Active seal system

One embodiment of the present disclosure is a unique active seal system. The active seal system includes a rotor and a stationary seal component disposed adjacent to the rotor. The rotor has a rotating seal component and a first electrical generator element. The stationary seal component has a second electrical generator element and a piezoelectric portion in electrical communication with the second electrical generator element.

FIELD OF THE DISCLOSURE

The present disclosure relates to gas turbine engines, and more particularly, to an active seal system for a gas turbine engine.

BACKGROUND

Gas turbine engine seal systems that effectively respond to changes in engine operating points remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology.

SUMMARY

One embodiment of the present disclosure is a unique active seal system. Another embodiment is another unique active seal system. Another embodiment is a unique method for operating a turbomachine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for active seal systems. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.

DETAILED DESCRIPTION

For purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the disclosure is intended by the illustration and description of certain embodiments of the disclosure. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present disclosure. Further, any other applications of the principles of the disclosure, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the disclosure pertains, are contemplated as being within the scope of the present disclosure.

Referring to the drawings, and in particularFIG. 1, there are illustrated some aspects of a non-limiting example of a gas turbine engine20in accordance with an embodiment of the present disclosure. In one form, engine20is a propulsion engine, e.g., an aircraft propulsion engine. In other embodiments, engine20may be any other type of gas turbine engine, e.g., a marine gas turbine engine, an industrial gas turbine engine, or any aero, aero-derivative or non-aero gas turbine engine. In one form, engine20is a two spool engine having a high pressure (HP) spool24and a low pressure (LP) spool26. In other embodiments, engine20may include only a single spool, or may include three or more spools, e.g., may include an intermediate pressure (IP) spool and/or other spools and/or partial spools, e.g., on-axis or off-axis compressor and/or turbine stages (i.e., stages that rotate about an axis that is the same or different than that of the primary spool(s)). In one form, engine20is a turbofan engine. In other embodiments, engine20may be any other type of gas turbine engine, such as a turboprop engine, a turboshaft engine, a propfan engine, a turbojet engine or a hybrid or combined cycle engine. As a turbofan engine, LP spool26is operative to drive a propulsor28in the form of a turbofan (fan) system, which may be referred to as a turbofan, a fan or a fan system. As a turboprop engine, LP spool26powers a propulsor28in the form of a propeller system (not shown), e.g., via a reduction gearbox (not shown). As a propfan engine, LP spool26powers a propulsor28in the form of a propfan. In other embodiments, propulsor28may take other forms, such as one or more helicopter rotors or tilt-wing aircraft rotors, for example, powered by one or more engines20in the form of one or more turboshaft engines.

In one form, engine20includes, in addition to fan28, a bypass duct30, a compressor32, a diffuser34, a combustor36, a high pressure (HP) turbine38, a low pressure (LP) turbine40, a nozzle42A, a nozzle42B, and a tailcone46, which are generally disposed about and/or rotate about an engine centerline49. In other embodiments, there may be, for example, an intermediate pressure spool having an intermediate pressure turbine or other turbomachinery components, such as those mentioned above. In one form, engine centerline49is the axis of rotation of fan28, compressor32, turbine38and turbine40. In other embodiments, one or more of fan28, compressor32, turbine38and turbine40may rotate about a different axis of rotation.

In the depicted embodiment, engine20core flow is discharged through nozzle42A, and the bypass flow from fan28is discharged through nozzle42B. In other embodiments, other nozzle arrangements may be employed, e.g., a common nozzle for core and bypass flow; a nozzle for core flow, but no nozzle for bypass flow; or another nozzle arrangement. Bypass duct30and compressor32are in fluid communication with fan28. Nozzle42B is in fluid communication with bypass duct30. Diffuser34is in fluid communication with compressor32. Combustor36is fluidly disposed between compressor32and turbine38. Turbine40is fluidly disposed between turbine38and nozzle42A. In one form, combustor36includes a combustion liner (not shown) that contains a continuous combustion process. In other embodiments, combustor36may take other forms, and may be, for example, a wave rotor combustion system, a rotary valve combustion system, a pulse detonation combustion system, a continuous detonation combustion system and/or a slinger combustion system, and may employ deflagration and/or detonation combustion processes.

Fan system28includes a fan rotor system48driven by LP spool26. In various embodiments, fan rotor system48may include one or more rotors (not shown) that are powered by turbine40. In various embodiments, fan28may include one or more fan vane stages (not shown inFIG. 1) that cooperate with fan blades (not shown) of fan rotor system48to compress air and to generate a thrust-producing flow. Bypass duct30is operative to transmit a bypass flow generated by fan28around the core of engine20. Compressor32includes a compressor rotor system50. In various embodiments, compressor rotor system50includes one or more rotors (not shown) that are powered by turbine38. Compressor32also includes a plurality of compressor vane stages (not shown inFIG. 1) that cooperate with compressor blades (not shown) of compressor rotor system50to compress air. In various embodiments, the compressor vane stages may include a compressor discharge vane stage and/or one or more diffuser vane stages. In one form, the compressor vane stages are stationary. In other embodiments, one or more vane stages may be replaced with one or more counter-rotating blade stages.

Turbine38includes a turbine rotor system52. In various embodiments, turbine rotor system52includes one or more rotors having turbine blades (not shown) operative to extract power from the hot gases flowing through turbine38(not shown), to drive compressor rotor system50. Turbine38also includes a plurality of turbine vane stages (not shown) that cooperate with the turbine blades of turbine rotor system52to extract power from the hot gases discharged by combustor36. In one form, the turbine vane stages are stationary. In other embodiments, one or more vane stages may be replaced with one or more counter-rotating blade stages. Turbine rotor system52is drivingly coupled to compressor rotor system50via a shafting system54. Turbine40includes a turbine rotor system56. In various embodiments, turbine rotor system56includes one or more rotors having turbine blades (not shown) operative to drive fan rotor system48. Turbine40also includes a plurality of turbine vane stages (not shown inFIG. 1) that cooperate with the turbine blades of turbine rotor system56to extract power from the hot gases discharged by turbine38. In one form, the turbine vane stages are stationary. In other embodiments, one or more vane stages may be replaced with one or more counter-rotating blade stages. Turbine rotor system56is drivingly coupled to fan rotor system48via a shafting system58. In various embodiments, shafting systems54and58include a plurality of shafts that may rotate at the same or different speeds and directions for driving fan rotor system48rotor(s) and compressor rotor system50rotor(s). In some embodiments, only a single shaft may be employed in one or both of shafting systems54and58. Turbine40is operative to discharge the engine20core flow to nozzle42A.

During normal operation of gas turbine engine20, air is drawn into the inlet of fan28and pressurized. Some of the air pressurized by fan28is directed into compressor32as core flow, and some of the pressurized air is directed into bypass duct30as bypass flow. Compressor32further pressurizes the portion of the air received therein from fan28, which is then discharged into diffuser34. Diffuser34reduces the velocity of the pressurized air, and directs the diffused core airflow into combustor36. Fuel is mixed with the pressurized air in combustor36, which is then combusted. The hot gases exiting combustor36are directed into turbines38and40, which extract energy in the form of mechanical shaft power to drive compressor32and fan28via respective shafting systems54and58. The hot gases exiting turbine40are discharged through nozzle system42A, and provide a component of the thrust output by engine20.

Engine20employs a plurality of seal systems for sealing fluids such as air and/or flowpath gases that include combustion products. For example and without limitation, some seal systems may be employed as fore, aft or interstage seals for fan28, compressor32, HP turbine38and/or LP turbine40. Seal systems may also be employed as thrust piston or thrust balance seals, which seal the gases used to balance engine rotor thrust. Seal systems may also be employed to control or limit the flow of gases into or out of engine sumps (not shown). Other seal systems may be employed for other purposes not mentioned herein. Seal types may include labyrinth seals having one or more knives that seal against another surface, such as a honeycomb or an abradable material. Other seal types may include brush seals. Yet other types of seals may include carbon or other contact seals, e.g., circumferential carbon seals and/or face seals. Still other seal types not mentioned herein may be employed. Some seal systems may employ a rotating seal component operating in conjunction with a stationary or static seal component to form a seal and control fluid flow therebetween. Other seal systems may employ a rotating seal component and another rotating seal component or a counter-rotating seal component to form a seal therebetween. In any event, it is desirable to control the flow through the seal systems, for example, in order to minimize engine losses, e.g., as with respect to fore, aft or interstage seals, as well as to more accurately control one or more of various engine parameters, e.g., thrust balance or sump purging and/or sump scavenge system operability (e.g., the latter of which may be affected by the amount of fluid entry or exit from a sump purge cavity).

Referring toFIG. 2, some aspects of a non-limiting example of a sealing system70in accordance with an embodiment of the present disclosure is schematically depicted. In one form, sealing system70is configured for use in engine20. In other embodiments, seal system70may be configured for use in any rotating machine or machine having rotating components. Seal system70includes a support72, an outer seal component74, an inner seal component76, a plurality of electrical generator elements78, a plurality of electrical generator elements80and an active fiber composition portion82, also referred to as a piezoelectric portion82. In some embodiments, only a single electrical generator element78and/or a single electrical generator element80may be employed. As with regard to active fiber composition portion82or piezoelectric portion82, the term, “composition,” refers to all or part of active fiber composition portion82or piezoelectric portion82being formed of a composition material, i.e., a material made from at least two constituent materials, wherein at least one of the two constituent materials exhibits piezoelectric properties.

Seal support72is configured to support outer seal component74, piezoelectric portion78and electrical generator elements78. In one form, seal support72is affixed to an engine structure84such as a case structure, for example, via a cross-key arrangement employing cross keys86. In other embodiments, seal support72may be affixed, coupled or otherwise engaged with any engine20structure, rotating or stationary, using any convenient means.

Outer seal component74is configured to cooperate with inner seal component76to control or restrict the flow of fluid, e.g., air or other gases, through seal system70, i.e., between outer seal component74and inner seal component76. In one form, outer seal component74is a circumferential seal ring, i.e., extending circumferentially at a substantially constant diameter. In other embodiments, outer seal component74may take other forms. In one form, outer seal component74is a honeycomb seal. In other embodiments, outer seal component74may be one or more of other types of seal components, including, for example and without limitation, an abradable material seal, a brush seal component or any other types of seal suitable for use in a gas turbine engine or other turbomachine. In one form, outer seal component74is stationary, i.e., is a static seal component. In other embodiments, outer seal component74may be rotating in the same direction as inner seal component76or may be counter-rotating as with respect to inner seal component76.

Inner seal component76is configured to cooperate with outer seal component74to seal, control and/or restrict the flow of fluid, e.g., air or other gases, through seal system70, i.e., between outer seal component74and inner seal component76. In one form, inner seal component76is a circumferential seal ring, i.e., extending circumferentially at a substantially constant diameter. In other embodiments, inner seal component76may take other forms, and may represent, for example and without limitation, a turbine blade or blade tip; a compressor blade or blade tip or a fan blade or blade tip, or compressor or turbine knife seals. In one form, inner seal component76is a knife seal, otherwise known as a labyrinth seal. In other embodiments, inner seal component76may be one or more of other types of seal components, including, for example and without limitation, an abradable material seal, a brush seal component or any other types of seal suitable for use in a gas turbine engine or other turbomachine. In one form, inner seal component76is rotating, i.e., is a rotating seal component. In other embodiments, inner seal component76may be a stationary seal component, i.e., is a static seal component. As a rotating seal or rotating seal component, inner seal component76may be, in various embodiments, configured to rotate in the same direction as outer seal component74or may be counter-rotating as with respect to outer seal component74. Inner seal component76forms a part of a rotor77that supplies rotation to inner seal component76. In various embodiments, inner seal component76may be formed as a part of rotor77, may be coupled or affixed to rotor77, or may be otherwise secured to rotor77. Outer seal component74is disposed adjacent to rotor77, in particular, to inner seal component76.

In one form, electrical generator elements78and80form an electrical generator. In a particular form electrical generator elements78and80form an inductive generator. Electrical generator elements78and80are configured to cooperate to generate electrical power in electrical generator element78when inner seal component76and rotor77are rotated. Electrical generator elements78and80are configured to increase the power supplied to piezoelectric portion82with increasing proximity, e.g., increasing proximity (increasing closeness) of electrical generator elements80to electrical generator elements78as inner seal component76increases in size, e.g., due to an increasing rate of rotation of rotor77.

Electrical generator elements78are in electrical communication with piezoelectric portion82, and are operative to deliver generated electrical power to piezoelectric portion82, in particular, to piezoelectric fibers disposed within the active fiber composition that forms piezoelectric portion82. In one form, a plurality of electrical generator elements78are employed, e.g., spaced apart circumferentially about support72and/or piezoelectric portion82. In other embodiments, only a single electrical generator element78may be employed. In one form, electrical generator elements78are disposed within support72. In other embodiments, electrical generator elements78may be disposed on an internal diameter or outside diameter of support72, within or on piezoelectric portion82, or any other location suitable for interaction with electrical generator elements80. In one form, electrical generator elements78are electrical windings. In other embodiments, electrical generator elements78may be in the form of electrical coils or one or more other devices configured to interact with electrical generator elements80for the purpose of generating electrical power in electrical generator elements78.

Electrical generator elements80are retained on rotor77. In one form, electrical generator elements80are riveted in place. In other embodiments, electrical generator elements80may be fastened to rotor77using any suitable means. In some embodiments, electrical generator elements80may be embedded within one or more portions of rotor77. In one form, a plurality of electrical generator elements80are employed, e.g., spaced apart circumferentially about rotor77. In other embodiments, only a single electrical generator element80may be employed. In one form, electrical generator elements80are disposed about the periphery of rotor77. In other embodiments, electrical generator elements80may be disposed in any convenient location having relative proximity to electrical generator elements78for the generation of electrical power. In one form, electrical generator elements80are magnets. In a particular form, electrical generator elements are formed of a ferromagnetic material. In other embodiments, electrical generator elements80may be formed of other materials.

Active fiber composition portion82, or piezoelectric portion82is in mechanical communication with, e.g., mechanically coupled to outer seal component74in a manner configured for transmitting loads to outer seal component74for controlling its size, e.g., diameter. In one form, piezoelectric portion82is bonded to outer seal component74. In other embodiments, other means of securing piezoelectric portion82to outer seal component74may be employed. In some embodiments, outer seal component74may be formed in whole or in part from piezoelectric portion82. In one form, piezoelectric portion82is a continuous piezoelectric ring. In other embodiments, piezoelectric portion82may be formed as a segmented ring. In still other embodiments, piezoelectric portion82may take other forms. Piezoelectric portion82is configured to expand when supplied with electrical power from electrical generator elements78, thereby expanding outer seal component74, and changing the size of outer seal component74in response to the electrical power received from electrical generator elements78. In one form, piezoelectric portion82includes piezoelectric elements embedded within one or more materials. For example, the piezoelectric materials may be embedded in a ceramic material; a composite material, such as a ceramic matrix composite, an organic matrix composite, a metal matrix composite, a carbon-carbon composite, and/or a reinforced polymer; and/or may be embedded in other senses of the term and within other materials in addition to or in place of the aforementioned materials, for example, embedding by lamination between layers of a metallic material, such as a steel, nickel, magnesium, aluminum, titanium, tungsten and/or various common metals, superalloys and/or other metals. In some embodiments, piezoelectric portion82may be made solely from one or more piezoelectric materials. A piezoelectric material is a material that exhibits piezoelectric properties, e.g., changes in physical dimensions based on changes in applied voltage or electrical power. In one form, the piezoelectric elements are piezoelectric materials in the form of piezoelectric fibers. In other embodiments, the piezoelectric elements may take other forms. In a particular form, the piezoelectric fibers are ceramic piezoelectric fibers. Examples of materials for forming ceramic piezoelectric fibers that are suitable for use in various locations of a gas turbine engine or other rotating machines include, but are not limited to, lead zirconate titanate (PZT) (e.g., available from PI Ceramic GmbH, headquartered in Lederhose, Germany); Bismuth Titanate (e.g., available from Piezo Technologies of Indianapolis, Ind., USA); and BiFeO3—PbZrO3—PbTiO3, a ternary solid solution. The gas turbine engine locations in which the ceramic piezoelectric fibers may be employed depends upon the temperature capabilities of the ceramic piezoelectric fiber material, which varies with the material's composition. For example, bismuth titanate exhibits a maximum temperature operating capability of approximately 770° F., whereas lead zirconate titanate exhibits a maximum temperature operating capability of approximately 300° F. Thus, bismuth titanate would be suitable for use in higher temperature locations of a gas turbine engine than those locations which would be appropriate for lead zirconate titanate usage. In other embodiments, other materials may be used to form the ceramic piezoelectric fibers.

In one form, the size change of piezoelectric portion82and outer seal component74varies with the amount of electrical power received by piezoelectric portion82from electrical generator elements78. The amount of electrical power generated by electrical generator elements78and80, and supplied to piezoelectric portion82via electrical generator elements78, varies with the proximity of electrical generator elements80with respect to electrical generator elements78, and hence, increases with increasing proximity of electrical generator elements80to electrical generator elements78. Power output also varies with rotational speed, e.g., of inner seal component76/rotor77. Radial growth of rotor77and inner seal component76, e.g., due to an increased rate of rotation of rotor77and inner seal component76and the concomitant centrifugal forces acting thereon, and/or temperature changes in rotor77and inner seal component76, and/or pressure loading of rotor77and inner seal component76, increases the proximity of electrical generator elements80to electrical generator elements78, which increases the electrical charge delivered by electrical generator elements78to piezoelectric portion82, thereby increasing the size, e.g., diameter, of piezoelectric portion82, and hence the size/diameter of outer seal component74, thereby controlling the gap between outer seal component74and inner seal component76and achieving a desired gap between outer seal component74and inner seal component76. Similarly, a reduction in the rate of rotation of rotor77and inner seal component76reduces the proximity of electrical generator elements80with respect to electrical generator elements78, thereby reducing the amount of electrical power generated and delivered to piezoelectric portion82, thereby reducing the size, e.g., diameter of piezoelectric portion82and hence that of outer seal component74, achieving a desired gap between outer seal component74and inner seal component76. Accordingly, in one aspect of embodiments of the present disclosure, a seal gap or flow area may be controlled essentially automatically by the rate of rotation of the rotor, e.g., rotor77/inner seal component76. In some embodiments, electronic components, may be employed to smooth or otherwise condition the about of power supplied to piezoelectric portion82. In other embodiments, electronic components may be employed in order to control the power delivered to piezoelectric portion82in order to optimize the gap between outer seal component74and inner seal component76at one or more operating conditions, including transient and/or steady state conditions.

During the operation of engine20, increases in the size, e.g., diameter, of inner seal component76, e.g., due to increases in rotational speed of rotor77, temperature increases and/or pressure increases in rotor77and/or inner seal component76, increase the proximity of electrical generator elements80as with respect to electrical generator elements78, resulting in increased power output from electrical generator elements80into piezoelectric portion82. The increased power increases the size, e.g., diameter, of piezoelectric portion82, and hence, outer seal component74, maintaining a desired gap between inner seal component76and outer seal component74. Conversely, decreases in the size, e.g., diameter, of inner seal component76, e.g., due to decreases in rotational speed of rotor77, temperature increases and/or pressure increases in rotor77and/or inner seal component76, decreases the proximity of electrical generator elements80as with respect to electrical generator elements78, resulting in decreased power output from electrical generator elements80into piezoelectric portion82. The decreased power decreases the size, e.g., diameter, of piezoelectric portion82, and hence, outer seal component74, maintaining a desired gap between inner seal component76and outer seal component74.

Embodiments of the present disclosure include an active seal system, comprising: a rotor having a rotating seal component and a first electrical generator element; and a stationary seal component disposed adjacent to the rotor and having a second electrical generator element and a piezoelectric portion in electrical communication with the second electrical generator element, wherein the first electrical generator element and the second electrical generator element are configured to cooperate to generate electrical power in the second electrical generator element when the rotor is rotated; and wherein the piezoelectric portion is configured to change a size of at least a part of the stationary seal component in response electrical power received from the second electrical generator element.

In a refinement, the first electrical generating element and the second electrical generating element form an electrical generator.

In another refinement, the electrical generator is an inductive generator.

In yet another refinement, the size change of the at least a part of the stationary seal component varies with an amount of the electrical power received by the piezoelectric portion.

In still another refinement, the amount of the electrical power received by the piezoelectric portion increases with increasing proximity of the first electrical generator element to the second electrical generator element.

In yet still another refinement, the active seal system is configured whereby radial growth of the rotor increases proximity of the first electrical generator element to the second electrical generator element.

In a further refinement, the at least a part of the stationary seal component is a static seal; wherein the piezoelectric portion is in mechanical communication with the static seal; and wherein the static seal is configured to seal a fluid in conjunction with a rotating seal.

In a yet further refinement, the rotating sealing component is a circumferential seal ring.

In a still further refinement, the stationary seal component is a circumferential seal ring.

In a yet still further refinement, the piezoelectric portion is formed of a composition material including an embedded piezoelectric material.

In another further refinement, the piezoelectric portion is formed at least in part of ceramic piezoelectric fibers.

In yet another further refinement, the piezoelectric portion is a component of a fluid seal operable to interface with another component of the active seal system to restrict or control the flow of a fluid through the active seal system.

In still another further refinement, the first electrical generating element is disposed about the periphery of the rotor.

Embodiments of the present disclosure include an active seal system, comprising: a first electrical generator element; a second electrical generator element; a piezoelectric structure in electrical communication with the second electrical generator element; and a static seal in mechanical communication with the piezoelectric structure, wherein the static seal is disposed about an axis, wherein the first electrical generator element and the second electrical generator element are configured to cooperate to generate electrical power in the second electrical generator element upon a rotation of the first electrical generator element about the axis; and wherein the piezoelectric portion is configured to change a size of the static seal in response electrical power received from the second electrical generator element.

In a refinement, the size change of the static seal varies with an amount of the electrical power received by the piezoelectric structure.

In another refinement, the amount of the electrical power received by the piezoelectric structure increases with increasing proximity of the first electrical generator element to the second electrical generating element.

In yet another refinement, the active seal system further comprises a rotating seal, wherein the static seal is configured to seal a fluid in conjunction with a rotating seal.

Embodiments of the present disclosure include a method for operating a turbomachine, comprising: rotating a first electrical generating element past a second electrical generating element to generate electrical power in the second electrical generating element; supplying the electrical power to a piezoelectric structure to change a size of the piezoelectric structure; and mechanically communicating the size change of the piezoelectric structure to a static seal structure to vary the size of the static seal.

In a refinement, the method further comprises positioning the second electrical generating element adjacent to or within the piezoelectric structure.

In another refinement, the method further comprises positioning the first electrical generating elements adjacent to or within a rotating seal disposed adjacent to the static seal.