Patent Application
20090202355
The present invention relates generally to blade tip shrouds and more particularly, but not exclusively, to a retaining system for retaining a blade tip shroud to a turbine blade in a gas turbine engine. Although, the present invention was developed for use in gas turbine engines, certain applications may be outside this field.
Blade tip shrouds typically wear during operation in gas turbine engines and require replacement. Current blade tip shrouds have issues including, for example, those respecting complexity of geometry, manufacturing cost, assembly time, limitations on shroud materials, ease of replacement, and fatigue life of the replacement. Thus, there is a need for the development of technology for removable blade tip shrouds within a gas turbine engine. The present invention satisfies this need in a novel and unobvious way.
One embodiment of the present invention is a blade with a replaceable blade tip shroud that includes an airfoil shaped spar extending from a leading edge to a trailing edge between a root end and a tip end. It also includes a plurality of tiles coupled to an exterior of the spar; a tip shroud positioned to overlap at least a portion of the tip end of the spar; and means for anchoring the tip shroud to the tip end of the spar.
In one refinement the tip shroud overlaps the entire tip end of the spar, and the tip shroud is configured to retain at least one of the tiles in place against movement from the root end toward the tip end.
In another refinement the tip shroud includes at least one groove shaped to receive the means for anchoring the tip shroud to the tip end of the spar.
In another refinement the tip end of spar also includes at least one groove shaped to receive the means for anchoring the tip shroud to the tip end of the spar.
In another refinement the spar is metal and the tip shroud is metal.
In another refinement the spar is metal and the tip shroud is ceramic.
Another embodiment of the present invention is an apparatus including a shroud tip held on a tip end of an airfoil shaped spar by a retaining clip positioned within a pair of grooves on the spar and a corresponding pair of grooves in the shroud tip.
In one refinement the retaining clip extends from a leading edge of the airfoil shaped spar toward a trailing edge of the airfoil shaped spar.
In another refinement the pair of grooves extends from a leading edge of the spar toward a trailing edge of the spar, and the pair of grooves do not extend all the way to the trailing edge.
In another refinement the retaining clip is airfoil shaped.
In another refinement a plurality of ceramic tiles are coupled to the spar.
In another refinement the tip shroud overlaps at least one of the plurality of tiles and retains it in place against movement toward the tip end.
In another refinement the spar is metal and the tip shroud is selected from the group consisting of a metal and a ceramic.
In another refinement the tip shroud is metal, and the tip shroud is a different metal than the spar.
Another embodiment of the present invention is a gas turbine engine blade with a replaceable tip shroud, including an airfoil shaped spar extending radially between a hub end and a tip end. The spar extends substantially axially between a leading edge and a trailing edge. The blade also includes a tip shroud positioned to at least partially radially overlap the tip end of the airfoil shaped spar. A retaining member extends from the leading edge toward the trailing edge. The retaining member radially overlaps both the tip shroud and the airfoil shaped spar.
In one refinement the tip shroud includes a first pair of channels shaped to receive the retaining member, and the tip end of the spar includes a corresponding second pair of channels shaped to receive the retaining member.
In another refinement a plurality of tiles are coupled to the spar.
In another refinement the tip shroud overlaps the entire tip end of the spar. The tip shroud is configured to retain at least one of the plurality of tiles in place against movement from the root end toward the tip end.
In another refinement the retaining member is an airfoil shaped clip with a pair of prongs. The prongs extend from the leading edge toward the trailing edge.
In another refinement the spar is metal and the tip shroud is selected from the group consisting of a metal and a ceramic.
One form of the present invention contemplates a replaceable blade tip shroud for a blade. Other forms of the present invention contemplate unique apparatuses, systems, devices, hardware, methods, and combinations of these for defining a replaceable blade tip shroud for a gas turbine engine. Further embodiments, forms, objects, features and aspects of the present inventions shall become apparent from the following description and drawings.
The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
With reference to
The gas turbine engines contemplated herein are applicable for use in aircraft, as industrial power plants, and as propulsion systems in vehicles and vessels. Industrial power plant applications include, for example, pumping sets for gas and oil transmission lines and electricity generation systems. The term “aircraft” is generic and includes helicopters, airplanes, missiles, unmanned space devices, transatmospheric vehicles and other substantially similar devices.
Turbine section 40 includes at least one rotor or disk 50 having a plurality of turbine blades coupled thereto. A rotatable shaft 60 is located within a mechanical housing/case 70 of the turbine section 40 and is coupled to the rotor 50. The rotor 50 and the shaft 60 may also be integrated together into a unitary component. One form of the present invention contemplates that the rotatable shaft 60 and the rotor 50 are supported by a plurality of bearings. As the hot exhaust gas passes from the combustor section 30 the plurality of turbine blades rotate as the gas expands and functions to extract work from the hot exhaust flow. While the present disclosure will be generally described with reference to a turbine blade it is contemplated that forms of the present invention will be applicable to other gas turbine engine components including, but not limited to, fan blades and compressor blades.
Referring now to
As described in further detail below, tip shroud 160 is preferably removably attached to the airfoil 120 proximate the tip end 190 of the airfoil 120. The tip shroud 160 includes an inner surface 200 and an outer surface 210. The outer surface 210 of the tip shroud 160 preferably includes at least one seal 220, and in this particular embodiment includes two seals 220. The seals 220 are preferably knife seals, and minimize leakage of working fluid from an outer flow path of air in the turbine section 40. Additionally, the seals 220 preferably include an abradable material layer 222 that is contactable with a housing (not shown in
As partially described previously, each blade 100 is attached to the rotor or disk 50 (not shown in
As shown in
Referring now to
In one form of the present invention, the outer surface 300 of the airfoil 120 is defined by a plurality of cover tiles 310 coupled to at least a portion of the exterior surface 320 of the spar 262, as shown in
The tiles 310 are substantially adjacent and coupled to the spar 262. One form of the present invention contemplates that the plurality of tiles 310 are not permanently affixed to the spar 262. Another form of the present invention contemplates that the plurality of tiles 310 are mechanically coupled to the spar 262 by a plurality of retaining elements (not shown). Still another form of the present invention contemplates that at least one of the plurality of tiles 310 is held in place by the tip shroud 160. As shown in
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.
