This disclosure relates generally to rotors and, more particularly, to trapped rotatable weights to improve rotor balance.
In recent years, turbine engines have been increasingly utilized in a variety of applications and fields. Turbine engines are intricate machines with extensive availability, reliability, and serviceability requirements. Turbine engines include rotors with fan blades. The rotor and fan blades rotate at high speed and subsequently compress the air flow. The high-pressure compressor then feeds the pressurized air flow to a combustion chamber to generate a high-temperature, high-pressure gas stream. One characteristic of a rotor is balance. The balance of the rotor corresponds to the location of the center of mass of the rotor with respect to the geometric center of the rotor. The closer the center of mass is to the geometric center, the more balanced the rotor is. During implementation, balanced rotors have less vibration than unbalanced rotors, thereby leading to less probability of damage or error, larger lifespan, etc.
Methods, apparatus, systems, and articles of manufacture corresponding to trapped rotatable weights to improve rotor balance are disclosed.
Certain examples provide an example apparatus comprising a lock nut, a rotor assembly, a channel defined by the lock nut and the rotor assembly, the channel wrapped circumferentially around a geometric center of the rotor assembly, and a weight trapped within the channel.
Certain examples provide an example turbine engine comprising a shaft and a rotor coupled to the shaft, the rotor including a section defining a channel around a geometric center of the rotor, the channel including a weight trapped within the channel and movable within the channel.
The figures are not to scale. Instead, the thickness of the layers or regions may be enlarged in the drawings. In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. As used in this patent, stating that any part (e.g., a layer, film, area, region, or plate) is in any way on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, indicates that the referenced part is either in contact with the other part, or that the referenced part is above the other part with one or more intermediate part(s) located therebetween. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. Stating that any part is in “contact” with another part means that there is no intermediate part between the two parts. Although the figures show layers and regions with clean lines and boundaries, some or all of these lines and/or boundaries may be idealized. In reality, the boundaries and/or lines may be unobservable, blended, and/or irregular.
Descriptors “first,” “second,” “third,” etc. are used herein when identifying multiple elements or components which may be referred to separately. Unless otherwise specified or understood based on their context of use, such descriptors are not intended to impute any meaning of priority, physical order or arrangement in a list, or ordering in time but are merely used as labels for referring to multiple elements or components separately 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 the same element may be referred to in a claim with a different descriptor such as “second” or “third.” In such instances, it should be understood that such descriptors are used merely for ease of referencing multiple elements or components.
In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific examples that may be practiced. These examples are described in sufficient detail to enable one skilled in the art to practice the subject matter, and it is to be understood that other examples may be utilized. The following detailed description is therefore, provided to describe an exemplary implementation and not to be taken limiting on the scope of the subject matter described in this disclosure. Certain features from different aspects of the following description may be combined to form yet new aspects of the subject matter discussed below.
When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As used herein, the terms “system,” “unit,” “module,” “engine,” “component,” etc., may include a hardware and/or software system that operates to perform one or more functions. For example, a module, unit, or system may include a computer processor, controller, and/or other logic-based device that performs operations based on instructions stored on a tangible and non-transitory computer readable storage medium, such as a computer memory. Alternatively, a module, unit, or system may include a hard-wires device that performs operations based on hard-wired logic of the device. Various modules, units, engines, and/or systems shown in the attached figures may represent the hardware that operates based on software or hardwired instructions, the software that directs hardware to perform the operations, or a combination thereof.
A turbine engine, also called a combustion turbine or a gas turbine, is a type of internal combustion engine. Turbine engines are commonly utilized 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. A basic operation of the turbine engine includes an intake of fresh atmospheric air flow through the front of the turbine engine with a rotor that includes fans. In some examples, the air flow travels through an intermediate-pressure compressor or a booster compressor located between the fan and a high-pressure compressor. The booster compressor is used to supercharge or boost the pressure of the air flow prior to the air flow entering the high-pressure compressor. The air flow can then travel through the high-pressure compressor that further pressurizes the air flow. The high-pressure compressor includes a group of blades (e.g., fans) attached to a shaft. The blades spin at high speed and subsequently compress the air flow. The high-pressure compressor then feeds the pressurized air flow to a combustion chamber. In some examples, the high-pressure compressor feeds the pressurized air flow at speeds of hundreds of miles per hour. In some instances, the combustion chamber includes one or more rings of fuel injectors that inject a steady stream of fuel into the combustion chamber, where the fuel mixes with the pressurized air flow.
In the combustion chamber of the turbine engine, the fuel is ignited with an electric spark provided by an igniter, where the fuel, in some examples, burns at temperatures of more than 2000 degrees Fahrenheit. The resulting combustion produces a high-temperature, high-pressure gas stream (e.g., hot combustion gas) that passes through another group of blades called a turbine. In some examples, a turbine includes an intricate array of alternating rotating rotors and stationary airfoil-section rotors. Alternatively, the turbine can be structured with adjacent rotating rotors or stationary airfoil section rotors, or in any combination of alternating or adjacent airfoil-section blades. As the hot combustion gas passes through the turbine, the hot combustion gas expands, causing rotating blades of the rotating rotors to spin. The rotating blades of the rotating rotors serve at least two purposes. A first purpose of the rotating blades is to drive the booster compressor and/or the high-pressure compressor to draw more pressured air into the combustion chamber. For example, the turbine is attached to the same shaft as the high-pressure compressor in a direct-drive configuration, thus, the spinning of the turbine causes the high-pressure compressor to spin. A second purpose of the rotating blades is to spin a generator operatively coupled to the turbine section to produce electricity. For example, the turbine can generate electricity to be used by an aircraft, a power station, etc.
In the example of an aircraft turbine engine, after passing through the turbine, the hot combustion gas exits the aircraft turbine engine through a nozzle at the back of the aircraft turbine engine. As the hot combustion gas exits the nozzle, the aircraft turbine engine and the corresponding aircraft coupled to the aircraft turbine engine are accelerated forward (e.g., thrusted forward). In the example of a land-based turbine engine, after passing through the turbine, the hot combustion gas is dissipated, used to generate steam, etc.
When the geometric center of a rotor and the center of mass of the rotor are not at the same point, the rotor is unbalanced. Unbalanced rotors create higher vibrations than balanced rotors (e.g., the more a rotor is unbalanced, the higher the vibrations that occur during rotation). Higher vibrations are undesirable as they lead to an increased likelihood of damage, increased energy consumption, decrease lifespan, and reduced efficiency. The more balanced a rotor is (e.g., the closer the center of mass is to the geometric center of the rotor), the lower the vibrations that occur while the rotor rotates (e.g., spins). During the manufacturing process, a technician performs a balancing test to identify how balanced the rotor is (e.g., where the center of mass is with respect to the geometric center). If the technician determines that the rotor is unbalanced by more than a threshold amount (e.g., the center of mass is more than a threshold distance away from the geometric center), the technician can add weights to different portions of the rotor, thereby adjusting the center of mass. The technician can then retest the balance of the rotor and add and/or subtract weight from the same or a different portion of the rotor until the balance of the rotor satisfies the balance threshold, thereby increasing the balance of the rotor to an acceptable level. The acceptable level and/or the balance threshold can be based on user, industry, manufacturers, and/or protocol standards.
Traditionally, the balance weights are installed after an initial rotor balance check but before installation of a rotor into the engine assembly. However, after the rotor is initially assembled, the center of mass can be moved during or after subsequent assembly procedures. Additionally, some traditional balance weights require removal of the rotor from the machine that tests the balance of the rotor to adjust, which is a tedious and time-consuming process. Examples disclosed herein provide a structure that facilitates balance weight adjustments after installation without disassembly of the rotor and/or other parts of a turbine engine by removal of the rotor, a locknut, and/or a tie bolt.
Traditional techniques for installing weights that can be adjusted after installation with minimal rotor disassembly include a housing including an open cavity that includes a slot wide enough so that a weight can be placed into the cavity. The slot can be structured so that the weight can only be put into the cavity when the weight is positioned at certain angles. In such traditional techniques, the weight includes a threaded insert through the weight so that a technician can secure the weight to housing with a screw or bolt. However, because the slot is big enough to allow the weight to enter the cavity, the weight can exit the cavity as well (e.g., if the screw or bolt that holds the balance weight in place breaks, fails, or becomes loose). Accordingly, if the screw or bolt fails to hold the weight in place, the weight can be projected out of the rotor and cause damage to the rotor and/or the rest of the turbine engine. Examples disclosed herein achieve rotor balance in a boltless rotor architecture, where a fixed number of weights are trapped (e.g., cannot be removed) in a channel (as referred to as annulus, slot, chamber, groove, cavity, etc.) corresponding to the rotor during installation (e.g., connecting the rotor to other parts via a lock nut and/or tie bolt). The trapped weights can be moved circumferentially within the channel (e.g., around the circumference of the geometric center of the rotor) to adjust the balance of the rotor (e.g., by moving the one or more weights, the center of mass of the rotor is moved). However, once the lock nut is installed, the balance weight cannot be removed from the rotor unless disassembled. Rather, the balance weight can only be rotated around the geometric center of the rotor to adjust the balance of the rotor. In some examples, the part of the rotor into which the weights are fixed in the cavity/channel can include tabs, slots, dimples, etc., to clock and/or lock the balance weight into a preset positions around the circumference of the rotor so that a balance weight can lock into positions corresponding to the tabs, slots, dimples, etc. Examples disclosed herein allow a rotor to be balanced before, during, and/or after installation of a rotor and/or within a balance test machine without disassembly of the rotor by removal of the rotor, a locknut, and/or a tie bolt.
The engine 102 of
In the illustrated example of
In some examples, each of the compressors 114, 116 can include a plurality of compressor stages, with each stage including both an annular array of stationary compressor vanes and an annular array of rotating compressor blades (e.g., rotors that are part of the compressor) positioned immediately upstream of the compressor vanes. Similarly, each of the turbines 120, 124 can include a plurality of turbine stages, each stage including both an annular array of stationary nozzle vanes and an annular array of rotating turbine blades positioned immediately downstream of the nozzle vanes.
Additionally, as shown in
In some examples, the second (low-pressure) drive shaft 126 is directly coupled to the fan rotor assembly 130 to provide a direct-drive configuration. Alternatively, the second drive shaft 126 can be coupled to the fan rotor assembly 130 via the speed reduction device 142 (e.g., a reduction gear or gearbox) to provide an indirect-drive or geared drive configuration. Such a speed reduction device(s) can also be provided between any other suitable shafts and/or spools within the engine 102 as desired or required.
During operation of the engine 102, an initial air flow (indicated by arrow 148) can enter the engine 102 through the associated inlet 150 of the fan casing 132. The air flow 148 then passes through the fan blades 136 and splits into a first compressed air flow (indicated by arrow 152) that moves through conduit 140 and a second compressed air flow (indicated by arrow 154) which enters the booster compressor 114. The pressure of the second compressed air flow 154 is then increased and enters the high-pressure compressor 116 (as indicated by arrow 156). After mixing with fuel and being combusted within the combustor 118, the combustion products 158 exit the combustor 118 and flow through the first turbine 120. Thereafter, the combustion products 158 flow through the second turbine 124 and exit the exhaust nozzle 128 to provide thrust for the engine 102.
The drive shaft 200 of
The balance weights 202 of
The dimples 204 of
The channel 206 of
The channel 206 shown in the example of
“Including” and “comprising” (and all forms and tenses thereof) are used herein to be open ended terms. Thus, whenever a claim employs any form of “include” or “comprise” (e.g., comprises, includes, comprising, including, having, etc.) as a preamble or within a claim recitation of any kind, it is to be understood that additional elements, terms, etc. may be present without falling outside the scope of the corresponding claim or recitation. As used herein, when the phrase “at least” is used as the transition term in, for example, a preamble of a claim, it is open-ended in the same manner as the term “comprising” and “including” 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 with B, (5) A with C, (6) B with C, and (7) A with B and with 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 implementations including 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 implementations including 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 implementations including 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 processes, instructions, actions, activities and/or steps, the phrase “at least one of A or B” is intended to refer to implementations including 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, singular references (e.g., “a”, “an”, “first”, “second”, etc.) do not exclude a plurality. The term “a” or “an” entity, as used herein, refers to one or more of that entity. The terms “a” (or “an”), “one or more”, and “at least one” can be used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements or method actions may be implemented by, e.g., a single unit or processor. Additionally, although individual features may be included in different examples or claims, these may possibly be combined, and the inclusion in different examples or claims does not imply that a combination of features is not feasible and/or advantageous.
Further aspects of the invention are provided by the subject matter of the following clauses:
Example 1 includes an apparatus comprising an engageable receptacle, a rotor assembly, a channel defined by the engageable receptacle and the rotor assembly, the channel wrapped circumferentially around a geometric center of the rotor assembly, and a weight trapped within the channel.
Example 2 includes the apparatus of example 1, wherein the weight moves circumferentially within the channel around the geometric center of the rotor assembly.
Example 3 includes the apparatus of example 1, wherein the weight is not removable from the channel without disassembling the engageable receptacle.
Example 4 includes the apparatus of example 1, wherein the weight includes a set screw to lock the weight to a position within the channel.
Example 5 includes the apparatus of example 4, wherein the rotor assembly includes at least one of a dimple, a tab, or a slot at the position of the channel.
Example 6 includes the apparatus of example 1, wherein a position of the weight within the channel affects balance of the rotor assembly.
Example 7 includes the apparatus of example 1, wherein the weight can be moved within the channel after the engageable receptacle and the rotor assembly are connected via a tie bolt.
Example 8 includes the apparatus of example 1, wherein the weight has first end and a second end narrower than the first end.
Example 9 includes the apparatus of example 8, wherein the engageable receptacle and the rotor assembly are structured so that the channel has a third and a fourth end narrower than the third end.
Example 10 includes the apparatus of example 9, wherein the third end of the channel corresponds to the first end of the weight and the fourth end of the channel corresponds to the second end of the weight so that the weight cannot be removed from the channel.
Example 11 includes the apparatus of example 1, wherein the rotor assembly is a first rotor assembly, the engageable receptacle is at least one of a lock nut or a second rotor assembly.
Example 12 includes a turbine engine comprising a shaft, and a rotor coupled to the shaft, the rotor including a section defining a channel around a geometric center of the rotor, the channel including a weight trapped within the channel and movable within the channel.
Example 13 includes the turbine engine of example 12, wherein the rotor and the shaft are to rotate.
Example 14 includes the turbine engine of example 12, wherein the rotor is coupled to the shaft via at least one of a lock nut or a tie bolt.
Example 15 includes the turbine engine of example 14, wherein the lock nut further defines the channel.
Example 16 includes the turbine engine of example 14, wherein the weight is removable from the channel by disassembling the lock nut.
Example 17 includes the turbine engine of example 12, wherein the weight is circumferentially movable within the channel around the geometric center of the rotor.
Example 18 includes the turbine engine of example 12, wherein the weight includes a set screw to lock the weight to a position within the channel.
Example 19 includes the turbine engine of example 18, wherein the rotor includes at least one of a dimple, a tab, or a slot at the position of the channel.
Example 20 includes the turbine engine of example 12, wherein a position of the weight within the channel affects balance of the rotor.
Example 21 includes the turbine engine of example 12, wherein the weight is movable within the channel after the rotor and the shaft are connected.
Example 22 includes the turbine engine of example 12, wherein the rotor is a first rotor, further including a second rotor attached to the first rotor, the second rotor further defining the channel.
From the foregoing, it will be appreciated that example methods and apparatus have been disclosed that correspond to trapped rotatable weights to improve rotor balance. The disclosed trapped rotatable weights allow for the position of preinstalled weights to be adjusted (e.g., moved) circumferentially around the geometric center of a rotor to adjust the balance of the rotor to meet a balance threshold without disassembly of the rotor, a tie bolt, and/or a locknut during balance testing and/or after installation. Additionally, because the rotatable balance weights are trapped (e.g., fixed, secured, etc.) in a channel, even if a screw nut that secures the balance weight into place fails/breaks, there is no risk of the balance weight being projected out of the channel and causing damage to other components of the engine.
Although certain example methods, apparatus and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the claims of this patent.
The following claims are hereby incorporated into this Detailed Description by this reference, with each claim standing on its own as a separate embodiment of the present disclosure.
This invention was made with Government support under W58RGZ-16-C-0047 awarded by the U.S. Army. The Government has certain rights in this invention.