Seal assembly for a turbine engine

Abstract

The seal assembly includes a plurality of seal segments for sealing between the rotor and the stator, where the rotor, the stator, and the plurality of seal segments when arranged together define a high pressure region and a low pressure region. The seal assembly also includes a biasing member engaged with the plurality of seal segments and at least one feature formed in the stator. Thus, the pressurized fluid engaged with the at least one feature provides a rearward-forward axial force that reduces friction between the stator and the interface aft surface of the plurality of seal segments.

Description

TECHNICAL FIELD

[0001] The present disclosure generally relates to turbine engines and, more particularly, to a seal assembly for a turbine engine. BACKGROUND OF THE DISCLOSURE

[0002] Gas turbine engines, such as turbofan engines, may be used for aircraft propulsion. A turbofan engine typically includes a bypass fan section and a turbine, such as a gas turbine engine, to drive the bypass fan. The turbine typically includes a compressor section, a combustor section, and a turbine section in a series flow arrangement. Both the compressor section and the turbine section are driven by one or more rotor shafts and typically include multiple rows or stages of rotor blades coupled to the rotor shafts. Each individual row of rotor blades is axially spaced from a successive row of rotor blades by a corresponding row of stator or stationary vanes. A radial gap is formed between an inner surface of the stator vanes and an outer surface of the rotor shaft. A gas turbine engine may further include various seals to reduce and / or prevent leakage of flow (e.g., working fluid flow) between various components of the gas engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] A complete and enabling disclosure of the present disclosure, including the best mode thereof, to one of ordinary skill in the art, is set forth in the specification, which makes reference to the accompanying drawings, in which:

[0004] Figure 1 is a cross-sectional view of a gas turbine engine in accordance with an aspect of the present disclosure.

[0005] Figure 2 is Figure 1 a cross-sectional schematic view of a portion of the turbine of

[0006] Figure 3 is a close-up schematic cross-sectional view of a portion of the turbine of Figure 2 taken along line 3-3.

[0007] Figure 4 is Figure 3 a close-up schematic cross-sectional view of a rotor, stator, carrier, and seal assembly of

[0008] Figure 5 particularly showing an aerodynamic seal assembly.

[0009] Figure 6 is a close-up schematic cross-sectional view of another embodiment of a rotor, stator, carrier, and seal assembly of a turbine in accordance with an aspect of the present disclosure, particularly showing an aerodynamic seal assembly.

[0010] Figure 7 A close-up schematic cross-sectional view of another embodiment of a rotor, stator, carrier, and seal assembly of a turbine according to aspects of the present disclosure, particularly showing an aerostatic seal assembly. DETAILED DESCRIPTION

[0011] Reference will now be made in detail to the current embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and alphabetical labels to refer to features in the drawings. Similar or like labels have been used in the drawings and description to refer to similar or like parts of the present disclosure.

[0012] The singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0013] In the context of "at least one of A, B, and C", the term "at least one" refers to only A, only B, only C, or any combination of A, B, and C.

[0014] The term "turbine" refers to a machine that includes one or more compressors, a heat generation section (e.g., a combustion section), and one or more turbines that together produce a torque output.

[0015] The term "gas turbine engine" or "turbine engine" refers to an engine that has a turbine as all or part of its power source. Example gas turbine engines include turbofan engines, turboprop engines, turbojet engines, turboshaft engines, etc., as well as hybrid electric versions of one or more of these engines.

[0016] The term "combustion section" refers to any heat addition system of a turbine. For example, the term combustion section may refer to including one or more of a deflagration combustion assembly, a rotating detonation combustion assembly, a pulse detonation combustion assembly, or other suitable heat addition components. In certain example embodiments, the combustion section may include an annular burner, a can burner, a tubo burner, a trapped vortex combustor (TVC), or other suitable combustion systems, or combinations thereof.

[0017] The terms "low" and "high" or their respective comparatives (e.g., lower, higher, where applicable) when used in conjunction with components such as compressors, turbines, shafts, or spools, all refer to relative speeds within the engine unless otherwise specified. For example, "low turbine" or "low-speed turbine" defines a component configured to operate at a rotational speed (e.g., maximum allowable speed) lower than that of the "high turbine" or "high-speed turbine" of the engine.

[0018] The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle. For example, for a gas turbine engine, front refers to a position closer to the engine inlet, and rear refers to a position closer to the engine nozzle or exhaust port.

[0019] The terms "upstream" and "downstream" refer to the relative directions with respect to the fluid flow in a fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction towards which the fluid flows.

[0020] The term "proximate" means closer to one end compared to the opposite end. For example, when used in conjunction with a first end and a second end, a high-pressure side and a low-pressure side, etc., the phrase "proximate to the first end" or "proximate to the high-pressure side" refers to a position closer to the first end compared to the second end, or a position closer to the high-pressure side compared to the low-pressure side, respectively.

[0021] For the relative positions of two similar components, the term "adjacent" means that there are no other similar components therebetween. For the relative positions of two different components, the term "adjacent" means that there is no intermediate structure separating the two components.

[0022] An "aerodynamic seal" generally refers to a mechanical seal that uses a dynamic rotor and one or more grooves on the rotor or stator, which form an air film, and the opposing sealing surfaces ride on the air film. An "aerostatic seal" generally refers to a mechanical seal that uses air from a high-pressure region guided through one or more feed ports (or aerostatic ports) to form an air film between the sealing surface and the opposing rotor. A "hybrid seal" generally refers to a combination of an aerodynamic seal having at least one groove and an aerostatic seal having one or more feed ports to guide air from a high-pressure region.

[0023] The present disclosure generally relates to a seal assembly having a plurality of seal segments for a turbine of a gas turbine engine. The turbine generally includes a compressor section arranged in a series flow order, the compressor section including a low-pressure compressor and a high-pressure compressor; a combustion section; and a turbine section including a high-pressure turbine and a low-pressure turbine. Each of the low-pressure compressor, the high-pressure compressor, the high-pressure turbine, and the low-pressure turbine includes a continuous row of stationary or stator vanes axially spaced apart by a continuous row of rotor blades. The rotor blades are generally coupled to a rotor shaft, and the stator vanes are circumferentially mounted around the outer surface of the rotor shaft in an annular configuration. A radial gap is formed between the outer surface of the rotor shaft and the inner portion of each ring or row of stator vanes. A radial gap may also be formed between the outer surface of the rotor shaft and the inner portion of a non-rotating stationary portion of the engine.

[0024] During operation, it is desirable to control (reduce or prevent) leakage of compressed air flow or combustion gas flow through these radial clearances. Accordingly, a seal assembly having a plurality of seal segments is used to seal these radial clearances. More specifically, the seal segments may be disposed between a rotor and a stator. Specifically, the rotor, stator, and seal segments are arranged together to define a high-pressure region and a low-pressure region. The segmented seal may be an aerodynamic seal, an aerostatic seal, or a hybrid seal. A spring engages the plurality of seal segments to urge the seal segments toward the rotor. The stator has at least one feature formed therein. Accordingly, the pressurized fluid engaging the feature provides an axial force from rear to front, and the axial force from rear to front reduces the friction between the interface rear surface of the seal segment and the stator.

[0025] In an embodiment, for example, the feature may be a groove formed in the surface of the stator that creates a medium-pressure region between the high-pressure region and the low-pressure region. In such an embodiment, the pressurized fluid in the medium-pressure region provides an axial force from rear to front that minimizes the friction between the interface rear surface of the seal segment and the stator. In an alternative embodiment, the feature may include at least one fluid passage formed in the stator. In such an embodiment, the fluid passage fluidly connects the high-pressure fluid in the high-pressure region to the interface rear surface of the seal ring and the stator to provide an axial force from rear to front that minimizes the friction between the interface rear surface of the seal segment and the stator.

[0026] Accordingly, the features described herein are particularly useful when the fence height (e.g., the distance between the radially outermost surface of the rotor and the radially innermost surface of the stator) is large. Specifically, the combination of a large seal pressure differential and a large fence height may result in a large axial plug load and undesirable frictional forces interfering with seal operation. Accordingly, the features described herein are particularly useful in addressing this issue.

[0027] Reference is now made to the drawings, where like numerals represent like elements throughout the drawings, Figure 1 which is a schematic cross-sectional view of a gas turbine engine 10 according to an embodiment of the present disclosure. More specifically, for Figure 1 the embodiment, the gas turbine engine 10 is a high-bypass turbofan jet engine, sometimes also referred to as a "turbofan engine". As Figure 1 shown, the gas turbine engine 10 defines an axial direction A (extending parallel to a longitudinal centerline 12 for reference), a radial direction R, and a circumferential direction C extending about the longitudinal centerline 12. Generally speaking, the gas turbine engine 10 includes a fan section 14 and a turbine 16 disposed downstream of the fan section 14.

[0028] The turbine 16 shown generally includes a substantially tubular outer casing 18 that defines an annular inlet 20. The outer casing 18 surrounds a compressor section in series flow relationship, which includes a booster or low pressure (LP) compressor 22 and a high pressure (HP) compressor 24; a combustion section 26; a turbine section, which includes a high pressure (HP) turbine 28 and a low pressure (LP) turbine 30; and an exhaust jet nozzle section 32. A high pressure (HP) shaft 34 (which may additionally or alternatively be a spool) drivingly connects the HP turbine 28 to the HP compressor 24. A low pressure (LP) shaft 36 (which may additionally or alternatively be a spool) drivingly connects the LP turbine 30 to the LP compressor 22. The compressor section, the combustion section 26, the turbine section, and the exhaust jet nozzle section 32 together define a working gas flow path 37.

[0029] For the embodiment shown, the fan section 14 includes a fan 38 having a plurality of fan blades 40 that are coupled to a disk 42 in a spaced-apart manner. As shown, the fan blades 40 extend generally radially outwardly from the disk 42 along a radial direction R. Each fan blade 40 is rotatable relative to the disk 42 about a pitch axis P by operably coupling the fan blade 40 to a suitable pitch changing mechanism 44, which is configured to collectively change the pitch of the fan blades 40, e.g., uniformly. The gas turbine engine 10 further includes a power gearbox 46, and the fan blades 40, the disk 42, and the pitch changing mechanism 44 are rotatable together about the longitudinal centerline 12 by way of the LP shaft 36 across the power gearbox 46. The power gearbox 46 includes a plurality of gears for adjusting the rotational speed of the fan 38 relative to the rotational speed of the LP shaft 36 such that the fan 38 can rotate at a more efficient fan speed.

[0030] Still referring to Figure 1 the embodiment, the disk 42 is covered by a rotatable front hub 48 (sometimes also referred to as a " spinner ") of the fan section 14. The front hub 48 has an aerodynamic profile to facilitate airflow through the plurality of fan blades 40.

[0031] Additionally, the fan section 14 includes an annular fan casing or outer nacelle 50 that circumferentially surrounds the fan 38 and / or at least a portion of the turbine 16. It should be understood that in the embodiment shown, the outer nacelle 50 is supported relative to the turbine 16 by a plurality of circumferentially spaced outlet guide vanes 52. Further, a downstream section 54 of the outer nacelle 50 extends over an outer portion of the turbine 16 so as to define a bypass airflow passage 56 therebetween.

[0032] During operation of the gas turbine engine 10, a volume of air 58 enters the gas turbine engine 10 through the outer nacelle 50 and the associated inlet 60 of the fan section 14. As the volume of air 58 passes through the fan blades 40, a first portion of air 62 is directed or guided into the bypass air flow path 56, and a second portion of air 64 is directed or guided into the working gas flow path 37, or more specifically, into the LP compressor 22 as shown by arrow 64. The ratio between the first portion of air 62 and the second portion of air 64 is commonly referred to as the bypass ratio. When the second portion of air 64 is directed through the HP compressor 24 and into the combustion section 26, its pressure increases, and in the combustion section 26, the second portion of air 64 is mixed with fuel and burned to provide combustion gases 66.

[0033] The combustion gases 66 are directed through the HP turbine 28, where a portion of the thermal energy and / or kinetic energy from the combustion gases 66 is extracted via successive stages of HP turbine stator vanes 68 coupled to the outer casing 18 and HP turbine rotor blades 70 coupled to the HP shaft 34, thereby rotating the HP shaft 34 and thus supporting the operation of the HP compressor 24. The combustion gases 66 are then directed through the LP turbine 30, where a second portion of thermal and kinetic energy is extracted from the combustion gases 66 via successive stages of LP turbine stator vanes 72 coupled to the outer casing 18 and LP turbine rotor blades 74 coupled to the LP shaft 36, thereby rotating the LP shaft 36 and thus supporting the operation of the LP compressor 22 and / or the rotation of the fan 38.

[0034] Subsequently, the combustion gases 66 are directed through the jet exhaust nozzle section 32 of the turbine 16 to provide propulsive thrust. At the same time, as the first portion of air 62 is directed through the bypass air flow path 56 before being exhausted from the fan nozzle exhaust section 76 of the gas turbine engine 10, the pressure of the first portion of air 62 significantly increases, also providing propulsive thrust. The HP turbine 28, the LP turbine 30, and the jet exhaust nozzle section 32 at least partially define a hot gas path 78 for directing the combustion gases 66 through the turbine 16.

[0035] However, it should be recognized that Figure 1 the gas turbine engine 10 shown is only an example, and in other embodiments, the gas turbine engine 10 can have any other suitable configuration. For example, although the gas turbine engine 10 shown is configured as a ducted gas turbine engine (e.g., including the outer nacelle 50), in other embodiments, the gas turbine engine 10 can be a non-ducted gas turbine engine (such that the fan 38 is a non-ducted fan and the exit guide vanes 52 project cantilevered from, for example, the outer casing 18).

[0036] Additionally, or alternatively, although the illustrated gas turbine engine 10 is configured as a geared gas turbine engine (e.g., including a power gearbox 46) and a variable pitch gas turbine engine (e.g., including a fan 38 configured as a variable pitch fan), in other embodiments, the gas turbine engine 10 may additionally or alternatively be configured as a direct drive gas turbine engine (such that the LP shaft 36 rotates at the same speed as the fan 38), a fixed pitch gas turbine engine (such that the fan 38 includes fan blades 40 that cannot rotate about the pitch axis P), or both. It should also be understood that in other embodiments, aspects of the present disclosure may be incorporated into any other suitable gas turbine engine. For example, in other embodiments, aspects of the present disclosure may (as appropriate) be incorporated into, for example, a turboprop gas turbine engine, a turboshaft gas turbine engine, or a turbojet gas turbine engine.

[0037] Now referring to Figure 2 and Figure 3 provides various views of a portion of the turbine 16 of Figure 1 . Specifically, Figure 2 shows a cross-sectional schematic view of a portion of the turbine 16 of Figure 1 . Figure 3 shows a detailed schematic cross-sectional view of a portion of the turbine 16 of Figure 1 . As will be understood and as generally shown in Figure 2 and Figure 3 , the turbine 16 generally includes a rotor 100, a stator 102, and a seal assembly 106 disposed between the rotor 100 and the stator 102. The rotor 100 can be any rotor of the turbine 16, such as the LP shaft 36, the HP shaft 34, etc. By way of example, and briefly reviewing Figure 1 , a circle SA has been added to Figure 1 to provide an example location where the seal assembly 106 of the present disclosure can be incorporated into the turbine of the present disclosure.

[0038] As specifically shown in Figure 3 , the stator 102 further includes stator vanes 115, and the seal assembly 106 is positioned at the inner end of the stator vanes 115 in the radial direction R of the turbine 16 in the illustrated embodiment. The turbine 16 further includes a first stage 117 of rotor blades 119 and a second stage 121 of rotor blades 119 spaced apart along the axial direction A of the gas turbine engine 10. The seal assembly 106 is positioned along the axial direction A between the first stage 117 of rotor blades 119 and the second stage 121 of rotor blades 119.

[0039] In the illustrated embodiment, the seal assembly 106 is positioned within the turbine section of the gas turbine engine 10, such as within the HP turbine 28 or the LP turbine 30. In this way, it will be understood that the rotor 100 can be a rotor coupled to the HP turbine 28 (such as the HP shaft 34) or a rotor coupled to the LP turbine 30 (such as the LP shaft 36). More specifically, in the illustrated embodiment, the rotor 100 is a connector extending between the disk 123 of the first stage 117 of the rotor blades 119 and the disk 123 of the second stage 121 of the rotor blades 119. However, it will be understood that in other embodiments, the seal assembly 106 can be integrated into, for example, the compressor section of the gas turbine engine 10.

[0040] Still referring Figure 2 , as will be explained in more detail below, the seal assembly 106 includes a plurality of seal segments 108 that extend circumferentially in the direction C between the rotor 100 and the stator 102. Additionally, in an embodiment, as Figure 2 and Figure 4 shown, the seal assembly 106 includes a sealing surface 116. Further, as Figure 4 specifically shown in, the rotor 100, the stator 102, and the plurality of seal segments 108 are arranged together to define a high-pressure region 110 and a low-pressure region 112. In a particular embodiment, as Figure 4 shown in, the high-pressure region 110 is located in front of the low-pressure region 112. Additionally, in an embodiment, as shown in the figure, the high-pressure region 110 generally includes an outer high-pressure region 138 outside the stator 102 and an inner high-pressure region 140 inside the stator 102. Thus, the seal assembly 106 is operable to prevent or minimize the airflow from the high-pressure region 110 to the low-pressure region 112 between the rotor 100 and the seal assembly 106.

[0041] It will be understood that the seal segments 108 can be in fluid communication with a high-pressure air source to provide a high-pressure fluid (e.g., P HIGH ) flow to the seal segments 108. In at least some aspects, the high-pressure air source can be the working gas flow path 37 provided through the gas turbine engine 10 and the seal assembly 106, for example, in the high-pressure region 110 of the seal assembly 106. In other aspects, the high-pressure air can be secondary flow path gas sourced from a gas flow path different from the working gas flow path 37.

[0042] Additionally, as Figure 2 , Figure 3 and Figure 4 shown, the seal assembly 106 includes a biasing member, such as a spring 114, that engages the seal segments 108. In an embodiment, for example and as shown in the figure, the spring 114 can be a compression spring that urges contact between the seal segments 108 and the rotor 100. Additionally, as Figure 3As shown, one or more sealing segments 108 of the sealing assembly 106 may include grooves 118 in their sealing surfaces 116. Thus, in an embodiment, the grooves 118 are configured to separate the sealing surface 116 from the main teeth or dams 111. One or more channels 113 formed in one or more of the plurality of sealing segments 108 are used to direct high-pressure air from the high-pressure region 110 to the grooves 118 such that the main teeth or dams 111 act as seals from the high-pressure region 110 to the low-pressure region 112.

[0043] More specifically, and with reference to Figure 2 , Figure 3 and Figure 4 , the spring 114 is shown as a garter spring 114 that simultaneously surrounds the plurality of sealing segments 108 but is not connected to the stator 102. In such an embodiment, as described above, the spring 114 is configured to push the sealing segments 108 toward the rotor 100. In an alternative embodiment, the spring 114 may also be configured as a helical spring that connects the sealing segments 108 to the stator 102. In such an embodiment, the spring 114 pushes the sealing segments 108 away from the rotor 100. Such an embodiment may generally be referred to herein as a retraction spring. Additionally, in such an embodiment, in the absence of differential sealing pressure, the retraction spring pulls the sealing segments 108 away from the rotor 100 or "retracts" from the rotor 100. Further, upon pressurization, the pressure overcomes the spring force and pushes the sealing segments 108 toward the rotor 100. In a further embodiment, other types of springs (e.g., tension springs, beam bending, etc.) may be used to connect the sealing segments 108 to the stator 102 and / or the rotor 100.

[0044] With particular reference to Figure 4 and Figure 5 , various cross-sectional views of different embodiments of a portion of the turbine 16 along line 3-3 are shown. In particular, as Figure 2 and Figure 4 and Figure 5 shown, the stator 102 includes at least one feature 120 formed therein. Thus, the pressurized fluid engaging the feature 120 provides an axial force F from back to front that reduces the friction between the interface rear surface 122 of the sealing segment 108 and the stator 102.

[0045] With particular reference to Figure 4 , the feature 120 is a groove 124 formed in the surface 126 of the stator 102 that forms a medium-pressure region 128 between the high-pressure region 110 and the low-pressure region 112. More specifically, as Figure 4As shown in the embodiment, the stator 102 generally has a U-shaped cross-sectional shape in the axial direction A of the gas turbine engine 10, which extends from the first side 130 of the seal assembly 106 in the low-pressure region 112 to the opposite second side 132 of the seal assembly 106 in the high-pressure region 110. Thus, in the embodiment, as Figure 4 shown, the intermediate-pressure region 128 is defined on the second side 132 of the seal section 108. In addition, as shown, the intermediate-pressure region 128 is in front of the seal assembly 106. It should be understood that the stator 102 can be a one-piece part or a segmented part. In such an embodiment where the stator 102 is formed of multiple parts, the U-shaped cross-section can be formed by a front cover plate and a rear inverted L-shaped shape, such that when the front cover plate and the inverted L-shaped shape are attached together (e.g., bolted, welded, brazed, etc.), the final cross-sectional shape of the stator 102 is a U-shaped cross-section.

[0046] In such an embodiment, the pressurized fluid 127 in the intermediate-pressure region 128 provides an axial force F from the rear to the front, which minimizes the friction (e.g., a frictional force acting in a radial direction perpendicular to the normal reaction acting in the axial direction) between the interface rear surface 122 of the seal assembly 106 and the stator 102.

[0047] Still referring to Figure 4 , the seal assembly 106 may further include a low-pressure vent 134 that fluidly connects the intermediate-pressure region 128 to the low-pressure region 112. More specifically, as shown, the low-pressure vent 134 is disposed in a straight-through channel 136 that extends through at least a portion of the U-shaped cross-sectional shape of the stator 102. Thus, as shown, the pressurized fluid 127 in the intermediate-pressure region 128 travels through the straight-through channel 136 of the stator 102 and exits to the low-pressure region 112 to provide an axial force F from the rear to the front, which minimizes the friction between the interface rear surface 122 of the seal assembly 106 and the stator 102. The reduced frictional force (in the radial direction) is particularly beneficial because it does not impede the ability of the seal section 108 to dynamically track the radial offset of the rotor 100. In contrast, high frictional force may cause the seal section 108 to become radially stuck on the rear support 122, resulting in the seal surface 116 rubbing against the moving rotor 100 and thus leading to seal failure.

[0048] Now referring to Figure 6 , another embodiment of the seal assembly 106 according to the present disclosure is shown. Specifically, as shown, the rotor 100, the stator 102, and a plurality of seal sections 108 are arranged together to define a high-pressure region 110 and a low-pressure region 112. This embodiment is similar in nature to the embodiment shown in Figure 2 and Figure 3 . In addition, as Figure 6As shown, the seal section 108 includes a passage 135 that allows airflow to flow from the medium-pressure region 128 to the low-pressure region 112, for example, through the body of the seal section 108.

[0049] In an additional embodiment, as shown, the seal assembly 106 may further include a high-pressure vent 142 that fluidly connects the outer high-pressure region 138 of the high-pressure region 110 to the inner high-pressure region 140 of the high-pressure region 110. More specifically, in an embodiment, as Figure 4 shown, the stator 102 is a U-shaped structure, and a medium-pressure region 128 is formed on the front side of the seal assembly 106. The U-shaped structure also causes the formation of an inner high-pressure region 140. Therefore, the pressure in the inner high-pressure region 140 needs to be equal to P HIGH , so as to generate sufficient closing force (in the radial direction) to push the seal section 108 towards the rotor 100. Therefore, the high-pressure vent 142 allows the outer high-pressure region 138 to be connected to the inner high-pressure region 140, thus ensuring sufficient sealing closing force.

[0050] Now referring to Figure 5 , as described above, a cross-sectional view of different embodiments of a portion of the turbine 16 along line 3-3 is shown, particularly showing different arrangements of the stator 102. For example, as shown, the feature 120 includes at least one fluid passage 144 formed therein. More specifically, as shown, the fluid passage 144 fluidly connects the high-pressure fluid 146 (e.g., P Figure 2 ) in the high-pressure region 110 to the interface rear surface 122 of the seal section 108 and the stator 102 to provide an axial force F from the rear to the front, which minimizes the friction between the interface rear surface 122 of the seal section 108 and the stator 102. In addition, as shown, the fluid passage 144 may include a main fluid passage 148 and at least one fluid passage branch 150, 152 extending from the main fluid passage 148. HIGH ) to the interface rear surface 122 of the seal section 108 and the stator 102 to provide an axial force F from the rear to the front, which minimizes the friction between the interface rear surface 122 of the seal section 108 and the stator 102. In addition, as shown, the fluid passage 144 may include a main fluid passage 148 and at least one fluid passage branch 150, 152 extending from the main fluid passage 148.

[0051] Therefore, in such an embodiment, as shown, the fluid passage branches 150, 152 may at least include a first fluid passage branch 150 and a second fluid passage branch 152. In addition, as shown, the first fluid passage branch 150 and the second fluid passage branch 152 may be linearly arranged in the radial direction. Therefore, the fluid passage branches 150, 152 are configured to pressurize the interface rear surface 122 with the high-pressure fluid 146 (e.g., P HIGH ). In this way, the force acting on the interface rear surface 122 is not equal to half of the high-pressure fluid (P HIGH ) plus the low-pressure fluid (P LOW ), but more of the high-pressure fluid 146 (e.g., P HIGH) is directed to the rear surface 122 of the interface to reduce the axial load (e.g., generated by the contact between the rear surfaces 122 of the interface). Additionally, in some embodiments, by providing a plurality of fluid channel branches linearly arranged in the radial direction R, the rear surface 122 of the interface will have P regardless of the radial position of the seal segment 108 HIGH . Additionally, as Figure 5 shown, the illustrated embodiment does not include a high-pressure vent 142 (as Figure 4 shown) because the embodiment does not include a separate outer region and inner region separated by the U-shaped structure of the stator 102, and the U-shaped structure of the stator 102 requires such ventilation as described herein.

[0052] Now referring to Figure 7 , a cross-sectional view of yet another different embodiment of a portion of the turbine 16 is shown, particularly showing a different arrangement of the stator 102. In particular, as shown, the illustrated embodiment is similar to Figure 3 and Figure 4 's embodiments, except that the illustrated seal is a aerostatic seal. Thus, as shown, the channels 113 and the grooves 118 are absent, and the seal segment 108 includes aerostatic ports 154. Thus, the illustrated seal assembly forms an air film between the seal face 116 and the opposing rotor 100 using air from the high-pressure region 110 directed via the aerostatic ports 154.

[0053] Further aspects are provided by the subject matter of the following clauses:

[0054] A turbine engine, comprising: a rotor; a stator; a circumferential seal assembly including a plurality of seal segments disposed between the rotor and the stator, wherein the rotor, the stator, and the plurality of seal segments are arranged together to define a high-pressure region and a low-pressure region; and a biasing member engaged with the seal assembly, wherein the stator includes at least one feature formed therein, and wherein pressurized fluid engaged with the at least one feature provides a rear-to-front axial force that reduces friction between the rear surface of the interface of the plurality of seal segments and the stator.

[0055] The turbine engine according to any of the preceding clauses, wherein the at least one feature includes a groove formed in a surface of the stator that creates a medium-pressure region between the high-pressure region and the low-pressure region, and wherein the pressurized fluid in the medium-pressure region provides the rear-to-front axial force that minimizes the friction between the rear surface of the interface of the plurality of seal segments and the stator.

[0056] A turbine engine according to any of the preceding clauses, wherein the high-pressure region is located in front of the low-pressure region, and the intermediate-pressure region is in front of the seal assembly.

[0057] A turbine engine according to any of the preceding clauses, wherein the stator includes a U-shaped cross-sectional shape in the axial direction of the turbine engine, the U-shaped cross-sectional shape extending from a first side of the seal assembly in the low-pressure region to an opposite second side of the seal assembly.

[0058] A turbine engine according to any of the preceding clauses, wherein the intermediate-pressure region is defined on a second side of the seal assembly.

[0059] A turbine engine according to any of the preceding clauses, wherein the seal assembly further includes a low-pressure vent that fluidly connects the intermediate-pressure region to the low-pressure region.

[0060] A turbine engine according to any of the preceding clauses, wherein the low-pressure vent extends through one or more of the plurality of seal segments.

[0061] A turbine engine according to any of the preceding clauses, wherein the low-pressure vent is disposed in a straight-through passage that extends through at least a portion of the U-shaped cross-sectional shape of the stator.

[0062] A turbine engine according to any of the preceding clauses, wherein the high-pressure region includes an outer high-pressure region and an inner high-pressure region, the outer high-pressure region being located outside the stator and the inner high-pressure region being located inside the stator.

[0063] A turbine engine according to any of the preceding clauses, wherein the seal assembly further includes a high-pressure vent that fluidly connects the outer high-pressure region to the inner high-pressure region, wherein the high-pressure vent is fluidly separated from the low-pressure vent.

[0064] A turbine engine according to any of the preceding clauses, wherein the at least one feature includes at least one fluid passage formed in the stator, the at least one fluid passage being configured to convey high-pressure fluid in the high-pressure region to a rear surface of an interface of the plurality of seal segments and the stator to provide an axial force from rear to front, the axial force from rear to front minimizing friction between the rear surface of the interface of the plurality of seal segments and the stator.

[0065] A turbine engine according to any of the preceding clauses, wherein the at least one fluid passage includes a main fluid passage and at least one fluid passage branch extending from the main fluid passage.

[0066] A turbine engine according to any of the preceding clauses, wherein the at least one fluid passage branch comprises at least a first fluid passage branch and a second fluid passage branch, and the first fluid passage branch and the second fluid passage branch are linearly arranged in the radial direction.

[0067] A turbine engine according to any of the preceding clauses, further comprising at least one of a turbine or a compressor, wherein the rotor is at least one of a turbine rotor of the turbine or a compressor rotor of the compressor.

[0068] A seal assembly, comprising: a plurality of seal segments disposed between a rotor and a stator, wherein when arranged together, the rotor, the stator, and the plurality of seal segments define a high-pressure region and a low-pressure region; a biasing member engaged with the plurality of seal segments; and at least one feature formed in the stator, and wherein pressurized fluid engaged with the at least one feature provides an axial force from rear to front that reduces friction between a rear surface of an interface of the plurality of seal segments and the stator.

[0069] A seal assembly according to any of the preceding clauses, wherein the at least one feature comprises a groove formed in a surface of the stator, the groove creating a medium-pressure region between the high-pressure region and the low-pressure region, and wherein the pressurized fluid in the medium-pressure region provides the axial force from rear to front that minimizes the friction between the rear surface of the interface of the plurality of seal segments and the stator.

[0070] A seal assembly according to any of the preceding clauses, wherein the high-pressure region is in front of the low-pressure region, and the medium-pressure region is in front of the seal assembly.

[0071] A seal assembly according to any of the preceding clauses, wherein the stator has a U-shaped cross-sectional shape that extends from a first side of the seal assembly in the low-pressure region to an opposite second side of the seal assembly, and the medium-pressure region is defined on the second side of the seal assembly.

[0072] A seal assembly according to any of the preceding clauses, wherein the seal assembly further comprises a low-pressure vent that fluidly connects the medium-pressure region to the low-pressure region, and wherein the low-pressure vent is disposed in at least one of a straight-through channel that extends through at least a portion of the U-shaped cross-sectional shape of the stator or through one or more of the plurality of seal segments.

[0073] The seal assembly according to any of the foregoing clauses, wherein the at least one feature includes at least one fluid passage formed in the stator, the at least one fluid passage being configured to convey high-pressure fluid in the high-pressure region to the interface rear surface of the plurality of seal segments and the stator to provide the rear-to-front axial force, the rear-to-front axial force minimizing the friction between the interface rear surface of the plurality of seal segments and the stator.

[0074] This written description uses examples to disclose the present disclosure, including the best mode, and also enables any person skilled in the art to practice the present disclosure, including making and using any device or system and performing any incorporated method. The patentable scope of the present disclosure is defined by the claims and may include other examples that occur to those skilled in the art. If these other examples include structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims, then these other examples are intended to fall within the scope of the claims.

Claims

1. A turbine engine, characterized in that: include: Rotor; stator; a circumferential seal assembly comprising a plurality of seal segments disposed between the rotor and the stator, wherein the rotor, the stator, and the plurality of seal segments are arranged together to define a high pressure region and a low pressure region; as well as a biasing member engaged with the seal assembly, wherein the stator includes at least one feature formed therein, and Wherein the pressurized fluid engaged with the at least one feature provides a back-to-forward axial force that reduces friction between interfacing rear surfaces of the plurality of seal segments and the stator.

2. The turbine engine according to claim 1, characterized in that wherein the at least one feature comprises a groove formed in a surface of the stator, the groove creating an intermediate pressure region between the high pressure region and the low pressure region, and wherein the pressurized fluid in the intermediate pressure region provides the back-to-forward axial force, the back-to-forward axial force minimizing the friction between the interface rear surfaces of the plurality of seal segments and the stator.

3. The turbine engine according to claim 2, characterized in that: The high pressure region is located in front of the low pressure region, and the medium pressure region is in front of the sealing assembly.

4. The turbine engine according to claim 2, characterized in that: Wherein the stator comprises a U-shaped cross-sectional shape in an axial direction of the turbine engine, the U-shaped cross-sectional shape extending from a first side of the seal assembly in the low-pressure region to an opposite second side of the seal assembly.

5. The turbine engine according to claim 4, characterized in that Wherein the medium pressure region is defined at the second side of the sealing assembly.

6. The turbine engine according to claim 5, characterized in that Wherein the seal assembly further defines a low pressure vent fluidly connecting the medium pressure region to the low pressure region.

7. The turbine engine according to claim 6, characterized in that Wherein the low pressure vent extends through one or more of the plurality of sealing segments.

8. The turbine engine according to claim 6, characterized in that Wherein the low pressure vent is disposed in a straight through passage extending through at least a portion of the U-shaped cross-sectional shape of the stator.

9. The turbine engine according to claim 6, characterized in that The high-pressure region includes an outer high-pressure region and an inner high-pressure region, wherein the outer high-pressure region is located outside the stator, and the inner high-pressure region is located inside the stator.

10. The turbine engine according to claim 9, characterized in that Wherein the sealing assembly further comprises a high pressure vent fluidly connecting the outer high pressure region to the inner high pressure region, wherein the high pressure vent is fluidly isolated from the low pressure vent.

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