Patent Application
20130111912
The subject matter disclosed herein relates generally to turbine systems, and more particularly to seals between transition ducts and turbine sections of turbine systems.
Turbine systems are widely utilized in fields such as power generation. For example, a conventional gas turbine system includes a compressor section, a combustor section, and at least one turbine section. The compressor section is configured to compress air as the air flows through the compressor section. The air is then flowed from the compressor section to the combustor section, where it is mixed with fuel and combusted, generating a hot gas flow. The hot gas flow is provided to the turbine section, which utilizes the hot gas flow by extracting energy from it to power the compressor, an electrical generator, and other various loads.
The combustor sections of turbine systems generally include tubes or ducts for flowing the combusted hot gas therethrough to the turbine section or sections. Recently, combustor sections have been introduced which include tubes or ducts that shift the flow of the hot gas. For example, ducts for combustor sections have been introduced that, while flowing the hot gas longitudinally therethrough, additionally shift the flow radially or tangentially such that the flow has various angular components. These designs have various advantages, including eliminating first stage nozzles from the turbine sections. The first stage nozzles were previously provided to shift the hot gas flow, and may not be required due to the design of these ducts. The elimination of first stage nozzles may eliminate associated pressure drops and increase the efficiency and power output of the turbine system.
However, the connection of these ducts to turbine sections is of increased concern. For example, because the ducts do not simply extend along a longitudinal axis, but are rather shifted off-axis from the inlet of the duct to the outlet of the duct, thermal expansion of the ducts can cause undesirable shifts in the ducts along or about various axes. Such shifts can cause unexpected gaps between the ducts and the turbine sections, thus undesirably allowing leakage and mixing of cooling air and hot gas.
Accordingly, an improved seal between a combustor duct and a turbine section of a turbine system would be desired in the art. For example, a seal that allows for thermal growth of the duct while preventing gaps between the duct and turbine section would be advantageous.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one embodiment, a turbine system is disclosed. The turbine system includes a transition duct. The transition duct includes an inlet, an outlet, and a passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The transition duct further includes an interface member for interfacing with a turbine section. The turbine system further includes a flexible metallic seal contacting the interface member to provide a seal between the interface member and the turbine section.
In another embodiment, a turbine system is disclosed. The turbine system includes a transition duct. The transition duct includes an inlet, an outlet, and a passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The transition duct further includes a first interface member. The turbine system additionally includes a turbine section comprising a second interface member. The turbine system further includes a flexible metallic seal contacting and providing a seal between the first interface member and the second interface member.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
Referring to
A combustor 15 in the gas turbine 10 may include a variety of components for mixing and combusting the working fluid and fuel. For example, the combustor 15 may include a casing 21, such as a compressor discharge casing 21. A variety of sleeves, which may be axially extending annular sleeves, may be at least partially disposed in the casing 21. The sleeves, as shown in
The combustor 15 may further include a fuel nozzle 40 or a plurality of fuel nozzles 40. Fuel may be supplied to the fuel nozzles 40 by one or more manifolds (not shown). As discussed below, the fuel nozzle 40 or fuel nozzles 40 may supply the fuel and, optionally, working fluid to the combustion zone 24 for combustion.
As shown in
As shown, the plurality of transition ducts 50 may be disposed in an annular array about a longitudinal axis 90. Further, each transition duct 50 may extend between a fuel nozzle 40 or plurality of fuel nozzles 40 and the turbine section 16. For example, each transition duct 50 may extend from the fuel nozzles 40 to the turbine section 16. Thus, working fluid may flow generally from the fuel nozzles 40 through the transition duct 50 to the turbine section 16. In some embodiments, the transition ducts 50 may advantageously allow for the elimination of the first stage nozzles in the turbine section, which may eliminate any associated drag and pressure drop and increase the efficiency and output of the system 10.
Each transition duct 50 may have an inlet 52, an outlet 54, and a passage 56 therebetween. The inlet 52 and outlet 54 of a transition duct 50 may have generally circular or oval cross-sections, rectangular cross-sections, triangular cross-sections, or any other suitable polygonal cross-sections. Further, it should be understood that the inlet 52 and outlet 54 of a transition duct 50 need not have similarly shaped cross-sections. For example, in one embodiment, the inlet 52 may have a generally circular cross-section, while the outlet 54 may have a generally rectangular cross-section.
Further, the passage 56 may be generally tapered between the inlet 52 and the outlet 54. For example, in an exemplary embodiment, at least a portion of the passage 56 may be generally conically shaped. Additionally or alternatively, however, the passage 56 or any portion thereof may have a generally rectangular cross-section, triangular cross-section, or any other suitable polygonal cross-section. It should be understood that the cross-sectional shape of the passage 56 may change throughout the passage 56 or any portion thereof as the passage 56 tapers from the relatively larger inlet 52 to the relatively smaller outlet 54.
The outlet 54 of each of the plurality of transition ducts 50 may be offset from the inlet 52 of the respective transition duct 50. The term “offset”, as used herein, means spaced from along the identified coordinate direction. The outlet 54 of each of the plurality of transition ducts 50 may be longitudinally offset from the inlet 52 of the respective transition duct 50, such as offset along the longitudinal axis 90.
Additionally, in exemplary embodiments, the outlet 54 of each of the plurality of transition ducts 50 may be tangentially offset from the inlet 52 of the respective transition duct 50, such as offset along a tangential axis 92. Because the outlet 54 of each of the plurality of transition ducts 50 is tangentially offset from the inlet 52 of the respective transition duct 50, the transition ducts 50 may advantageously utilize the tangential component of the flow of working fluid through the transition ducts 50 to eliminate the need for first stage nozzles in the turbine section 16, as discussed below.
Further, in exemplary embodiments, the outlet 54 of each of the plurality of transition ducts 50 may be radially offset from the inlet 52 of the respective transition duct 50, such as offset along a radial axis 94. Because the outlet 54 of each of the plurality of transition ducts 50 is radially offset from the inlet 52 of the respective transition duct 50, the transition ducts 50 may advantageously utilize the radial component of the flow of working fluid through the transition ducts 50 to further eliminate the need for first stage nozzles in the turbine section 16, as discussed below.
It should be understood that the tangential axis 92 and the radial axis 94 are defined individually for each transition duct 50 with respect to the circumference defined by the annular array of transition ducts 50, as shown in
As discussed, after hot gases of combustion are flowed through the transition duct 50, they may be flowed from the transition duct 50 into the turbine section 16. As shown in
The turbine section 16 may further include a plurality of buckets 112 and a plurality of nozzles 114. Each of the plurality of buckets 112 and nozzles 114 may be at least partially disposed in the hot gas path 104. Further, the plurality of buckets 112 and the plurality of nozzles 114 may be disposed in one or more annular arrays, each of which may define a portion of the hot gas path 104.
The turbine section 16 may include a plurality of turbine stages. Each stage may include a plurality of buckets 112 disposed in an annular array and a plurality of nozzles 114 disposed in an annular array. For example, in one embodiment, the turbine section 16 may have three stages, as shown in
A second stage of the turbine section 16 may include a second stage nozzle assembly 123 and a second stage buckets assembly 124. The nozzles 114 included in the nozzle assembly 123 may be disposed and fixed circumferentially about the shaft 18. The buckets 112 included in the bucket assembly 124 may be disposed circumferentially about the shaft 18 and coupled to the shaft 18. The second stage nozzle assembly 123 is thus positioned between the first stage bucket assembly 122 and second stage bucket assembly 124 along the hot gas path 104. A third stage of the turbine section 16 may include a third stage nozzle assembly 125 and a third stage bucket assembly 126. The nozzles 114 included in the nozzle assembly 125 may be disposed and fixed circumferentially about the shaft 18. The buckets 112 included in the bucket assembly 126 may be disposed circumferentially about the shaft 18 and coupled to the shaft 18. The third stage nozzle assembly 125 is thus positioned between the second stage bucket assembly 124 and third stage bucket assembly 126 along the hot gas path 104.
It should be understood that the turbine section 16 is not limited to three stages, but rather that any number of stages are within the scope and spirit of the present disclosure.
As discussed above, the outlet 54 of each of the plurality of transition ducts 50 may be longitudinally, radially, and/or tangentially offset from the inlet 52 of the respective transition duct 50. These various offsets of the transition ducts 50 may cause unexpected movement of the transition ducts 50 due to thermal growth during operation of the system 10. For example, the outlet 54 of a transition duct 50 may interface with the turbine section 16 to allow the flow of hot gas therebetween. However, thermal growth may cause the outlet 54 to move with respect to the turbine section 16 about or along one or more of the longitudinal axis 90, tangential axis 92, and/or radial axis 94.
To prevent gaps between an outlet 54 and turbine section 16, the present disclosure may further be directed to one or more seals 140. Each seal 140 may be provided at an interface between the outlet 54 and turbine section 16. Further, each seal 140 may be flexible. A flexible seal is a seal with at least a portion that flexes to correspond to the contour of a mating surface with which the seal is interfacing to provide a seal therewith, and to maintain such contour and resulting seal during movement of or with respect to such mating surface. A flexible seal according to the present disclosure can flex to maintain such contour and seal during operation of the turbine system 10 despite unexpected movement of the transition duct 50 and outlet 54 along or about one or more of the axes 90, 92, 94. Additionally, each seal 140 according to the present disclosure may be metallic. A metallic seal is a seal with at least a portion formed from a metal or metal alloy or superalloy. For example, a metallic seal may include aluminum, iron, nickel, or any suitable alloy or superalloy thereof, and/or may include any other suitable metal or alloy or superalloy thereof. The present inventors have discovered that flexible metallic seals are particularly advantageous at sealing the interface between an outlet 54 and a turbine section 16, because the flexible metallic seals 140 can accommodate the unexpected movement of the outlet 54 along or about the various axis 90, 92, 94.
As shown in
Each interface members 142 may interface with any suitable contact surface 143 on the turbine section 16. The seal 140 may be positioned to, and may, contact the contact surface 143. Such contact surface 143 may be part of, or be, a second interface member 144, as shown in
As shown, a seal 140 according to the present disclosure may contact a first interface member 142 and associated second interface member 144 and contact surface 143 thereof. Such contact may allow the first and second members 142, 144 to interface, and may provide a seal between the first interface member 142 and second interface member 144, and thus between a transition duct 50 and turbine section 16.
Exemplary seals 140 are shown in
Further, in some embodiments, at least a portion of the seal 140, such as of the seal plate 150 thereof, may have a contour that generally corresponds to the contour of the surface that the portion is contacting when the seal 140 is in an operating condition. An operating condition is a condition wherein the seal 140 is subjected to the temperature or temperature range and pressure or pressure range that it may be subjected to during normal operation of the system 10. For example, in one embodiment, the operating condition may be the condition that the seal 140 is being subjected to inside of the system 10 during operation thereof. The surface may be, for example, the contact surface 143. The portion having such contour may, in some embodiments, be the flexible portion. The corresponding contour of the portion of the seal 140 or seal plate 150 and the surface that the portion is contacting may facilitate sealing when the seal 140 contacts the interface members. Such portion may further flex as necessary along or about one or more axes 90, 92, 94 during operation of the turbine system 10 to maintain such corresponding contour and to maintain such seal.
In some embodiments, a seal 140 according to the present disclosure may further include a retention plate 152. The retention plate 152 may contact one of the first interface member 142 or second interface member 144 and may be disposed between the seal plate 150 and that member. In some embodiments, the retention plate 152 may retain the seal 140 in contact with the interface member that the retention plate 152 is contacting, such as the first interface member 142. For example, in some embodiments, the retention plate 152 may be mounted to a surface of the interface member through a suitable adhesive, weld, or other suitable mounting apparatus or method. In other embodiments, an interface member, such as the first interface member 142 as shown, may define a channel 154. At least a portion of the retention plate 152, such as a hook portion 156, may be disposed in the channel 154. Such portion may further, in some embodiments, be mounted in the channel 154 through use of a suitable adhesive, weld, or other suitable mounting apparatus or method. Such portion may retain the seal 140 in contact with the interface member. In other embodiments, the retention plate 152 may not be mounted to a surface or in a channel 154, and may rather be retained to the surface or in the channel 154 due to the geometry and forces of the various assembled components, such as the interface members and seal 140, and/or due to the pressure that the seal 140 is subjected to during operation of the system 10.
In some embodiments, a seal 140 according to the present disclosure may further include a contact plate 158. A contact plate 158 may be positioned to contact, and be in contact with, a surface of an interface member, such as the contact surface 143 of a second interface member 144. The contact plate 158 may be positioned between such surface and the seal plate 150. The contact plate 158 may stabilize and maintain a seal between the seal 140 and that interface member, such as the second interface member 144, and may further stabilize the positioning of the seal 140 with respect to the other interface member 142.
In some embodiments, as shown in
A seal 140 of the present disclosure may advantageously allow the transition duct 50, such as the outlet 54 of the transition duct 50, to move about or along one or more of the various axis 90, 92, 94 while maintaining a seal with the turbine section 16. This may advantageously accommodate the thermal growth of the transition duct 50, which may be offset as discussed above, while allowing the transition duct 50 to remain sufficiently sealed to the turbine section 16. In exemplary embodiments, for example, the seal 140 may allow movement of the transition duct 50, such as of the outlet 54 of the transition duct 50, about or along one, two, or three of the longitudinal axis 90, the tangential axis 92 and the radial axis 94. In exemplary embodiments, the seal 140 allows movement about or along all three axes. Thus, seals 140 advantageously provide a seal that accommodates the unexpected movement of the transition ducts 50 of the present disclosure.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
This invention was made with government support under contract number DE-FC26-05NT42643 awarded by the Department of Energy. The government has certain rights in the invention.
