Patent Application
20170292391
The subject matter disclosed herein relates to steam turbines. Specifically, the subject matter disclosed herein relates to nozzles in steam turbines.
Steam turbines include static nozzle assemblies that direct flow of a working fluid into turbine buckets connected to a rotating rotor. The nozzle construction (including a plurality of nozzles, or “airfoils”) is sometimes referred to as a “diaphragm” or “nozzle assembly stage.” Steam turbine diaphragms include two halves, which are assembled around the rotor, creating horizontal joints between these two halves. Each turbine diaphragm stage is vertically supported by support bars, support lugs or support screws on each side of the diaphragm at the respective horizontal joints. The horizontal joints of the diaphragm also correspond to horizontal joints of the turbine casing, which surrounds the steam turbine diaphragm.
Steam turbine drum nozzles are loaded into the diaphragm (drum) within a circumferential slot or groove. These drum nozzles are assembled similarly to conventional nozzle assemblies, however, these drum nozzles conventionally include a dovetail/hooked interface with the (radially) outer diaphragm ring, and a cover at the opposite end, which defines a radially inner flowpath. These drum nozzle assemblies do not conventionally include an inner diaphragm ring, as the radially inner cover acts to define the flowpath. When loading drum nozzles into the diaphragm ring, the first nozzle proximate one of the horizontal joints is conventionally held in position while a pin is wedged behind the nozzle to hold it in place. The wedge corner of the nozzle dovetail is typically measured and aligned with the horizontal joint of the diaphragm ring. Following placement of the first nozzle, additional nozzles are then placed within the circumferential slot until the half stage (either upper or lower) of the assembly is complete. When the final nozzle is placed in the slot, additional measurements are performed to determine whether and how much that nozzle and/or adjacent nozzles will need to be machined (or replaced with nozzles of a different size) in order to align with the horizontal joint of the diaphragm ring on this other end of the slot. Additionally, nozzle assemblies are designed with a predetermined gap between the upper-half nozzles and the lower-half nozzles proximate the horizontal joint. This gap helps to control the throat passing area, harmonic content and/or twisting of the rings at the horizontal joint. It may be difficult to measure and verify this gap due to the edge on the conventional nozzles, and it may also be difficult to hold the first nozzle in place when additional nozzles are forcibly loaded into the circumferential slot.
Various embodiments include a steam turbine drum nozzle, along with a related assembly and steam turbine. Particular embodiments include a nozzle having: an airfoil; a radially inner sidewall coupled with a first end of the airfoil; and a radially outer sidewall coupled with a second end of the airfoil, the second end opposing the first end, wherein the radially outer sidewall includes: a first section radially outward of the airfoil; a thinned section coupled with the first section; and a second section coupled with the thinned section radially outward of the airfoil, the second section having a radially outer face and a circumferentially facing side abutting the radially outer face, wherein the second section includes a circumferentially extending slot, and wherein the second section includes a relief slot extending into a body of the second section from the circumferentially facing side.
A first aspect of the disclosure includes a nozzle having: an airfoil; a radially inner sidewall coupled with a first end of the airfoil; and a radially outer sidewall coupled with a second end of the airfoil, the second end opposing the first end, wherein the radially outer sidewall includes: a first section radially outward of the airfoil; a thinned section coupled with the first section; and a second section coupled with the thinned section radially outward of the airfoil, the second section having a radially outer face and a circumferentially facing side abutting the radially outer face, wherein the second section includes a circumferentially extending slot, and wherein the second section includes a relief slot extending into a body of the second section from the circumferentially facing side.
A second aspect of the disclosure includes a steam turbine having: a drum nozzle ring having a circumferentially extending slot therein; and a plurality of drum nozzles aligned within the circumferentially extending slot, at least one of the plurality of drum nozzles including: an airfoil; a radially inner sidewall coupled with a first end of the airfoil; and a radially outer sidewall coupled with a second end of the airfoil, the second end opposing the first end, wherein the radially outer sidewall includes: a first section radially outward of the airfoil; a thinned section coupled with the first section; and a second section coupled with the thinned section radially outward of the airfoil, the second section having a radially outer face and a circumferentially facing side abutting the radially outer face, wherein the second section includes a circumferentially extending slot, and wherein the second section includes a relief slot extending into a body of the second section from the circumferentially facing side.
A third aspect of the disclosure includes a non-transitory computer readable storage medium storing code representative of a steam turbine drum nozzle, the steam turbine drum nozzle physically generated upon execution of the code by a computerized additive manufacturing system, the code including: code representing the steam turbine drum nozzle, the steam turbine drum nozzle including: an airfoil; a radially inner sidewall coupled with a first end of the airfoil; and a radially outer sidewall coupled with a second end of the airfoil, the second end opposing the first end, wherein the radially outer sidewall includes: a first section radially outward of the airfoil; a thinned section coupled with the first section; and a second section coupled with the thinned section radially outward of the airfoil, the second section having a radially outer face and a circumferentially facing side abutting the radially outer face, wherein the second section includes a circumferentially extending slot, and wherein the second section includes a relief slot extending into a body of the second section from the circumferentially facing side.
These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure, in which:
It is noted that the drawings of the invention are not necessarily to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings.
The subject matter disclosed herein relates to steam turbines. Specifically, the subject matter disclosed herein relates to nozzles in steam turbines.
According to various embodiments of the disclosure, a steam turbine drum nozzle includes at least one relief slot in the circumferentially facing side of the nozzle dovetail section. In various embodiments, the relief slot abuts the circumferentially extending slot at the radially outer face of the dovetail section. In some embodiments, the relief slot at least partially surrounds the circumferentially extending slot. In some embodiments, the relief slot extends from the circumferentially extending slot to an axially facing side of the dovetail section. In some embodiments, the relief slot can extend into the dovetail section from the circumferentially facing side of the nozzle dovetail section at an angle of approximately greater than zero degrees and less than five degrees (e.g., 1-5 degrees in some cases). In various embodiments, this relief slot extends at an angle from the circumferentially facing side such that it is substantially coplanar with the horizontal joint surface of the drum nozzle ring. The relief slot(s) can allow for improved alignment and/or installation of steam turbine drum nozzle(s) when compared with conventional nozzles and assemblies.
As denoted in these Figures, the “A” axis represents axial orientation (along the axis of the turbine rotor, sometimes referred to as the turbine centerline). As used herein, the terms “axial” and/or “axially” refer to the relative position/direction of objects along axis A, which is substantially parallel with the axis of rotation of the turbomachine (in particular, the rotor section). As further used herein, the terms “radial” and/or “radially” refer to the relative position/direction of objects along axis (r), which is substantially perpendicular with axis A and intersects axis A at only one location. Additionally, the terms “circumferential” and/or “circumferentially” refer to the relative position/direction of objects along a circumference (c) which surrounds axis A but does not intersect the axis A at any location. Identically labeled elements in the Figures depict substantially similar (e.g., identical) components.
Turning to
In some cases, drum nozzle 20 can include a starting or initial drum nozzle placed in a drum nozzle assembly 60, partially shown in the schematic perspective view in
To illustrate an example of an additive manufacturing process,
AM control system 904 is shown implemented on computer 930 as computer program code. To this extent, computer 930 is shown including a memory 932, a processor 934, an input/output (I/O) interface 936, and a bus 938. Further, computer 930 is shown in communication with an external I/O device/resource 940 and a storage system 942. In general, processor 934 executes computer program code, such as AM control system 904, that is stored in memory 932 and/or storage system 942 under instructions from code 920 representative of drum nozzle 20, 120 (
Additive manufacturing processes begin with a non-transitory computer readable storage medium (e.g., memory 932, storage system 942, etc.) storing code 920 representative of drum nozzle 20, 120 (
In various embodiments, components described as being “coupled” to one another can be joined along one or more interfaces. In some embodiments, these interfaces can include junctions between distinct components, and in other cases, these interfaces can include a solidly and/or integrally formed interconnection. That is, in some cases, components that are “coupled” to one another can be simultaneously formed to define a single continuous member. However, in other embodiments, these coupled components can be formed as separate members and be subsequently joined through known processes (e.g., soldering, fastening, ultrasonic welding, bonding). In various embodiments, electronic components described as being “coupled” can be linked via conventional hard-wired and/or wireless means such that these electronic components can communicate data with one another.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
