature dependence of the second material not absolutely necessary. In this embodiment the adhesion between the insert and the bore so she chooses to go through with a constipation occurring higher pressure difference at the use of the applied pressure no longer withstands, so that the insert releases from the hole.

The inventive embodiment of Coolant passages are suitable for Components of turbomachines, in particular as Cooling air outlet openings for film or impingement cooling in turbine blades. Of course you can a passage formed in this way also in use other areas where a constipation the passage openings may have undesirable consequences.

Brief description of the drawings

Fig. 1

ein Beispiel für den Verlauf von Kühlkanälen in einer Turbinenschaufel in zwei unterschiedlichen Ansichten;

Fig. 2

ein Beispiel für die übliche Ausgestaltung einer Durchtrittsöffnung in einer zu kühlenden Komponente;

Fig. 3

ein Beispiel für die Ausgestaltung einer Durchtrittsöffnung in einer zu kühlenden Komponente gemäß der vorliegenden Erfindung;

Fig. 4

der Zustand der Verstopfung einer Durchtrittsöffnung gemäß Fig. 3;

Fig. 5

der Zustand der Durchtrittsöffnung gemäß Fig. 4 nach kurzer Zeit; und

Fig. 6

der Zustand der Durchtrittsöffnung gemäß Fig. 4 nach dem Lösen des Einsatzes.

The present invention will be briefly explained again with reference to an embodiment in conjunction with the drawings. Hereby show:

Fig. 1

an example of the course of cooling channels in a turbine blade in two different views;

Fig. 2

an example of the usual embodiment of a passage opening in a component to be cooled;

Fig. 3

an example of the configuration of a passage opening in a component to be cooled according to the present invention;

Fig. 4

the condition of the blockage of a passage opening according to FIG. 3;

Fig. 5

the state of the passage opening of Figure 4 after a short time. and

Fig. 6

the state of the passage opening according to FIG. 4 after the release of the insert.

Ways to carry out the invention

Fig. 1 shows in two different views schematically the structure of a turbine blade with the cooling channels running in it. In the sectional view 1a is the rotor-side inlet 3 for to recognize the cooling medium in the turbine blade. The inflowing cooling air is indicated by the three arrows. Within the turbine blade 1, the cooling air via corresponding cooling channels 2 to the front and trailing edge of the turbine blade passed to the the cooling air exits through passages, such as this also indicated by the arrows in the figure is. In the area of the cooling channel deflection 4 at the Blade tip of the turbine blade 1 is usually a Staubaustragsöffnung 5 is formed over the with the cooling medium entrained particles due to their Inertia escape from the turbine blade. These Dust discharge is designed to prevent the unwanted larger particles are not up to the fine ones Passage openings at the front or rear edge get the turbine blade and there the passages clog.

Fig. 1b shows the schematic structure of Turbine blade again in a perspective View. In this view is with the two block arrows again entering the cooling channels 2 Cooling air indicated. The cooling air passes over the passage openings 6 for impingement cooling from the cooling channels from and hits the outside of the shell from the inside Turbine blade to cool it. The cooling air is then over cooling pins, so called cooling pins 7, to the Trailing edge of the turbine blade continued and exit there. In the figure, the passage openings are still 8 for film cooling the outside to recognize the turbine blade over the likewise a part of the cooling air emerges from the cooling channels 2.

Due to the very small opening cross section of the Passage openings 6, 8 for the impact cooling or The film cooling is at risk of constipation these passages through dust or dirt particles, those with the cooling medium, usually the Cooling air to be carried. Despite upstream Dust and in the cooling channel 2 within the Turbine blade 1 arranged dust discharge 5, the risk of constipation is not complete exclude. If such a blockage occurs on, but it comes at the appropriate cooling point to a significant temperature load, the until damage to the corresponding component can lead.

Due to the inventive design of the Passages can be the danger of a Damage to the component to be cooled in a Blockage of the passages clearly to reduce.

Fig. 2 shows schematically the typical structure a passage opening 8 for cooling medium, of the Material of the component to be cooled, here the metal 9 of the airfoil, is surrounded. In the same way this could also be a dust discharge opening act.

The passage opening of the present invention In contrast, has a first opening and a Insert arranged in the first opening with a second opening cross-section, as is apparent from the Schematized representation of FIG. 3 can be seen. A first opening, bore, 10 of the passage opening 8 is bounded by the metal 9 of the airfoil. Within the first opening 10 in the airfoil is an insert 11 attached, which consists of an example temperature-dependent filling material is formed. Of the through this use reduced opening cross-section the passage opening 8 corresponds to that in a typical passage existing Opening cross-section, as realized in FIG is.

Occurs now during operation, a blockage this passage opening 8 with a dust particle 12th on, as shown schematically in Fig. 4 is, then the film cooling is interrupted at this point, leaving the turbine blade 1 in the area the passage opening 8 is heated more. Thereby the temperature at the transition point between the Insert 11 and the metal 9 of the airfoil also increased. When reaching a certain Limit temperature then dissolves the insert 11 from the Bore 10, as shown in FIG. 5, since the connection between insert and component becomes thermally unstable.

The material of the insert 11 is chosen such that the adhesion between the metal 9 of the airfoil and the material of the insert 11 from a elevated temperature during normal cooling is not reached, but after a blockage Occurs, decreases sharply or disappears completely. The existing pressure difference of the pressure before and behind the passage opening 8 then leads to the discharge the insert together with the contained therein Dust particles 12, so that the passage opening. 8 then again free (Fig. 6). The passage opening 8 has after this release of the insert 11th a larger cross section - according to the first opening 10 - on, the risk of damage the component to be cooled through the blockage however avoided.

• Materialien die im Kühlmedium (abhängig von der Temperatur) oxidieren und deren Oxide bei einer bestimmten Temperatur verdampfen, wie Chromoxid oberhalb 900°C, Molybdänoxid und Wolframoxid oberhalb 600°C. Diese Materialien können sowohl für die Verbindung oder auch für den Einsatz selbst eingesetzt werden.
• Materialien die ihren Schmelzpunkt überschreiten (als reine Elemente oder als Verbindungen), wie Silber welches bei 960°C schmilzt, Kupfer, welches bei 1083°C schmilzt oder Gold, welches bei 1063°C schmilzt, oder bei Bedarf auch Al, Zn, Cd, In, Tl, Ge, Sn, Pb, Sb, und Bi, welche im reinen Zustand den Bereich von 660°C bis hinunter zu 156°C abdecken, welche aber auch in Verbindung untereinander und mit anderen Elementen beinahe auf jeden beliebigen Schmelzpunkt einzustellen sind (Wood-Metall60°C bis zu den Weichloten mit TA<450°C und den Hartloten mit TA>450°C (Messinglote, Neusilberlote, Silberlote, Al-Si-Lote, welche den Bereich bis über 800°C abdecken, B-Cu55ZnAg mit T A=830°C). Nickelbasislote mit Silizium allein und/oder mit Bor, wobei sich deren Schmelzpunkte durch Diffusion unter dem Einfluss von Temperatur und Zeit und Materialien noch verändern (erhöhen) decken den Temperaturbereich bis 1200°C ab. Kommt es unmittelbar beim Einbau der Schaufel zu erhöhter Temperaturbelastung, so wird die Verbindung bei der Arbeitstemperatur des Lotes versagen und die Kühlmenge wird erhöht, kommt es verzögert zu erhöhter Temperatur, so versagt die Verbindung erst bei höherer Temperatur verglichen mit der Löttemperatur. Ist die Abdiffusion von Elementen unerwünscht, so kann z.B. statt der Bor-Variante auch eine Silizium-Variante mit verringerter Diffusion ausgewichen werden. Soll der Schmelzpunkt des Lotes langfristig tiefgehalten werden, so ist für Hochtemperaturlote mit Diffusionssperren zu arbeiten. Glaslote, z.B. bleireiche Gläser mit 400 bis 500°C Löttemperatur, Compositlote u.a. mit Codierit-Zusatz und Lötgläser können je nach Bedarf ebenfalls eingesetzt werden.
• Materialien die wegen Überschreitung ihrer Zeitstandfestigkeit versagen, wie z.B. Silber-Kupfer-Zink-Lote oberhalb 300°C, oder austenitische Stähle oberhalb 600°C.
• Materialien die Versagen wegen Überschreitung ihrer Erweichungstemperatur c wie z.B. bei selbstfliessenden NiCrFeSiB Korrosionsschutzschichten, aus welchen die Einsätze hergestellt werden können.
• Materialien mit geringen Wärmeausdehnungskoeffizienten, welche bei thermischer Überlastung aufgrund der auftretenden Spannungen und ihrer Sprödigkeit versagen wie Keramiken (SiN₄, ZrO₂ unstabilisiert oder teilstabilisiert, Gläser).

As thermally unstable materials for the connection between the insert 11 and the metal 9 of the airfoil or for the insert 11 itself are in particular:

• Materials that oxidize in the cooling medium (depending on the temperature) and whose oxides evaporate at a certain temperature, such as chromium oxide above 900 ° C, molybdenum oxide and tungsten oxide above 600 ° C. These materials can be used both for the compound or for the use itself.
• Materials which exceed their melting point (as pure elements or as compounds), such as silver which melts at 960 ° C, copper which melts at 1083 ° C or gold which melts at 1063 ° C, or if necessary also Al, Zn, Cd , In, Tl, Ge, Sn, Pb, Sb, and Bi, which in the pure state cover the range of 660 ° C down to 156 ° C, but which also in combination with each other and with other elements almost to any melting point are (wood-metal 60 ° C up to the soft solders with TA <450 ° C and the brazing alloys with TA> 450 ° C (brass solders, nickel silver solders, silver solders, Al-Si solders, which cover the range up to 800 ° C, B -Cu55ZnAg with TA = 830 ° C) Nickel-based solders with silicon alone and / or with boron, whose melting points still change (increase) due to diffusion under the influence of temperature and time and materials cover the temperature range up to 1200 ° C it immediately upon installation of the blade to elevated temperature turbocharging, so the connection will fail at the working temperature of the solder and the cooling amount is increased, it comes to a delayed elevated temperature, so the connection fails only at a higher temperature compared to the soldering temperature. If the diffusion of elements is undesirable, then, for example, instead of the boron variant, a silicon variant with reduced diffusion can be avoided. If the melting point of the solder is to be kept low in the long term, it is necessary to work with high-temperature solders with diffusion barriers. Glass solders, eg lead-rich glasses with a soldering temperature of 400 to 500 ° C, composite solders with codierite addition and solder glasses, for example, can also be used as required.
• Materials that fail due to exceeding their creep rupture strength, such as silver-copper-zinc solders above 300 ° C, or austenitic steels above 600 ° C.
• Materials failure due to exceeding their softening temperature c such as self-fluxing NiCrFeSiB corrosion protection layers, from which the inserts can be made.
• Materials with low coefficients of thermal expansion, which fail in thermal overload due to the stresses and their brittleness as ceramics (SiN ₄ , ZrO ₂ unstabilized or partially stabilized, glasses).

The above list is meant to be exemplary and not final.

LIST OF REFERENCE NUMBERS

1

turbine blade

2

cooling channels

3

Rotor-side inlet

4

Cooling channel deflection

5

Dust hole

6

Passage openings for impact cooling

7

Kühlpins

8th

Passage openings, in particular for film cooling

9

Metal of the airfoil

10

Bore of the passage opening, first opening

11

commitment

12

dust particles

Claims (22)

1. Coolable component, in particular for a continuous flow machine, having an aperture opening for a cooling medium, which is formed by a first opening (10) with a first opening cross section in the component (1) and in which an insert (11) is arranged, which reduces the size of the first opening cross section to a second opening cross section, with a connection being produced at the boundary surface between the hole interior and the insert (11), characterized in that the connection is a thermally unstable connection, which is released when a limit temperature is exceeded.
2. Coolable component according to Claim 1,
   characterized in that the thermally unstable connection is produced directly by the adhesion of the insert (11) in the first opening (10).
3. Coolable component according to Claim 1,
   characterized in that the thermally unstable connection is produced directly by means of a thermally unstable material, in particular an adhesive or a solder.
4. Coolable component according to Claim 3,
   characterized in that the thermally unstable material is arranged as a layer between the insert (11) and the component.
5. Coolable component according to one of the preceding Claims, characterized in that the size of the second opening cross section is designed to ensure a minimum mass flow of the cooling medium through the second opening cross section.
6. Coolable component according to Claim 5,
   characterized in that the thermally unstable connection is selected such that the limit temperature occurs at a value which is not reached during maintenance of the minimum mass flow, and in that, if the mass flow is less than the minimum, the limit temperature is increased such that, when the mass flow is less than the minimum, the connection becomes unstable and the insert (11) is released from the aperture opening, thus opening up the first, larger opening cross section.
7. Coolable component according to one of the preceding Claims, characterized in that the insert (11) is composed of a Bondcoat material and/or a TBC material.
8. Coolable component according to one of Claims 1 to 6, characterized in that the thermally unstable connection and/or the insert (11) are/is composed of a material which oxidizes in the cooling medium and whose oxides vaporize at the desired temperature.
9. Coolable component according to Claim 8,
   characterized in that the oxides which are formed are oxides from the chromium oxide, molybdenum oxide and tungsten oxide series.
10. Coolable component according to one of Claims 1 to 6, characterized in that the thermally unstable connection is composed of a material which is above its melting point at the desired temperature.
11. Coolable component according to Claim 10,
    characterized in that the thermally unstable connection contains metals from the Ag, Cu, Au, Al, Zn, Cd, In, Tl, Ge, Sn, Pb, Sb and Bi series individually or in conjunction with one another.
12. Coolable component according to Claim 11,
    characterized in that the thermally unstable connection contains wood metal, soft solder, hard solder such as brass solder, nickel silver solder, silver solder, aluminium silver solder, B-Cu55ZnAg or nickel-based solder with silicon on its own and/or with boron.
13. Coolable component according to Claim 10,
    characterized in that the thermally unstable connection contains glass solder, in particular high-lead glass, composite solder with a codierite additive, or solder glass.
14. Coolable component according to one of Claims 1 to 6, characterized in that the thermally unstable connection and/or the insert (11) are/is composed of a material which fails when its creep strength is exceeded.
15. Coolable component according to Claim 14,
    characterized in that the material is a silver copper tin solder or an austenitic steel.
16. Coolable component according to one of Claims 1 to 6, characterized in that the thermally unstable connection and/or the insert (11) are/is composed of a material which fails when the softening temperature is exceeded.
17. Coolable component according to Claim 16,
    characterized in that the material is a self-flowing NiCrFeSiB corrosion protection layer.
18. Coolable component according to one of Claims 1 to 6, characterized in that the thermally unstable connection and/or the insert (11) are/is composed of a material which has a low thermal coefficient of expansion and which fails as a result of stresses that occur and as a result of its brittleness when thermally overloaded.
19. Coolable component according to Claim 18,
    characterized in that the material is a ceramic, in particular SiN₄, unstabilized or partially stabilized ZrO₂, or a glass.
20. Method for production of an aperture opening for a cooling medium flow rate, which can be predetermined, in a component according to one of the preceding Claims, with a first opening (10) with a first opening cross section being introduced into the component (1),
    characterized by the following steps:
    introduction of the first opening, with a first opening cross section, which is larger than is required for the cooling medium flow which can be predetermined; introduction of an insert (11) into the first opening (10); production of the connection between the insert and the component.
21. Method according to Claim 20, characterized in that, in order to introduce the insert (11), the first opening (10) is completely closed, and in that an opening with the second opening cross section is then produced in the material which has been introduced for closure purposes.
22. Method according to one of Claims 20 or 21,
    characterized by the further method step
    that, before the insert (11) is introduced, in thermally unstable material is applied to the outer surface of the insert and/or to the inner surface of the first opening.

Images