The embodiments described herein are generally directed to an actuation system, and, more particularly, to a system for guide vane actuation in a turbomachine.
The compressor of a gas turbine engine with variable guide vanes generally comprises an actuation ring that is connected by lever arms to outer ends of the variable guide vanes in a stator assembly. The guide vanes are uniformly adjustable within a fixed range of angles by relative rotational movement between the actuation ring and the stator assembly. For example, the actuation ring may be rotated, thereby causing a uniform shift in the ends of the lever arms connected to the actuation ring. This uniform shift in the lever arms causes the guide vanes to uniformly rotate within the stator assembly by virtue of their fixed connections to the opposite ends of the lever arms. During operation, the connections between the actuation ring and guide vanes can undergo significant torsional stress.
U.S. Pat. No. 7,198,461 describes an actuation system with a stator vane that is connected to an adjusting ring by an adjusting lever. A cut-out in one end of the adjusting lever is installed around two stub-like elements on the end of a shank of the stator vane, and affixed to the shank by a fastening screw that is fastened to a threaded shank. The other end of the adjusting lever is fastened to a pin-like element on the adjusting ring by a spherical bearing.
The present disclosure is directed toward overcoming one or more of the problems discovered by the inventor.
In an embodiment, an actuation system comprises: at least one guide vane comprising an airfoil and a stem, wherein the stem comprises at least one notch on a radially outward end of the stem; and an actuation connection comprising a lever arm having a first aperture through a first end of the lever arm and a second aperture through a second end of the lever arm, and a spherical plain bearing configured to be mounted inside the first aperture, wherein the second aperture is defined by at least one edge that is configured to engage with the at least one notch in the stem of the at least one guide vane.
In an embodiment, an actuation system comprises, in one or more stages: a stator assembly comprising a plurality of guide vanes extending along radial axes of a longitudinal axis of the actuation system, wherein each of the plurality of guide vanes comprises an airfoil and a stem, and wherein each stem comprises two notches on a radially outward end of the stem; an actuation ring comprising a plurality of mating pins extending along radial axes of the longitudinal axis of the actuation system; and a plurality of actuation connections between a respective one of the plurality of mating pins and the stem of a respective one of the plurality of guide vanes, wherein each of the plurality of actuation connections comprises a lever arm having a first aperture through a first end of the lever arm and a second aperture through a second end of the lever arm, and a spherical plain bearing mounted inside the first aperture and engaged with the respective mating pin, wherein the second aperture is defined by two edges that engage with the two notches in the stem of the respective guide vane.
The details of embodiments of the present disclosure, both as to their structure and operation, may be gleaned in part by study of the accompanying drawings, in which like reference numerals refer to like parts, and in which:
and
The detailed description set forth below, in connection with the accompanying drawings, is intended as a description of various embodiments, and is not intended to represent the only embodiments in which the disclosure may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that embodiments of the invention can be practiced without these specific details. In some instances, well-known structures and components are shown in simplified form for brevity of description.
For clarity and ease of explanation, some surfaces and details may be omitted in the present description and figures. In addition, references herein to “upstream” and “downstream” or “forward” and “aft” are relative to the flow direction of the primary gas (e.g., air) used in the combustion process, unless specified otherwise. It should be understood that “upstream,” “forward,” and “leading” refer to a position that is closer to the source of the primary gas or a direction towards the source of the primary gas, and “downstream,” “aft,” and “trailing” refer to a position that is farther from the source of the primary gas or a direction that is away from the source of the primary gas. Thus, a trailing edge or end of a component (e.g., a turbine blade) is downstream from a leading edge or end of the same component. Also, it should be understood that, as used herein, the terms “side,” “top,” “bottom,” “front,” “rear,” “above,” “below,” and the like are used for convenience of understanding to convey the relative positions of various components with respect to each other, and do not imply any specific orientation of those components in absolute terms (e.g., with respect to the external environment or the ground).
In an embodiment, gas turbine engine 100 comprises, from an upstream end to a downstream end, an inlet 110, a compressor 120, a combustor 130, a turbine 140, and an exhaust outlet 150. In addition, the downstream end of gas turbine engine 100 may comprise a power output coupling 104. One or more, including potentially all, of these components of gas turbine engine 100 may be made from stainless steel and/or durable, high-temperature materials known as “superalloys.” A superalloy is an alloy that exhibits excellent mechanical strength and creep resistance at high temperatures, good surface stability, and corrosion and oxidation resistance. Examples of superalloys include, without limitation, Hastelloy, Inconel, Waspaloy, Rene alloys, Haynes alloys, Incoloy, MP98T, TMS alloys, and CMSX single crystal alloys.
Inlet 110 may funnel a working fluid F (e.g., the primary gas, such as air) into an annular flow path 112 around longitudinal axis L. Working fluid F flows through inlet 110 into compressor 120. While working fluid F is illustrated as flowing into inlet 110 from a particular direction and at an angle that is substantially orthogonal to longitudinal axis L, it should be understood that inlet 110 may be configured to receive working fluid F from any direction and at any angle that is appropriate for the particular application of gas turbine engine 100. While working fluid F will primarily be described herein as air, it should be understood that working fluid F could comprise other fluids, including other gases.
Compressor 120 may comprise a series of compressor rotor assemblies 122 and stator assemblies 124. Each compressor rotor assembly 122 may comprise a rotor disk that is circumferentially populated with a plurality of rotor blades. The rotor blades in a rotor disk are separated, along the axial axis, from the rotor blades in an adjacent disk by a stator assembly 124. Compressor 120 compresses working fluid F through a series of stages corresponding to each compressor rotor assembly 122. The compressed working fluid F then flows from compressor 120 into combustor 130.
Combustor 130 may comprise a combustor case 132 that houses one or more, and generally a plurality of, fuel injectors 134. In an embodiment with a plurality of fuel injectors 134, fuel injectors 134 may be arranged circumferentially around longitudinal axis L within combustor case 132 at equidistant intervals. Combustor case 132 diffuses working fluid F, and fuel injector(s) 134 inject fuel into working fluid F. This injected fuel is ignited to produce a combustion reaction in one or more combustion chambers 136. The combusting fuel-gas mixture drives turbine 140.
Turbine 140 may comprise one or more turbine rotor assemblies 142 and stator assemblies 144 (e.g., nozzles). Each turbine rotor assembly 142 may correspond to one of a plurality or series of stages. Turbine 140 extracts energy from the combusting fuel-gas mixture as it passes through each stage. The energy extracted by turbine 140 may be transferred (e.g., to an external system) via power output coupling 104.
The exhaust E from turbine 140 may flow into exhaust outlet 150. Exhaust outlet 150 may comprise an exhaust diffuser 152, which diffuses exhaust E, and an exhaust collector 154 which collects, redirects, and outputs exhaust E. It should be understood that exhaust E, output by exhaust collector 154, may be further processed, for example, to reduce harmful emissions, recover heat, and/or the like. In addition, while exhaust E is illustrated as flowing out of exhaust outlet 150 in a specific direction and at an angle that is substantially orthogonal to longitudinal axis L, it should be understood that exhaust outlet 150 may be configured to output exhaust E towards any direction and at any angle that is appropriate for the particular application of gas turbine engine 100.
The particular actuation system that is used is not essential to disclosed embodiments. However, in the illustrated embodiment, each actuation ring 126 may be connected to an actuation assembly 128 that is configured to rotate the actuation ring 126 within a limited range of degrees. For example, a first actuation assembly 128A may be configured to rotate actuation rings 126A, 126C, and 126E, while a second actuation assembly 128B may be configured to rotate actuation rings 126B, 126D, and 126F. The rotation of an actuation ring 126 by an actuation assembly 128 causes the guide vanes within the corresponding stator assembly 124 to uniformly rotate by virtue of the actuation connections 200 between the actuation ring 126 and the stator assembly 124.
Actuation ring 126 may comprise a surface 322. A mating pin 324 extends outward, along a radial axis, from surface 322 of actuation ring 126. Mating pin 324 may be fastened to actuation ring 126 through surface 322 via any of various fastening means, such as, by a press fit, mating threads on the outside of mating pin 324 to threads on the inside of an aperture in surface 322, inserting a thread portion of mating pin 324 through surface 322 and mating it to a nut on the other side of surface 322, and/or the like. It should be understood that surface 322 is an annular surface that faces radially outward, and that mating pins 324 may be spaced around the entire circumference of surface 322 at equidistant intervals that correspond to the equidistant intervals between stems 316 of guide vanes 310.
Lever arm 330 comprises two ends along an axial direction. The first end of lever arm 330 may be attached to mating pin 324 via a spherical plain bearing 340 within a first aperture extending radially through the first end. The second end of lever arm 330 may be attached to stem 316 of guide vane 310. In particular, a second aperture extending radially through the second end of lever arm 330 may be positioned around shank 318, such that lever arm 330 rests on the radially outward end of stem 316. A washer 350 may be positioned around shank 318, such that washer 350 rests on lever arm 330 above the second aperture in the second end of lever arm 330. A nut 360 with internal threads may be screwed onto a threaded portion of shank 318, below wrenching flat 319, to clamp washer 350 against lever arm 330. Since guide vane 310 is configured to rotate, wrenching flat 319 can be used to prevent shank 318 from rotating while nut 360 is tightened onto the threaded portion of shank 318.
Second aperture 334 is positioned around the radially outward end of stem 316, and is sized and/or shaped to interface with one or more notches 317 in stem 316. In particular, a long edge of second aperture 334 of lever arm 330 interfaces or engages with the laterally facing surface of notch 317 to restrict movement of lever arm 330. As illustrated, the laterally facing surface of notch 317 may comprise an angled or tapered flat. While only one notch 317 is illustrated in
The disclosed embodiments of actuation connection 200 enable actuation of variable guide vanes 310 within a stator assembly 124 in a compressor 120 of a gas turbine engine 100. Specifically, a plurality of actuation connectors 200 connect mating pins 324 on an actuation ring 126 to stems 316 on the outer ends of guide vanes 310 in a stator assembly 124. Rotation of actuation ring 126 causes corresponding rotation in guide vanes 310, so as to control the angle of guide vanes 310 within stator assembly 124. This actuation of guide vanes 310 can be used to control the flow of a working fluid F within compressor 120 of gas turbine engine 100, as that working fluid F flows through stator assembly 124. It should be understood that a plurality of stator assemblies 124 may be paired with corresponding actuation rings 126 to achieve this actuation mechanism for a plurality of stages within compressor 120.
It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. Aspects described in connection with one embodiment are intended to be able to be used with the other embodiments. Any explanation in connection with one embodiment applies to similar features of the other embodiments, and elements of multiple embodiments can be combined to form other embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages.
The preceding detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. The described embodiments are not limited to usage in conjunction with a particular type of turbomachine. Hence, although the present embodiments are, for convenience of explanation, depicted and described as being implemented in a gas turbine engine, it will be appreciated that it can be implemented in various other types of turbomachines and machines with variable guide vanes, and in various other systems and environments. For example, while the disclosed embodiments have been primarily described with respect to a stator assembly 124 in a compressor 120, the disclosed embodiments could be equally applied to a stator assembly 144 in a turbine 140. Furthermore, there is no intention to be bound by any theory presented in any preceding section. It is also understood that the illustrations may include exaggerated dimensions and graphical representation to better illustrate the referenced items shown, and are not considered limiting unless expressly stated as such.