Patent Application
20200040753
This invention relates generally to sealing leakage paths in an engine. More particularly, the invention relates to seals, such as spline seals, used in leakage paths of turbine hardware or other hardware where seals are used to seal leaks between components.
Both stationary and rotating turbine engine components such as turbine stators or nozzles, blades, blade shrouds, and combustors are often configured as a ring of side-by-side segments. It is known that leakage at gaps between adjacent segments leads to inefficiencies in aircraft engines. As such, air leakage between adjacent segments must be minimized in order to meet engine performance requirements. This is often accomplished using spline seals which are small metallic strips that are received in seal slots formed in two adjacent segments, bridging the gaps therebetween. Each of the slots formed in the adjacent segments accepts one-half of the spline seal.
In traditional seal assembly, sealing leakage paths requires tedious assembly and provides a lot of opportunity to misplace seals and/or install seals incorrectly due to assembling a plurality of modules where numerous seals must be carefully inserted to seal each of the leakage paths. For example, in a ring of turbine blades or a ring of stationary turbine nozzles or a ring of turbine shrouds, there might be between 30 and 70 joint lines, each one having a seal. Assembling all of the seals is complex and time-consuming.
The problem with the prior art is that the complex nature of installing the seals may result in misplaced and/or incorrectly installed seals, resulting in air leakage between adjacent segments and a loss of efficiency. Even when installed correctly, sealing effectiveness and flow control could be improved.
At least one of the above-noted problems is addressed by the use of seals that are cast-in and/or manufactured by other manufacturing methods that permit the seals to be connected to and/or integrally formed with one of the adjacent segments and permit the seals to remain in position during assembly of the adjacent segments, thereby preventing misplaced and/or incorrect installation of the seals.
According to one aspect of the technology described herein, a turbomachinery sealing apparatus including a first turbomachinery component having a first end face, and a seal extending away from the first end face, the seal being connected to a wall of the component by a tab extending between the wall and the seal.
According to another aspect of the technology described herein, A method of assembling a turbomachinery sealing apparatus includes the steps of: providing a first turbomachinery component, the first turbomachinery component having a seal connected thereto by a tab; providing a second turbomachinery component; and positioning the first and second turbomachinery components adjacent each other such that the seal spans a gap between the two turbomachinery components.
According to another aspect of the technology described herein, a method of assembling a turbomachinery component includes the steps of: providing a plurality of turbomachinery segments, each of the plurality of turbomachinery segments having a first end face and a second end face opposite the first end face, the first end face including a first seal slot and the second end face including a second seal slot, the first seal slot having a seal disposed therein, the seal being connected to a wall of the first seal slot by a tab extending between the wall and the seal; and arranging the plurality of turbomachinery segments with a first end face of one of the turbomachinery segments positioned adjacent to a second end face of an adjacent turbomachinery segment such that a portion of the respective seal extends into the second seal slot.
The invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which:
Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views,
The first nozzle segment 10 includes an inner band 12 that is connected to an outer band 14 by an airfoil 16. The outer band 14 has an inboard surface 18 and an outboard surface 20. An end face 22 of the outer band 14 is positioned between the inboard surface 18 and the outboard surface 20. Likewise, second nozzle segment 100 includes an inner band 112 that is connected to an outer band 114 by an airfoil 116. The outer band 114 has an inboard surface 118 and an outboard surface 120. An end face 122 of the outer band 114 is positioned between the inboard surface 118 and the outboard surface 120.
Referring now to
The seal slot 30 is defined by a bottom wall 32, an inboard wall 34, and an outboard wall 36 and is enclosed by two end walls (not shown). Inboard wall 34 and outboard wall 36 extend from the bottom wall 32 to a rim 38 at the end face 22.
Likewise, seal slot 130 is defined by a bottom wall 132, an inboard wall 134, and an outboard wall 136 and is enclosed by two end walls (not shown). The inboard wall 134 and the outboard wall 136 extend from the bottom wall 132 to a rim 138 at the end face 122.
The seal slots 30, 130 have a basic depth D, defined by its shallowest portion, which represents a desired seating depth of the corresponding spline seal 40. For example, the seating depth D may be on the order of one-half of the total width W of the spline seal 40. When assembled, the spline seal 40 essentially fills the entire volume of the seal slots 30, 130.
As shown in
Note, in general the area labeled “P1” is part of a secondary flowpath i.e., it is on the “cold side” of the hardware. The area labeled “P2” is part of the primary flowpath, i.e., is on the “hot side” of the hardware where the hot combustion gases are flowing. The seal 40 prevents the hot combustion gases from flowing into the secondary flowpath. Generally, the pressure differential is maintained to provide a backflow margin, i.e., to make sure that hot flowpath gases are not ingested into the secondary flowpath even if the seal 40 is not complete. Accordingly, there are instances in which it is desirable to minimize a purge flow, and the ability to meter the flow using the seal would be helpful. As discussed above, such assembly is complex and tedious due to the number of seals and segments being assembled and due to seals being misplaced and/or incorrectly installed.
Referring to
As illustrated, the seal 40 is connected to bottom wall 32, 132 of slot 30, 130 by a tab or sprue 150 between the seal 40 and bottom wall 32, 132. As used herein, the term “connected” when describing two elements refers to a joining or interconnection between those elements, and not merely contact (e.g., friction, pressure) between the two. As used herein the term “tab” refers to a relatively slender mechanical interconnecting element, which need not have any particular cross-sectional shape. Synonyms for the term “tab” include, for example: sprue, ligament, connector, or beam. As shown, the tab or sprue 150 has a thickness “Tt” less than a thickness “Ts” of the seal 40. It should be appreciated, instead of seal 40 being connected to bottom wall 32, 132, seal 40 may be connected by one or more tabs to one or more of the inboard wall 34, the outboard wall 36, the inboard wall 134, or the outboard wall 136 so long as the seal 40 is connected to at least one of the walls of the slots 30, 130 to allow assembly of adjacent turbine nozzle segments 10, 100.
The tab or sprue 150 may operate in different ways. For example, the tab or sprue 150 may be very thin and/or otherwise breakable. Its purpose would be to fixture the seal 40 in place to make assembly easier. So, for example two turbine nozzle segments 10, 100 could be assembled together with one of the turbine nozzle segments 10, 100 having the integrated seal 40. Then once they were assembled, a tool could be used to break off or knock apart the seal to free it (could be done by pin strike or cutting/grinding tool),
In another example,
Numerous physical configurations of the seal structure described above are possible. For example,
The second component 204 has end faces 224 on opposite sides thereof, each having a seal 240 connected thereto by a tab 250. The tab 250 may have a thickness less than a thickness of the seal 240. In this example, the seals 240 extend away from the end faces 224 at an oblique angle, defining a rough V-shape in a front or rear elevation view.
The components 202, 204, and 206 may be assembled by moving them in the direction of the arrows, namely in a combination of axial and lateral movements.
The embodiment of
The current technology provides the benefits of eliminating assembly steps, simplifying the overall assembly process, and allowing for tightly controlled manufacturing tolerances to introduce better sealing effectiveness and drive flow away from potential leakage paths; thus, improving performance.
The foregoing has described a turbomachinery apparatus and method. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
