Patent Description:
The invention concerns a gas turbine blade in accordance with appended claim <NUM> and a method according to appended claim <NUM>.

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings.

Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

Also, it should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms "including," "having," and "comprising," as well as derivatives thereof, mean inclusion without limitation. The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term "or" is inclusive, meaning and/or, unless the context clearly indicates otherwise. The phrases "associated with" and "associated therewith," as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

Also, although the terms "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

In addition, the term "adjacent to" may mean: that an element is relatively near to but not in contact with a further element; or that the element is in contact with the further portion, unless the context clearly indicates otherwise. Further, the phrase "based on" is intended to mean "based, at least in part, on" unless explicitly stated otherwise. Terms "about" or "substantially" or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard is available, a variation of twenty percent would fall within the meaning of these terms unless otherwise stated.

<FIG> illustrates an example of a gas turbine engine <NUM> including a compressor section <NUM>, a combustion section <NUM>, and a turbine section <NUM> arranged along a central axis <NUM>. The compressor section <NUM> includes a plurality of compressor stages <NUM> with each compressor stage <NUM> including a set of turbine blades <NUM> and a set of stationary vanes <NUM> or adjustable guide vanes. A rotor <NUM> supports the turbine blades <NUM> for rotation about the central axis <NUM> during operation. In some constructions, a single one-piece rotor <NUM> extends the length of the gas turbine engine <NUM> and is supported for rotation by a bearing at either end. In other constructions, the rotor <NUM> is assembled from several separate spools that are attached to one another or may include multiple disk sections that are attached via a bolt or plurality of bolts.

The compressor section <NUM> is in fluid communication with an inlet section <NUM> to allow the gas turbine engine <NUM> to draw atmospheric air into the compressor section <NUM>. During operation of the gas turbine engine <NUM>, the compressor section <NUM> draws in atmospheric air and compresses that air for delivery to the combustion section <NUM>. The illustrated compressor section <NUM> is an example of one compressor section <NUM> with other arrangements and designs being possible.

In the illustrated construction, the combustion section <NUM> includes a plurality of separate combustors <NUM> that each operate to mix a flow of fuel with the compressed air from the compressor section <NUM> and to combust that air-fuel mixture to produce a flow of high temperature, high pressure combustion gases or exhaust gas <NUM>. Of course, many other arrangements of the combustion section <NUM> are possible.

The turbine section <NUM> includes a plurality of turbine stages <NUM> with each turbine stage <NUM> including a number of rotating turbine blades <NUM> and a number of stationary blades or vanes. The turbine stages <NUM> are arranged to receive the exhaust gas <NUM> from the combustion section <NUM> at a turbine inlet <NUM> and expand that gas to convert thermal and pressure energy into rotating or mechanical work. The turbine section <NUM> is connected to the compressor section <NUM> to drive the compressor section <NUM>. For gas turbine engines <NUM> used for power generation or as prime movers, the turbine section <NUM> is also connected to a generator, pump, or other device to be driven. As with the compressor section <NUM>, other designs and arrangements of the turbine section <NUM> are possible.

A control system <NUM> is coupled to the gas turbine engine <NUM> and operates to monitor various operating parameters and to control various operations of the gas turbine engine <NUM>. In preferred constructions the control system <NUM> is typically micro-processor based and includes memory devices and data storage devices for collecting, analyzing, and storing data. In addition, the control system <NUM> provides output data to various devices including monitors, printers, indicators, and the like that allow users to interface with the control system <NUM> to provide inputs or adjustments. In the example of a power generation system, a user may input a power output set point and the control system <NUM> may adjust the various control inputs to achieve that power output in an efficient manner.

The control system <NUM> can control various operating parameters including, but not limited to variable inlet guide vane positions, fuel flow rates and pressures, engine speed, valve positions, generator load, and generator excitation. Of course, other applications may have fewer or more controllable devices. The control system <NUM> also monitors various parameters to assure that the gas turbine engine <NUM> is operating properly. Some parameters that are monitored may include inlet air temperature, compressor outlet temperature and pressure, combustor outlet temperature, fuel flow rate, generator power output, bearing temperature, and the like. Many of these measurements are displayed for the user and are logged for later review should such a review be necessary.

<FIG> illustrates a perspective view of a turbine blade <NUM> as may be found in a gas turbine engine <NUM>. The turbine blade <NUM> includes an airfoil <NUM>, a platform <NUM>, and a root <NUM>. The root <NUM> may be connected to a rotor <NUM> of the gas turbine engine <NUM>. A platform <NUM> is formed at a radially outward portion of the root <NUM> and is in between the root <NUM> and the airfoil <NUM>. The airfoil <NUM> is attached to the platform <NUM> and extends in a radial direction outwards from the platform <NUM> to a tip <NUM>. The airfoil <NUM> includes an outer surface having a pressure side <NUM> and a suction side <NUM>. The pressure side <NUM> and suction side meet at an upstream leading edge <NUM> and a downstream trailing edge <NUM>. The terms 'leading' and 'trailing' are used in relation to a fluid flow of the working flow of the gas turbine engine <NUM>. In an embodiment, a platform impingement plate <NUM> is shown in <FIG> residing on the side of the platform <NUM> facing the root <NUM> and opposite the airfoil <NUM>.

<FIG> shows a further view of the platform impingement plate <NUM>. The platform impingement plate <NUM> attaches to a first surface of the platform facing the root <NUM> and on the surface opposite the surface of the platform from which the airfoil <NUM> extends. Additionally, the platform impingement plate <NUM> resides on the pressure side <NUM> of the turbine blade <NUM>.

<FIG> shows a perspective top view of the platform impingement plate <NUM>. The platform impingement plate <NUM> includes a circumferential edge <NUM> that contacts and is attached to the first surface of the platform <NUM>. The circumferential edge <NUM> is in continuous contact with the first surface of the platform <NUM>. The edge <NUM> surrounds a cavity <NUM>, the cavity <NUM> defined by a plate surface <NUM> and the surrounding edge <NUM>. The plate surface <NUM> may include at least one impingement hole <NUM>. In an embodiment, the plate surface <NUM> includes more than one impingement hole <NUM>. The impingement holes <NUM> enable a fluid flow to cool the first surface of the platform. The platform impingement plate <NUM> includes a flat member <NUM> having a face attached to the plate surface <NUM>. The flat member <NUM> includes at least one end portion, the end portion extends beyond the plate surface <NUM> and includes a curved end. The curved end fits into a groove in the platform <NUM>. An embodiment shown in <FIG> includes a flat member <NUM> having two end portions, each end portion including a curved end. Each of the curved ends fit into a corresponding groove in the platform <NUM> so that the platform impingement plate <NUM> may be attached to the platform <NUM>. In an embodiment, the curved ends are slightly larger than the grooves so that they deform slightly when installed to hold the platform impingement plate <NUM> in place.

In an embodiment, the platform impingement plate <NUM> is additively manufactured. Additive Manufacturing (AM) enables the manufacturing of components that are difficult to manufacture using conventional manufacturing techniques such as the curved ends of the flat member <NUM>.

<FIG> shows a perspective view of turbine blade <NUM> viewed so that a bottom of the root <NUM> may be seen. A bottom face of the root <NUM> includes at least one root cavity <NUM>. In the embodiment of the turbine blade <NUM> shown in <FIG>, the root <NUM> includes three root cavities <NUM>. In a root cavity <NUM> on the far right of <FIG>, an orifice plate <NUM> is shown having a plate that covers the opening into the root cavity <NUM>.

<FIG> shows a perspective view of the orifice plate <NUM> as shown in the root cavity <NUM> of root <NUM> in <FIG>. The orifice plate <NUM> includes a plate <NUM> having at least one orifice <NUM>. In the embodiment shown, the plate <NUM> includes an octagonal shape. Extending from a first surface of the plate <NUM> is at least one insertion plate <NUM>. In the embodiment of <FIG>, two insertion plates <NUM> extend from the first surface of the plate <NUM>. The insertion plates <NUM> may be inserted into the root cavity <NUM> where they are fitted into the root cavity <NUM>. In an embodiment, the plate <NUM> may include at least one fin <NUM> extending from a second surface of the plate <NUM> opposite the first surface.

<FIG> illustrates the platform <NUM> at the trailing edge <NUM>. The platform <NUM> on the trailing edge side extends to the end of the trailing edge <NUM> such that it may be shorter than a traditional turbine blade. The shorter platform <NUM> is easier to cool and to prevent oxidation and TBC damage.

Turbine engine internal components, such as the turbine blade <NUM> shown in <FIG>, often incorporate a thermal barrier coating (TBC) of metal-ceramic material that is applied directly to the external surface of the component substrate surface or over an intermediate metallic bond coat that was previously applied to the substrate surface. The TBC provides an insulating layer over the component substrate, which reduces the substrate temperature. <FIG> includes a perspective view of turbine blade <NUM> having a thermal protection system <NUM> that may include a bond coat applied to the substrate. The thermal protection system <NUM> may also include a thermal barrier coating applied over the bond coat as a topcoat. In an alternate embodiment, the thermal barrier coating is applied directly to the metallic substrate. In an embodiment, the thermal protection system <NUM> is applied to portions of the airfoil <NUM> and/or applied to the platform <NUM>. For example, the bond coat may be applied to the entire airfoil substrate including the tip <NUM>, leading edge <NUM>, trailing edge <NUM>, suction side <NUM>, and pressure side <NUM>. The bond coat may be applied to the platform <NUM>. Surfaces included for the bond coat application may include those denoted by A, B, C, and D. In an embodiment, the bond coat comprises platinum aluminum alloy (PtAl). The topcoat may be applied by an Electron Beam Physical Vapor Deposited (EBPVD) process over the bond coat on the platform <NUM> and portions of the airfoil <NUM>. In an embodiment, the topcoat is applied to the tip <NUM>, pressure side <NUM>, suction side <NUM> and leading edge <NUM>, but not on the trailing edge <NUM>. The thermal protection system <NUM>, PtAl bond coat and EBPVD topcoat, has a better surface finish than air plasma sprayed (APS) coatings resulting in an efficiency advantage.

<FIG> shows a partial perspective view of a turbine blade <NUM> having a sealing wire <NUM>. The turbine blade <NUM> in <FIG> includes a platform <NUM> including a side surface <NUM> with a groove formed in the side surface <NUM>. The sealing wire <NUM>, as shown in <FIG>, includes a first curved portion and a second flat portion such that the sealing wire <NUM> includes a D-shaped cross section. The sealing wire <NUM> is oriented such that the second flat portion faces toward the inner diameter of the gas turbine engine. Utilizing a sealing wire instead of sealing strip, as has been utilized previously, incurs less machining to install within the platform <NUM> and includes a dynamic damping advantage. Specifically, the sealing wire <NUM> is compressed between two adjacent turbine blades <NUM> and is resilient such that vibrations between the turbine blade <NUM> are reduced.

<FIG> illustrates a turbine blade <NUM> having a platform <NUM> with a damping cavity <NUM> on the trailing edge side of the platform <NUM>. The damping cavity <NUM> receives a leading edge portion <NUM> of an adjacent guide vane <NUM> of the next stage. During operation of the gas turbine engine <NUM>, the interaction of the leading edge portion <NUM> with the damping cavity <NUM> damps vibration. The adjacent guide vane <NUM> includes a T-shaped platform <NUM> that reduces hot gas ingestion into the platform cavity.

Claim 1:
A gas turbine blade (<NUM>), comprising:
a root (<NUM>) for connecting to a rotor (<NUM>) of a gas turbine engine;
a platform (<NUM>) attached to the root and defining at least one groove;
a platform impingement plate (<NUM>), comprising:
a circumferential edge (<NUM>) surrounding a cavity (<NUM>), the edge positioned to contact a first surface of the platform, a first plate surface and a second plate surface opposite said first plate surface,
said first plate surface positioned to form the cavity (<NUM>) between the first surface and the first plate surface, and
an airfoil (<NUM>) comprising a metallic substrate extending from a second surface of the platform opposite the first surface to a tip, the airfoil including a pressure side (<NUM>) and a suction side (<NUM>),
the pressure side and the suction side meeting at a trailing edge and a leading edge,
wherein the plate first and second surfaces include at least one impingement hole (<NUM>) through which a fluid flow flows to cool the first surface of the platform,
characterised in that the blade further comprises a flat member (<NUM>) having a face attached to the second plate surface and at least one end portion, wherein each end portion extends beyond the first and second plate surfaces and includes a curvature so that each curved end portion is inserted into a corresponding groove in the platform.