TURBOMACHINE COMPONENT, PARTICULARLY A GAS TURBINE ENGINE COMPONENT, WITH A COOLED WALL AND A METHOD OF MANUFACTURING

Abstract

A turbomachine component, particularly a gas turbine engine component, has at least one part built in parts from a curved or planar panel, particularly a sheet metal, the part having a plurality of cooling channels via which a cooling fluid, particularly air, is guidable, wherein at least one of the plurality of cooling channels has a continuously tapered section. The at least one of the plurality of cooling channels has a single inlet port from a first surface of the panel and a single outlet port for the cooling fluid to another surface, particularly a surface opposite to the first surface, or to the first surface. Further the panel is built via laser sintering or laser melting or direct laser deposition. A gas turbine engine is equipped with such a component. A method of manufacturing includes incorporating cooling channels having a continuously tapered section.

Claims

1. A turbomachine component, comprising at least one part built in parts from a curved or planar panel, the part comprising a plurality of cooling channels via which a cooling fluid is guidable, wherein at least one of the plurality of cooling channels has a continuously tapered section, wherein the at least one of the plurality of cooling channels has a single inlet port from a first surface of the panel and a single outlet port for the cooling fluidto another surface or to the first surface, and wherein the panel is built via laser sintering or laser melting or direct laser deposition.

2. The turbomachine component according to claim 1, wherein the tapered section of the at least one of the plurality of cooling channels is located in an area of a major expanse of the panel.

3. The turbomachine component claim 1, wherein at least one of the inlet port and outlet port are generally perpendicular to a plane of the panel.

4. The turbomachine Turbomachine component according to claim 1, wherein the at least one of the plurality of cooling channels further comprises a continuously widening section, the widening section being located downstream of the tapered section in respect of a flow of the cooling fluid during operation.

5. The turbomachine component according to claim 1, wherein the tapered section of the at least one of the plurality of cooling channels is permanently tapered between the inlet port and the outlet port.

6. The turbomachine component according to claim 1, wherein the at least one of the plurality of cooling channels further comprises at least one section with constant cross section upstream of the tapered section and/or downstream of the tapered section and/or interrupting the tapered section, wherein the tapered section covers at least 80% of a length of the at least one of the plurality of cooling channels.

7. The turbomachine component according to claim 1, wherein a cross section of the at least one of the plurality of cooling channels is rectangular and the at least one of the plurality of cooling channels is formed by two pairs of surfaces, the pairs of surfaces having surfaces substantially opposite to another.

8. The turbomachine component according to claim 7, wherein tapering in the tapered section is realised by reducing the distance of a first pair of the two pairs of opposite surfaces and/or a second pair of the two pairs of opposite surfaces.

9. The turbomachine component according to claim 1, wherein a rate of tapering is adapted to the heat distribution to be experienced by the part during operation.

10. The turbomachine component according to claim 1, wherein a rate of tapering is adapted proportionally to a temperature rise of the cooling fluid within the at least one of the plurality of cooling channels during operation.

11. The turbomachine component according to claim 1, wherein the at least one part comprises a fluid guiding surface to guide a hot working fluid in a turbomachine when the turbomachine component is arranged in the turbomachine and the turbomachine is in operation.

12. A gas turbine engine component of a gas turbine engine, comprising a part according to claims 1 which is located in a hot region of the gas turbine engine, a transition duct downstream of a combustion chamber, a heat shield, an exhaust nozzle, and a casing, wherein the cooling fluid is provided from a compressor of the gas turbine engine.

13. A manufacturing method of a part of a turbomachine component ora gas turbine combustion component, the method comprising: building up material via laser sintering or laser melting or direct laser deposition to form a part as defined according to claim 1 including incorporated cooling channels having a continuously tapered section.

14. The turbomachine component according to claim 1, wherein the component is a gas turbine engine component.

15. The turbomachine component according to claim 1, wherein the curved or planar panel comprises a sheet metal.

16. The turbomachine component according to claim 1, wherein the cooling fluid comprises air.

17. The turbomachine component according to claim 1, wherein the another surface comprises a surface opposite to the first surface.

18. The turbomachine component according to claim 7, wherein the at least one of the plurality of cooling channels is rectangular square.

19. The turbomachine component according to claim 10, wherein temperatures of the part taken at different locations of a region of the part is substantially the same at the different locations and/or wherein a heat flux or heat gradient within the at least one of the plurality of cooling channels remains substantially constant.

20. The gas turbine engine component of claim 12, wherein the hot region of the gas turbine engine comprises at least one of a combustion chamber wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematical drawings, of which:

[0042] FIG. 1: shows a longitudinal section of a section of a typical gas turbine transition duct;

[0043] FIG. 2: shows illustration of known cooling air channels in a to be cooled component;

[0044] FIGS. 3 to 6: show different of illustrations of embodiments of cooling air channels in a to be cooled component according to the invention;

[0045] FIG. 7: shows an exploded illustration of several layers forming a to be cooled component with tapered cooling channels, which is not part of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0046] The illustrations in the drawings are schematical. It is noted that for similar or identical elements in different figures, the same reference signs will be used to denote the same or equivalent features.

[0047] Some of the features and especially the advantages will be explained for an assembled gas turbine, but obviously the features can be applied also to single components of the gas turbine but may show the advantages only once assembled and during operation. But when explained by means of a gas turbine during operation none of the details should be limited to a gas turbine solely while in operation. As the invention is inspired to counteract problems of combustion processes, the features can also applied to different types of machines that comprise a combustor of a different type, e.g. a combustor that operates with different types of fuels differing from gas and/or oil typically provided to a gas turbine combustor.

[0048] A gas-turbine engine may serve as one example of a rotating machine. The gas turbine—short for gas-turbine engine - comprises an air inlet at one end followed by a compressor stage in which incoming air is compressed for application to one or more combustors as combustion devices, which may be annular or so-called can-annular or silo type, the latter being distributed circumferentially around the turbine axis. Fuel is introduced into the combustors and there is mixed with a major part of the compressed air taken from the compressor. Hot gases with high velocity as a consequence of combustion in the combustors are directed to a set of turbine blades within a turbine section, being guided (i.e. redirected) by a set of guide vanes. The turbine blades and a shaft—the turbine blades being fixed to that shaft—form the rotor and are rotated about an axis as a result of the impact of the flow of the hot gases. The rotating rotor (or another rotor) also rotates blades of the compressor stage, so that the compressed air supply to the combustors is also provided by the rotor (including the used blades and vanes) once in operation. There may be more than one rotor in the gas-turbine engine.

[0049] As an example of a rotating machine component a transition duct 10 is shown in FIG. 1, which shows a cross sectional view of a section of such a transition duct and other parts of the gas turbine in that region. The transition duct 10 may provide a transition from a combustion chamber to a downstream turbine section. The turbine section is annular. The combustion chamber section may for example be annular as well or can-annular (i.e. formed by a plurality of combustor cans all arranged about an axis). In the latter case the transition duct will perform a transformation from a plurality of elliptical or oval cross sections (at the combustor end) to a single annular cavity (at the turbine section end) for guiding the working fluid. A transition duct of the latter type is shown in the previously mentioned patent publication US 2006/0130484 A1. The transition duct 10 comprises a transition duct shell 10A which has an inner surface for guiding the hot working fluid and having an outer surface which may be directed to a cavity in which a cooling fluid may be present. This cavity may be called a cooling air cavity 12. Whereas the hot working fluid within the transition duct 10 is provided by the combustion chamber(s) which is/are located upstream of the transition duct 10, the cooling air cavity 12 is provided with cooling air from the compressor (not shown in the figure). The transition duct shell 10A comprises a part 2 in which cooling channels 3 are incorporated. In the cross sectional view of FIG. 1, which is a cross section along the axis of rotation of the rotating machine, only one cooling channel is depicted but typically a plurality of cooling channels will be arranged distributed over the part 2. The part 2 may be a complex structure which at least comprises one plate 11 which advantageously is curved in axial direction (like in FIG. 1) and also curved around the path for the working media in circumferential direction. The plate 11 may substantially be fairly thin material, i.e. with larger expanse in one direction and small expanse in width. Particularly a curved or contoured plate 11 may be made from sheet metal and formed into the desired form. The part 2 comprises a plurality of cooling channels 3 via which cooling fluid from the cooling air cavity 12 can be guided through the part 2 and eventually be injected into the working media stream. Cooling fluid within the cooling channel 3 is identified in the figure by reference sign 5. The hot working fluid within the main gas path is identified in the figure by reference numeral 6. The cooling channel 3 has an inlet port 1—a single inlet port per cooling channel - which allows cooling fluid from the cooling air cavity 12 to enter the cooling channel 3. Furthermore, the cooling channel 3 has an outlet port 7—a single outlet port per cooling channel. A first surface 15 of the plate 11 is also shown in the figure and is directed to a cooled side, i.e. facing the cooling air cavity 12. The opposite surface of the plate 11 is a second surface 16 and is facing the hot working media within the transition duct 10. The cooling channel 3 (also called cooling duct) can be a prior art cooling duct with an unmodified cross section as substantially shown in FIG. 1 or could be the cooling channel 3 according to the invention with a continuously tapered section. This will be explained further in the following figures as the tapering can not clearly be highlighted in FIG. 1 which is supposed to show the general configuration of the inventive components.

[0050] FIG. 2—including its different sketches - shows cross sectional views and also a top view as seen from the first surface 15 for a prior art configuration without a tapered section. A top view shows the inlet port 1 and indicating the outlet port 7 and also indicating the cooling channels 3 wherein the parts that are included internally in the part 2 or which can not be seen from the first surface 15 are only shown as dotted lines. Several cross sectional views are taken along lines A-A, B-B, C-C and D-D. The cross section taken along the line A-A may be a similar view as seen in FIG. 1, only the curvature of FIG. 1 is not shown in FIG. 2. A cross section taken along the planes B-B, C-C, D-D are planes perpendicular to the view of the cut A-A. Along the cut A-A, a cooling channel 3 is shown with the inlet port 1 and the outlet port 7 with a cooling fluid 5 flow within the cooling channel 3 from the inlet port 1 to the outlet port 7. The first surface 15 directed to a cooled side and also the second surface 16 directed to the hot working media is identified in the figure of the cut A-A. The different cuts at the planes B-B, C-C, D-D show that the cross sectional areas which are identified by a first pair of surfaces 20A, 20B and a second pair of surfaces 21A, 21B are identical at each of the locations B-B, C-C, D-D. In FIG. 2 the cross sections are also identical for several of the parallel cooling channels 3 (five cooling channels are shown in FIG. 2 but typically more would be present in the part 2 to allow cooling over the full circumference of the plate 11). This unmodified cross-section reflects the prior art. As one example, which is also shown in FIG. 2, one of the cooling channels will provide cooling air in one direction and a second cooling channel will provide cooling air in an opposite direction. This may improve the overall cooling quality of the hot part 2 in this configuration.

[0051] Referring now to FIG. 3 which shows a configuration according to the invention in which a tapered section 8 is present in the cooling channel 3. In FIG. 3, the tapered section 8 will be present over the whole length of the cooling channel 3 between the inlet port 1 and the outlet ports 7. In a not shown embodiment the length of the tapered section 8 may only be a sub-section of the cooling channel 3 length. In the example of FIG. 3, all shown cooling channels are filled with cooling air flowing in the same direction meaning that at one end of the plate 11, the inlet ports 1 will be located, and at a second end of the plate 11, the outlet ports 7 will be located. As can be seen in the cut along plane A-A but also along the cuts along B-B, C-C, D-D a height H of the cooling channel cross section will be reduced from the location at or near the inlet port 1 in direction to the location C-C and continues to be reduced up to a downstream end of a cooling channel 3 at a location D-D close to the outlet port 7. Also the width of the cooling air channels W will be reduced in size from B-B via C-C to the location of D-D. Therefore, the cross sectional area is continuously tapered along the length of the cooling channel 3. The cross sectional area is indicated by the reference numeral 4. In the example of FIG. 3, the cross sectional area is of square shape—or could also be rectangular—and will be reduced in size in both directions width and height, so that in every cross sectional view the cross section of the cooling channel 3 has a shape of a square. Therefore, the overall shape of the cooling channel 3 is substantially a truncated pyramid with four faces, considering plate 11 is flat (which may not be the case in a real component). Obviously it has to be understood that FIG. 3 is a simplification in which the cooling channel 3 is located within a flat plate. Nevertheless, in reality the cooling channel 3 may be curved as described with reference to FIG. 1.

[0052] It is assumed now that the hot air, which is indicated by an arrow with reference numeral 6, is guided in parallel (and in the same direction) to the cooling fluid 5 along or over the surface 16 from a region B-B to a region D-D. That means in the region B-B a higher temperature is affecting the part 2 and therefore also affecting a cooling fluid temperature within the cooling channel 3, that will rise in consequence. While the cooling fluid temperature rises along the cooling channel 3 from A to B the cross section of the cooling passage or cooling channel will be decreased. This has the effect that the cooling fluid will accelerate. That also means that at a location C-C a constant cooling air mass flow with higher velocity is passing that position C-C but having at the same time already a higher temperature level than at location B-B. All in all, considering also the narrowed size of the cooling channel 3, at position C-C the cooling capacity of the cooling air can remain substantially at the same level as in location B-B such that the part 2 is sufficiently cooled at both locations B-B and C-C. The same effect continues further on until D-D such that the cross sectional area 4 furthermore continues to be tapered and furthermore the temperature rises within the cooling channel 3, but nevertheless due to the higher speed, the heat transfer coefficient will rise and the cooling effect will remain at the higher level.

[0053] Altogether, this variable cross section area of internal cooling channels 3 enables the internal cooling channels 3 to provide an efficient cooling technique particularly for applications where it may be impossible or difficult to alternate the channel flow direction as shown in FIG. 2 or to implement other means of cooling. Variable cooling channel 3 size also enables an efficient way of handling hot spots or cool spots within the component which will be explained later on in relation to a further figure.

[0054] According to FIG. 4 an alternative to FIG. 3 is shown in which the height of the cooling channel 3 remains identical along the length of the cooling channel 3 which is also seen in the cross sectional view of the figures B-B, C-C, D-D. In this alternative embodiment, only the width of the cooling air channel is modified such that the width W.sub.B at the location B-B is greater than the width W.sub.C at a location C-C and the latter is again greater than the width W.sub.D at a location D-D. Therefore, FIG. 4 shows a cooling channel 3 with rectangular cross section in which only one dimension of the rectangular is modified in size. In consequence the cooling channel 3 is tapered, but only in respect of one direction.

[0055] FIG. 5 shows a similar implementation but in which the rectangular cross section of a cooling channel 3 is modified in the other direction by modifying the height. As seen in the figure, the width W.sub.B is identical to the width W.sub.C and the width W.sub.D. The height H.sub.B at location B-B is greater than the height H.sub.C at the location C-C which is again greater than the height H.sub.D at the location D-D. Again, the cross section of the cooling channel 3 is continuously tapered.

[0056] In FIG. 6, generally a similar configuration is shown, in which a local hotspot 17 is supposed to be present during operation. The local hotspot 17 may be present always at the same location due to the arrangement of the combustor or due to other constructional features. Therefore it may be possible to construct the part 2 such that the cooling is improved at and/or near the region of the local hotspot 17. This is realized as explained in accordance with FIG. 6. According to FIG. 6, a continuously tapered section 8 is present continuing to reduce the cross sectional area of the cooling channel 3 until the region where the hotspot is located and afterwards—i.e. downstream—the tapering is not continued in the same direction but the cooling channel 3 is widened again in a widening section 9 (you could also say, section 9 shows a tapering but opposite to the flow direction within the cooling channel 3).

[0057] The term “widening”, like “tapering”, is intended to mean a change of size in respect of the cross section of the cooling channel 3.

[0058] Tapering and widening is meant in the sense of convergent walls followed by divergent walls of the cooling channel 3. Optionally a section with constant cross sectional area may be present.

[0059] This configuration of FIG. 6 allows an increased cooling fluid velocity in the area of the local hotspot 17 within the cooling channel 3. This allows in turn providing an improved way of cooling, particularly in regions where more or additional cooling is required. This additional cooling can be performed without injecting a higher amount of cooling air into a cooling channel 3. In FIG. 6 also another change compared to the previous figures is shown. It is shown that a cooling channel which is closer to a hotspot may have such a consecutive tapering and widening structure whereas a cooling channel which has a distance to such a local hotspot 17 may have a continuous cross sectional area along the length of the cooling channel 3. So the shape of several cooling channels 3 are not identical anymore, different to the shown exemplary embodiments of the FIGS. 2-5 in which all cooling channels 3 are sized similarly for all cooling channels 3 in the part.

[0060] As there are typically several cooling channels 3 in one part 2, there may be at least one cooling channels 3 of these several cooling channels 3 that has a different cross-sectional area shape throughout its length than the remaining cooling channels 3.

[0061] Such individually shaped cooling channels 3 may individually be generated if the part 2 is built by additive manufacturing techniques like selective laser melting or selective laser sintering or direct laser deposition. These methods allow the creation of all kinds of complex shapes for these cooling channels 3. Also the cross section does not need to be rectangular or square when these techniques are used. Different forms of cross sectional shapes can be provided by these additive manufacturing techniques, e.g. ovally or circularly shaped cross sections of the cooling channels 3, leading to cylindrical cooling channels in which the tapering can be realised by reducing the radius of the cylinder.

[0062] FIG. 7 shows a different way of machining these types of tapered cooling channels 3, which is not part of the invention as additive manufacturing techniques are not used. In this embodiment, three layers or panels of sheet metal are provided and machined and combined together thereafter. On a first panel 30, the inlet ports 1 will be drilled or machined or cast. On a second panel 31, outlet ports 7 can be drilled or machined or cast as well. On a third panel 32, which is an intermediate panel or a mid panel, which in the end will be located between the first panel 30 and the second panel 31, slots 35 will be manufactured to implement the cooling channels 3. The slots may be formed by a cutting machine, for example via a cutting disk such that the cutting disk will be lowered into the material continuously while the cutting disk is moved along the surface such that the slot width will be widened while the cutting disk is lowered into the third panel 32. The slots shall be positioned in alignment with the cooling inlet ports 1 and the cooling outlet ports 7 of the first panel 30 and the second panel 31. Finally, these three sheet metals 30, 31, 32 can be attached or joined to one another in a sandwich type manner—e.g. by diffusion bonding or hot isostatic pressing—such that these three layers will generate the plate 11 as mentioned for the previous figures. This plate 11 may be planar at a first processing step but may be later formed into the proper curved surface area as required, for example for the transition duct.

[0063] The sandwich processing will be performed in a way that the first panel 30 is attached to a first surface 33 of the intermediate panel 32 and a second panel 31 is attached to a second surface 34 of the intermediate panel 32.

[0064] The explained method as explained in accordance with FIG. 7 allows only tapering in one direction of the cooling channel, namely the width of the cooling channel. If tapering in two directions (width and height) would be required, additional depressions with reducing depth in the first and second panel 30, 31 could result in a height reducing cross section. The depressions would need to be aligned with the tapered slot of the third panel 32 so that altogether they will form the cooling channel.

[0065] As an alternative—but not shown in a figure—the three layer sandwich structure can also be replaced by a two layer sandwich structure, in which a layer comprises the inlet holes and the cooling channels (alternatively the outlet holes and the cooling channels). The cooling channels will not be full cuts through the material but just end milled (or produced by an alternative method), such that a lengthy depression is manufactured with differing depth and/or width of the depression. Again this alternative is not part of the invention as additive manufacturing techniques are not used.

[0066] Previously the invention was explained in conjunction with a transition duct 10. Other elements of a gas turbine engine or other types of rotating machine that experience strong heat can also be equipped with these tapered cooling channels. For example in a gas turbine engine, a combustion chamber liner can be equipped with these type of cooling channels. Also heat shields, for example use in the combustion chamber or at the turbine section of a gas turbine engine, can be equipped with these cooling channels. Furthermore the invention can be applied for exhaust nozzles in gas turbines or turbine shrouds. Besides, the invention can also be used for a casing located in a hot region of an engine.

[0067] Beyond that, other types of machines can use this inventive feature to provide an additional cooling as long as cooling air may be provided to that component. As a gas turbine engine has a compressor included into the system in which air is compressed which can be used also as cooling air, the invention is specifically advantageous to be incorporated in a gas turbine engine.

[0068] The invention is particularly advantageous as components can be cooled without needing excessive extra air. This is advantageous as a reduction in the need of cooling air can improve the overall efficiency of the engine. The cooling can be implicitly be controlled by changing the width and/or the height of a cooling channel and not by actively injecting more or less cooling air into cooling channels. Therefore no other active control measure is needed. By changing the channel cross sectional area, the velocity of the cooling air within the cooling channel and consequently the heat transfer coefficient can effectively be controlled. The cooling effect is improved without the need of having additional extra cooling air, which otherwise would decrease the performance of the engine.

[0069] To summarise, when using additive manufacturing for building the part 2 with its cooling channels 3, additive manufacturing allows to change the cross-section of the cooling channels substantially without structural limitations. In a simple embodiment, the cross-section in the tapered section 8 changes constantly with the same rate over a length of the cooling channel. In a more complex embodiment, the cross-section changes in relation to the expected temperature level during operation. Thus, the tapering may be steep in one region and gently in another region based on the expected temperature level in the regions.

[0070] Further, it may be noted that the invention is related to cooling channel which are elongated. In other words, the cooling channel has a longitudinal expanse. A pure through hole through a wall is not a cooling channel of that kind. An elongated channel may be for example a channel with a length that is 50 times or 100 times—or even above—of the cross sectional diameter taken at any position of the cooling channel.

[0071] Beside—even though such a cooling channel defines a passage from one side (first surface 15) of a wall to another side (another surface 16) of the wall—typically the cooling channel is located in a region of a major expanse of that wall, wherein the wall represents the panel 11. It is not sufficient that a cooling channel is a through hole of a wall, perpendicular to the wall or angled. The cooling channel is a duct or conduit or tube or pipe incorporated in the panel 11.

[0072] The invention is advantageous as to allow cooling channel individual cross-sectional gradient along a length of the cooling channel. I.e. two cooling separate channels may have different shapes. The cooling channel individual cross-sectional gradient may be configured in relation to the expected local temperature during operation.