Hot gas path component with built-in heat exchanger for a gas turbine

Abstract

The present invention relates to hot gas path components for gas turbines with built-in heat exchangers. In particular, a hot gas path component for a gas turbine engine, comprising: a tubular wall structure (13) having an inner shell (15), an outer shell (16) and a plurality of ribs (17) connecting the inner shell (15) and the outer shell (16) to each other; a plurality of cooling channels (18) extending through the tubular wall structure (13) between the inner shell (15) and the outer shell (16) and being defined by respective pairs of adjacent ribs (17); a heat exchanger (20) configured to circulate a heat exchange fluid (QC) through the inner shell (15), to guide the heat exchange fluid (QC) from the inner shell (15) through at least some of the ribs (17) to the outer shell (16) and to circulate the heat exchange fluid (QC) through the outer shell (16).

Description

[0001] Cross-references to related applications

[0002] This patent application claims priority to European Patent Application No. 20187969.9, filed on 27 July 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to a hot gas path component with a built-in heat exchanger for a gas turbine engine. Background Technology

[0004] As is known, the combustor of a gas turbine engine includes a hot gas path in which fuel is mixed with air and burned. The heat generated is then fed to the turbine or expansion section of the gas turbine engine to convert thermal and kinetic energy into mechanical energy.

[0005] The hot gas path is essentially defined by a tubular wall with an inner hot surface and an outer cold surface, and can be formed by several components. These components may include one or more combustion sections defining corresponding combustion volumes (e.g., in the case of a sequential combustor), and transition ducts. The transition ducts are configured to guide hot gases into the turbine inlet and thus expose them to high temperatures. Other components of the gas turbine engine that define the hot gas path, and especially the transition ducts, require cooling to prevent damage from overheating and to extend their lifespan. For the purpose of cooling the hot gas path components, a portion of the total airflow is typically drawn from the compressor and fed to the cooling system through a plenum surrounding the combustor. Several known cooling systems can be used, such as impingement cooling, convection cooling, or near-wall cooling. However, all known systems are limited by the fact that they do not allow for further increases in the ignition temperature within the hot gas path, as would be desirable, or otherwise would affect the operation of the gas turbine unit.

[0006] A common problem is the large temperature difference between the inner surface exposed to hot airflow and the outer surface in contact with cooling fluid or, in any case, relatively fresh air. When a gas turbine engine starts up or experiences large load changes, the inner surface undergoes greater thermal expansion than the outer surface, and this mismatch can cause strong static mechanical stress and creep, resulting in a shortened component life. Summary of the Invention

[0007] One object of the present invention is to provide a hot gas path component for a gas turbine engine that allows for overcoming or at least mitigating the limitations described herein.

[0008] According to the present invention, a hot gas path component for a gas turbine engine is provided, comprising:

[0009] A tubular wall structure having an inner shell, an outer shell, and multiple ribs connecting the inner shell and the outer shell to each other;

[0010] Multiple cooling channels extend through the tubular wall structure between the inner and outer shells and are defined by corresponding pairs of adjacent ribs;

[0011] A heat exchanger configured to circulate heat exchange fluid through an inner shell, to guide the exchange fluid from the inner shell through at least some of the ribs to an outer shell, and to circulate heat exchange fluid through the outer shell.

[0012] Hot gas components can be any component that defines the flow path of hot gas in a gas turbine engine, such as the bushing of the combustion chamber of a single-stage, first-stage, or second-stage combustor, or a transition piece connecting the combustion chamber to the inlet of a high-pressure or low-pressure turbine in a gas turbine engine. Therefore, the inner and outer sides of the tubular wall structure experience a significant temperature difference during operation. A heat exchanger allows for balancing the temperature distribution between the inner shell exposed to hot gas and the outer shell in contact with relatively fresh air from the compressor. The heat exchange fluid essentially circulates first in the inner shell and draws heat from the hot gas flowing in the hot gas path, thereby lowering the average temperature of the inner shell. The heat exchange fluid is then directed to the outer shell and circulates therein to dissipate the collected heat and raise the average temperature. The difference in average temperature between the inner and outer shells can be significantly reduced, and mechanical stresses caused by mismatches in thermal expansion are thus alleviated. Reduced mechanical stress obviously benefits the lifespan of the component.

[0013] According to one aspect of the invention, the heat exchanger includes an inner heat exchange passage extending in an inner shell, an outer heat exchange passage extending in an outer shell, and a connection passage extending through a corresponding rib and configured to fluidly connect the corresponding inner heat exchange passage and the corresponding outer heat exchange passage.

[0014] The heat exchanger is integrated into the tubular wall structure and requires no additional components. Simultaneously, the space occupied is not significantly increased, and no undesirable aerodynamic effects, such as vortices or pressure drops in the cooling channels, are involved. The cost and complexity of the manufacturing process are also not significantly affected.

[0015] Although straight pathways connected by bends do indeed generate effective heat transfer, the shapes of internal heat exchange pathways, external heat exchange pathways, and connecting pathways are not limited to a specific pattern (or style) and can be selected according to design preferences. For example, serpentine pathways can be conceived and integrated into any of the inner shell, outer shell, and ribs.

[0016] According to one aspect of the invention, the heat exchanger includes an inlet passage having a corresponding inlet opening in the outer surface of the housing and passing through a corresponding rib to reach a corresponding internal heat exchange passage.

[0017] The heat exchange fluid, which may be relatively fresh air fed into the compartment by the compressor of the gas turbine engine, is directly delivered to the inner shell to maximize the extraction of heat from the hot gas flowing in the hot gas path.

[0018] According to one aspect of the invention, the external heat exchange passage is fluidly connected to the corresponding cooling passage through an outlet opening.

[0019] Because the available pressure drop ensures sufficient flow and heat exchange, the heat exchange fluid is effectively discharged within the cooling channels. Since the external heat exchange pathways extend (or extend) near the cooling channels, the airflow through the cooling channels remains undisturbed and the design is simple.

[0020] According to one aspect of the invention, the heat exchanger includes an intermediate passage formed in a corresponding rib and connected to a corresponding internal heat exchange passage via a corresponding connecting passage and further fluidly connected to a corresponding cooling passage via a corresponding outlet opening.

[0021] Intermediate pathways offer increased flexibility in heat exchanger design and allow for heat redistribution within the fins to reduce localized mechanical stresses according to preference or specific needs. Intermediate pathways can be straight or in any other suitable configuration, such as a serpentine pattern.

[0022] According to one aspect of the invention, external heat exchange passages are formed in the housing at corresponding ribs or between corresponding pairs of adjacent ribs.

[0023] Similarly, internal heat exchange pathways are formed in the inner shell at the corresponding ribs or between corresponding pairs of adjacent ribs.

[0024] According to one aspect of the invention, the heat exchanger includes an internal heat exchange passage and an external heat exchange passage, as many as the number of fins.

[0025] The location, shape, and local density of heat exchange pathways can be flexibly selected according to design preferences to optimize heat distribution and take into account potential specific needs. For example, in some locations, the density of heat exchange pathways can be greater to mitigate the adverse effects of hot spots. Providing both internal and external heat exchange pathways at each rib maximizes heat distribution.

[0026] According to one aspect of the invention, the internal heat exchange passage and the external heat exchange passage are symmetrically distributed along the periphery of the tubular wall structure.

[0027] Since hot air components often exhibit a shape that is symmetrical with respect to the central plane or longitudinal axis, the symmetrical distribution of heat exchange pathways is effective in terms of balancing temperature and avoids mechanical stress concentration caused by thermal mismatch.

[0028] According to one aspect of the invention, heat exchange circuits are formed by connecting each other through a corresponding internal heat exchange circuit and a corresponding external heat exchange circuit, and multiple heat exchange circuits are arranged sequentially at corresponding subsequent longitudinal positions of the tubular wall structure.

[0029] Therefore, separate heat exchange loops can be provided at corresponding different sections of the tubular wall structure. Fresh heat exchange fluid can be supplied at different longitudinal locations, and the lengths of the heat exchange loops and the sections of the tubular wall structure can be selected to achieve satisfactory heat distribution and reduction of mechanical stress throughout the hot gas path component.

[0030] According to one aspect of the invention, each internal heat exchange passage is fluidly connected to a plurality of external heat exchange passages and / or each external heat exchange passage is fluidly connected to a plurality of internal heat exchange passages.

[0031] According to one aspect of the invention, the internal heat exchange passage and the external heat exchange passage extend along the longitudinal direction of the tubular wall structure.

[0032] According to one aspect of the invention, the ribs extend longitudinally relative to the tubular wall structure and transversely to the inner and outer shells.

[0033] According to one aspect of the invention, a gas turbine engine includes a hot gas path component.

[0034] According to one aspect of the invention, a gas turbine engine includes a compressor and an air chamber fed by the compressor, wherein the housing of a hot gas component is fluidly connected to the chamber and a heat exchanger uses the air supplied from the chamber.

[0035] In a gas turbine engine, the compressor provides multiple sources of cooling air that can be obtained at different compressor stages. Therefore, the heat exchanger can use air at appropriate temperature and pressure conditions fed through the compartment, which is directly delivered to and circulated within the inner casing to maximize heat transfer and temperature balance. Attached Figure Description

[0036] The invention will now be described with reference to the accompanying drawings, which illustrate some non-limiting embodiments of the invention, wherein:

[0037] - Figure 1 It is a side view cut along the axial and longitudinal plane of the gas turbine engine;

[0038] - Figure 2 It is made according to an embodiment of the present invention. Figure 1 A perspective view of the hot gas path components of a gas turbine engine;

[0039] - Figure 3 It is along Figure 2 The plane III-III intercepts Figure 2 Side section view of the hot air path component;

[0040] - Figure 4 It is along Figure 3 The plane IV-IV intercepts Figure 2 Front section view of the hot air path component;

[0041] - Figure 5 This is a side cross-sectional view of a hot gas path component of a gas turbine engine according to different embodiments of the present invention;

[0042] - Figure 6 This is a side cross-sectional view of a hot gas path component of a gas turbine engine according to another embodiment of the present invention;

[0043] - Figure 7 This is a front cross-sectional view of a hot gas path component of a gas turbine engine according to another embodiment of the present invention;

[0044] - Figure 8 It is along Figure 7 The plane VIII-VIII intercepts Figure 7 Side section view of the hot air path component;

[0045] - Figure 9 This is a side cross-sectional view of a hot gas path component of a gas turbine engine according to another embodiment of the present invention;

[0046] - Figure 10 This is a front cross-sectional view of a hot gas path component of a gas turbine engine according to another embodiment of the present invention;

[0047] - Figure 11 This is a front cross-sectional view of a hot gas path component of a gas turbine engine according to another embodiment of the present invention; and

[0048] - Figure 12 This is a front cross-sectional view of a hot gas path component of a gas turbine engine according to another embodiment of the present invention. Detailed Implementation

[0049] Figure 1A simplified view of a gas turbine engine, generally indicated by reference numeral 1, is shown. The gas turbine engine 1 includes a compressor 2, a combustor assembly 3, and a turbine 5. The compressor section 2 and the turbine 5 extend along the main axis A. The combustor assembly 3 may be as shown in... Figure 1 The examples are sequential burner assemblies or single-stage burner assemblies. In one embodiment, burner assembly 3 includes a plurality of sequential cylindrical (or canister-shaped) burners 7 arranged circumferentially about the main axis A.

[0050] The compressor 2 of the gas turbine engine 1 provides a compressed airflow, which is added to and combusted in the cylindrical combustor 7. A portion of the airflow delivered by the compressor 2 is supplied to the combustor assembly 3 and to the turbine section 5 for cooling purposes. Specifically, the cooling airflow QC is taken from the intermediate stage of the compressor 2 and supplied to the air chamber 6 surrounding the cylindrical combustor 7.

[0051] In one embodiment, each of the cylindrical burners 7 includes a first-stage burner 8 and a second-stage burner 9, as well as a transition duct 10, which are arranged sequentially and define a hot gas path component of a hot gas path 12.

[0052] In the following text, reference will be made to the second-stage burner 9; it should be understood that the description also applies to all other hot gas path components. For example, in Figure 2-4 As shown, the hot gas path component according to the invention, in one embodiment particularly the second-stage burner 9, is made as a single piece and includes a tubular wall structure 13 extending along a longitudinal axis L from an upstream end 13a to a downstream end 13b. The tubular wall structure 13 further includes an inner shell 15, an outer shell 16, and a plurality of ribs 17 connecting the inner shell 15 and the outer shell 16 to each other. The inner shell 15 defines a hot gas path 12, while the outer shell communicates with a chamber 6. The ribs 17 extend in the longitudinal direction of the tubular wall structure 13 and transversely to the inner shell 15 and the outer shell 16, for example, vertically. Cooling channels 18 extend through the tubular wall structure 13 between the inner shell 15 and the outer shell 16 and are defined by corresponding pairs of adjacent ribs 17 and separated from each other.

[0053] The heat exchanger 20 is integrated in the tubular wall structure 13 and configured to allow heat exchange fluid to circulate through the inner shell 15, guide the exchange fluid from the inner shell 15 through the ribs 17 to the outer shell 16, and allow heat exchange fluid to circulate through the outer shell 16. The heat exchanger 20 includes an inlet passage 21, an inner heat exchange passage 22, an outer heat exchange passage 23, and a connection passage 25.

[0054] The inlet passage 21 has a corresponding inlet opening 26 in the outer surface 16a of the outer shell 16. Therefore, the inlet passage 21 is fluidly connected to the chamber 6, and airflow is supplied to the heat exchanger 20 as a heat exchange fluid. The inlet passage 21 extends through the corresponding rib 17 and reaches the corresponding internal heat exchange passage 22 in the inner shell 15.

[0055] In one embodiment, an internal heat exchange passage 22 is formed in the inner shell 15 at the junction of the inner shell 15 and the rib 17. Similarly, an external heat exchange passage 23 is formed in the outer shell 16 at the junction of the outer shell 16 and the rib 17. The internal heat exchange passage 22 and the external heat exchange passage 23 are provided at each rib 17 and extend along the longitudinal direction of the tubular wall structure 13 in the inner shell 15 and the outer shell 16, respectively. Therefore, the heat exchanger 20 includes as many internal heat exchange passages 22 and external heat exchange passages 23 as the ribs 17, and the internal heat exchange passages 22 and external heat exchange passages 23 are symmetrically distributed along the periphery of the tubular wall structure 13. Figure 2-4 In the example, the internal heat exchange path 22 and the external heat exchange path 23 are straight lines.

[0056] Each internal heat exchange passage 22 is connected to a corresponding external heat exchange passage 23 via a connecting passage 25 that extends through the corresponding rib 17 and can extend parallel to the corresponding inlet passage 21.

[0057] The external heat exchange passage 23 is fluidly connected to the corresponding cooling passage 18 via an outlet opening 27 formed on the side of the corresponding rib 17. The pressure drop in the cooling passage 18 relative to the chamber 6 is sufficient to ensure that the heat exchange fluid circulates through the heat exchanger 20 and is discharged in the cooling passage 18. The discharge angle of the external heat exchange passage 23 can be selected to prevent eddies in the cooling fluid flowing through the cooling passage 18.

[0058] As in Figure 5 As illustrated, the heat exchanger 20 may include a plurality of heat exchange loops 28 in the rib 17, each having an independent inlet opening 26 at a corresponding longitudinal location in the tubular wall 13. Each heat exchange loop 28 includes at least one inlet passage 21, an inner heat exchange passage 22 connected to each other, and an outer heat exchange passage 23.

[0059] exist Figure 6 and Figure 7In one embodiment shown, the heat exchanger 20 includes an intermediate passage 30 formed in corresponding ribs 17 between the inner shell 15 and the outer shell 16, and extending parallel to the corresponding inner heat exchange passage 22 and the outer heat exchange passage 23. The intermediate passage 30 is connected to the corresponding inner heat exchange passage 22 via a corresponding connecting passage 25. Furthermore, the intermediate passage 30 is fluidly connected in parallel to the corresponding outer heat exchange passage 23 between the corresponding connecting passage 25 and the outlet opening 27.

[0060] Alternatively, the intermediate passage 30 can also be fluidly connected in series between the corresponding internal heat exchange passage 22 and external heat exchange passage 23, such as in Figure 8 In some embodiments, or connected downstream of the corresponding external heat exchange passage 23, such as in Figure 9 In the embodiments described above.

[0061] exist Figure 10 In one embodiment, internal heat exchange passages 22 are formed in the inner shell 15 between corresponding pairs of adjacent ribs 17, and adjacent internal heat exchange passages 22 are fluidly connected to each other by additional connecting passages 31 extending circumferentially in the inner shell 15. Connecting passages 25 connect external heat exchange passages 23 to corresponding connecting passages 31. Thus, each external heat exchange passage 23 is fluidly connected to a plurality of internal heat exchange passages 22.

[0062] exist Figure 11 In another embodiment, external heat exchange passages 23 are formed in the housing 16 between corresponding pairs of adjacent ribs 17, and adjacent external heat exchange passages 23 are fluidly connected to each other by additional connecting passages 32 extending circumferentially in the housing 16. Connecting passages 25 connect internal heat exchange passages 22 to corresponding connecting passages 32. Thus, each internal heat exchange passage 22 is fluidly connected to a plurality of external heat exchange passages 22.

[0063] exist Figure 12 In one embodiment, all internal heat exchange passages 22 and external heat exchange passages 23 are fluidly connected to each other.

[0064] Finally, it is obvious that the described transition channels may be modified and varied without departing from the scope of the invention as defined in the appended claims.

[0065] Specifically, any other components of the hot gas path may have the structure described above, and any suitable combination of these components may be obtained according to design preferences.

[0066] Internal and external heat exchange pathways do not need to be provided at every fin or every channel. Depending on specific requirements, fewer internal and / or external heat exchange pathways may be sufficient to achieve satisfactory temperature balance and stress reduction. Internal, external, and intermediate heat exchange pathways have been proposed as straight lines, but can be provided in any suitable configuration, such as a serpentine shape. Connections between internal and external heat exchange pathways can also be provided according to specific requirements.

Claims

1. A hot gas path component for a gas turbine engine, comprising: - a tubular wall structure (13) having an inner shell (15) delimiting a hot gas path, an outer shell (16) and a plurality of ribs (17) connecting the inner shell (15) and the outer shell (16) to each other; - a plurality of cooling channels (18) extending through the tubular wall structure (13) between the inner shell (15) and the outer shell (16) and being defined by respective pairs of adjacent ribs (17); - a heat exchanger (20) configured to circulate a heat exchange fluid (QC) through the inner shell (15), to guide the heat exchange fluid (QC) from the inner shell (15) through at least some of the ribs (17) to the outer shell (16) and to circulate the heat exchange fluid (QC) through the outer shell (16); - wherein the heat exchanger (20) comprises inner heat exchange passages (22) extending in the inner shell (15), outer heat exchange passages (23) extending in the outer shell (16) and connecting passages extending through respective ribs (17) and configured to fluidly couple respective inner heat exchange passages (22) and respective outer heat exchange passages (23); - characterized in that the heat exchanger (20) comprises inlet passages (21) having respective inlet openings (26) in an outer surface (16a) of the outer shell (16) and passing through respective ribs (17) to respective inner heat exchange passages (22) and in that the outer heat exchange passages (23) are fluidly coupled to respective cooling channels (18) through outlet openings.

2. The hot gas path member of claim 1, wherein, - the heat exchanger (20) comprises intermediate passages (30) formed in respective ribs (17) and connected to respective inner heat exchange passages (22) through respective connecting passages and further fluidly coupled to respective cooling channels (18) through respective outlet openings.

3. The hot gas path member of claim 1, wherein, - the outer heat exchange passages (23) are formed in the outer shell (16) at or between respective pairs of adjacent ribs (17).

4. The hot gas path member of claim 1, wherein, - the inner heat exchange passages (22) are formed in the inner shell (15) at or between respective pairs of adjacent ribs (17).

5. The hot gas path member of claim 1, wherein, - the heat exchanger (20) comprises as many inner heat exchange passages (22) and outer heat exchange passages (23) as ribs (17).

6. The hot gas path member of claim 1, wherein, - the inner heat exchange passages (22) and the outer heat exchange passages (23) are distributed symmetrically along a periphery of the tubular wall structure (13).

7. The hot gas path member of claim 1, wherein - heat exchange circuits (28) are each formed by a respective one of the inner heat exchange passages (22) and a respective one of the outer heat exchange passages (23) fluidly coupled to each other by a respective one of the connecting passages (25) and a plurality of heat exchange circuits (28) are arranged in succession at respective subsequent longitudinal positions of the tubular wall structure (13).

8. The hot gas path member of claim 1, wherein, Each inner heat exchange passage (22) is fluidly coupled to a plurality of outer heat exchange passages (23) and / or each outer heat exchange passage (23) is fluidly coupled to a plurality of inner heat exchange passages (22).

9. The hot gas path member of claim 1, wherein, The inner heat exchange passages (22) and the outer heat exchange passages (23) extend along a longitudinal direction of the tubular wall structure (13).

10. The hot gas path member of claim 1, wherein, The ribs (17) extend longitudinally with respect to the tubular wall structure (13) and transversely to the inner shell (15) and the outer shell (16).

11. A gas turbine engine comprising a hot gas path member (10) according to any of the preceding claims.

12. The gas turbine engine of claim 11, wherein, The gas turbine engine comprises a compressor and an air plenum fed by the compressor, wherein the outer shell (16) of the hot gas member is fluidly coupled to the plenum and the heat exchanger (20) is supplied with air from the plenum.

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