Fast active clearance control system for interstage and intermediate seals

Abstract

Example apparatus, systems, and methods for fast active clearance control of inter-stage and intermediate stage seals are disclosed. An example apparatus for controlling clearance of a turbine engine includes a housing surrounding at least a portion of the turbine engine and defining an opening therethrough; a nozzle including a reference pressure sensor and a static pressure sensor on a tip of the nozzle; an actuator comprising a multilayer stack of a material; a rod coupled to the first actuator and coupled to the nozzle through an opening in the housing, the rod moving the nozzle based on contraction or expansion of the multilayer stack of material; and a controller for calculating and setting a gap between the rotor and the nozzle by supplying a current to the multilayer stack to cause at least one of expansion or contraction of the multilayer stack.

Description

Technical Field

[0001] The present disclosure relates generally to gas turbine engines and, more particularly, to a rapid active clearance control system for interstage and intermediate seals of a gas turbine engine. Background Art

[0002] A gas turbine engine typically includes an inlet section, a compressor section, a combustion section, a turbine section, and an exhaust section in a series flow sequence. In operation, air enters the inlet section and flows to the compressor section, where one or more axial flow compressors gradually compress the air until it reaches the combustion section. Fuel mixes with the compressed air and burns in the combustion section, thereby producing combustion gases. The combustion gases flow from the combustion section through a hot gas path defined in the turbine section and then exit the turbine section via the exhaust section.

[0003] Generally, it is desirable for a gas turbine engine to maintain a clearance between the blade tips of the gas turbine engine and the stationary components of the gas turbine engine (e.g., the gas turbine engine casing, the stator, etc.). During operation, the gas turbine engine is exposed to heat (e.g., hot and cold air pumped into the gas turbine engine, etc.) and mechanical loads (e.g., centrifugal forces on the gas turbine engine blades, etc.), which can cause the gas turbine engine casing and the rotor to expand and contract. The expansion and contraction of the gas turbine engine casing controls the clearance between the blade tips and the stationary components of the gas turbine engine. It is necessary to continuously control the clearance between the blade tips and the engine casing (which fluctuates during normal operation of the gas turbine engine) to avoid damage to the gas turbine engine (e.g., wear, breakage, etc. due to unintentional friction), and to control the clearance for better engine performance and operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1 is a schematic cross-sectional illustration of an example gas turbine engine according to examples disclosed herein.

[0005] Figure 2 is a schematic cross-sectional view of an example gas turbine engine having a conventional active clearance control (ACC) system.

[0006] FIG. 3 is a schematic cross-sectional view of an ACC system for a high pressure turbine engine.

[0007] FIG. 4 is a schematic cross-sectional view of an ACC system for a low-pressure turbine engine.

[0008] Figure 5 is a schematic cross-sectional illustration of a second example ACC system for a high pressure turbine engine according to the teachings disclosed herein.

[0009] Figure 6is a schematic cross-sectional illustration of a third example ACC system for a high pressure turbine engine according to the teachings disclosed herein.

[0010] Fig. 7A is an example transfer curve determined using the clearance and pressure efficiency of a new blade.

[0011] Figure 7B is an example transfer curve determined using clearance and pressure efficiency for a blade with tip losses.

[0012] Fig. 8A Example transfer curves for clearance and pressure efficiency determination using both new blades and blades with tip losses during high power operation are shown.

[0013] Figure 8B Example transfer curves for clearance and pressure efficiency determination using both new blades and blades with tip losses during low power operation are shown.

[0014] Fig.9A An example one-point pressure measurement at the midpoint is shown.

[0015] Fig. 9B An example one point pressure measurement at a rear point is shown.

[0016] Fig. 10A A two-point pressure measurement method at the front point and the midpoint is shown.

[0017] Fig. 10B A two-point pressure measurement method at the front and rear points is shown.

[0018] Fig.11A A first three-point pressure measurement method at the front point, the middle point and the back point is shown.

[0019] Fig. 11B A second three-point pressure measurement method at the front point, the middle point, and the back point is shown.

[0020] Fig.12 is a schematic cross-sectional illustration of a second example ACC system for a low-pressure turbine engine according to the teachings disclosed herein.

[0021] Fig.13 is a schematic cross-sectional illustration of a third example ACC system for a low-pressure turbine engine according to the teachings disclosed herein.

[0022] Fig.14 is a block diagram of an active gap controller that may implement the examples disclosed herein.

[0023] Fig.15 yes Fig.14 Block diagram of the gap determination circuit.

[0024] Fig.16 shows that a delegate can be executed to implement Fig.15 A flow chart of example machine readable instructions for an example gap determination circuit.

[0025] Fig.17 is constructed to execute Fig.16 Instructions to achieve Fig.15 Block diagram of an example processing platform for example gap determination instructions.

[0026] Fig.18 is a schematic cross-sectional illustration of a fourth example ACC system for a high pressure turbine engine according to the teachings disclosed herein.

[0027] These figures are not drawn to scale. Instead, the thickness of a layer or region may be exaggerated in the drawings. Although the figures show layers and regions with clear lines and boundaries, some or all of these lines and / or boundaries may be idealized. In reality, boundaries and / or lines may be unobservable, mixed, and / or irregular. Typically, the same reference numerals will be used throughout the drawings and the accompanying written description to refer to the same or similar parts.

[0028] As used herein, unless otherwise specified, the term "above" describes the relationship of two parts relative to the earth. A first part is above a second part if at least one portion of the second part is between the earth and the first part. Similarly, as used herein, a first part is "below" a second part when the first part is closer to the earth than the second part. As described above, the first part can be above or below the second part, with one or more of the following: other parts between it, other parts not between it, the first part and the second part in contact, or the first part and the second part not in direct contact with each other. As used in this patent, stating that any part (e.g., a layer, film, zone, region, or plate) is in any way on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part means that the referred part is either in contact with other parts, or the referred part is above other parts, with one or more intermediate parts located between them.

[0029] As used herein, unless otherwise specified, connection references (e.g., attachment, coupling, connection, and engagement) may include intermediate members between elements to which the connection reference refers and / or relative movement between those elements. Thus, connection references do not necessarily infer that two elements are directly connected and / or have a fixed relationship to each other. As used herein, stating that any part is "in contact" with another part is defined to mean that there are no intermediate parts between the two parts.

[0030] Unless otherwise specifically stated, descriptors such as "first," "second," "third," and the like used herein do not confer or otherwise indicate any meaning of priority, physical order, arrangement in a list, and / or ordering in any manner, but are merely used as labels and / or arbitrary names to distinguish elements for ease of understanding the disclosed examples. In some examples, the descriptor "first" may be used to refer to an element in the detailed description, while a different descriptor (e.g., "second" or "third") may be used in the claims to refer to the same element. In this case, it should be understood that such descriptors are only used to clearly identify elements that may, for example, otherwise share the same name. As used herein, "approximately" and "approximately" refer to dimensions that may not be accurate due to manufacturing tolerances and / or other real-world defects. DETAILED DESCRIPTION

[0031] In the detailed description that follows, reference is made to the accompanying drawings that form a part thereof, and in the accompanying drawings, specific examples that can be practiced are shown by way of illustration. These examples are described in sufficient detail to enable those skilled in the art to practice the subject matter, and it should be understood that other examples may be utilized. Therefore, the following detailed description is provided to describe example embodiments and should not be construed as limiting the scope of the subject matter described in this disclosure. Certain features from the different aspects described below may be combined to form yet another new aspect of the subject matter discussed below.

[0032] "Include" and "comprising" (and all their forms and tenses) are used herein as open-ended terms. Thus, whenever a claim uses any form of "include" or "comprising" (e.g., includes, comprises, has, etc.) as a preamble or in any type of claim statement, it should be understood that additional elements, terms, etc. may be present without exceeding the scope of the corresponding claim or statement. As used herein, when the phrase "at least" is used as a transitional term, such as in the preamble of a claim, it is open-ended, just as the terms "include" and "comprising" are open-ended. The term "and / or" when used, for example, in a form such as A, B, and / or C, refers to any combination or subset of A, B, C, such as (1) A alone, (2) B alone, (3) C alone, (4) A and B, (5) A and C, (6) B and C, or (7) A and B and and C. As used herein in the context of describing structures, components, items, objects, and / or things, the phrase “at least one of A and B” is intended to refer to embodiments that include any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, as used herein in the context of describing structures, components, items, objects, and / or things, the phrase “at least one of A or B” is intended to refer to embodiments that include any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. As used herein in the context of describing the performance or execution of processes, instructions, actions, activities, and / or steps, the phrase “at least one of A and B” is intended to refer to embodiments that include any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, as used herein in the context of describing the performance or execution of a process, instruction, action, activity, and / or step, the phrase "at least one of A or B" is intended to refer to an embodiment that includes any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B.

[0033] As used herein, singular references (e.g., "a," "an," "first," "second," etc.) do not exclude the plural. As used herein, the term "a" or "an" entity refers to one or more of that entity. The terms "a" (or "an"), "one or more," and "at least one" are used interchangeably herein. In addition, although listed separately, multiple devices, elements, or method actions may be implemented by, for example, the same unit or processor. In addition, although individual features may be included in different examples or claims, these may possibly be combined, and inclusion in different examples or claims does not mean that a combination of features is not feasible and / or disadvantageous.

[0034] As used herein, the terms "system," "unit," "module," "engine," and the like may include hardware and / or software systems that operate to perform one or more functions. For example, a module, unit, or system may include a computer processor, a controller, and / or other logic-based device that performs operations based on instructions stored on a tangible and non-transitory computer-readable storage medium (e.g., a computer memory). Alternatively, a module, unit, engine, or system may include a hard-wired device that performs operations based on the hard-wired logic of the device. The various modules, units, engines, and / or systems shown in the accompanying drawings may represent hardware that operates based on software or hard-wired instructions, software that instructs hardware to perform operations, or a combination thereof.

[0035] The terms "upstream" and "downstream" refer to relative directions with respect to the flow of fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing. As used herein, "vertical" refers to a direction perpendicular to the ground. As used herein, "horizontal" refers to a direction parallel to the centerline of the gas turbine engine 100. As used herein, "lateral" refers to a direction perpendicular to the axial and vertical directions (e.g., in and out Figure 1 , Figure 2 etc. plane).

[0036] In some examples used herein, the term "substantially" is used to describe a relationship between two parts that is within three degrees of said relationship (e.g., a substantially co-linear relationship is within three degrees of linearity, a substantially perpendicular relationship is within three degrees of perpendicularity, a substantially parallel relationship is within three degrees of parallelism, etc.).

[0037] A turbine engine, also known as a combustion turbine or gas turbine, is an internal combustion engine. Turbine engines are commonly used in aircraft and power generation applications. As used herein, the terms "asset," "aircraft turbine engine," "gas turbine," "land-based turbine engine," and "turbine engine" are used interchangeably. The basic operation of a turbine engine includes taking in a fresh stream of atmospheric air through the front of the turbine engine with a fan. In some examples, the airflow travels through an intermediate pressure compressor or a supercharger compressor located between the fan and the high pressure compressor. The turbine engine also includes a turbine with a complex array of alternating rotating and stationary airfoil section blades. As the hot combustion gases pass through the turbine, the hot combustion gases expand, causing the rotating blades to rotate.

[0038] Components of a turbine engine (e.g., fan, supercharger compressor, high-pressure compressor, high-pressure turbine, low-pressure turbine, etc.) can degrade over time due to harsh operating conditions (e.g., extreme temperatures and vibrations). During operation, turbine engine components are exposed to heat (e.g., hot air and / or cold air pumped into the turbine engine, etc.) and mechanical loads (e.g., centrifugal forces on turbine engine blades, etc.), which can cause the turbine engine casing and / or compressor casing within the turbine engine and other components of the turbine engine and / or its compressor to expand and contract. The expansion and contraction of the turbine engine casing and / or compressor casing within the turbine engine can change the clearance between the tip of the blade and the stationary component of the turbine engine. In some examples, if the clearance between the tip of the blade and the stationary component is not controlled, the tip of the blade and the stationary component may collide during operation and cause further degradation of the turbine engine component.

[0039] An active clearance control (ACC) system has been developed to improve engine performance by managing the clearance between the gas turbine containment structure and the tips of the rotating blades without unexpected harmful friction events during flight and ground operations. Conventional ACC systems involve using cooling air from a fan or compressor to control the clearance between the blade tips and already contracting engine components (e.g., stator, casing, etc.). A limitation of conventional ACC systems is that the clearance is modulated in only one direction (e.g., engine component contraction). For hot rotor conditions (e.g., engine component expansion), conventional ACC systems wait for rotor-stator thermal / mechanical growth matching to escape the hot rotor conditions (e.g., modulating blade tip clearance). Tip clearance is maintained at a minimum to ensure maximum propulsion efficiency. For example, combustion gas temperatures may exceed 1000 degrees Celsius, causing turbine blade expansion as well as containment structure expansion, increasing tip clearance and reducing overall turbine efficiency (e.g., increasing fuel burn and fuel consumption). Controlling the thermal expansion and contraction of the containment structure allows for control of turbine tip clearance.

[0040] Conventional ACC systems have no direct control over the stator nozzles (also called vanes) and the connected compressor interstage seals. The compressor interstage seals rely passively on the ACC. The ACC is not connected to the compressor, which means that the nozzles are usually suspended between two hangers that are connected to the casing with the mid-stage seals. The hangers have attached shrouds that are affected by blade temperature and pressure, which can sometimes cause uneven displacement between the front and rear sides. This uneven displacement causes the nozzle to wobble, resulting in pressure loss at the interstage seals and the mid-stage seals.

[0041] Interstage seal gaps can cause problems with front and rear pressure balance. If the gap is too large, the front side of the blade has a tendency to heat up, causing airflow and pressure loss to the rear side. The change in pressure changes the displacement of the hanger and shroud, causing nozzle wobble and further pressure loss.

[0042] In the case of elevated temperatures, the heat causes thermal expansion of the housing and attached components radially inward. The interstage seal gap closes due to the expansion. For current conventional ACC systems, there is a time delay in opening the interstage seal gap because the ACC only has the ability to control movement inward, toward the blades.

[0043] The examples disclosed herein improve the ACC system using an actuator with a multilayer stack of piezoelectric material (also referred to herein as a multilayer stack, piezoelectric material, or piezoelectric stack), which provides fast active clearance control of interstage and intermediate seals without the mechanical delay seen in traditional ACC systems. The examples disclosed herein maintain the desired clearance between the interstage seal and the rotor without requiring additional margin for various operating conditions, which leads to performance improvements and provides better exhaust gas temperature (EGT) control capabilities. In some examples, when an electric current is applied, the multilayer stack produces a linear displacement. The linear displacement can have a force, and the examples disclosed herein apply the linear force of the multilayer stack (made of piezoelectric material) to the ACC system to achieve fast active clearance control of the interstage and intermediate seals. The examples disclosed herein apply the mechanical force of the linear displacement of the multilayer stack to the modulated ACC system. The examples disclosed herein may include other materials that produce linear displacement, such as shape memory alloys (SMA), etc. The range of displacement is increased by adding layers of piezoelectric material or SMA, wherein more layers in the stack provide a larger radial range of motion and give the ACC system greater muscle capacity.

[0044] The examples disclosed herein use actuators to accommodate multi-layer stacking. The actuators achieve clearance in two directions (e.g., radially inward and outward). The examples disclosed herein do not require additional clearance margin for maximum transient closure or hot rotor conditions like conventional ACC systems. The examples disclosed herein provide significant specific fuel consumption (SFC) improvements in tighter clearances and better EGT control because there is no additional margin for transient closure or hot rotor conditions.

[0045] The example actuator design is a direct linear square actuator which is a piston style tube. The example actuator can be scaled up if more muscle is desired. The range and requirements depend on the individual modules, however, the forces associated with the example actuator are in the range of about 450 lbf to about 700 lbf. The example stack / muscle is in the range of about 5 mils to about 14 mils. The example operating temperature range is about 120 degrees Fahrenheit to about 250 degrees Fahrenheit. The example actuator modulates a 1 mil derivative with a response time of about 1 millisecond. In an alternative design, the actuator is round / disc shaped.

[0046] In the examples disclosed herein, using an actuator in conjunction with a multi-layer stack may provide the flexibility to implement many different housing designs utilizing a compact and simple piezoelectric stack while providing the same high mechanical force as a conventional ACC.

[0047] Some examples provide an engine controller, referred to as a full authority digital engine (or electronic equipment) control (FADEC). The FADEC includes a digital computer, referred to as an electronic engine controller (EEC) or engine control unit (ECU), and associated accessories that control the performance of an aircraft engine. The FADEC can be used with a variety of engines, such as piston engines, jet engines, other aircraft engines, etc. In some examples, the EEC / ECU is provided separately from the FADEC, allowing the pilot and / or other operator to manually override or intervene.

[0048] In examples disclosed herein, an engine controller receives values ​​of a plurality of input variables related to flight conditions (e.g., air density, throttle lever position, engine temperature, engine pressure, etc.). The engine controller uses the flight condition data to calculate engine operating parameters, such as fuel flow, stator nozzle position, bleed valve position, etc. The engine operating parameters may be used by the engine controller to control the operation of the multi-layer stack to modulate blade tip and seal clearances in a turbine engine.

[0049] Reference will now be made in detail to embodiments of the current disclosed technology, one or more examples of which are shown in the accompanying drawings. Each example is provided by way of explanation of the current disclosed technology rather than by way of limitation of the current disclosed technology. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the current disclosed technology without departing from the scope or spirit of the current disclosed technology. For example, a feature shown or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the current disclosed technology is intended to cover such modifications and variations within the scope of the appended claims and their equivalents.

[0050] Figure 1 is a schematic cross-sectional view of a conventional turbofan gas turbine engine 100. Figure 1 As shown, the gas turbine engine 100 defines a longitudinal or axial centerline axis 102 extending therethrough for reference. In general, the gas turbine engine 100 may include a core turbine 104 disposed downstream of a fan section 106 .

[0051] The core turbine 104 generally includes a substantially tubular outer casing 108 defining an annular inlet 110. The outer casing 108 may be formed by a single casing or multiple casings. The outer casing 108 surrounds a compressor section having a supercharger or low-pressure compressor 112 ("LP compressor 112") and a high-pressure compressor 114 ("HP compressor 114"), a combustion section 116, a turbine section having a high-pressure turbine 118 ("HP turbine 118") and a low-pressure turbine 120 ("LP turbine 120"), and an exhaust section 122 in a series flow relationship. A high-pressure shaft or spool 124 ("HP shaft 124") is drivingly coupled to the HP turbine 118 and the HP compressor 114. A low-pressure shaft or spool 126 ("LP shaft 126") is drivingly coupled to the LP turbine 120 and the LP compressor 112. The LP shaft 126 may also be coupled to a fan spool or shaft ("fan shaft 128") of the fan section 106. In some examples, LP shaft 126 may be directly coupled to fan shaft 128 (ie, a direct drive configuration). In an alternative configuration, LP shaft 126 may be coupled to fan shaft 128 via reduction gearbox 130 (ie, an indirect drive or gear drive configuration).

[0052] like Figure 1 As shown, fan section 106 includes a plurality of fan blades 132 coupled to and extending radially outward from fan shaft 128. An annular fan casing or nacelle 134 circumferentially surrounds fan section 106 and / or at least a portion of core turbine 104. Nacelle 134 is supported relative to core turbine 104 by a plurality of circumferentially spaced outlet guide vanes 136. In addition, a downstream section 138 of nacelle 134 may surround an outer portion of core turbine 104 to define a bypass airflow passage 140 therebetween.

[0053] like Figure 1As shown, air 142 enters an inlet portion 144 of the gas turbine engine 100 during operation of the gas turbine engine 100. A first portion 146 of the air 142 flows into the bypass airflow passage 140, while a second portion 148 of the air 142 flows into the inlet 110 of the LP compressor 112. One or more sequential stages of LP compressor stator nozzles 150 and LP compressor rotor blades 152 coupled to the LP shaft 126 progressively compress the second portion 148 of the air 142 flowing through the LP compressor 112 on the way to the HP compressor 114. Next, one or more sequential stages of HP compressor stator nozzles 154 and HP compressor rotor blades 156 coupled to the HP shaft 124 further compress the second portion 148 of the air 142 flowing through the HP compressor 114. This provides the compressed air 158 to the combustion section 116, where the compressed air 158 is mixed with fuel and combusted to provide combustion gases 160.

[0054] The combustion gases 160 flow through the HP turbine 118, wherein one or more sequential stages of HP turbine stator nozzles 162 and HP turbine rotor blades 164 coupled to the HP shaft 124 extract a first portion of kinetic and / or thermal energy from the combustion gases 160. This energy extraction supports the operation of the HP compressor 114. The combustion gases 160 then flow through the LP turbine 120, wherein one or more sequential stages of LP turbine stator nozzles 166 and LP turbine rotor blades 168 coupled to the LP shaft 126 extract a second portion of thermal and / or kinetic energy therefrom. This energy extraction causes the LP shaft 126 to rotate, thereby supporting the operation of the LP compressor 112 and / or the rotation of the fan shaft 128. The combustion gases 160 then exit the core turbine 104 through its exhaust section 122.

[0055] As with the gas turbine engine 100, the core turbine 104 has similar purposes and also has similar environments in land-based gas turbines, turbojet engines (where the ratio of the first portion 146 of the air 142 to the second portion 148 of the air 142 is less than that of a turbofan), and unducted fan engines (where the fan section 106 does not have a nacelle 134). In each of the turbofan engine, the turbojet engine, and the unducted engine, a speed reduction device (e.g., a speed reduction gearbox 130) may be included between any shaft and the spool. For example, the speed reduction gearbox 130 may be disposed between the LP shaft 126 and the fan shaft 128 of the fan section 106.

[0056] Figure 2is a schematic cross-sectional view of an example gas turbine engine having a conventional active clearance control (ACC) system 200. The ACC system 200 includes an example main pipe 205, an example high pressure turbine 210, an example low pressure turbine 215, example manifolds 220A, 220B, 220C, example flanges 225A, 225B, and example intermediate rings 230A, 230B. Figure 2 In the example shown, air from a fan (eg, from fan section 106) enters a main tube 205, wherein the airflow in the main tube 205 is determined by Figure 2 In some examples, for the high pressure turbine 210, the inlet of the main pipe 205 is located at the fan (e.g., Figure 1 of the fan section 106) or the compressor (e.g., Figure 1 In some examples, the ACC system 200 is applicable to a compressor (e.g., Figure 1 The HP compressor 114 and the LP compressor 112) and the low-pressure turbine 215. The main pipe 205 delivers air from the fan to the manifolds 220A, 220B, 220C. The manifolds 220A, 220B, 220C evenly distribute the air from the fan to the high-pressure turbine 210 and the low-pressure turbine 215. In some examples, the high-pressure turbine 210 is substantially similar to the HP turbine 118, and the low-pressure turbine 215 is substantially similar to the LP turbine 120. The flanges 225A, 225B and the intermediate rings 230A, 230B are joined to the outer surfaces of the high-pressure turbine 210 housing and the low-pressure turbine 215 housing. The flanges 225A, 225B and the intermediate rings 230A, 230B are configured to contract radially inwardly and / or expand radially outwardly in response to changes in temperature (e.g., changes in temperature caused by air from the manifolds 220A, 220B, 220C). In some examples, at least some of the air is directed to impinge on surfaces of flanges 225A, 225B and intermediate rings 230A, 230B. In some examples, the inward contraction and outward expansion of flanges 225A, 225B and intermediate rings 230A, 230B can change blade tip clearances in high-pressure turbine 210 and low-pressure turbine 215.

[0057] In the following examples, EGT refers to the temperature of the turbine exhaust gas during its exit from the turbine unit, which is measured using a thermocouple mounted in the exhaust stream. Active clearance control maintains optimal or otherwise improved clearances to a certain extent to help ensure that EGT remains below its limit (e.g., temperature threshold), thereby improving engine efficiency and time on wing. Similarly, maintaining tighter blade tip clearances to reduce air leakage over the tips of the blades 164, 168, otherwise the rotor inlet temperature increases to achieve the same performance level, and the life cycle of hot section components is shortened to produce the same amount of work due to increased temperatures (e.g., thermal fatigue). In addition, optimizing tip clearances via ACC ensures engine efficiency and can reduce maintenance costs.

[0058] FIG. 3 is a diagram for example Figure 1 3 is a schematic cross-sectional view of an existing ACC system 300 of an example high pressure turbine of a gas turbine engine 100. The existing ACC system 300 includes a casing 305, guide hooks 310A, 310B, a hanger 315, a shroud 320, blades 325, an intermediate stage seal 307, a stator nozzle 335, and an interstage seal 340. In the example shown in FIG. 3, the casing 305 is a device that surrounds the HP turbine 118, the LP turbine 120, and / or the compressor (e.g., Figure 1 The housing 305 includes guide hooks 310A, 310B, and the guide hooks 310A, 310B connect the housing 305 to the hanger 315. The hanger 315 is connected to the shroud 320. The stator nozzle 335 having the interstage seal 340 is also connected to the hanger 315. The mid-stage seal 307 balances the pressure of the stator nozzle 335 of the front cavity and the rear cavity.

[0059] In the example shown in FIG3 , the existing ACC system 300 determines the clearance between the shroud 320 and the blades 325, and the clearance between the interstage seal 340 and the rotor 345. The existing ACC system 300 uses the ACC 330 to control the movement of the shroud 320 and the stator nozzle 335 in only one direction (e.g., inward toward the blades 325). The existing ACC system 300 uses the ACC 330 to control the movement of the shroud 320 and the stator nozzle 335 in only one direction (e.g., inward toward the blades 325). Figure 2The housing 305 is cooled by a cooling airflow (shown in FIG. 1 ). The housing 305 contracts (e.g., moves inward) when cooled by the airflow. The housing 305 causes the hanger 315, the shroud 320, and the stator nozzle 335 to move inward toward the blades 325. The existing ACC system 300 cannot move the housing 305, the hanger 315, the shroud 320, and the stator nozzle 335 to expand. For example, the ACC system 300 cannot expand the housing 305 (e.g., move outward) to increase the gap between the shroud 320 and the blades 325 or between the interstage seal 340 and the rotor 345. In such an example, the existing ACC system 300 waits for the gap between the shroud 320 and the blades 325 or between the interstage seal 340 and the rotor 345 to open (e.g., increase). The existing ACC system 300 does not provide two-way control of the gap between the shroud 320 and the blades 325 or between the interstage seal 340 and the rotor 345.

[0060] In some examples (e.g., prior art ACC system 300 of FIG. 3 ), the ACC system directs airflow around the engine casing to control clearances between the casing and the blade tips and between the interstage seals and the rotor. For example, the ACC system controls cooling airflow from the compressor or fan to the casing 305 (e.g., Figure 2 As shown). In some examples, the ACC system mixes hot air and cold air from the compressor and bypass duct (comprising gas turbine engine airflow bypassing the engine core) to a desired temperature, respectively. In some examples, the ACC system helps maintain and adjust the clearance between the interstage seal and the rotor in the existing ACC system. In the existing ACC system (e.g., the existing ACC system 300 of FIG. 3), the cooling airflow around the engine casing (e.g., casing 305) adjusts the clearance by controlling the thermal expansion and contraction of the casing. In some examples, the ACC 330 controls the cooling airflow to shrink the turbine engine casing. For example, the existing ACC system 300 directs the cooling airflow to the casing 305 to shrink the casing 305, and restricts the cooling airflow to the casing 305 to expand the casing 305. The ACC system 300 controls the cooling airflow to adjust the clearance to compensate for any changes in the blades of the turbine engine. In some examples, the ACC system 300 is controlled by a controller (e.g., FADEC) in the turbine engine. The FADEC sends an electrical control signal to the ACC system 300 to send a signal to the ACC system 300 to modulate the airflow to control the thermal expansion of the casing. The ACC system 300 ultimately controls the amount of cooling airflow to manage turbine engine casing temperature, thereby regulating interstage seal clearances. Clearance control cannot be performed in real time, and there is limited control over the contraction or expansion of the casing 305 or any component with displacement dependent thereon.

[0061] 4 is a schematic cross-sectional view of an example ACC system 400 in a low pressure turbine (LPT) implementation. With this existing LPTACC system 400, the casing 410 is directly connected to the shroud 420 and the stator nozzle 430. The airfoils 425 are on either side of the stator nozzle 430. The heat shield 415 is in place to mitigate thermal expansion of the casing as pressure increases. Similar to the ACC system in FIG. 3 , the ACC 405 directs airflow around the casing 410 of the engine to control the clearance between the casing 410 and the blade tips, as well as the clearance between the interstage seals and the rotor. For example, the ACC 405 controls the cooling airflow from the compressor or fan to the casing 410 (e.g., Figure 2 ). Clearance control cannot be performed in real time, and there is no finite control over the contraction or expansion of the housing 410 or any component having displacement dependent thereon.

[0062] Figure 5 is a schematic cross-sectional view of an example high pressure turbine ACC system 500 according to the teachings disclosed herein. Figure 5 The exemplary ACC system 500 of includes an actuator 550, a rod 560, an intermediate stage seal 517, a housing 505, guide hooks 510A, 510B, a pylon 515, a shroud 520, a vane 525, a stator nozzle 535, a placement seal 507 in the housing 505 that allows placement of the rod 560, and an interstage seal 540. The actuator 550 includes, for example, a multi-layer stack 555. In this example, a front pressure sensor 565 and an aft pressure sensor 570 are attached to the interstage seal 540 to measure pressure and send the measured values ​​to an active clearance controller 575. The active clearance controller 575 integrates feedback from the front sensor 565 and the aft sensor 570 with the actuator motion to achieve limited control of the displacement of the stator nozzle 535 and the interstage seal 540. Figure 5 The example ACC system 500 includes an open gap between the interstage seal 540 and the rotor 545 .

[0063] The active clearance controller 575 integrates feedback from the front sensor 565 and the rear sensor 570 with the actuator motion and can be set as a closed loop or an open loop. In both cases, the active clearance controller 575 not only takes into account the positioning of the stator nozzle 535 and the interstage seal 540 relative to the rotor 545, but also takes into account the positioning of the pylon 515 and the shroud 520 relative to the blades 525 on either side of the stator nozzle 535. The active clearance controller takes into account the changing pressure and temperature that produces flow from upstream (relatively high pressure) to downstream (relatively low pressure) on either side of the stator nozzle. A balance is maintained between the clearance allowed by the interstage seal 540 and the rotor 545, the rear side pressure between the rear shroud 520b and the rear blade 525b, and the front side pressure between the front shroud 520a and the front blade 525a. The pressure and subsequent clearance are measured by the rear pressure sensor 570 and the front pressure sensor 565. The active clearance controller 575 takes into account pressure, clearance, blade tip loss, nozzle swing and other engine parameters, such as power application, altitude, etc., to adjust all actuators 550 and multi-layer stacks 555. When each actuator 550 and multi-layer stack 555 is connected to the rod 560 and then connected to the stator nozzle 535, the active clearance controller 575 has limited control radially inward and outward of the clearance between the interstage seal 540 and the rotor 545. In addition, the use of piezoelectric materials for the multi-layer stack 555 enables a fast response that is essentially real time.

[0064] In a closed loop control system, a clearance calculation is used where a target clearance is set. The actual clearance is calculated and compared to the target clearance. The clearance calculation includes engine speed, turbine pressure, turbine temperature, compressor temperature, and compressor pressure to calculate the actual clearance. The actuator 550 having a multi-layer stack 555 is then manipulated to achieve the target clearance. The calculation and actuator manipulation are performed substantially in real time.

[0065] In the case of an active clearance controller using an open loop system to control the clearance, the transfer curve is used to relate the normalized pressure measurement to the clearance measurement (combined with Figures 7A-8B Example conversion curves are provided). First, pressure is obtained from pressure sensors 565, 570. Once the pressure is measured, it is normalized and the gap is calculated using the conversion curve. The gap is compared to a predetermined setting value for the gap. The active gap controller then signals the actuator 550 and multilayer stack 555 to achieve the target by moving the associated rod 560. The measurement, comparison, and actuation are performed substantially in real time to help ensure that the proper gap is maintained and friction / crushing events are avoided.

[0066] Figure 6 An alternative embodiment of an ACC system 600 is shown. Figure 6The example ACC system 600 includes an active clearance controller 675, an actuator 650, a rod 660, a housing 605, a pylon 615, a shroud 620, vanes 625, a stator nozzle 635, a mid-stage seal 617, a placement seal 607 that enables placement of the rod 660 through the housing 605, and an inter-stage seal 640. Figure 6 The actuator 650 includes a multi-layer stack 655, which expands (or elongates) in the radial direction and contracts in the axial direction. In the example disclosed herein, the housing 605 includes guide hooks 610A, 610B, and the guide hook 610B connects the housing 605 to the hanger 615. The hanger 615 is connected to the shroud 620. The stator nozzle 635 with the interstage seal 640 is also attached to the hanger at the tip. Pressure sensors 665, 670 are located on the front and rear sides of the interstage seal 640. In this example, two sets of actuators 650 and the multi-layer stack 655 are used to control the radial actuation of the stator nozzle 635 and the interstage seal 640 to control the gap between the interstage seal 640 and the rotor 645.

[0067] Stator nozzle swing causes pressure imbalance. Pressure imbalance reduces the effectiveness of the seal, subsequently causing flow and deeper friction than the design intent, thereby changing the thermal conditions around the seal and affecting part life. As the swing and friction continue, the associated risk of potential part failure increases. In addition, nozzle swing can cause flow path step imbalance, thereby affecting aerodynamic efficiency. The use of two actuators and a multi-layer stack connected to the stator nozzle 635 provides further control over nozzle swing, which is an uneven displacement of the front and rear sides of the stator nozzle 635 and the interstage seal 640. The equal displacement of the front and rear sides of the interstage seal 640 produces improved control of the airflow from the front side to the rear side, resulting in less difficulty in controlling temperature and pressure differentials compared to the stator nozzle 635 affected by nozzle swing. Two actuators 650 and a piezoelectric stack 655 with a rod 660 connected to the stator nozzle 635 are used in conjunction with the actuators 650, the multi-layer stack 655, and the rod 660 connected to the pylon 615 and the shroud 620 to provide complete control of temperature, pressure, and blade tip losses. The result is improved maintenance of aerodynamic efficiency, improved maintenance of thermal conditions around the interstage seal 640, and prevention of negative impacts on part life.

[0068] exist Figure 5 and Figure 6 In the example shown, the actuator 550, 650 is located outside the housing 505, 607, so that the housing 505, 607 surrounds all components except the actuator 550, 650 and the active clearance controller 575, 675. In some examples, the housing 505, 605 is around the high pressure turbine (e.g., Figure 1HP turbine 118), low pressure turbine (e.g. Figure 1 LP turbine 120) and / or compressor (e.g., Figure 1 In some examples, the actuator 550, 650 is positioned outside the housing 505, 605 to prevent material temperature limitations from affecting the actuator 550, 650 by positioning the insulation of the actuator case to maintain thermal conditions. For example, if the actuator 550, 650 is located inside the housing 505, 605, then the actuator 550, 650 may be located inside the housing 505, 605. Figure 1 The hot gas temperatures in the high pressure turbine of the HP turbine 118 may cause material limitations of the actuators 550, 650. In the example ACC systems 500 and 600, the actuators 550, 650 include a multilayer stack 555, 655 of piezoelectric material. In some examples, the multilayer stack of piezoelectric materials 555, 655 includes quartz, topaz, etc. However, other piezoelectric materials or other materials that produce linear displacement, such as shape memory alloy (SMA) materials, etc., may be additionally and / or alternatively included. In some examples, positioning the actuators 550, 650 and the multilayer stack 555, 655 outside the housing 505, 605 helps to keep the piezoelectric material in a cold condition regardless of temperature limitations. The location of the actuators 550, 650 and the multilayer stack 555, 655, for example, provides the advantage of easy maintenance and parts replacement.

[0069] Shape memory alloy materials are additionally and / or alternatively used to generate linear displacement. The insulation of the actuator 550, 650 extends the limits of the thermal conditions of the shape memory alloy materials in the actuator. The shape memory alloy material deforms based on the thermal conditions. The thermal conditions are controlled based on the power provided to the actuator 550, 650.

[0070] exist Figure 5 and Figure 6In the example shown, the multilayer stack 555, 655 is connected to the rod 560, 660. The rod 560, 660 is connected to the stator nozzle 635 and the interstage seal 640. Since the actuator 550, 650 and the multilayer stack 555, 655 are located outside the housing 505, 605, the rod 560, 660 is inserted through the housing 505, 605 to connect to the multilayer stack 555, 655 and the stator nozzle 535, 635. In some examples, the opening in the housing 505, 605 for inserting the rod 560, 660 causes possible leakage through the housing 505, 605. In such an example, the rod 560, 660 is surrounded by the placement seal 507, 607 to seal the opening in the housing 505, 605 through which the rod 560, 660 is inserted. In one example, the placement seal 507, 607 is a W-shaped seal. In another example, a VSV sealing system or a mature sealing technology is used. In an alternative example, a completely sealed duct system is used.

[0071] exist Figure 5 and Figure 6 In the example shown, the multilayer stack 555, 655 generates a linear displacement of the rod 560, 660 in response to an electrical signal generated by an example active gap controller 575, 675. Fig.14 An example implementation of a controller 575, 675 that generates an electrical signal is shown in FIG, which is described in further detail below. In some examples, the rod 560, 660 uses the linear displacement generated by the multi-layer stack 555, 655 to move the stator nozzle 635. Figure 5 and Figure 6 In the example shown, the stator nozzles 535, 635 and the interstage seals 540, 640 are connected and move together. Figure 5 and Figure 6 In the example shown, the rod 560, 660 moves the stator nozzle 535, 635 and the interstage seal 540, 640 using the linear displacement generated by the actuator 550, 650 and the multilayer 555, 655. In some examples, the range of linear displacement is increased by adding more layers of piezoelectric material to the multilayer stack 555, 655. For example, adding layers to the multilayer stack 555, 655 increases the radial range of motion and muscle capability of the ACC system.

[0072] exist Figure 5 In the example shown, the ACC system 500 has an open gap, which is represented by the opening between the shroud 520 and the blade 525. The multilayer stack 555 included in the actuator 550 controls the open gap. In the ACC system 500, the actuator 550 receives a first electrical signal from the example controller, and the actuator 550 provides the first electrical signal to the multilayer stack 555. The first electrical signal causes a linear displacement of the multilayer stack 555 (e.g., Figure 5 525). As shown in the example of , each stack in the multi-layer stack 555 is long and thin. An example range of linear displacement is 200 to 300 microns, which translates to 10 to 15 mils for muscle capacity. The linear displacement of the multi-layer stack 555 moves the rod 560 upward (e.g., away from the blade 525). The rod 560 moves the hanger 515 and the shroud 520 upward (e.g., away from the blade 525), which increases the opening gap.

[0073] exist Figure 5 and Figure 6 In the example shown, the actuator 550, 650 adjusts the clearance in two directions (e.g., contraction and expansion). The actuator 550, 650 can be installed for a single shroud (e.g., shroud 520, 620), a partial group (e.g., a subset) of shrouds (e.g., a group for three shrouds, a group for five shrouds, etc.), or for the entire group or set of shrouds in the turbine (e.g., shrouds around the 360-degree inner surface of the casing 505, 605). The actuator 550, 650 can also be installed for a single stator nozzle (e.g., stator nozzle 535, 635), a partial group (e.g., a subset) of stator nozzles (e.g., a group for three stator nozzles, a group for five stator nozzles, etc.), or for the entire group or set of stator nozzles in the turbine (e.g., stator nozzles around the 360-degree inner surface of the casing 505, 605).

[0074] Fig. 7A and 7B are example conversion curves 700, 720 for new blade tip conditions and deteriorated blade tip conditions. The curves plot the clearance 705 of the blade as a function of pressure efficiency (also referred to as P η , Peta or pressure eta) 710. Pressure efficiency can be defined as the difference between the pressure at the reference point and the pressure before the measurement divided by the difference between the reference point and the pressure after the measurement (see Equation 3). Fig. 7A The new condition 715 is shown in the conversion curve 700 of Figure 7B The deteriorating blade condition 725 is shown in the transfer curve 720 of FIG. As the example engine deteriorates and blade tip changes are observed, a shift from the transfer curve at the new condition occurs. This enables real-time assessment of tip loss. For example, Figure 5 The active clearance controller 575 communicates with the front pressure sensor 565 and the rear pressure sensor 570 under new engine conditions. A reference pressure is obtained at the compressor outlet (not shown). The active clearance controller calculates P using equation (2) η 710, and then use the calculated P η710 and the previously associated transfer curve 700 plotted with the new condition 715 to determine the associated clearance 705 amount. In the example of a deteriorating engine condition, a different transfer curve 720 with a deteriorating blade condition 725 is plotted to associate the clearance 705 amount and observe the deviation of the new engine from the transfer curve 700. The clearance 705 amount is then used to control the actuator 550 having the multi-layer stack 555 to subsequently drive the interstage seal 540 to obtain the clearance 705 between the interstage seal 540 and the rotor 545. In an example high power application with new engine conditions, the forward pressure is measured at 100 psia, the aft pressure is measured at 60 psia, and the reference pressure at the compressor outlet is measured at 300 psia. According to equation (2), P η Calculated to be 0.83. Then use Fig. 7A To find the P corresponding to 0.83 η In an example high power application with deteriorating engine conditions, the front pressure is measured at 90 psia, the rear pressure is measured at 50 psia, and the reference pressure at the compressor outlet is measured at 250 psia. According to equation (2), P η Calculated to be 0.80. Then use Figure 7B To find the P corresponding to 0.80 η gap.

[0075] Fig. 8A and 8B Example conversion curves 800, 820 are shown for high power and low power operation (e.g., ground use or use in flight), respectively. The conversion curves 800, 820 plot the blade clearance 705 as a function of the pressure efficiency 710 for new conditions 805, 825 and deteriorated conditions 810, 830. For example, Figure 6 The active clearance controller 675 communicates with the front pressure sensor 665, the rear pressure sensor 670 and the reference compressor outlet pressure sensor (not shown). The reference pressure, the front pressure and the rear pressure are measured during ground use operation (high power operation). η After 710, the active clearance controller 675 uses the transfer curve 800 with high power conditions plotted for new engine conditions 805 and deteriorating engine conditions 810 to determine the amount of clearance 705 associated with a given condition. This amount of clearance 705 is then achieved by moving the actuator 650 with the multi-layer stack 655. The displacement of the stator nozzle 635 and the interstage seal 640 is then controlled by the expansion or contraction of the piezoelectric material within the multi-layer stack 655. Given a low power condition, such as an in-flight cruise condition, the P is plotted for a new engine condition 825 and a deteriorating engine condition 830 using the example low power transfer curve 820. η710 is a graph relative to clearance 705. In an example high power application with new engine conditions, the front pressure is measured at 100 psia, the rear pressure is measured at 60 psia, and the reference pressure at the compressor outlet is measured at 300 psia. According to equation (2), P η Calculated to be 0.83. Then use Fig. 8A To find the P corresponding to 0.83 η In an example high power application with deteriorated engine conditions, the front pressure is measured at 90 psia, the rear pressure is measured at 50 psia, and the reference pressure at the compressor outlet is measured at 250 psia. According to equation (2), P η Calculated to be 0.80. Then use Fig. 8A To find the P corresponding to 0.80 η In an example low-power application with new engine conditions, the front pressure is measured at 60 psia, the rear pressure is measured at 30 psia, and the reference pressure at the compressor outlet is measured at 150 psia. According to equation (2), P η Calculated as 0.75. Then use Figure 8B To find the P corresponding to 0.75 η In an example low power application with deteriorated engine conditions, the front pressure is measured at 50 psia, the rear pressure is measured at 20 psia, and the reference pressure at the compressor outlet is measured at 120 psia. According to equation (2), P η Calculated to be 0.70. Then use Figure 8B To find the P corresponding to 0.70 η gap.

[0076] Fig.9A and 9B A state diagram is shown indicating the progression of airflow and pressure for real-time interstage seal clearance assessment via a one-point pressure measurement at midpoint 900 or aft point 950. Airflow moves from upstream forward point 920 to downstream aft point 922. An interstage seal clearance 925 is shown between stator 910 and rotor 915. Fig.9A In , the total pressure (Pt) 930 and the static pressure (Ps) 935 are measured at the same midpoint on the stator 910. Fig. 9B In the example, Pt and Ps are measured at the same rear point on the stator 910. η is calculated from the difference between the reference point (compressor outlet pressure (not shown)) and the static pressure 935 divided by the difference between the reference point and the total pressure 930. An example P is shown in Equation 1 below: η calculate.

[0077]

[0078] Fig. 10A and 10B A method of real-time interstage seal clearance assessment is shown by two-point pressure measurement under the front-mid measurement system 1000 or the front-rear point measurement system 1050. The airflow moves from the upstream front point 1020 to the downstream rear point 1022. The interstage seal clearance 1025 is shown between the stator 1010 and the rotor 1015. Fig. 10A In FIG. 1 , the front pressure (Pfwd) 1030 and the midpoint pressure (Pmid) 1035 are measured on the stator 1010. Fig. 9B In the example, Pfwd and the back pressure are measured on the stator 910. η is calculated from the difference between the reference point (compressor outlet pressure (not shown)) and the front pressure 1030 divided by the difference between the reference point and the rear pressure 1040. An example P is shown in Equation 2 below: η calculate.

[0079]

[0080] Fig.11A and 11B A method of real-time seal clearance assessment at a front point 1130, a midpoint 1135, and a rear point 1140 is shown by a three-point pressure measurement system 1100, 1150. The airflow moves from the upstream front point 1120 to the downstream rear point 1122. An interstage seal clearance 1125 is shown between the stator 1110 and the rotor 1115. η is calculated by dividing the difference between the front point 1130 and the midpoint 1135 by the difference between the front point 1130 and the rear pressure 1140. An example P is shown in Equation 3 below: η calculate.

[0081]

[0082] FIG. 9A to FIG. 11B The pressure measurement method described in Figure 5 and Figure 6 The example HPT system shown or Fig.12 and Fig.13 The single-point measurement method offers a simple design with only one instrument and a change in mounting location, but the overall static pressure instrument design is complex and has a limited lifespan. For the two-point measurement method, two pieces of instrumentation are used, but there is flexibility in the instrumentation. Static pressure measurements using traditional sensors are designed to last longer than the single-point measurement method. In the three-point measurement method, there is greater instrument installation complexity involved, but the three probes produce a larger amount of data and improve the accuracy of the measurement compared to the single-point and two-point measurement methods.

[0083] Fig.12is a schematic cross-sectional diagram of an example LPT implementation of an ACC system 1200 according to the teachings disclosed herein. Fig.12 It is a combination of a conventional ACC tip clearance control system and an interstage seal piezoelectric system. The example system 1200 includes an ACC 1205, an engine case 1210, a honeycomb shroud 1220, a heat shield 1215, an airfoil 1225, a stator nozzle 1230, pressure sensors 1250, 1255, 1260, 1265, an actuator 1235 with a multilayer stack 1240, and a rod 1245. In this example, two pressure sensors 1250, 1255 are used for tip control, but are used in an open-loop control with feedback of actual measurement of the clearance. In order to compare the pressure sensors used for tip control, two additional pressure sensors 1260, 1265 are used for interstage seal control. The heat shield 1215 is used to isolate the engine case 1210 from the heat generated by hot gases. In this example, the pressure sensor collects pressure data and sends the collected pressure data to the active clearance controller 1205. As previously described, the active clearance controller 1270 includes an open-loop and / or closed-loop controller. The controller 1270 integrates the sensor data to send signals to the actuator 1235 and the example multilayer stack 1240 to expand or contract the piezoelectric material within the multilayer stack 1240 to move the rod 1245 radially inward and outward in substantially real time, and subsequently move the stator nozzle 1230. For example, the active gap controller 1270 measures the front pressure from the front pressure sensor 1260 and the rear pressure from the rear pressure sensor 1265, respectively.

[0084] Fig.13 1 is a schematic cross-sectional view of a second example LPT implementation of an ACC system 1300 according to the teachings disclosed herein. The example system 1300 includes an ACC 1370, an engine case 1310, a honeycomb shroud 1320, a heat shield 1315, an airfoil 1325, a stator nozzle 1330, pressure sensors 1350, 1355, 1360, 1365, an actuator 1335 with a multi-layer stack 1340, and a rod 1345. In this example, the pressure sensor collects pressure data and sends it to an active clearance controller 1370. As previously described, the active clearance controller 1370 includes an open-loop and / or closed-loop controller. The controller integrates the sensor data to send signals to the actuator 1335 and the multi-layer stack 1340 to expand or contract the piezoelectric material within the multi-layer stack, thereby moving the rod 1345 radially inward and outward, and subsequently moving the stator nozzle 1330. In this example, there is a second actuator 1335 and multilayer stack 1340 connected to a second rod 1345 and shroud 1320. In this example, second actuator 1335 controls airfoil tip clearance to maximize engine performance.

[0085] Fig.14 is a block diagram of an example controller 1400 of an example ACC system according to examples disclosed herein, such as Figure 5 , 6 , 12 and 13 of the ACC system 500, 600, 1200, 1300. Fig.14 , the controller 1400 may be a full authority digital engine control (FADEC) unit, an engine control unit (ECU), an electronic engine control (EEC) unit, etc., and / or any other type of data acquisition and / or control computing device, a processor platform (e.g., a processor-based computing platform), etc. The controller 1400 communicates with the example pressure sensors 665, 670, the engine sensor 1410, and the actuator 650. The controller 1400 includes an example clearance determination circuit.

[0086] exist Fig.14 In the example shown, the controller 1400 receives values ​​of multiple input variables related to flight conditions (e.g., air density, throttle lever position, engine temperature, engine pressure, direct clearance measurement, indirect clearance measurement, etc.). The controller 1400 receives flight condition data from engine sensors 1410. The engine sensors 1410 may be mounted on the gas turbine engine 100 and / or positioned elsewhere in the aircraft (e.g., on the wing, in the cockpit, in the main cabin, in the engine compartment, in the cargo, etc.). For example, the communication between the controller 1400 and the engine sensors 1410 may be one-way communication and / or two-way communication. The controller 1400 uses the flight condition data to calculate engine operating parameters, such as fuel flow, stator nozzle position, bleed valve position, etc. The controller 1400 also obtains feedback data from pressure sensors 665 and 670. For example, the controller 1400 continuously monitors engine conditions through the engine sensors 1410. The engine sensors indicate operating parameters of the engine, such as altitude, temperature, air speed, etc. The controller 1400 calculates fuel flow, stator nozzle position, and other operating parameters using data received from the engine sensors 1410. The controller 1400 integrates all data and uses the clearance determination circuit 1405 to actuate the connected actuator 650.

[0087] exist Fig.14 In the example shown, the clearance determination circuit 1405 obtains sensor data from an example engine sensor 1410. The sensor data includes flight condition data obtained from the gas turbine engine 100. The clearance determination circuit 1405 monitors engine conditions based on the sensor data from the engine sensor 1410. In some examples, the clearance determination circuit 1405 determines whether the turbine casing is expanding or contracting based on the engine conditions determined from the obtained flight condition data. Fig.14In the example shown, the clearance determination circuit 1405 generates an electrical signal to the actuator 650 of the ACC system. For example, the clearance determination circuit 1405 obtains sensor data about the temperature in the engine housing from the engine sensor 1410. The clearance determination circuit 1405 determines that the turbine housing is shrinking based on the engine sensor data. Based on the pressure sensor data also obtained from the pressure sensors 665, 670, the clearance determination circuit 1405 calculates P η And P η The value is associated with the gap value. The gap determination circuit 1405 then sends an electrical signal to the actuator 650 to obtain the determined gap and ensure that the proper gap is maintained.

[0088] Fig.15 It is used to calculate the gap determination calculation Fig.14 A block diagram of an example implementation of a gap determination circuit 1405 is shown. Fig.15 The gap determination circuit 1405 may be instantiated (e.g., created as an instance, generated for any length of time, materialized, realized, etc.) by a programmable circuit such as a central processing unit (CPU) executing a first instruction. Additionally or alternatively, Fig.15 The gap determination circuit may be instantiated (e.g., created as an instance, generated in any length of time, embodied, implemented, etc.) by (i) an application specific integrated circuit (ASIC) and / or (ii) a field programmable gate array (FPGA), which is constructed and / or configured to perform operations corresponding to the first instruction in response to the execution of the second instruction. It should be understood that, therefore, Fig.15 Some or all of the circuits may be instantiated at the same or different times. For example, Fig.15 Some or all of the circuits of can be instantiated in one or more threads that are executed simultaneously on hardware and / or serially on hardware. In addition, in some examples, Fig.15 Some or all of the circuits may be implemented by microprocessor circuits executing instructions and / or FPGA circuits performing operations to implement one or more virtual machines and / or containers.

[0089] The gap determination circuit 1405 includes an example measurement circuit 1510 , an example transfer curve generation circuit 1515 , an example actuator control circuit 1520 , an example gap calculation circuit 1525 , and an example data storage 1505 .

[0090] In some examples, measurement circuit 1510 is instantiated by a programmable circuit that executes sensor measurement instructions and / or is configured to perform such as Fig.16 The operations represented by the flowchart.

[0091] In some examples, the transfer curve generation circuit 1515 is instantiated by a programmable circuit that executes transfer curve generation instructions and / or is configured to perform operations such as Fig.16 The operations represented by the flowchart.

[0092] In some examples, gap calculation circuit 1525 is instantiated by a programmable circuit that executes gap calculation instructions and / or is configured to perform operations such as Fig.16 The operations represented by the flowchart.

[0093] In some examples, actuator control circuit 1520 is instantiated by a programmable circuit that executes actuator control instructions and / or is configured to perform functions such as Fig.16 The operations represented by the flowchart.

[0094] In some examples, the gap determination circuit 1405 includes means for determining the gap. For example, the means for determining can be implemented by the gap determination circuit 1405. In some examples, the gap determination circuit 1405 can be implemented by, for example, Fig.17 For example, the gap determination circuit 1405 can be instantiated by an example microprocessor executing machine executable instructions, such as by Fig.16 In some examples, the gap determination circuit 1405 may be instantiated by a hardware logic circuit, which may be implemented by an ASIC, XPU, or FPGA circuit, which is configured and / or constructed to perform operations corresponding to machine-readable instructions. Additionally or alternatively, the gap determination circuit 1405 may be instantiated by any other combination of hardware, software, and / or firmware. For example, the gap determination circuit 1405 may be implemented by at least one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, XPUs, comparators, operational amplifiers (op-amps), logic circuits, etc.), which are configured and / or constructed to execute some or all of the machine-readable instructions and / or to execute some or all of the operations corresponding to the machine-readable instructions without executing software or firmware, but other structures are equally suitable.

[0095] The example measurement circuit 1510 measures engine component data and pressure data from the engine sensors and pressure sensors 665, 670. The measurements may be performed using one or more sensors (e.g., conventional static pressure sensors, optical sensors, laser-based sensors, capacitive sensors, eddy current sensors, microwave sensors, etc.). In some examples, the example measurement circuit 1510 initiates measurements at a rear, middle, and / or front position relative to a given clearance, as determined based on the direction of combustion gas flow. In some examples, during initial testing to develop a conversion curve that relates pressure to clearance measurements, the measurement circuit 1510 may determine when to initiate pressure measurements based on a given power level (e.g., low power, high power), a specific altitude (e.g., at 35,000 feet, etc.), an ambient temperature, and / or a specific flight cycle (e.g., takeoff, cruise, landing, etc.). In the example, for high power levels, the medium engine has a core speed (PCN25%) in the range of 105% to 110%, while for low power levels, PCN25% is between 75% and 85%, and for the medium level example, PCN25% is 85% to 105%.

[0096] The example conversion curve generation circuit 1515 generates Figures 7A-8B The example conversion curves take into account many factors, such as altitude, power application and / or flight period. The example conversion curves are used to determine the pressure efficiency (P η ) and clearance. For example, the example conversion curve generation circuit 1515 receives inputs from the engine and pressure sensors 665, 670, 1410 and calculates a normalized pressure efficiency curve. Therefore, a given clearance (mils) can be determined based on the pressure measurement. This enables the clearance determination circuit 1405 to develop a conversion curve that can be used to identify curve shifts caused by blade tip loss to achieve more accurate clearance adjustments in real time based on pressure measurement data.

[0097] The example gap calculation circuit 1525 obtains data from the measurement circuit 1510, obtains the generated transfer curve from the transfer curve generation circuit 1515, and calculates the actual gap. The example gap calculation circuit 1525 then compares the actual gap to the target gap retrieved from the data memory 1505. The difference in gap is the gap adjustment to be made.

[0098] The example actuator control circuit 1520 obtains the gap adjustment data from the gap calculation circuit 1525. The example actuator control circuit 1520 and Figure 6 The actuator 650 communicates with the actuator 650 and sends a signal to adjust the actuator 650 having the multi-layer stack 655 to cause the associated gap to contract or expand.

[0099] In the example using multiple actuators 650 and multiple multilayer stacks 655, the clearance calculation circuit 1525 compensates for nozzle swing and interstage seal clearance, both of which are dependent on the clearance of the front bracket 615a and the front shroud 620a relative to the blades 625, and the clearance of the rear bracket 615b and the rear shroud 620b relative to the blades 625.

[0100] The example data storage 1505 may be used to store any information associated with the example gap determination circuit 1405. For example, the data storage 1505 may store pressure measurements obtained using one or more pressure sensors 665, 670, 1410, conversion curves generated using conversion curve generation circuit 1515, and / or output by the actuator control circuit 1520 using the gap calculation circuit 1525 to make gap adjustments based on real-time data. Fig.15 The example data storage 1505 of the illustrated example is implemented by any memory, storage device, and / or storage disk for storing data, such as flash memory, magnetic media, optical media, etc. In addition, the data stored in the example data storage 1505 can be in any data format, such as binary data, comma-delimited data, tab-delimited data, structured query language (SQL) structures, image data, etc.

[0101] although Fig.15 It is shown in Fig.14 Example implementation of the gap determination circuit 1405, but Fig.15 One or more of the elements, processes and / or devices shown in the drawings may be combined, divided, rearranged, omitted, eliminated and / or implemented in any other manner. In addition, the measurement circuit 1510, the conversion curve generation circuit 1515, the gap calculation circuit 1525, the actuator control circuit 1520 and / or more generally, Fig.15 The example gap determination circuit 1405 can be implemented by hardware alone or by hardware in combination with software and / or firmware. Thus, for example, the measurement circuit 1510, the conversion curve generation circuit 1515, the gap calculation circuit 1525, the actuator control circuit 1520, and / or more generally, any of the example gap determination circuit 1405 can be implemented by programmable circuits in combination with machine-readable instructions (e.g., firmware or software), processor circuits, analog circuits, digital circuits, logic circuits, programmable processors, programmable microcontrollers, graphics processing units (GPUs), digital signal processors (DSPs), ASICs, programmable logic devices (PLDs), and / or field programmable logic devices (FPLDs) such as FPGAs. In addition, Fig.15 An example gap determination circuit 1405 may include in addition to Fig.15 One or more elements, processes and / or devices other than or in place of the elements, processes and / or devices shown in Fig.15The elements, processes and / or devices shown in the drawings, and / or may include more than one of any or all of the elements, processes and devices shown.

[0102] exist Fig.16 , which may be executed by a programmable circuit to implement and / or instantiate an Fig.14 and / or Fig.15 The gap determination circuit 1405 represents example operations that may be performed by a programmable circuit to implement and / or instantiate Fig.15 The gap determination circuit 1405. The machine-readable instructions may be one or more executable programs or a portion of one or more executable programs executed by a programmable circuit, such as the following in combination Fig.17 The programmable circuit 1712 shown in the example processor platform 1700 discussed, and / or may be part of one or more functions or functions to be performed by an example programmable circuit (e.g., FPGA). In some examples, machine-readable instructions cause operations, tasks, etc. to be performed and / or executed in an automated manner in the real world. As used herein, "automated" means without human involvement.

[0103] The program may be embodied in instructions (e.g., software and / or firmware) stored on one or more non-transitory computer-readable and / or machine-readable storage media, such as cache memory, magnetic storage devices or disks (e.g., floppy disks, hard disk drives (HDDs), etc.), optical storage devices or disks (e.g., Blu-ray discs, compact disks (CDs), digital versatile disks (DVDs), etc.), redundant arrays of independent disks (RAIDs), registers, ROMs, solid-state drives (SSDs), SSD memories, non-volatile memories (e.g., electrically erasable programmable read-only memories (EEPROMs), flash memory, etc.), volatile memories (e.g., any type of random access memory (RAM), etc.), and / or any other storage devices or storage disks. The instructions of the non-transitory computer-readable and / or machine-readable media may be programmed and / or executed by programmable circuits located in one or more hardware devices, but the entire program and / or portions thereof may alternatively be executed and / or instantiated and / or embodied in dedicated hardware by one or more hardware devices other than programmable circuits. The machine-readable instructions may be distributed across multiple hardware devices and / or executed by two or more hardware devices (e.g., a server and a client hardware device). For example, the client hardware device may be implemented by an endpoint client hardware device (e.g., a hardware device associated with a human and / or machine user) or an intermediate client hardware device gateway (e.g., a radio access network (RAN)) that may facilitate communications between a server and an endpoint client hardware device. Similarly, a non-transitory computer-readable storage medium may include one or more media. Furthermore, although reference is made to Fig.16 The flowchart shown in describes an example program, but many other methods of implementing the example gap determination circuit 1405 may be used instead. For example, the execution order of the blocks of the flowchart may be changed, and / or some of the blocks described may be changed, eliminated, or combined. Additionally or alternatively, any or all of the blocks of the flowchart may be implemented by one or more hardware circuits (e.g., processor circuits, discrete and / or integrated analog and / or digital circuits, FPGAs, ASICs, comparators, operational amplifiers (op-amps), logic circuits, etc.), which are constructed to perform corresponding operations without executing software or firmware. The programmable circuits may be distributed at different network locations and / or local to one or more hardware devices (e.g., single-core processors (e.g., single-core CPUs), multi-core processors (e.g., multi-core CPUs, XPUs, etc.)). For example, the programmable circuit may be a CPU and / or FPGA located in the same package (e.g., the same integrated circuit (IC) package or in two or more separate housings), one or more processors in a single machine, multiple processors distributed on multiple servers in a server rack, multiple processors distributed on one or more server racks, etc., and / or any combination thereof.

[0104] The machine-readable instructions described herein may be stored in one or more of a compressed format, an encrypted format, a segmented format, a compiled format, an executable format, a packaged format, etc. The machine-readable instructions described herein may be stored as data (e.g., computer-readable data, machine-readable data, one or more bits (e.g., one or more computer-readable bits, one or more machine-readable bits, etc.), a bit stream (e.g., a computer-readable bit stream, a machine-readable bit stream, etc.), etc.) or a data structure (e.g., as part of an instruction, code, code representation, etc.) that can be used to create, manufacture, and / or generate machine-executable instructions. For example, the machine-readable instructions may be segmented and stored on one or more storage devices, disks, and / or computing devices (e.g., servers) located in the same or different locations of a network or a collection of networks (e.g., in the cloud, an edge device, etc.). The machine-readable instructions may need to be installed, modified, adapted, updated, combined, supplemented, configured, decrypted, decompressed, unpacked, distributed, redistributed, compiled, etc., so that they can be directly read, interpreted, and / or executed by a computing device and / or other machine. For example, machine-readable instructions may be stored in multiple portions that are separately compressed, encrypted, and / or stored on separate computing devices, where the portions, when decrypted, decompressed, and / or combined, form a set of computer-executable and / or machine-executable instructions that implement one or more functions and / or operations that together may form a program such as described herein.

[0105] In another example, the machine-readable instructions may be stored in a state where they can be read by a programmable circuit, but a library (e.g., a dynamic link library (DLL)), a software development kit (SDK), an application programming interface (API), etc. may need to be added in order to execute the machine-readable instructions on a particular computing device or other device. In another example, the machine-readable instructions and / or corresponding programs may need to be configured (e.g., stored settings, data inputs, recorded network addresses, etc.) before they can be executed in whole or in part. Therefore, as used herein, a machine-readable, computer-readable and / or machine-readable medium may include instructions and / or programs regardless of the specific format or state of the machine-readable instructions and / or programs.

[0106] The machine-readable instructions described herein may be represented by any past, present, or future instruction language, scripting language, programming language, etc. For example, the machine-readable instructions may be represented using any of the following languages: C, C++, Java, C#, Perl, Python, JavaScript, Hypertext Markup Language (HTML), Structured Query Language (SQL), Swift, etc.

[0107] As mentioned above, Fig.16 The example operations of may be implemented using executable instructions (e.g., computer-readable and / or machine-readable instructions) stored on one or more non-transitory computer-readable and / or machine-readable media. As used herein, the terms non-transitory computer-readable medium, non-transitory computer-readable storage medium, non-transitory machine-readable medium, and / or non-transitory machine-readable storage medium are expressly defined to include any type of computer-readable storage device and / or storage disk, and exclude propagating signals and exclude transmission media. Examples of such non-transitory computer-readable media, non-transitory computer-readable storage media, non-transitory machine-readable media, and / or non-transitory machine-readable storage media include optical storage devices, magnetic storage devices, HDDs, flash memory, read-only memory (ROM), CDs, DVDs, caches, any type of RAM, registers, and / or any other storage device or storage disk where information is stored for any duration (e.g., for an extended period of time, permanently, in transient situations, for temporary buffering, and / or for caching information). As used herein, the terms "non-transitory computer-readable storage device" and "non-transitory machine-readable storage device" are defined to include any physical (mechanical, magnetic and / or electrical) hardware to retain information over a period of time, but exclude propagating signals and exclude transmission media. Examples of non-transitory computer-readable storage devices and / or non-transitory machine-readable storage devices include any type of random access memory, any type of read-only memory, solid-state memory, flash memory, optical disks, magnetic disks, disk drives, and / or redundant array of independent disks (RAID) systems. As used herein, the term "device" refers to a physical structure, such as a mechanical and / or electrical device, hardware and / or circuit, which may or may not be configured by computer-readable instructions, machine-readable instructions, etc., and / or is manufactured to execute computer-readable instructions, machine-readable instructions, etc.

[0108] Fig.16 It means that it can be executed in combination with Figure 5 , 6 , 12 and 13 are implemented by the exemplary ACC system Fig.15 A flow chart of machine readable instructions for an example active gap controller 1400 is provided. Fig.16 The routine 1600 begins execution at block 1605, where the example measurement circuit 1510 obtains sensor data from the example engine sensor 1410. In some examples, the sensor data includes information obtained by the engine sensor 1410 from the engine (e.g., Figure 1The sensor data may include flight condition data obtained from a gas turbine engine 100 of the embodiment of the present invention. In some examples, the flight condition data of the sensor data includes values ​​of multiple input variables related to the flight conditions (e.g., air density, throttle lever position, engine temperature, engine pressure, etc.). The sensor data varies according to the operation.

[0109] At block 1610, the example measurement circuit 1510 obtains sensor data from the example pressure sensors 665, 670. In some examples, the sensor data includes Fig.9A and 9B Single point pressure measurement as shown, Fig. 10A and 10B A two-point measurement system as shown, or Fig.11A and 11B The three-point measurement system described above. In some examples, a reference pressure is taken at the compressor outlet. For example, the reference pressure is measured using a pressure sensor at the compressor outlet.

[0110] At block 1615, the conversion curve generation circuit 1515 receives the sensor-based input data and determines the normalized pressure efficiency (P η ) and the correlation between the blade clearance. The correlation between the normalized pressure efficiency and the blade clearance is used by the conversion curve generation circuit 1515 to generate a conversion curve. The conversion curve generation is performed at box 1620. For example, in order to collect data to create an initial correlation, a test can be performed. In some examples, the conversion curve generation circuit 1515 can generate a conversion curve for a series of test flights, for a new engine, or for an engine in various flight cycles. The data collection for conversion curve generation enables the conversion curve to be verified, and the engine with gradual blade loss is observed and / or tested to study the impact of blade length changes on pressure efficiency measurements. In some examples, tests can be performed at different power levels (low power, high power, etc.) and a range of altitudes. An example range of altitude is 5000 feet (low altitude) to 35000 feet (high altitude). Comprehensive testing and conversion curve development allows the use of the gap determination circuit 1405 in actual flight gap monitoring and helps the ACC 1400 to make more precise adjustments to the gap.

[0111] At block 1625, the example transfer curve generation circuit 1515 determines a correlation between normalized pressure efficiency and blade clearance. The transfer curve generation circuit 1515 uses the correlation to generate a transfer curve. The transfer curve is generated for a given power level and / or altitude based on the pressure data and data obtained from a series of test flights conducted to observe blade tip losses.

[0112] Once the conversion curves are generated for various power levels and / or altitudes, the measurement circuit 1510 measures real-time pressure measurements and feeds this data to the clearance calculation circuit 1525. At box 1625, the clearance calculation circuit 1525 uses the generated conversion curve to determine the real-time clearance. At box 1630, the blade tip loss is determined based on the offset of the curve and the interpolation between the curves. For example, the conversion curve is generated from a simulation of a new engine. During real-time flight data collection, pressure measurements are taken and used to calculate pressure efficiency. Expected pressure measurements are generated from initial test conditions. Deviations from expected pressure measurements indicate blade tip loss or offset curves.

[0113] Once the blade tip loss data is calculated based on the shift of the transfer curve at box 1630, the blade tip loss data is input to the active clearance controller 1400 at box 1635 for storage and later use. At box 1640, the actuator control circuit 1520 uses the real-time clearance and associated blade tip loss to send electrical signals to the actuators 550, 650, 1235, 1335 and the multi-layer stacks 555, 655, 1240, 1340 to actuate the blade tip loss data. Figure 5 , 6 , 12 and 13, and adjust the gap between the stator nozzles 535, 635, 1230, 1330 and the interstage seals 540, 640.

[0114] Fig.17 is constructed to execute and / or instantiate Fig.16 Example machine readable instructions and / or example operations to implement Fig.14 1405. The programmable circuit platform 1700 may be, for example, a server, a personal computer, a workstation, a self-learning machine (e.g., a neural network), or any other type of computing and / or electronic device.

[0115] The programmable circuit platform 1700 of the illustrated example includes a programmable circuit 1712. The programmable circuit 1712 of the illustrated example is hardware. For example, the programmable circuit 1712 can be implemented by one or more integrated circuits, logic circuits, FPGAs, microprocessors, CPUs, GPUs, DSPs, and / or microcontrollers from any desired family or manufacturer. The programmable circuit 1712 can be implemented by one or more semiconductor-based (e.g., silicon-based) devices. In this example, the programmable circuit 1712 implements the gap determination circuit 1405.

[0116] The programmable circuit 1712 of the illustrated example includes a local memory 1713 (e.g., cache, registers, etc.). The programmable circuit 1712 of the illustrated example communicates with a main memory 1716 including a volatile memory 1714 and a non-volatile memory 1716 via a bus 1718. The volatile memory 1714 may be comprised of a synchronous dynamic random access memory (SDRAM), a dynamic random access memory (DRAM), Dynamic Random Access Memory The non-volatile memory 1716 may be implemented by flash memory and / or any other desired type of memory device. Access to the main memory 1714, 1716 of the illustrated example is controlled by a memory controller 1717. In some examples, the memory controller 1717 may be implemented by one or more integrated circuits, logic circuits, microcontrollers, or any other type of circuitry from any desired family or manufacturer to manage the flow of data to and from the main memory 1714, 1716.

[0117] The programmable circuit platform 1700 of the illustrated example also includes an interface circuit 1720. The interface circuit 1720 can be implemented by hardware according to any type of interface standard, such as an Ethernet interface, a universal serial bus (USB) interface, interface, a near field communication (NFC) interface, a peripheral component interconnect (PCI) interface, and / or a peripheral component interconnect express (PCIe) interface.

[0118] In the example shown, one or more input devices 1722 are connected to the interface circuit 1720. The input devices 1722 allow a user (e.g., a human user, a machine user, etc.) to input data and / or commands into the programmable circuit 1712. The input devices 1722 may be implemented, for example, by pressure sensors, temperature sensors, etc.

[0119] One or more output devices 1724 are also connected to the interface circuit 1720 of the illustrated example. The output device 1724 may be implemented, for example, by a display device (e.g., a light emitting diode (LED), an organic light emitting diode (OLED), a liquid crystal display (LCD), a cathode ray tube (CRT) display, an in-situ switching (IPS) display, a touch screen, etc.). Therefore, the interface circuit 1720 of the illustrated example typically includes a graphics driver card, a graphics driver chip, and / or a graphics processor circuit such as a GPU.

[0120] The interface circuitry 1720 of the illustrated example also includes communication devices, such as transmitters, receivers, transceivers, modems, residential gateways, wireless access points, and / or network interfaces, to facilitate the exchange of data with external machines (e.g., any type of computing device) via a network 1726. Communications may be via, for example, an Ethernet connection, a digital subscriber line (DSL) connection, a telephone line connection, a coaxial cable system, a satellite system, a line-of-sight wireless system, a line-of-sight wireless system, a cellular telephone system, an optical connection, etc.

[0121] The programmable circuit platform 1700 of the illustrated example also includes one or more mass storage disks or devices 1728 for storing firmware, software and / or data. Examples of such mass storage disks or devices 1728 include magnetic storage devices (e.g., floppy disks, drives, HDDs, etc.), optical storage devices (e.g., Blu-ray disks, CDs, DVDs, etc.), RAID systems, and / or solid-state storage disks or devices such as flash memory devices and / or SSDs.

[0122] Can be Fig.16 The machine-readable instructions 1732 implemented by the machine-readable instructions may be stored on the mass storage device 1728, the volatile memory 1714, the non-volatile memory 1716, and / or at least one non-transitory computer-readable storage medium, such as a removable CD or DVD.

[0123] like Fig.17 As shown, the measurement circuit 1510, the transfer curve generation circuit 1515, the actuator control circuit 1520 and the gap calculation circuit can be instantiated in the programmable circuit 1712. Data storage can be established by local memory 1713, volatile memory 1714, non-volatile memory 1716 or mass storage device 1728.

[0124] Fig.18 It is shown that in addition to using piezoelectric materials or SMA materials with multi-layer stacks, a robotic arm can be used in conjunction with actuator 1850. Fig.18 An example ACC system 1800 is shown, which can be used as a robot arm actuator. The ACC system 1800 includes an active clearance controller 1875, an engine case 1805, a plurality of adjustment sleeves 1807, guide hooks 1810A, 1810B, a front pylon 1815a, a front shroud 1820a, a rear pylon 1815b, a rear shroud 1820b, a stator nozzle 1835, an intermediate stage seal 1817, an interstage seal 1840, a rotor 1845, a blade 1825, a front pressure sensor 1865, a rear pressure sensor 1870, an annular synchro ring 1848, a synchro arm 1846, and an externally threaded rod 1860 having an outboard end 1844.

[0125] For example, the active clearance controller 1875 and the actuator 1850 can be connected to an annular synchro ring 1848 having a synchro arm 1846. The example synchro arm 1846 is connected to a first end of an externally threaded rod 1860 having an outboard end 1844. The externally threaded rod 1860 is threaded through an adjustment sleeve 1807, wherein the internal and external threads are located within a threaded internal bore in the example engine case 1805. The second end of the externally threaded rod 1860 is connected to the example stator nozzle 1835. Angular rotation of the synchro ring 1848 causes pivotal movement of the synchro arm 1846. These components are coupled so that the externally threaded rod can rotate with the pivotal movement of the synchro arm 1846, thereby moving the externally threaded rod radially inward or outward and adjusting the coupled stator nozzle 1835. In turn, the movement of the rod 1860 and the stator nozzle 1835 affects the clearance of the interstage seal 1840 and the example rotor 1845. An example active clearance controller 1875 is connected to the front pressure sensor 1865 and the rear pressure sensor 1870. Using the methods disclosed herein, the active clearance controller 1875 utilizes the transfer curve to determine the clearance between the interstage seal 1840 and the rotor 1845. The active clearance controller 1875 takes into account the expansion of the engine case 1805 due to heat, the displacement of the front pylon 1815 and the shroud 1820, the rear pylon 1815 and the shroud 1820, and the determined clearances of the stator nozzle 183 and the interstage seal 1840 and the rotor 1845. An electrical signal is sent to the actuator 1850, which actuates the annular synchro ring 1848. The annular synchro ring 1848 rotates, causing the synchro arm 1846, which is connected to the first end of the externally threaded rod 1860, to pivot. The externally threaded rod 1860 rotates so that the internally and externally threaded sleeves 1807 within the engine housing 1805 allow the rod to be adjusted radially inward or outward to adjust the displacement of the stator nozzle 1835 and the interstage seal 1840. The active clearance controller 1875 has limited real-time control over the clearance by adjusting the displacement of the interstage seal 1840. In an example real-world muscle range, a medium engine uses a range of greater than 15 mils, while a large engine uses a range of greater than 30 mils.

[0126] As can be appreciated from the foregoing, example methods, apparatus, and articles of manufacture have been disclosed for improving clearance control of interstage and mid-stage seals in gas turbine engines. The disclosed examples propose an improved ACC design using a combination of piezoelectric actuators, pressure measurements, and active clearance controllers to achieve tighter clearances under any operating conditions with fast mechanical ACC modulation. The disclosed examples use piezoelectric materials to generate high mechanical power and provide fast response clearance control in two directions (inward and outward) without time delay. The disclosed examples use multi-layer stacks of piezoelectric materials to manage the range of displacements that affect the range of ACC system muscle capabilities. The disclosed examples propose real-time clearance assessment methods and fast responses to improve efficiency and operability of engine conditions, control interstage seal clearances, and prevent nozzle swing.

[0127] Example methods, apparatus, systems, and articles of manufacture are disclosed herein to provide rapid active clearance control of interstage and mid-stage seals. Further examples and combinations thereof include the following:

[0128] An apparatus for controlling clearance of a turbine engine, the apparatus comprising: a casing surrounding at least a portion of the turbine engine; at least a portion of the turbine engine including a nozzle receiving an airflow, the nozzle including a reference pressure sensor at a first location on a tip of the nozzle and a static pressure sensor at a second location on the tip of the nozzle, a first actuator for controlling clearance between a rotor and the nozzle, the actuator including a multi-layer stack of material, wherein the actuator is positioned at a third location outside of the casing; a first rod coupled to the first actuator and the nozzle through an opening in the casing at the third location, the rod moving the nozzle based on contraction or expansion of the multi-layer stack of material, and a controller for calculating and setting the clearance between the rotor and the nozzle by supplying current to the multi-layer stack in the first actuator.

[0129] An apparatus according to any preceding clause, wherein the multi-layer stack of material is a first multi-layer stack of material, wherein the opening is a first opening, and further comprising: a second actuator, the second actuator being used to control the gap between the blade and the nozzle, the second actuator comprising a second multi-layer stack of material, wherein the second actuator is positioned at a fourth position outside the shell, and a second rod, the second rod being connected to the second actuator and the nozzle through a second opening in the shell at the fourth position, the second rod moving the nozzle based on the second multi-layer stack of material.

[0130] An apparatus as described in any preceding clause, wherein the controller uses a closed loop system that sets a target clearance, and the controller manipulates the actuator to achieve the target clearance based on a clearance calculation, the clearance calculation including at least engine speed, turbine pressure, turbine temperature, compressor temperature and compressor pressure.

[0131] An apparatus as described in any preceding clause, wherein the reference pressure measurement and the static pressure measurement are used to develop a normalized pressure measurement, the normalized pressure measurement is used to generate a conversion curve relating the normalized pressure measurement to a clearance measurement, the conversion curve is used to compare with the real-time pressure measurement to adjust the blade tip clearance.

[0132] Apparatus according to any preceding clause, wherein the controller uses an open loop system that sets a target gap based on the transfer curve and the normalised pressure measurements, the open loop system manipulating the actuator to achieve the target gap.

[0133] A device as described in any preceding clause, wherein the multilayer stack of material includes at least one of a piezoelectric material or a shape memory alloy.

[0134] An apparatus as described in any preceding clause, wherein the reference pressure sensor is disposed at least one of a compressor outlet position, a rear position on the nozzle, an intermediate position on the nozzle, or a front position on the nozzle.

[0135] An apparatus as described in any preceding clause, wherein the static pressure sensor is disposed at least one of a rear position, a middle position or a front position.

[0136] Apparatus as claimed in any preceding clause, wherein the conversion curve is generated during testing at a plurality of altitudes.

[0137] An apparatus as in any preceding clause, wherein the transfer curve is generated during testing at a plurality of power levels, the plurality of power levels comprising at least one of low power or high power.

[0138] An apparatus for controlling clearances in a turbine engine, the apparatus comprising: a controller for determining a first target clearance between a rotor and a nozzle and a second target clearance between a blade and a shroud, the controller communicating with at least one pressure sensor, a control system for supplying power to a plurality of actuators, a first actuator for actuating a first rod to achieve the first target clearance based on the controller determination, the first actuator being located outside an engine casing and coupled to a first end of the first rod, the first rod being positioned to pass through a first seal in the engine casing, a second end of the first rod being coupled to the nozzle, and a second actuator for actuating a second rod to achieve the second target clearance based on the control system determination, the second actuator being located outside the engine casing and coupled to a first end of the second rod, the second rod being positioned to pass through a second seal in the engine casing, a second end of the second rod being coupled to a hanger from which the shroud is suspended.

[0139] An apparatus as in any preceding clause, wherein the controller uses a closed loop system that determines the first and second target clearances based on a calculation including engine speed, turbine pressure, turbine temperature, compressor temperature and compressor pressure.

[0140] Apparatus according to any preceding clause, wherein the controller uses an open loop system that sets the first and second target gaps based on a transfer curve and normalised pressure measurements.

[0141] An apparatus according to any preceding clause, wherein the normalized pressure measurement is developed from a reference pressure measurement and a static pressure measurement, the normalized pressure measurement is used to generate a conversion curve relating the normalized pressure measurement to a gap measurement, the conversion curve being used to compare with a real-time pressure measurement to achieve the first and second target gaps.

[0142] Apparatus as claimed in any preceding clause, wherein the conversion curve is generated during testing at a plurality of altitudes.

[0143] An apparatus as in any preceding clause, wherein the transfer curve is generated during testing at a plurality of power levels, the plurality of power levels comprising at least one of low power or high power.

[0144] An apparatus as described in any preceding clause, wherein the transfer curve is generated during testing of a plurality of flight cycles.

[0145] An apparatus as in any preceding clause, wherein the first actuator comprises a multi-layer stack of material comprising at least one of a piezoelectric material or a shape memory alloy.

[0146] An apparatus as described in any preceding clause, wherein the at least one pressure sensor measures pressure at one of a compressor outlet location, a forward location on the nozzle, a rearward location on the nozzle, or a midpoint location on the nozzle.

[0147] A device for controlling clearance of a turbine engine, the device comprising: a casing surrounding at least a portion of the turbine engine; the at least a portion of the turbine engine comprising a nozzle for receiving an airflow, the nozzle comprising a reference pressure sensor at a first position on the tip of the nozzle and a static pressure sensor at a second position on the tip of the nozzle; a mechanical arm for controlling the clearance between a rotor and the nozzle, wherein the mechanical arm is positioned at a third position outside the casing; a rod coupled to an actuator and the nozzle through an opening in the casing at the third position, the rod moving the nozzle based on contraction or expansion of a multi-layer stack of materials; and a controller for calculating and setting the clearance between the rotor and the nozzle by supplying current to the multi-layer stack in the actuator.

[0148] An apparatus as in any preceding clause, wherein the controller uses a closed loop system that determines the first and second target clearances based on a calculation including engine speed, turbine pressure, turbine temperature, compressor temperature and compressor pressure.

[0149] Apparatus according to any preceding clause, wherein the controller uses an open loop system that sets the first and second target gaps based on a transfer curve and normalised pressure measurements.

[0150] An apparatus according to any preceding clause, wherein the normalized pressure measurement is developed from a reference pressure measurement and a static pressure measurement, the normalized pressure measurement is used to generate a conversion curve relating the normalized pressure measurement to a gap measurement, the conversion curve being used to compare with a real-time pressure measurement to achieve the first and second target gaps.

[0151] Apparatus as claimed in any preceding clause, wherein the conversion curve is generated during testing at a plurality of altitudes.

[0152] An apparatus as in any preceding clause, wherein the transfer curve is generated during testing at a plurality of power levels, the plurality of power levels comprising at least one of low power or high power.

[0153] An apparatus as described in any preceding clause, wherein the transfer curve is generated during testing of a plurality of flight cycles.

[0154] An apparatus as in any preceding clause, wherein the actuator comprises a multi-layer stack of material comprising at least one of a piezoelectric material or a shape memory alloy.

[0155] An apparatus as described in any preceding clause, wherein the at least one pressure sensor measures pressure at one of a compressor outlet location, a forward location on the nozzle, a rearward location on the nozzle, or a midpoint location on the nozzle.

[0156] A system for controlling clearance in a turbine engine, the system comprising at least one actuator containing a multi-layer stack of material that moves a rod in a radial direction, the rod being coupled to a nozzle, at least one sensor placed inside the engine casing, and a controller that uses the at least one sensor to monitor a parameter, converts the monitored parameter to an actual clearance between the tip of the nozzle and the rotor, determines a difference between the actual clearance and a predetermined target clearance, and supplies power to the multi-layer stack to actuate the rod to achieve the target clearance.

[0157] A system as described in any preceding clause, wherein the sensor is a pressure sensor placed on the tip of the nozzle within the engine housing.

[0158] A system as in any preceding clause, wherein the sensor is a pressure sensor placed on a shroud within the engine casing.

[0159] A system as in any preceding clause, wherein the predetermined target clearance is obtained from test data collected for various flight cycles, altitudes, and engine power levels.

[0160] A system as described in any preceding clause, wherein the actuator is located external to the engine housing.

[0161] A system as in any preceding clause, wherein the multilayer stack comprises at least one of a piezoelectric material or a smart metal alloy.

[0162] A system as described in any preceding clause, wherein the normalized pressure measurement comprises a difference between a reference pressure and the static pressure, divided by a difference between the reference pressure and the total pressure.

[0163] A system as in any preceding clause, wherein the normalized pressure measurement comprises a difference between a reference pressure and a front pressure, divided by a difference between the reference pressure and a rear pressure.

[0164] A system as in any preceding clause, wherein the normalized pressure measurement comprises a difference between the static pressure and a reference pressure, divided by a difference between the total pressure and the reference pressure.

[0165] A system as in any preceding clause, wherein the normalized pressure measurement comprises the difference between the leading point pressure and the midpoint pressure, divided by the difference between the leading pressure and the trailing pressure.

[0166] A system as claimed in any preceding clause, wherein the controller is an active clearance controller, the active clearance controller comprising a clearance determination circuit connected to the engine sensor, the pressure sensor and the actuator.

[0167] A system as described in any preceding clause, wherein the gap determination circuit further includes a measurement circuit, a transfer curve generation circuit, a gap calculation circuit, an actuator control circuit and a data memory.

[0168] A system as described in any preceding clause, wherein the normalized pressure measurement comprises a difference between a reference pressure and the static pressure, divided by a difference between the reference pressure and the total pressure.

[0169] A system as in any preceding clause, wherein the normalized pressure measurement comprises a difference between a reference pressure and a front pressure, divided by a difference between the reference pressure and a rear pressure.

[0170] A system as in any preceding clause, wherein the normalized pressure measurement comprises a difference between the static pressure and a reference pressure, divided by a difference between the total pressure and the reference pressure.

[0171] A system as in any preceding clause, wherein the normalized pressure measurement comprises the difference between the leading point pressure and the midpoint pressure, divided by the difference between the leading pressure and the trailing pressure.

[0172] A system as claimed in any preceding clause, wherein the controller is an active clearance controller, the active clearance controller comprising a clearance determination circuit connected to the engine sensor, the pressure sensor and the actuator.

[0173] A system as described in any preceding clause, wherein the gap determination circuit further includes a measurement circuit, a transfer curve generation circuit, a gap calculation circuit, an actuator control circuit and a data memory.

[0174] Although certain example methods, apparatus, and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. For example, the disclosed example methods, apparatus, and articles of manufacture are implemented in conjunction with a gas turbine engine, however, the disclosed examples may be implemented in conjunction with a compressor. On the contrary, this patent covers all methods, apparatus, and articles of manufacture that fully fall within the scope of the claims of this patent.

[0175] The following claims are incorporated into this detailed description by reference, with each claim standing on its own as a separate embodiment of the present disclosure.

Claims

1. A device for controlling clearance of a turbine engine, characterized in that The device comprises: a casing surrounding at least a portion of the turbine engine and defining an opening therethrough; a nozzle of the turbine engine, the nozzle comprising a reference pressure sensor at a first location on a tip of the nozzle and a static pressure sensor at a second location on the tip of the nozzle; an actuator comprising a multi-layer stack of materials, wherein the actuator is positioned at a third location exterior to the housing; a rod coupled to the first actuator at the third position and to the nozzle through the opening in the housing, the rod moving the nozzle based on contraction or expansion of the multi-layer stack of material; and A controller is configured to calculate and set the gap between the rotor and the nozzle by supplying current to the multi-layer stack in the actuator to at least one of expand or contract the multi-layer stack.

2. The device according to claim 1, characterized in that wherein the multi-layer stack of material is a first multi-layer stack of material, wherein the opening is a first opening, wherein the actuator is a first actuator, wherein the rod is a first rod, and further comprising: a second actuator for controlling the clearance between the vane and the nozzle, the second actuator comprising a second multi-layer stack of material, wherein the second actuator is positioned at a fourth location exterior to the housing; and A second rod is coupled to the second actuator and the nozzle through a second opening in the housing at the fourth position, the second rod moving the nozzle based on a second multi-layer stack of the material.

3. The device according to claim 1, characterized in that Wherein the controller uses a closed loop system that sets a target clearance, and the controller manipulates the actuator to achieve the target clearance based on a clearance calculation that includes at least engine speed, turbine pressure, turbine temperature, compressor temperature, and compressor pressure.

4. The device according to claim 1, characterized in that wherein the reference pressure measurement obtained from the reference pressure sensor and the static pressure measurement obtained from the static pressure sensor are used to develop a normalized pressure measurement, the normalized pressure measurement is used to generate a conversion curve relating the normalized pressure measurement to a clearance measurement, the conversion curve is used to compare with the real-time pressure measurement to adjust the blade tip clearance.

5. The device according to claim 4, characterized in that Wherein the controller uses an open loop system that sets a target gap based on the transfer curve and the normalized pressure measurement, the open loop system operating the actuator to achieve the target gap.

6. The device according to claim 1, characterized in that The multilayer stack of materials includes at least one of a piezoelectric material or a shape memory alloy.

7. The device according to claim 1, characterized in that The reference pressure sensor is disposed at least one of a compressor outlet position, a rear position on the nozzle, a middle position on the nozzle, or a front position on the nozzle.

8. The device according to claim 1, characterized in that The static pressure sensor is arranged at least one of a rear position, a middle position or a front position.

9. The device according to claim 4, characterized in that The conversion curves were generated during testing at multiple altitudes.

10. The device according to claim 4, characterized in that Wherein the transfer curve is generated during testing at multiple power levels, the multiple power levels including at least one of low power or high power.

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