Disclosed embodiments relate generally to the field of turbomachinery, such as may involve fluidized catalytic cracking (FCC) expanders or gas turbine engines, and, more particularly, to a blade platform seal and damper assembly, and, methodology for forming said assembly.
An FCC process may be used to convert high-molecular weight hydrocarbon fractions of petroleum crude oils to usable products (e.g., gasoline) with the aid of a catalyst in a reactor. High-temperature flue gas may be produced in connection with the FCC process, and the high-temperature flue gas may be passed through an FCC expander to extract and convert energy from the flue gas into mechanical work that may be used to drive process machinery. Although the flue gas may be processed through one or more stages of separation, an undesirable amount of catalyst particulates can remain entrained in the flue gas that is passed through the FCC expander.
The relatively high temperatures involved, the corrosive nature, and the erosive tendency of the hot, catalyst particulate laden flue gas may cause rapid deterioration by erosion and/or by corrosion of rotating and stationary components of the FCC expander, including but not limited to, the inlet, the rotor assembly including the rotor disc and blades, and the stator assembly. In particular, the rim of the rotor disc and the respective roots of the rotor blades attached to the rotor disc are susceptible to catalyst build up during operation. This region of the FCC expander may also subject to turbulent and varying flows, which can exacerbate the foregoing issues.
For one example of structures used in connection with an FCC expander, reference is made to International Patent Application PCT/US2017/016348, titled “Systems and Methods for Cooling a Rotor Assembly Disposed Within a Cavity of an Expander Fluidly Coupled with a Cooling Source”.
As noted above, certain prior art turbomachinery, such as expanders/turbines, that may be involved in connection with FCC processes may be exposed to relatively high-temperature flue gas that can include corrosive particulates. These corrosive particulates have the potential to shorten the life of components that are exposed to the high-temperature flue gas. The present inventor has recognized that certain exposed areas may encompass highly thermo-mechanically stressed regions, such as where rotor blades may be attached to the rotor disc. Accordingly, in view of such recognition, disclosed assemblies—in a cost-effective and reliable manner—provide a sealing functionality, which avoids or substantially reduces exposure of such regions to the high-temperature flue gas.
Additionally, unsteady aerodynamic excitations can develop during the operation of the turbomachinery, and these excitations can subject the rotor blades to dynamically changing loads. These dynamically changing loads can result in elastic displacements near blade attachment areas and in the blade platform and, in turn, these displacements can result in dynamically changing stresses that can lead to premature failure of the involved structures. The present inventor has further recognized that certain prior art damping designs tend to rely on frictional surface interactions in the firtree attachment area to dampen effects of such excitations. Consequently, the damping provided by such prior art designs may be limited to the firtree attachment area and practically not available radially beyond the upper firtree interface.
Accordingly, in view of such further recognition disclosed assemblies further provide a damping functionality, which substantially attenuates such excitations and thus substantially reduce the potential of structural fatigue of the involved structures. Disclosed assemblies additionally offer a novel technical solution involving a camming action, such as by way of interaction of camming surfaces in a disclosed seal and damper member with corresponding surfaces in a groove of disclosed blade platform to achieve superior sealing functionality that, for example, extends the dampened region beyond the upper firtree interface and thus is conducive to a more effective dampening of the blade platform. Without limitation, this feature is believed to provide a significant technical advantage over prior art design in terms of providing blade damping before the dynamically changing loads can reach the highly stressed firtree attachment area.
The present inventor has additionally recognized that the sealing and damping functionality provided by disclosed assemblies should be continually and reliably provided during operation of the turbomachinery, notwithstanding of dynamically changing operational conditions that may occur, such as dynamically changing loads and/or exposure to thermal gradients. Accordingly, disclosed assemblies are designed to consistently remain engaged between any two adjacent blade platforms, notwithstanding of dynamically changing operational conditions that may occur during operation of the turbomachinery to effectively provide appropriate damping and sealing to the involved structures.
The present inventor has yet further recognized that traditional manufacturing techniques may not be necessarily conducive to a cost-effective and/or realizable manufacture of certain components that may be involved to efficiently implement the foregoing sealing and damping structures. For example, traditional manufacturing techniques tend to fall short from consistently limiting manufacturing variability; and may also fall short from cost-effectively and reliably producing relatively complex geometries such as may be involved in certain disclosed components.
In view of this further recognition, in one non-limiting embodiment, the present inventor further proposes use of three-dimensional (3D) Printing/Additive Manufacturing (AM) technologies, such as laser sintering, selective laser melting (SLM), direct metal laser sintering (DMLS), electron beam sintering (EBS), electron beam melting (EBM), etc., that may be conducive to cost-effective fabrication of a seal and damper member, which is a component of a disclosed platform seal and damper assembly. For readers desirous of general background information in connection with 3D Printing/Additive Manufacturing (AM) technologies, see, for example, a textbook titled “Additive Manufacturing Technologies, 3D Printing, Rapid Prototyping, and Direct Digital Manufacturing”, by Gibson I., Stucker B., and Rosen D., 2010, published by Springer, which is incorporated herein by reference.
In the following detailed description, various specific details are set forth in order to provide a thorough understanding of such embodiments. However, those skilled in the art will understand that disclosed embodiments may be practiced without these specific details that the aspects of the present invention are not limited to the disclosed embodiments, and that aspects of the present invention may be practiced in a variety of alternative embodiments. In other instances, methods, procedures, and components, which would be well-understood by one skilled in the art have not been described in detail to avoid unnecessary and burdensome explanation
Furthermore, various operations may be described as multiple discrete steps performed in a manner that is helpful for understanding embodiments of the present invention. However, the order of description should not be construed as to imply that these operations need be performed in the order they are presented, nor that they are even order dependent, unless otherwise indicated. Moreover, repeated usage of the phrase “in one embodiment” does not necessarily refer to the same embodiment, although it may. It is noted that disclosed embodiments need not be construed as mutually exclusive embodiments, since aspects of such disclosed embodiments may be appropriately combined by one skilled in the art depending on the needs of a given application.
As illustrated in
As shown in
As illustrated in
Rotor assembly 118 may include a rotor disc 128 disposed in cavity 104 and axially spaced from stator assembly 116. Rotor disc 128 may be coupled to or integral with a rotary shaft 130 of expander 100 and thus may be configured to rotate with rotary shaft 130 about center axis 124. That is, center axis 124 may be referred to as a rotation axis.
Rotor assembly 118 may further include a plurality of rotor blades 140 attached to rotor disc 128 and configured to rotate about center axis 124 in response to flow of flue gas (arrow F) that may be directed by stator vanes 120. Each rotor blade 140 may include a blade platform 146 interposed between a root 142 and an airfoil 144. Each root 142 may be configured to be inserted into and retained in a respective slot that may be defined by rotor disc 128 via any retaining structure or technique known to those of skill in the art.
In one non-limiting embodiment, each root 142 may be shaped in the form of a fir tree and retained in a respective matching slot. As disposed in expander 100, a respective airfoil 144 of each rotor blade 140 may radially extend into flow path 106 and may be impacted by the flow of flue gas (arrow F) directed by stator vanes 120, thereby causing rotation of rotor blades 140 and rotary disc 128 about center axis 124.
The disclosure will proceed to describe below structural and/or operational relationships of components and/or features of a disclosed seal and damping assembly interposed between any two adjacent blade platforms 146.
As can be appreciated in
In one non-limiting embodiment, as may be appreciated in
In one non-limiting embodiment, trailing edge 166 of blade platform 146 includes a radially-extending protrusion 182 arranged to axially retain a second end 184 of seal and damper member 152. Second end 184 is opposite to the first end 180 of seal and damper member 152.
Continuing with the non-limiting example shown in
In one non-limiting embodiment, a cross-section 186 of the body that forms seal and damper member 152 may comprise, without limitation, a parallelogram-shaped cross-section. The body seal and damper member 152 includes a pair of adjoining surfaces 190, 188 (e.g., camming surfaces) configured to respectively engage in response to a camming action the pair of surfaces 168, 170 (
Non-limiting examples of additive manufacturing techniques to form the seal and damper member may include laser sintering, selective laser melting (SLM), direct metal laser sintering (DMLS), electron beam sintering (EBS), electron beam melting (EBM), etc. Non-limiting examples of machining techniques that may be used to configure the axially-extending groove may include electrical discharge machining, electrochemical machining, etc. It will be appreciated that once a model has been generated, or otherwise available (e.g., loaded into a 3D digital printer, or loaded into a processor that controls the additive manufacturing technique and/or the machining technique), then forming steps 204, 205 need not be preceded by a generating step 202.
In operation, disclosed embodiments—in a cost-effective and reliable manner—provide a sealing functionality, which avoids or substantially reduces exposure of highly thermo-mechanically stressed regions, such as regions where rotor blades may be attached to the rotor disc, to the high-temperature flue gas. Additionally, in operation, disclosed assemblies are able to consistently remain engaged between any two adjacent blade platforms, notwithstanding of dynamically changing operational conditions that may occur during operation of the turbomachinery to effectively provide appropriate damping and sealing to the involved structures.
While embodiments of the present disclosure have been disclosed in exemplary forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions can be made therein without departing from the scope of the invention and its equivalents, as set forth in the following claims.
This application claims benefit of the Jan. 2, 2019 filing date of U.S. provisional application 62/787,533, which is incorporated by reference herein.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/045436 | 8/7/2019 | WO | 00 |
Number | Date | Country | |
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62787533 | Jan 2019 | US |