Description:FIELD
[0001] The present disclosure relates generally to a viscous damper
configured to adjust the amplitude of oscillations of a component. Specifically,
the present disclosure relates generally to a viscous damper for a turbomachine
component that utilizes glass as the viscous fluid.
BACKGROUND
[0002] Turbomachines are utilized in a variety of industries and applications
for energy transfer purposes. For example, a gas turbine engine generally
includes a compressor section, a combustion section, a turbine section, and an
exhaust section. The compressor section progressively increases the pressure of a
working fluid entering the gas turbine engine and supplies this compressed
working fluid to the combustion section. The compressed working fluid and a
fuel (e.g., natural gas) mix within the combustion section and burn in a
combustion chamber to generate high pressure and high temperature combustion
gases. The combustion gases flow from the combustion section into the turbine
section where they expand to produce work. For example, expansion of the
combustion gases in the turbine section may rotate a rotor shaft connected, e.g., to
a generator to produce electricity. The combustion gases then exit the gas turbine
via the exhaust section.
[0003] Typically, turbomachine rotor blades are exposed to unsteady
aerodynamic loading which causes the rotor blades to vibrate. If these vibrations
are not adequately damped, they may cause high cycle fatigue and premature
failure in the blades. Of all the turbine stages, the last-stage blade (LSB) is the
tallest and therefore is the most vibrationally challenged component of the turbine.
Conventional vibration damping methods for turbine blades include platform
dampers, damping wires, shrouds, and the like.
[0004] Platform dampers sit underneath the surface of the blade platform and
are effective for medium and long shank blades, which experience motion at the
blade platform. Aft-stage blades have short shanks to reduce the weight of the
3
blade and in turn reduce the pull load on the rotor, which renders platform
dampers ineffective.
[0005] Generally, turbomachine rotor blades get their damping primarily from
the shrouds. Shrouds can be located at the blade tip (tip shroud) or at a partial
span between the hub and tip (part-span shroud). These shrouds contact against
adjacent blades and provide damping when they rub against each other.
[0006] While shrouds provide damping and stiffness to the airfoil, they make
the blade heavier, which in turn increases the pull load on the rotor and increases
the weight and cost of the rotor. Thus, light-weight solutions for aft-stage blades
are attractive to drive overall power output of the turbomachine. Generally,
shrouds can create aerodynamic performance losses. For example, tip shrouds
need a large tip fillet to reduce stress concentrations which creates tip losses, and
part-span shrouds create an additional blockage in the flow path and reduce
aerodynamic efficiency. Lastly, it has been shown that tip shrouds induce
significant twist in the vibration mode shapes of the blade causing high aeroelastic
flutter instability.
[0007] Viscous dampers may be employed for reducing the vibrations in a
turbomachine component. However, known viscous dampers often include fluids
that are reactive with metals, such that the viscous dampers have limited hardware
life due to erosion of the metal casings. Accordingly, a viscous damper that
reduces blockages in the flow path (e.g., by eliminating one or more shrouds),
without reacting with the viscous damper casing, is desired and would be
appreciated in the art.
BRIEF DESCRIPTION
[0008] Aspects and advantages of the rotor blades, vibrational dampening
elements, and methods in accordance with the present disclosure will be set forth
in part in the following description, or may be obvious from the description, or
may be learned through practice of the technology.
[0009] In accordance with one embodiment, a rotor blade is provided. The
rotor blade includes a platform, a shank extending radially inward from the
4
platform, and an airfoil extending radially outward from the platform. One or
more fluid chambers are defined within the rotor blade. Glass is disposed within
each fluid chamber of the one or more fluid chambers. A mass is disposed within
each fluid chamber of the one or more fluid chambers. The mass is movable
within the glass relative to the airfoil.
[0010] In accordance with another embodiment, a vibrational dampening
element is provided. The vibrational dampening element is attached to a turbine
component and configured to adjust an amplitude of oscillations of the turbine
component. The vibrational dampening element includes a mass and a casing
encapsulating the mass. The casing of the vibrational dampening element defines
a fluidic chamber around the mass, and the fluidic chamber is filled with glass.
[0011] In accordance with yet another embodiment, a method of adjusting an
amplitude of oscillations of a turbine component disposed in a turbine section of a
turbomachine is provided. The method includes providing the turbine component
having a fluid chamber and a mass disposed within the fluid chamber. The method
further includes disposing glass within the fluid chamber. Operation of the turbine
results in a decrease of a viscosity of the glass to produce a molten-state glass,
such that the mass is translated through the molten-state glass to adjust an
amplitude of oscillations of the turbomachine component.
[0012] These and other features, aspects, and advantages of the present rotor
blades, vibrational dampening elements, and methods will become better
understood with reference to the following description and appended claims. The
accompanying drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the technology and, together with the
description, serve to explain the principles of the technology.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] A full and enabling disclosure of the present rotor blades, vibrational
dampening elements, and methods, including the best mode of making and using
the present systems and methods, directed to one of ordinary skill in the art, is set
5
forth in the specification, which makes reference to the appended figures, in
which:
[0014] FIG. 1 illustrates a schematic illustration of a turbomachine in
accordance with embodiments of the present disclosure;
[0015] FIG. 2 illustrates an exemplary turbine section of a gas turbine
including a plurality of turbine stages arranged in serial flow order, in accordance
with embodiments of the present disclosure;
[0016] FIG. 3 illustrates a perspective view of a rotor blade, in accordance
with embodiments of the present disclosure;
[0017] FIG. 4 illustrates a cross-sectional view of the rotor blade from along
the line 4-4 shown in FIG. 3, in accordance with embodiments of the present
disclosure;
[0018] FIG. 5 illustrates a cross-sectional view of the rotor blade from along
the line 5-5 shown in FIG. 3, in accordance with embodiments of the present
disclosure;
[0019] FIG. 6 illustrates a cross-sectional side view of a rotor blade, in
accordance with embodiments of the present disclosure;
[0020] FIG. 7 illustrates a cross-sectional side view of a rotor blade, in
accordance with embodiments of the present disclosure;
[0021] FIG. 8 illustrates an airfoil with viscous dampers, in accordance with
embodiments of the present disclosure;
[0022] FIG. 9 illustrates a cross-sectional view of the airfoil shown in FIG. 8
from along the line 9-9, in accordance with embodiments of the present
disclosure;
[0023] FIG. 10 illustrates a graph of a force displacement loop, in accordance
with embodiments of the present disclosure;
[0024] FIG. 11 illustrates a graph of the viscosity of a chalcogenide glass
plotted against temperature, in accordance with embodiments of the present
disclosure;
[0025] FIG. 12 illustrates a graph of the viscosity of a sealing glass plotted
against temperature, in accordance with embodiments of the present disclosure;
6
[0026] FIG. 13 illustrates a perspective view of a vibrational dampening
element, in accordance with embodiments of the present disclosure;
[0027] FIG. 14 illustrates a cross-sectional view of the vibrational dampening
element shown in FIG. 13 from along a radial direction, in accordance with
embodiments of the present disclosure;
[0028] FIG. 15 illustrates a cross-sectional view of the vibrational dampening
element shown in FIG. 13 from along an axial centerline of the vibrational
dampening element, in accordance with embodiments of the present disclosure;
[0029] FIG. 16 illustrates a cross-sectional view of a vibrational dampening
element from along a radial direction, in accordance with embodiments of the
present disclosure;
[0030] FIG. 17 illustrates a perspective view of a vibrational dampening
element, in accordance with embodiments of the present disclosure;
[0031] FIG. 18 illustrates a cross-sectional view of the vibrational dampening
element shown in FIG. 17, in accordance with embodiments of the present
disclosure;
[0032] FIG. 19 illustrates a cross-sectional view of the vibrational dampening
element shown in FIG. 17, in accordance with embodiments of the present
disclosure;
[0033] FIG. 20 illustrates two neighboring turbomachine rotor blades,
including a first rotor blade in which the vibrational dampening element shown in
FIG. 17 has been mounted in a first orientation and a second adjacent rotor blade
in which the vibrational dampening element shown in FIG. 17 has been mounted
in a second orientation, in accordance with embodiments of the present disclosure;
and
[0034] FIG. 21 is a flow chart of a method of operating a turbomachine to
adjust an amplitude of oscillations of a turbine component disposed in a turbine
section of a turbomachine, in accordance with embodiments of the present
disclosure.
7
DETAILED DESCRIPTION
[0035] Reference now will be made in detail to embodiments of the present
rotor blades, vibrational dampening elements, and methods, one or more examples
of which are illustrated in the drawings. Each example is provided by way of
explanation, rather than limitation of, the technology. In fact, it will be apparent
to those skilled in the art that modifications and variations can be made in the
present technology without departing from the scope or spirit of the claimed
technology. For instance, features illustrated or described as part of one
embodiment can be used with another embodiment to yield a still further
embodiment. Thus, it is intended that the present disclosure covers such
modifications and variations as come within the scope of the appended claims and
their equivalents.
[0036] The detailed description uses numerical and letter designations to refer
to features in the drawings. Like or similar designations in the drawings and
description have been used to refer to like or similar parts of the invention. As
used herein, the terms “first”, “second”, and “third” may be used interchangeably
to distinguish one component from another and are not intended to signify
location or importance of the individual components.
[0037] As used herein, the terms “upstream” (or “forward”) and
“downstream” (or “aft”) refer to the relative direction with respect to fluid flow in
a fluid pathway. For example, “upstream” refers to the direction from which the
fluid flows, and “downstream” refers to the direction to which the fluid flows.
The term “radially” refers to the relative direction that is substantially
perpendicular to an axial centerline of a particular component, the term “axially”
refers to the relative direction that is substantially parallel and/or coaxially aligned
to an axial centerline of a particular component, and the term “circumferentially”
refers to the relative direction that extends around the axial centerline of a
particular component. Terms of approximation, such as “generally,” or “about,”
include values within ten percent greater or less than the stated value. When used
in the context of an angle or direction, such terms include within ten degrees
greater or less than the stated angle or direction. For example, “generally
8
vertical” includes directions within ten degrees of vertical in any direction, e.g.,
clockwise or counter-clockwise.
[0038] Referring now to the drawings, FIG. 1 provides a schematic diagram
of one embodiment of a turbomachine, which in the illustrated embodiment is a
gas turbine 10. Although an industrial or land-based gas turbine is shown and
described herein, the present disclosure is not limited to a land-based and/or
industrial gas turbine, unless otherwise specified in the claims. For example, the
rotor blades as described herein may be used in any type of turbomachine,
including but not limited to a steam turbine, an aircraft gas turbine, or a marine
gas turbine.
[0039] As shown, the gas turbine 10 generally includes an inlet section 12, a
compressor section 14 disposed downstream of the inlet section 12, one or more
combustors (not shown) within a combustor section 16 disposed downstream of
the compressor section 14, a turbine section 18 disposed downstream of the
combustor section 16, and an exhaust section 20 disposed downstream of the
turbine section 18. Additionally, the gas turbine 10 may include one or more
shafts 22 coupled between the compressor section 14 and the turbine section 18.
[0040] The compressor section 14 may generally include a plurality of rotor
disks 24 (one of which is shown) and a plurality of rotor blades 26 extending
radially outwardly from and connected to each rotor disk 24. Each rotor disk 24
in turn may be coupled to or form a portion of the shaft 22 that extends through
the compressor section 14. The rotor blades 26 are arranged in stages with
corresponding arrays of stationary vanes (not shown) that are coupled to the
compressor casing.
[0041] The turbine section 18 may generally include a plurality of rotor disks
28 (one of which is shown) and a plurality of rotor blades 30 extending radially
outwardly from and being interconnected to each rotor disk 28. Each rotor disk
28 in turn may be coupled to or form a portion of the shaft 22 that extends through
the turbine section 18. The turbine section 18 further includes an outer casing 31
that circumferentially surrounds a portion of the shaft 22 and the rotor blades 30,
thereby at least partially defining a hot gas path 32 through the turbine section 18.
9
The rotor blades 30 are arranged in stages with corresponding arrays of stationary
vanes (100, as shown in FIG. 2) that are coupled to the turbine casing.
[0042] During operation, a working fluid such as air flows through the inlet
section 12 and into the compressor section 14 where the air is progressively
compressed through multiple stages of rotating blades 26 and stationary vanes,
thus providing pressurized air to the combustors of the combustor section 16. The
pressurized air is mixed with fuel and burned within one or more combustors to
produce combustion gases 34. The combustion gases 34 flow through the hot gas
path 32 from the combustor section 16 into the turbine section 18, where energy
(kinetic and/or thermal) is transferred from the combustion gases 34 through
multiple stages of the rotor blades 30 and stationary vanes, causing the shaft 22 to
rotate. The mechanical rotational energy may then be used to power the
compressor section 14 and/or to generate electricity. The combustion gases 34
exiting the turbine section 18 may then be exhausted from the gas turbine 10 via
the exhaust section 20.
[0043] FIG. 2 illustrates an exemplary turbine section 18 of the gas turbine 10
including a plurality of turbine stages arranged in serial flow order. Each stage of
the turbine includes a row of stationary turbine nozzles or vanes (e.g., nozzles
100) disposed axially adjacent to a corresponding rotating row of turbine rotor
blades (e.g., blades 50). Four turbine stages are illustrated in FIG. 2. The exact
number of stages of the turbine section 18 may be more or less than the four
stages illustrated in FIG. 2. The four stages are merely exemplary of one turbine
design and are not intended to limit the presently claimed turbine rotor blade in
any manner.
[0044] Each stage comprises a plurality of turbine nozzles or vanes 100 and a
plurality of turbine rotor blades 50. The turbine nozzles 100 are mounted to the
outer casing 31 and are annularly arranged about an axis of a turbine shaft 22.
The turbine rotor blades 50 are annularly arranged about the turbine shaft 22 and
coupled to the turbine rotor 36.
[0045] It will be appreciated that the turbine nozzles 100 and turbine rotor
blades 50 are disposed or at least partially disposed within the hot gas path 32 of
10
the turbine section 18. The various stages of the turbine 10 at least partially define
the hot gas path 32 through which combustion gases 34, as indicated by arrows,
flow during operation of the gas turbine 10.
[0046] FIG. 3 provides a perspective view of a rotor blade 50 as may be
incorporated in any stage of the turbine section 18 or the compressor section 14.
In exemplary embodiments, the rotor blade 50 may be configured for use within
the turbine section 18. As shown in FIG. 3, the turbine rotor blade 50 includes a
platform 66, a shank 51, and an airfoil 52. As shown, the shank 51 may extend
radially inward from the platform 66 with respect to the axial centerline of the gas
turbine 10. In many embodiments, the airfoil 52 may extend from the platform 66
opposite the shank 51. For example, the airfoil 52 may extend radially outward
from the platform with respect to the axial centerline of the gas turbine 10. In
various embodiments, the airfoil 52 includes a pressure side wall 54 and an
opposing suction side wall 56. The pressure side wall 54 and the suction side wall
56 meet or intersect at a leading edge 58 and a trailing edge 60 of the airfoil 52.
The leading edge 58 and the trailing edge 60 may be spaced apart from one
another and define the terminal ends of the airfoil 52 in the axial direction A. A
straight chord line (not shown) extends between the leading edge 58 and the
trailing edge 60 such that pressure and suction side walls 54, 56 extend in chord or
chordwise between the leading edge 58 and the trailing edge 60.
[0047] The pressure side wall 54 generally comprises an aerodynamic,
concave external surface of the airfoil 52. Similarly, the suction side wall 56 may
generally define an aerodynamic, convex external surface of the airfoil 52. The
leading edge 58 of airfoil 52 may be the first portion of the airfoil 52 to engage,
i.e., be exposed to, the combustion gases 34 along the hot gas path 32. The
combustion gases 34 may be guided along the aerodynamic contour of airfoil 52,
i.e., along the suction side wall 56 and pressure side wall 54, before being
exhausted at the trailing edge 60.
[0048] As shown in FIG. 3, the airfoil 52 includes a root or first end 64, which
intersects with and extends radially outwardly from the platform 66 of the turbine
rotor blade 50. The root 64 of the airfoil 52 may be defined at an intersection
11
between the airfoil 52 and the platform 66. The airfoil 52 terminates radially at a
second end or tip 68 of the airfoil 52. The tip 68 is disposed radially opposite the
root 64. As such, the tip 68 may generally define the radially outermost portion of
the rotor blade 50 and, thus, may be configured to be positioned adjacent to a
stationary shroud or seal (not shown) of the turbine section 18.
[0049] The pressure and suction side walls 54, 56 extend in span and define a
span length 70 of the airfoil 52 between the root 64 and/or the platform 66 and the
tip 68 of the airfoil 52. In other words, each rotor blade 50 includes an airfoil 52
having opposing pressure and suction side walls 54, 56 that extend in chord or
chordwise between opposing leading and trailing edges 58, 60 and that extend in
span or span-wise 70 between the root 64 and the tip 68 of the airfoil 52.
[0050] In particular configurations, the airfoil 52 may include a fillet 72
formed between the platform 66 and the airfoil 52 proximate to the root 64. The
fillet 72 can include a weld or braze fillet, which can be formed via conventional
MIG welding, TIG welding, brazing, etc., and can include a profile that can
reduce fluid dynamic losses as a result of the presence of fillet 72. In particular
embodiments, the platform 66, the airfoil 52, and the fillet 72 can be formed as a
single component, such as by casting and/or machining and/or 3D printing and/or
any other suitable technique now known or later developed and/or discovered. In
particular configurations, the rotor blade 50 includes a mounting portion 74 (such
as a dovetail joint), which is formed to connect and/or to secure the rotor blade 50
to the rotor disk 28 and/or the shaft 22.
[0051] The span length 70 may be measured from the root 64 to the tip 68 of
the airfoil 52. A percentage of the span length 70 may be used to indicate a
position along the span length 70. For example, “0% span” may refer to the root
64 of the airfoil 52. Similarly, “100% span” may refer the tip 68 of the airfoil.
[0052] FIG. 4 illustrates a cross-sectional view of the rotor blade 50 from
along the line 4-4 shown in FIG. 3, and FIG. 5 illustrates a cross-sectional view of
the rotor blade 50 from along the line 5-5 shown in FIG. 3, in accordance with
embodiments of the present disclosure. As shown, a fluid chamber 200 may be
defined within the airfoil 52, such that the airfoil 52 is a substantially hollow
12
body. For example, as shown in FIG. 4, the fluid chamber 200 may be defined
collectively by the leading edge 58, the trailing edge 60, the pressure side wall 54,
and the suction side wall 56. In some embodiments, the fluid chamber 200 may
extend radially between the root 64 and the tip 68 of the airfoil 52. In alternate
embodiments (not shown), the fluid chamber 200 may extend radially over a
portion of the span length 70 between the root 64 and the tip 68 of the airfoil 52.
[0053] In exemplary embodiments, glass 201 may fill the fluid chamber 200,
such that a mass 202 is surrounded by glass 201 within the fluid chamber 200 (as
shown by the white space surrounding the mass 202 in FIG. 4). For example, in
exemplary embodiments, glass 201 may entirely fill the fluid chamber 200 (e.g.,
100% of the space between the mass and the surrounding walls). However, in
other embodiments, the glass 201 may only partially fill the fluid chamber 200,
and the remainder may be filled with another fluid (such as air). The glass 201
may be in a solid state when the rotor blade 50 is non-operational, such that the
mass 202 may be rigidly held or non-movable within the glass 201 when the rotor
blade 50 is not at operating temperatures. Once the rotor blade 50 reaches
operating temperatures, the viscosity of the glass 201 may decrease, and the glass
201 may soften or liquefy, such that the mass 202 may be movable within the
glass 201 relative to the airfoil 52.
[0054] The mass 202 may be disposed within the fluid chamber 200. In many
embodiments, where the mass 202 may be formed of metal or other suitable
material, the use of glass 201 as the viscous damping fluid may be advantageous
as the glass 201 will not react or erode the mass 202. The mass 202 may be
movable within the glass 201 relative to the airfoil 52 at the operating
temperatures of the turbine. For example, the mass 202 may be spaced apart from
the interior surfaces of the airfoil 52, e.g., spaced apart from the leading edge 58,
the trailing edge 60, the pressure side wall 54, and/or the suction side wall 56. In
some embodiments, the mass 202 may be completely detached from the rotor
blade 50, such that the mass 202 is entirely movable within the fluid chamber 200
during operation.
13
[0055] In other embodiments, the mass 202 may be attached to the rotor blade
50 on one end, such that the mass 202 may be cantilevered within the fluid
chamber 200. For example, as shown in FIG. 5, the mass 202 may extend between
a first end 204 coupled to the rotor blade 50 (or platform 66) and a second end
206 disposed within the fluid chamber 200. In many embodiments, the first end
204 of the mass 202 may be attached to the root 64 of the airfoil 52 (such as an
interior surface of the pressure or suction side walls 54, 56), attached to the
platform 66, or attached to one of the pair of guides 218, 220. In yet still further
embodiments, the mass 202 may be suspended within the fluid chamber 200 (and
the glass 201) by one or more support members (such as a compliant support or
bellows, as shown in FIG. 14).
[0056] In various embodiments, the mass 202 may have a variety of heights
(e.g., the radial distance between the first end 204 and the second end 206). In
some embodiments, as shown, the second end 206 may be closer to the tip 68 than
the root 64 of the airfoil 52. In other embodiments (not shown), the second end
206 may be closer to the root 64 than the tip 68 of the airfoil 52.
[0057] As should be appreciated, the airfoil 52 may define a camber line 210
(FIG. 4) that extends between the leading edge 58 and the trailing edge 60. For
example, the camber line 210 may join the leading and trailing edges 58, 60 of the
airfoil 52 equidistant from the pressure side wall 54 and the suction side wall 56.
Additionally, the airfoil 52 may define a chord line 212, which may is defined as a
straight line between the leading edge 58 and the trailing edge 60.
[0058] In many embodiments, the mass 202 may include a first portion 214
and a second portion 216. In many embodiments, the first portion 214 may be
longer than the second portion 216. The first portion 214 may be oriented
generally parallel to the pressure side wall 54 and/or the suction side wall 56.
Additionally, or alternatively, the first portion 214 may extend generally along the
camber line 210 when in a resting position (e.g., when the rotor blade 50 is not in
operation). The second portion 216 may extend generally perpendicularly to one
or more of the first portion 214, the pressure side wall 54, the suction side wall 56,
and/or the chord line 212. In many embodiments, the first portion 214 and the
14
second portion 216 may extend generally perpendicularly to one another at their
respective midpoints. For example, the first portion 214 may extend generally
perpendicularly from the second portion 216 at the midpoint of the second portion
216. Likewise, the second portion 216 may extend generally perpendicularly from
the first portion 214 at the midpoint of the first portion 214. In this way, the mass
202 may advantageously have a center of mass at the intersection of the first
portion 214 and the second portion 216 that equalizes the force distribution when
actively damping vibrations of the rotor blade 50.
[0059] In exemplary embodiments, a first pair of guides 218 may extend
inwardly from the pressure side wall 54, and a second pair of guides 220 extend
inwardly from the suction side wall 56. As illustrated, the first pair of guides 218
may be directly opposite the second pair of guides 220. As shown, a first channel
219 may be defined between the first pair of guides 218, and a second channel
221 may be defined between the second pair of guides 220. The second portion
216 of the mass 200 may extend into the first channel 219 and the second channel
221, such that the guides 218, 220 may partially restrict movement of the mass
202 along a camber-wise direction.
[0060] As shown in FIG. 5, the fluid chamber 200 may extend radially
between the root 64 and the tip 68 of the airfoil 52. In some embodiments (not
shown), the fluid chamber 200 may extend within the platform 66 and/or the
shank 51, such that the fluid chamber 200 may be collectively defined by the
airfoil 52, the platform 66, and/or the shank 51. In many embodiments, the mass
202 may be entirely detached from the rotor blade 50 and entirely surrounded by
glass 201 within the fluid chamber 200. In such embodiments, the mass 202 may
be unrestricted to movement within the glass 201 during operation (e.g., at
operating temperatures of the gas turbine). In other embodiments, as shown in
FIG. 5, the mass 202 may be attached to the rotor blade 50 on one or more ends.
For example, the mass 202 may be cantilevered from the rotor blade 50 within the
fluid chamber 200.
[0061] FIG. 6 and FIG. 7 illustrate different cross-sectional side views of an
exemplary rotor blade 50, each in accordance with embodiments of the present
15
disclosure. As shown, the airfoil 52 may define a radial channel 222 that extends
within the airfoil 52 between the root 64 and the tip 68. For example, the radial
channel 222 may be collectively defined (or bound) by the suction side wall 56,
the pressure side wall 54, and one or more ribs 224 extending between the
pressure side wall 54 and the suction side wall 56. In exemplary embodiments,
separating walls 226 may partition or separate the radial channel 222 into one or
more fluid chambers 228. A mass 230 may be disposed within each fluid chamber
228 of the one or more fluid chambers 228. The mass may include a main body
232 and one or more protrusions 234 extending from the main body 232.
Additionally, glass 201 may fill each of the fluid chambers 228, such that each
mass 230 is generally surrounded by glass 201. Each mass 230 may be fully
movable within the glass 201 and in the respective fluid chamber 228 when the
rotor blade 50 is at operating temperature. In some embodiments, the mass 230
may be entirely detached from the rotor blade 50. In other embodiments, the mass
230 may be attached to the rotor blade 50 on one end (e.g., via one or more of the
protrusions 234), such that the mass 230 is cantilevered within the respective fluid
chamber 228.
[0062] FIG. 8 illustrates an airfoil 52, in which the dashed lines represent
internal passages, and FIG. 9 illustrates a cross section of the airfoil 52 from along
the line 9-9 shown in FIG. 8, in accordance with embodiments of the present
disclosure. As shown, one or more cooling passages 154 may be defined in the
airfoil 52. Each cooling passage 154 may extend radially through the airfoil 36 (as
shown). In some embodiments (not shown), each of the cooling passages 154 may
extend radially through the platform 66 and/or the shank 51. Additionally, one or
more cooling passages 154 may be connected to form a cooling circuit. FIG. 8
illustrates a first cooling circuit 156 and a second cooling circuit 158, each of
which includes a plurality of connected cooling passages 154. A cooling medium
(such as air or steam) may be flowed through the cooling passages 154 to cool
rotor blade 50 during operation.
[0063] One or more damping passages 160 may be defined in and extend
radially through the airfoil 52. In some embodiments, a damping passage 160 may
16
be one of the cooling passages 154. In other embodiments, the damping passage
60 may be separate and independent from the cooling passages 154, such that
cooling medium is not flowed through the damping passage 160. Damping
passage 160 may extend and be defined radially through the entire rotor blade 50
or only a portion thereof. For example, as discussed, at least a portion of (which
may be the entire) damping passage 160 may extend and be defined through the
airfoil 52.
[0064] As shown in FIGS. 8 and 9, one or more viscous damper stacks 170
may be provided in the airfoil 52 in accordance with the present disclosure. Each
viscous damper stack 170 may be disposed within a damping passage 160. Each
damper stack 170 may include a plurality of vibrational dampening elements 172
in contact with one another (e.g., stacked together). As should be understood and
appreciated, each vibrational dampening element 172 may be any one of the
vibrational dampening elements discussed herein, such as the vibrational
dampening element 300 shown and described with reference to FIGS. 13-16, or
the vibrational dampening element 400 shown and described with reference to
FIGS. 17-20. Each vibrational dampening element 172 may be in contact with a
neighboring vibrational dampening element 172 in the viscous damper stack 170
and may further be in contact with walls defining the damping passage 160 (e.g., a
channel defined between the pressure side wall 54 and the suction side wall 56).
[0065] As shown in FIG. 9, each vibrational dampening element 172 may
include a casing 174 that defines a fluid chamber 176. A mass 178 may be
disposed in the fluid chamber 176 and may be free to move within the fluid
chamber 176 under operating conditions of the rotor blade 50. Each mass 178 may
include a main body 180 and one or more protrusions 182 extending from the
main body 180. Additionally, glass 201 may fill each of the fluid chambers 176,
such that the mass 178 is generally surrounded by glass 201 within the casing 174.
Each mass 178 may be fully movable within the glass 201 and in the respective
fluid chamber 176 defined by the respective casing 174 (e.g., when the rotor blade
50 is at operating temperature). In some embodiments, the mass 178 may be
entirely detached from the respective casing 174. In other embodiments, the mass
17
178 may be attached to the respective casing 174 on one end (e.g., via one or
more of the protrusions 182).
[0066] The use of viscous damper stacks 170 in accordance with the present
disclosure advantageously provides improved damping of rotor blades 50. For
example, by providing such damper stacks 170 internally in individual rotor
blades 50, the viscous damper stacks 170 operate to dampen the absolute motion
of the individual rotor blades 50 regardless of the relative motion between
neighboring blades. Each vibrational dampening element 172 in the viscous
damper stack 170 may generate its own viscous dampening forces that reduce the
vibrations of the rotor blade 50. However, the use of viscous damper stacks 170
may be particularly advantageous, as the relative sliding contact between the
casings 174 (and/or between the dampening elements 172 and the walls of the
damping passage 160) will the increase the overall damping effectiveness. In
some embodiments, each vibrational dampening element 172 in the viscous
damper stack 170 may share a common casing, such that a singular casing defines
multiple fluid chambers filled with glass and having a respective mass disposed
therein. Additionally, each vibrational dampening element 172 in the viscous
damper stack 170 may have a different type of glass disposed in the respective
fluid chambers 176, which may allow damping to be tuned to different modes as a
function of spanwise location and temperature.
[0067] Referring now to FIG. 10, a graph 1000 of a force displacement loop is
illustrated in accordance with embodiments of the present disclosure. For
example, FIG. 10 may illustrate the force experienced by the mass (such as the
mass 202, 230, 308, or 408) as a result of its displacement within a fluid. The yaxis
is a ratio between the force experienced by the mass and the maximum force
experienced by the mass. The x-axis is a ratio between the displacement of the
mass within the fluid chamber and the maximum displacement of the mass within
the fluid chamber. Particularly, the solid line 1002 may illustrate the force (such
as the reactive force) experienced by a mass as a result of its displacement within
a Newtonian viscous fluid. By contrast, the dashed line 1004 may illustrate the
force (such as the reactive force) experienced by a mass as a result of its
18
displacement within a non-Newtonian viscous fluid (particularly a shear-thinning
fluid).
[0068] As shown, the solid line 1002 or Newtonian force-displacement loop is
generally circular or elliptical in shape. By contrast, as shown by the dashed line
1004, the shear-thinning effects of the non-Newtonian fluid causes the loop to be
more “rectangular”: The force rises sharply as the mass moves away from the
extreme displacement position (e.g., ±1) then remains relatively constant along
most of the stroke. When the mass accelerates the shear rate ( ) increases, but the
viscosity (?) decreases, resulting in a much smaller rise of the stress . The
opposite happens during deceleration of the mass. Therefore, the variation of the
force is mild along most of the piston stroke, which is desirable as it maximizes
the absorbed energy for a given force capacity.
[0069] Utilizing glass 201 as a viscous damping fluid within the rotor blade
50 or within a vibrational dampening element 172, 300, 400 may be particularly
advantageous due to the shear thinning behavior of the glass 201. For example,
the glass 201 may be shear thinning such that as an acceleration of the mass 202
increases within the glass 201, a resistive shear force of the glass 201 decreases.
For example, at operating temperatures, the shear thinning property of the viscous
semi-molten glass may provide a relatively constant force upon a damper
mechanism (e.g., the respective masses 202, 230, 308, 408). For example, the
mass oscillates within the molten glass in response to vibrations of the
turbomachine component. The damping force also varies less with frequency for
shear-thinning fluids than with shear-thickening viscous fluids or Newtonian
fluids. This behavior - due to shear thinning - maximizes the absorbed energy for
a given damper designed to provide a certain maximum damper force.
[0070] As should be understood and appreciated, the viscosity of a fluid is a
measure of its resistance to deformation at a given rate. The viscosity of glass is
typically measured in Pascal Seconds (Pa-s) and is represented by the Greek letter
eta (?). The viscosity of glass changes with temperature. There are four
temperature points used to define the viscosity of glass, e.g., strain, annealing,
19
softening, and working. The strain point of a glass is the temperature of the glass
at a viscosity of ?=1013.5 Pa-s. The annealing point of a glass is the temperature of
the glass at a viscosity of ?=1012 Pa-s. The softening point of a glass is the
temperature of the glass at a viscosity of ?=106.65 Pa-s. The working point of a
glass is the temperature of the glass at a viscosity of ?=103 Pa-s. For the purposes
of dampening, such as within the rotor blade 50 or within a vibrational dampening
element attached to the rotor blade 50, the glass 201 may have a softening
temperature (e.g., the temperature of the glass 201 at a viscosity of ?=106.65) that
is lower than the operating temperature of the rotor blade 50 (as shown in FIG.
11). During operation of the rotor blade 50, the glass 201 may have a viscosity
capable of dampening vibrations of the rotor blade 50.
[0071] In embodiments described herein, the softening temperature of the
glass 201 employed in the viscous dampers described herein is lower than the
operating temperature of the rotor blade 50 when employed in a turbomachine.
With such properties, the glass 201 will undergo viscosity transition, that is a
gradual and reversible transition from a hard and relatively brittle "glassy" state
into a viscous or rubbery state as the temperature of the turbine blade 50 is
increased.
[0072] For example, in exemplary embodiments, the glass 201 may have a
softening temperature 808, 908 (e.g., the temperature of the glass 201 at a
viscosity of ?=106.65) of between about 100°C to about 900°C. In other
embodiments, the glass 201 may have a softening temperature 808, 908 of
between about 100°C to about 700°C. In many embodiments, the glass 201 may
have a softening temperature 808, 908 of between about 100°C to about 600°C. In
various embodiments, the glass 201 may have a softening temperature 808, 908 of
between about 100°C to about 500°C. In some embodiments, the glass 201 may
have a softening temperature 808, 908 of between about 100°C to about 400°C. In
particular embodiments, the glass 201 may have a softening temperature 808, 908
of between about 100°C to about 300°C. With some glass compositions, it may be
particularly advantageous for the softening temperature (e.g., 801) to be lower
than the operating temperature range (e.g., 804) of the rotor blade 50, such that all
20
of the glass 201 within the rotor blade 50 will advantageously experience a
decrease in viscosity with increased temperature (e.g., soften or liquify with an
increase in temperature), thereby allowing the mass 202, 230 to move within the
respective fluid chamber 200, 228 and damp the oscillations of the rotor blade 50.
[0073] Additionally, in some embodiments, the glass 201 may have a working
temperature 806, 906 (e.g., the temperature of the glass 201 at a viscosity of
?=103) that is between about 100°C and about 1000°C. In other embodiments, the
glass 201 may have a working temperature 806, 906 that is between about 100°C
and about 800°C. In many embodiments, the glass 201 may have a working
temperature 806, 906 that is between about 100°C and about 600°C. In further
embodiments, the glass 201 may have a working temperature 806, 906 that is
between about 100°C and about 400°C.
[0074] In many embodiments (e.g., embodiments using chalcogenide glass as
represented in FIG. 11), the glass 201 may include a viscosity of between about
10-4 pascal seconds (Pa-s) and about 10-2 Pa-s at a temperature of between about
600°C and about 900°C. For example, the viscosity of the glass 201 may decrease
from about 10-2 Pa-s (at a temperature of about 600°C) to a viscosity of about 10-4
Pa-s (at a temperature of about 900°C) as the temperature increases from about
600°C and about 900°C. In certain embodiments, the glass 201 may include a
viscosity of between about 10-4 pascal seconds (Pa-s) and about 10 Pa-s at a
temperature of between about 600°C and about 900°C. For example, the viscosity
of the glass 201 may decrease from about 10 Pa-s (at a temperature of about
600°C) to a viscosity of about 10-4 Pa-s (at a temperature of about 900°C) as the
temperature increases from about 600°C and about 900°C. In other embodiments,
the glass 201 may include a viscosity of between about 10-3 pascal seconds (Pa-s)
and about 10 Pa-s at a temperature of between about 600°C and about 900°C. For
example, the viscosity of the glass 201 may decrease from about 10 Pa-s (at a
temperature of about 600°C) to a viscosity of about 10-3 Pa-s (at a temperature of
about 900°C) as the temperature increases from about 600°C and about 900°C. In
yet still further embodiments, the glass 201 may include a viscosity of between
about 10-2 pascal seconds (Pa-s) and about 10 Pa-s at a temperature of between
21
about 600°C and about 900°C. For example, the viscosity of the glass 201 may
decrease from about 10 Pa-s (at a temperature of about 600°C) to a viscosity of
about 10-2 Pa-s (at a temperature of about 900°C) as the temperature increases
from about 600°C and about 900°C.
[0075] As discussed below in more detail, the glass 201 may be selected from
a variety of glass types. However, in particularly advantageous embodiments, the
glass 201 may be a glass having a softening point and/or a working point that is
below the operating temperature range of the rotor blade (e.g., lower than about
700°C), such that the glass 201 may flow, move, and act as a viscous fluid within
the rotor blade 50 when at operating temperatures. For example, in various
embodiments, the glass 201 may be a chalcogenide glass (such as the
chalcogenide glass 802 with a viscosity profile shown in FIG. 11) and/or a sealing
glass (such as the sealing glass 902 with a viscosity profile shown in FIG. 12).
[0076] FIG. 11 illustrates a graph 800 of the viscosity (Pa-s) of a chalcogenide
glass 802 plotted against temperature (°C). In particular embodiments, the glass
201 may be the chalcogenide glass 802 having a viscosity that changes with
temperature generally (e.g., ±10%) in accordance with FIG. 11. A chalcogenide
glass is a glass containing one or more chalcogens (such as sulfur, selenium and
tellurium, but excluding oxygen). For example, in many embodiments, the
chalcogenide glass 802 may include both selenium (Se) and tellurium (Te). In
exemplary embodiments, the chalcogenide glass may include a greater proportion
of selenium than tellurium. For example, the chalcogenide glass may have various
proportions of selenium and tellurium, such as Se90Te10, Se80Te20, or Se70Te30. The
chalcogenide glass 802 may advantageously have a working point 806 and a
softening point 808 that are below the operating temperature range 804 of the
rotor blade 50.
[0077] FIG. 12 illustrates a graph 900 of the viscosity (Pa-s) of a sealing glass
902 plotted against temperature (°C). In particular embodiments, the glass 201
may be the sealing glass 902 having a viscosity that changes with temperature
generally (e.g., ±10%) in accordance with FIG. 12. The sealing glass 902 may
22
advantageously have a working point 906 and a softening point 908 that are
within the operating temperature range 904 of the rotor blade 50.
[0078] As shown in FIG. 11 and 12, the rotor blade 50 may include an
operating temperature (such as a steady-state material operating temperature of
the rotor blade 50 within the turbomachine) of between about 600°C and about
900°C. For example, the operating temperature may be the temperature of the
rotor blade 50 during operation of the turbomachine. In other embodiments, the
rotor blade 50 may include an operating temperature of between about 650°C and
about 850°C. In many embodiments, the rotor blade 50 may include an operating
temperature of between about 700°C and about 800°C. Additionally, and
advantageously, one or both of the softening temperature (e.g., the temperature of
the glass 201 at a viscosity of ?=106.65) and the working temperature (e.g., the
temperature of the glass 201 at a viscosity of ?=103) of the glass 201 may fall
within or below the operating temperature range 804, which allows the glass 201
to be used as a viscous damping fluid for the rotor blade 50.
[0079] Referring back to FIG. 3 and simultaneously to FIG. 13, a vibrational
dampening element 300 may be attached to or within the rotor blade 50, in order
to adjust the amplitude of oscillations of the rotor blade 50 when the gas turbine
10 is in operation. As shown, in some embodiments, the vibrational dampening
element(s) 300 may be attached proximate the leading edge 58 of the airfoil 52. In
other embodiments (not shown), the vibrational dampening element(s) 300 may
be attached proximate the trailing edge 60, on or underneath the platform 66, on
or within the pressure side wall 54, on or within the suction side wall 56, and/or
on or within the shank 51.
[0080] In exemplary embodiments, the vibrational damping element 300 may
be attached to the interior of the rotor blade 50, e.g., by welding or brazing, such
that it reduces and/or eliminates the oscillations of the rotor blade 50 without
creating any impediment to the flow of combustion gases over the exterior of the
airfoil 52. For example, the vibrational damping element(s) 300 may be disposed
within the airfoil 52, such that they are fixedly coupled to an interior surface of
the airfoil 52. In such embodiments, the vibrational damping element 300 may be
23
housed within the airfoil 52, thereby advantageously providing damping to the
rotor blade 50 without creating any blockage to the flow of combustion gases 34.
In other embodiments (not shown), the vibrational damping 300 element may be
directly fixedly coupled to the exterior surface of the airfoil 52, e.g., by welding
and/or brazing. The vibrational dampening element 300 may be large enough to
significantly decrease and/or eliminate damage-causing vibrations of the airfoil 52
during operation, but small enough not to cause an impediment to the flow of
combustion gases over the airfoil 52, thereby maintaining the aerodynamic
efficiency of the rotor blade 50.
[0081] As shown in FIG. 3, one or more vibrational dampening elements 300
may be positioned along various locations of the airfoil 52, e.g., between 0% and
100% of the span length 70 of the airfoil 52. For example, the rotor blade 50 may
include one or more mid-span vibrational dampening elements 302, which may be
positioned in the mid-span region of the airfoil 52. For example, the mid-span
vibrational dampening element(s) 302 may be positioned on the airfoil 52
between about 25% and about 75% of the span length 70 of the airfoil 52. In
particular embodiments, one or more vibrational dampening elements 300 may be
positioned on the airfoil 52 between about 40% and about 60% of the span length
70 of the airfoil 52.
[0082] As shown in FIG. 3, the rotor blade 50 may further include one or
more tip-span vibrational dampening elements 304, which are radially separated
from the mid-span vibrational dampening element(s) 302. In various
embodiments, the tip-span vibrational dampening element(s) 304 may be
positioned between about 75% and about 100% of the span length 70 of the airfoil
52. In particular embodiments, the tip-span vibrational dampening element(s) 304
may be positioned between about 90% and about 100% of the span length 70 of
the airfoil 52.
[0083] In many embodiments, each of the dampening elements 302, 304 may
be sized differently, in order to target a specific frequency range of the rotor blade
50. For example, the tip-span vibrational damping element(s) 304 may be sized
such that they are tuned to natural frequencies where the rotor blade 50 mode of
24
vibration is predominantly at the tip. Similarly, the mid-span vibrational
dampening element 302 may be sized such that they are tuned to natural
frequencies where the rotor blade 50 mode of vibration is predominantly in the
mid-span region. For example, each vibrational dampening element 300 may be
sized to be tuned to a frequency of the rotor blade 50 based on the respective span
locations of the airfoil 52 to which they are attached or embedded.
[0084] FIG. 13 illustrates a perspective view of an exemplary vibrational
dampening element 300, FIG. 14 is a cross-sectional view of the vibrational
dampening element 300 from along a radial direction R, and FIG. 15 is a crosssectional
view of the vibrational dampening element 300 from along line 15-15 of
FIG. 14. As shown, the axial centerline 301 of the vibrational dampening element
300 defines an axial direction A substantially parallel to and/or along axial
centerline 301, a radial direction R perpendicular to axis A, and a circumferential
direction C extending around axis A. In exemplary embodiments, the axial
centerline 301 of the vibrational dampening element 300 may be aligned (or
coaxial) with the direction of oscillations or vibrations of the component to which
it is attached.
[0085] In many embodiments, the vibrational dampening element 300
includes a casing 306 that encapsulates or surrounds a mass 308. For example, as
shown in FIG. 14, the casing 306 may be spaced apart from the mass 308, such
that a fluidic chamber 309 is defined in the space between the mass 308 and the
casing 306. In this way, the mass 308 may be suspended in fluid within the casing
306, such that the mass 308 is capable of movement relative to the casing 306 and
within the fluid. For example, when the vibrational dampening element 300 is
attached to an oscillating component, the mass 308 may oscillate within the fluid
encapsulated by the casing 306, which forces the fluid between the fluidic
portions 318, 328 of the fluidic chamber 309 defined between the casing 306 and
the mass 308, thereby dampening the oscillations of the component.
[0086] In exemplary embodiments, a fluidic chamber 309 may be defined
between the mass and the casing and filled with a fluid (such as glass, or
particularly glass 201 described above). For example, the casing 306 may define
25
an interior surface having a shape that mimics an exterior surface shape of the
mass 308. In various embodiments, the interior surface of the casing 306 may be
spaced apart from the mass 308, thereby defining the fluidic chamber 309 in the
space between the mass 308 and the casing 306. In many embodiments, the fluidic
chamber 309 may include a first fluidic portion 318 and a second fluidic portion
328. The first fluidic portion 318 may be defined between a first side 320 of the
mass 308 and the casing 306, and the second fluidic portion 328 may be defined
between a second side 330 of the mass 308 and the casing 306.
[0087] In exemplary embodiments, the mass 308 may include a main body
310 and a member or annular member 312 that extends from the main body 310.
For example, the annular member 312 may extend in the circumferential direction
C and surround the main body 310 of the mass 308, such that mass 308 defines a
circular cross-sectional shape (FIG. 15). In many embodiments, the main body
310 of the mass 308 may define a first thickness 314 from the first side 320 to the
second side 330 of the main body 310, and the annular member 312 of the mass
308 may define a second thickness 316 from the first side 320 to the second side
330 of the annular member 312. As shown in FIG. 14, the second thickness 316 of
the annular member 312 may be smaller than the first thickness 314 of the main
body 310. With this configuration, the majority of the weight of the mass 308 may
be centrally located, i.e., proximate the axial centerline 301 of the vibrational
dampening element 300.
[0088] As discussed above, a first fluidic portion 318 of the fluidic chamber
309 may be disposed between the first side 320 of the mass 308 and the casing
306. As shown, the first fluidic portion 318 may include a first central portion 322
that extends along the main body 310 on the first side 320, a first accumulator
portion 324 that extends along the annular member 312 on the first side 320, and a
first connection portion 326 disposed between the first central portion 322 and the
first accumulator portion 324. For example, the first central portion 322 may be
disposed axially between the first side 320 of the main body 310 and the casing
306 with respect to the axial centerline 301 of the vibrational dampening element
300. The first accumulator portion 324 may be defined axially between the first
26
side 320 of the annular member 312 and the casing 306. The first connection
portion 326 may be defined radially between the main body 310 and the casing
306. In various embodiments, both the first accumulator portion 324 and the first
connection portion 326 may be annular passageways that are defined in the
circumferential direction C. For example, the first central portion 322 may extend
radially between the axial centerline 301 and the first connection portion 326,
such that the first connection portion 326 provides for fluid communication
between the first central portion 322 and the first accumulator portion 324 of the
first fluidic portion 318.
[0089] In particular embodiments, as discussed, a second fluidic portion 328
of the fluidic chamber 309 may be disposed between a second side 330 of the
mass 308 and the casing 306. As shown, the second fluidic portion 328 may
include a second central portion 332 that extends along the main body 310 on the
second side 330, a second accumulator portion 334 that extends along the annular
member 312 on the second side 330, and a second connection portion 336
disposed between the second central portion 332 and the second accumulator
portion 334. For example, the second central portion 332 may be disposed axially
between the second side 330 of the main body 310 and the casing 306 with
respect to the axial centerline 301 of the vibrational dampening element 300. The
second accumulator portion 334 may be defined axially between the second side
330 of the annular member 312 and the casing 306. In various embodiments, both
the second accumulator portion 334 and the second connection portion 326 may
be annular passageways that are defined in the circumferential direction C. For
example, the second central portion 332 may extend radially between the axial
centerline 301 and the second connection portion 336, such that the second
connection portion 336 provides for fluid communication between the second
central portion 332 and the second accumulator portion 334 of the second fluidic
portion 328.
[0090] In various embodiments, the vibrational dampening element 300 may
further include a first bellows tube 358 that extends between the first side 320 of
the annular member 312 and the casing 306 and a second bellows tube 360 that
27
extends between the second side 330 of the annular member 312 and the casing.
The bellows tubes 358, 360 may be compliant, such that they can bend or flex
along the axial centerline 301 to allow for the mass to oscillate axially within the
fluid and provide viscous damping forces when attached to a vibrating component
(such as the turbine rotor blade 50). For example, in exemplary embodiments,
mass 308 may suspended within fluid (e.g., glass 201) by the first bellows tube
358 and the second bellows tube 360. In various embodiments, the first bellows
tube 358 and the second bellows tube 360 may be annular, such that they extend
in the circumferential direction C around the main body 310 of the mass 308. In
this way, the first bellows tube 358 and the second bellows tube 360 may
surround the main body 310 of the mass 308 and partially define the first fluidic
portion 318 and the second fluidic portion 328 respectively.
[0091] As shown in FIGS. 14 and 15, a primary passage 362 may extend
between the first fluidic portion 318 and the second fluidic portion 328, in order to
provide for fluid communication therebetween. For example, the primary passage
362 may extend directly from the first central portion 322 of the first fluidic
portion 318 to the second central portion 332 of the second fluidic portion 328. In
various embodiments, the primary passage 362 may extend along the axial
centerline 301 of the vibrational dampening element 300, such that the primary
passage 362 extends coaxially with the axial centerline 301. In other embodiments
(not shown), multiple primary passages may extend between the first fluidic
portion 318 and the second fluidic portion 328 of the fluidic chamber 309, such
that they symmetrically surround the axial centerline 301 of the vibrational
dampening element 300. In exemplary embodiments, when the vibrational
dampening element 300 is attached to a vibrating or oscillating component (such
as the turbomachine rotor blade 50 shown in FIG. 3 or the airfoil of FIG. 8), the
primary passage 362 may be oriented generally along the direction of oscillations
of the component.
[0092] In many exemplary embodiments, the vibrational dampening element
300 may further include a plurality of secondary passages 364 circumferentially
spaced apart from one another and defined within the mass 308. The plurality of
28
secondary passages 364 may be disposed around the periphery of the vibrational
dampening element 300, such that they are positioned about and surround the
axial centerline 301. In particular embodiments, each of the secondary passages
364 may be defined within the annular member 312, such that they each extend
generally axially between the first fluidic portion 318 and the second fluidic
portion 328. For example, each secondary passage 364 in the plurality of
secondary passages 364 may extend through the annular member 312 from the
first accumulator portion 324 of the first fluidic portion 318 to the second
accumulator portion 334 of the second fluidic portion 328.
[0093] The vibrational dampening element 300 described herein may work on
the principle of a tuned vibration absorber. For example, during operation of the
vibrational dampening element 300, a fluid (such as glass, or particularly glass
201 described above) may flow between the first fluidic portion 318 and the
second fluidic portion 328 via the primary passage 362 and the plurality of
secondary passages 364. For example, when the vibrational dampening element
300 is attached to a vibrating component, such as a turbine rotor blade 50, the
viscous forces generated in primary passage 362 and the secondary passages 364
from fluid rapidly traveling between the fluidic portions 318, 328 of the fluidic
chamber 309 advantageously dampens the amplitude of oscillations of the
vibrating component. The viscous damping forces produced within the vibrational
dampening element 300 counteract the vibrations of the component to which the
vibrational dampening element 300 is attached and advantageously reduce the
amplitude of vibrations of the vibrating component.
[0094] In exemplary embodiments, the plurality of secondary passages 364
ensures no pressure build-up in the fluid within the accumulator portions 324,
334, i.e., around the periphery of the vibrational dampening element 300. In this
way, the plurality of secondary passages 364 advantageously increase the
effectiveness of the vibrational dampening element 300 by ensuring that there are
no stiff regions.
[0095] In many embodiments, the natural frequency of the vibrational
dampening element 300 may be tuned to the mode of interest by changing the
29
stiffness of the bellows tubes 358, 360. Similarly, the natural frequency of the
vibrational dampening element 300 may be tuned by adjusting the density, size, or
weight of the mass 308. This advantageously allows for the vibrational dampening
300 element to be tuned based on the component to which it will be attached, e.g.,
the first, second, and/or third stage turbine rotor blades may each include a
vibrational dampening element 300 that is separately and specifically tuned for
each stage blade.
[0096] The vibrational dampening element 300 described herein may be
advantageous over prior designs of dampening elements, e.g., damping elements
having only single passage connecting two fluid chambers. For example, the
accumulator portions 324, 334 and the plurality of secondary passages 364 ensure
that no forces leak into stiffness around the periphery of the dampening element
300 and ensure no pressure build-up in the fluid surrounding the bellows tubes
358, 360.
[0097] FIG. 16 illustrates a cross-sectional view of a vibrational dampening
element 300 from along a radial direction R, in accordance with other
embodiments of the present disclosure. As shown, the annular member 312 may
be corrugated such that it includes multiple wrinkles, folds, and/or ridges, which
advantageously provides for increased compliance in the axial direction (i.e., the
direction of oscillation of the mass 308 when attached to a vibrating component).
[0098] In various embodiments, the annular member 312 may extend
continuously between a corrugated portion 342 and a straight portion 344. The
corrugated portion 342 of the annular member 312 may extend continuously
between a plurality of peaks 338 and valleys 340, which are radially and axially
separated from one another. As shown in FIG. 16, the corrugated portion 342 of
the annular member 312 may extend radially from the main body 310 to the
straight portion 344. The straight portion 344 may extend radially from the
corrugated portion 342 to a free end 345. In the embodiment shown in FIG. 16,
the plurality of secondary passages 364 may be defined within the straight portion
344 of the annular member.
30
[0099] As shown in FIG. 16, the casing 306 may be generally spaced from the
mass 308, in order to partially define the first fluidic portion 318 and the second
fluidic portion 328 on either side of the mass 308. As shown, the casing 306 may
include a first portion 350 and a second portion 352 that couple to opposite sides
of the mass 308. For example, the first portion 350 may couple to the free end 345
on a first side of the annular member 312, and the second portion 352 of the
casing 306 may couple to the free end 345 on a second side of the annular
member 312.
[00100] In the embodiment shown in FIG. 16, the first fluidic portion 318 may
further include a first corrugated passage 354 and a second corrugated passage
356 disposed on opposite sides of the corrugated portion 342 of the annular
member 312. For example, the first corrugated passage 354 and the second
corrugated passage 356 may extend along the corrugated portion 342 on opposite
sides of the annular member 312. In such embodiments, as shown, the first
accumulator portion 324 of the first fluidic portion 318 and the second
accumulator portion 334 of the second fluidic portion 328 may extend along the
straight portion 344 on opposite sides of the annular member 312.
[00101] FIGS. 17-19 illustrate a vibrational dampening element 400, in
accordance with an alternative embodiment of the present disclosure. As shown,
the vibrational dampening element 400 may be a “hammer” damper, such that it
includes a large mass attached to a slender beam or member. FIG. 17 illustrates a
perspective view of the vibrational dampening element 400, in which the casing
406 is shown in dashed lines. FIG. 18 illustrates a cross-sectional view of the
vibrational dampening element 400 from along a first direction, and FIG. 19
illustrates a cross-sectional view of the vibrational dampening element 400 from
along a second direction, which is perpendicular to the first direction.
[00102] In exemplary embodiments, the vibrational dampening element 400
may include a fluidic chamber 409 that is defined between a mass 408 and a
casing 406 and filled with a fluid (such as glass, or particularly glass 201
described above). For example, the casing 406 may define an interior surface
having a shape that mimics an exterior surface shape of the mass 408. In various
31
embodiments, the interior surface of the casing 406 may be spaced apart from the
mass 408, thereby defining the fluidic chamber 409 in the space between the mass
408 and the casing 406. In many embodiments, the fluidic chamber 409 may
include a first fluidic portion 418 and a second fluidic portion 428. The first
fluidic portion 418 may be defined between a first side 420 of the mass 408 and
the casing 406, and the second fluidic portion 428 may be defined between a
second side 430 of the mass 308 and the casing 306.
[00103] As shown in FIGS. 17-19 collectively, the vibrational dampening
element 400 includes a casing 406 that encapsulates or surrounds a mass 408. As
shown, the mass 408 may include a main body 410 and a member 412 that
extends from the main body and couples to the casing 406. For example, as shown
in FIGS. 18 and 19, the member 412 of the mass 408 may be attached to the
casing 406 and cantilevered therefrom, such that the first fluidic portion 418 and
the second fluidic portion 428 are defined in the space between the mass 408 and
the casing 406. In this way, the main body 410 of the mass 408 may be capable of
movement relative to the casing 406 and within the fluid held by the fluidic
chamber 409. For example, when the vibrational dampening element 400 is
attached to an oscillating component (such as a turbomachine rotor blade 50 or
other component), the main body 410 of the mass 408 may oscillate within the
fluid encapsulated by the casing 406, which forces the fluid to move between the
fluidic portions 418, 428 of the fluidic chamber 409 defined between the casing
406 and the mass 408, thereby producing viscous forces that dampen the
oscillations of the component.
[00104] As shown in FIGS. 18 and 19, the first fluidic portion 418 of the
fluidic chamber 409 may be defined between a first side 420 of the mass 408 and
the casing 406, and the second fluidic portion 428 of the fluidic chamber 409 may
be defined between a second side 430 of the mass 408 and the casing 406. When
the vibrational dampening element 400 is attached to a component (such as the
turbomachine rotor blade 50 shown in FIG. 3), the first side 420 and the second
side 430 may be generally perpendicular to a direction of vibrations 402 of the
component, such that the fluidic portions 418, 428 of the fluidic chamber 409 are
32
disposed opposite one another with respect to the direction of vibrations 402 of
the component. In this way, the first fluidic portion 418 and the second fluidic
portion 428 may extend generally perpendicularly to the direction of vibrations
402 of the component. In exemplary embodiments, primary passages 450 may
extend along the main body 410 of the mass 408 generally parallel to the direction
of vibrations 402 and fluidly couple the first fluidic portion 418 to the second
fluidic portion 428.
[00105] In many embodiments, the first fluidic portion 418 of the fluidic
chamber 409 may further include a first accumulator portion 424 that extends
along the member 412 of the mass 408, and the second fluidic portion 428 may
include a second accumulator portion 434 that extends along an opposite side of
the member 412 as the first accumulator portion 424. For example, the first
accumulator portion 424 and the second accumulator portion 434 may extend be
disposed on opposite sides of the member 412 and may extend generally
perpendicularly to the direction of vibrations 402 of the component. In exemplary
embodiments, secondary passages 452 may extend along the member 412
generally parallel to the direction of to the direction of vibrations 402 and fluidly
couple the first accumulator portion 424 to the second accumulator portion 434.
[00106] FIG. 20 illustrates two neighboring turbomachine rotor blades 50, a
first of which has the vibrational dampening element 400 mounted in a first
orientation and a second of which has the vibrational dampening element 400
mounted in a second direction opposite the first direction. As shown in the first
rotor blade (left side of FIG. 20), the vibrational dampening element 400 may be
mounted to or within the airfoil 52 such that the main body 410 of the mass 408 is
radially outward of the member 412 with respect to the radial direction of the gas
turbine 10. In such a configuration, the member 412 may be under a tensile
centrifugal loading. In another configuration, as shown in the second rotor blade
(right side of FIG. 20), the vibrational dampening element 400 may be mounted to
or within the airfoil 52 such that the main body 410 of the mass 408 is radially
inward of the member 412 with respect to the radial direction of the gas turbine
33
10. In such a configuration, the member 412 may be under a compressive
centrifugal loading.
[00107] During operation of the vibrational dampening element 400, i.e., when
the vibrational dampening element 400 is attached to an oscillating or vibrating
component, fluid may be forced by the mass 408 to flow between the first fluidic
portion 418 and the second fluidic portion 428 via the primary passages 450 and
the secondary passages 452. For example, when the vibrational dampening
element 400 is attached to or within an oscillating component, such as a turbine
rotor blade 50, the viscous forces are generated in primary passages 450 and the
secondary passages 452 from fluid rapidly traveling between the fluidic portions
418, 428 of the fluidic chamber 409. The viscous forces counteract the vibrations
of the component and reduce the amplitude of oscillations of the component. In
exemplary embodiments, the plurality of secondary passages 452 between the
accumulator portions 424, 434 ensures no pressure build-up in the fluid within the
accumulator portions 424, 434, i.e., around the member 412.
[00108] Referring now to FIG. 21, a flow diagram of method 2100 of operating
a turbomachine having a turbine section 18 with one or more turbine components
is provided to adjust an amplitude of oscillations of one or more turbine
components disposed in the turbine section 18 of the turbomachine 10. In various
embodiments, the one or more turbine components may be any component within
the turbine section 18 of the gas turbine 10. In particular embodiments, the turbine
component may be a rotor blade 50 disposed in the turbine section 18 and/or a
vibrational dampening element 172, 300, 400 disposed the turbine section 18.
However, it should be understood that the method 2100 may be utilized with any
suitable component of the gas turbine 10 without deviating from the scope of the
present disclosure. Additionally, although FIG. 21 depicts steps performed in a
particular order for purposes of illustration and discussion, the methods discussed
herein are not limited to any particular order or arrangement. One skilled in the
art, using the disclosures provided herein, will appreciate that various steps of the
methods disclosed herein can be omitted, rearranged, combined, and/or adapted in
various ways without deviating from the scope of the present disclosure.
34
[00109] As shown, in many implementations, the method 2100 may include a
step 2102 of providing the turbine component having a fluid chamber and a mass
disposed within the fluid chamber. For example, in embodiments in which the
turbine component is a rotor blade 50, the fluid chamber may be the fluid chamber
200. Alternatively, or additionally, in embodiments in which the turbomachine
component is a vibrational dampening element 300, 400, the fluid chamber may
be the fluidic chamber 309, 409.
[00110] In many embodiments, as shown, the method 2100 may further include
a step 2104 of disposing glass 201 within the fluid chamber. For example, this
may be done by injecting molten-state glass into the fluid chamber. Alternatively,
or additionally, the fluid chamber may be filled with glass beads that are in a solid
state and are subsequently melted during operation of the turbomachine. In many
embodiments, the fluid chamber surrounding the mass may be fully filled with
glass 201, such that the mass is entirely surrounded by glass. In other
embodiments, the fluid chamber may only be partially filled with glass 201, such
as 90% filed with glass 201, or such as 60% filled with glass 201, or such as 30%
filled with glass 201. In such embodiments, the remainder of the fluid chamber
may be filled with air or another viscous fluid, such as liquid gallium.
[00111] In exemplary embodiments, operation of the turbine results in a
decrease of a viscosity of the glass 201 to produce a molten-state glass (e.g., a
glass having a viscosity at or below one or both of the softening point or the
working point). Once the glass 201 is in a molten state, the mass may be
translated through the molten-state glass to adjust an amplitude of oscillations of
the turbomachine component. For example, the viscosity of the glass 201 and the
size of the mass may be tuned to alter the dampening properties based on the
desired needs at the respective location of the turbomachine component.
[00112] In some embodiments, the method 2100 may further include operating
the turbomachine such that a temperature of the one or more turbine components
increases from a predetermined low temperature range to a predetermined high
temperature range. For example, the predetermined low temperature range may be
generally room temperature (or the temperature of the ambient environment in
35
which the turbomachine is located), and the predetermined high temperature range
may be the temperature of the turbomachine component during operation of the
turbomachine.
[00113] For example, the turbomachine component may be in the
predetermined low temperature range when the turbomachine is shut off or
otherwise not in operation. Additionally, or alternatively, the predetermined low
temperature range may be between about -50°C and about 70°C, or such as
between about -25°C and about 50°C, or such as between about -10°C and about
40°C, or such as between about 0°C and about 30°C.
[00114] Additionally, the turbomachine component may be in the
predetermined high temperature range when the turbomachine is in steady-state
operating conditions. Specifically, the predetermined high temperature range may
be the operating temperature of the turbomachine component (e.g., the material
temperature of the rotor blade 50 and/or the vibrational dampening element 300,
400 when the turbomachine is operating). In this way, the predetermined high
temperature range may be of between about 600°C and about 900°C, or such as
between about 650°C and about 850°C, or such as between about 700°C and
about 800°C. In many implementations, because the glass is housed within the
turbomachine component, increasing the temperature of the turbomachine
component to the predetermined high temperature range also increases the
temperature of the glass 201 to the predetermined high temperature range. In
exemplary embodiments, the predetermined high temperature range may be
higher than one or both of the softening temperature and/or the working
temperature of the glass 201. Stated otherwise, the glass 201 may advantageously
have a softening temperature lower than the predetermined high temperature
range, such that the viscosity of the glass decreases with an increase in the
temperature, thereby allowing the mass 202 to move and dampen vibrations of the
turbomachine component.
[00115] In particular embodiments, the method 2100 may further include
decreasing a viscosity of the glass 201 such that the glass 201 shifts from a solid
state to a molten state as a result of increasing the temperature of the one or more
36
turbine components to the predetermined high temperature range. Stated
otherwise, as a result of increasing the temperature of the one or more turbine
components to the predetermined high temperature range, the glass 201 decreases
in viscosity and shifts from a solid state to a molten state. The molten state of the
glass 201 may be characterized as when the glass 201 is at a temperature that is
greater than one or both of the softening temperature and/or the working
temperature. Similarly, the solid state of the glass 201 may be characterized as
when the glass 201 is at a temperature that is lower than one or both of the
softening temperature and/or the working temperature. In many implementations,
because the glass 201 is housed within the turbomachine component, increasing
the temperature of the turbomachine component to the predetermined high
temperature range also increases the temperature of the glass 201 to the
predetermined high temperature range. The glass 201 may advantageously have a
softening temperature lower than the predetermined high temperature range, such
that the viscosity of the glass decreases with an increase in the temperature,
thereby allowing the mass 202 to move and dampen vibrations of the
turbomachine component.
[00116] In many embodiments, the method 2100 may further include adjusting
an amplitude of oscillations of the one or more turbine components by moving the
mass 202 (e.g., counter-oscillating) within the glass 201 when the glass 201 is in a
molten state. This may counteract the oscillations of the turbomachine component,
thereby reducing vibrations.
[00117] In optional embodiments, the method 2100 may further include
operating the turbomachine such that a temperature of the one or more turbine
components decreases from the predetermined high temperature range to the
predetermined low temperature range. As a result, the glass 201 may increase in
viscosity from the molten state to the solid state such that the mass is not movable
within the glass 201. For example, in the solid state, the mass 202 may be
rigidized within the glass 201 (e.g., rigidly held by the solid-state glass 201), such
as during turndown (shutoff) of the turbomachine, start-up of the turbomachine, or
non-operation of the turbomachine.
37
[00118] 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 include
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 language of the claims.
[00119] Further aspects of the invention are provided by the subject matter of
the following clauses:
[00120] A rotor blade for a turbomachine, the rotor blade comprising: a
platform; a shank extending radially inward from the platform; and an airfoil
extending radially outward from the platform, wherein one or more fluid
chambers are defined within the rotor blade; glass disposed within each fluid
chamber of the one or more fluid chambers; and a mass disposed within each fluid
chamber of the one or more fluid chambers, the mass movable within the glass
relative to the airfoil.
[00121] The rotor blade as in one or more of these clauses, wherein the airfoil
includes a leading edge, a trailing edge, a pressure side wall extending between
the leading edge and the trailing edge, and a suction side wall extending between
the leading edge and the trailing edge, wherein the one or more fluid chambers is
defined collectively by the leading edge, the trailing edge, the pressure side wall,
and the suction side wall.
[00122] The rotor blade as in one or more of these clauses, wherein the mass
includes a first portion extending between the leading edge and the trailing edge
and a second portion extending generally perpendicularly to the first portion.
[00123] The rotor blade as in one or more of these clauses, wherein a first pair
of guides extend from the pressure side wall and a second pair of guides extend
38
from the suction side wall, and wherein the second portion is disposed between
the first pair of guides and the second pair of guides.
[00124] The rotor blade as in one or more of these clauses, wherein the airfoil
extends from a root coupled to the platform to a tip, and wherein the mass is
attached at the root of the airfoil.
[00125] The rotor blade as in one or more of these clauses, wherein the airfoil
defines a radial channel, and wherein separating walls extend within the radial
channel and at least partially define the one or more fluid chambers.
[00126] The rotor blade as in one or more of these clauses, wherein the glass
includes a viscosity of between about 10-4 pascal seconds (Pa-s) and about 10-2
Pa-s at a temperature of between about 600°C and about 900°C.
[00127] The rotor blade as in one or more of these clauses, wherein the glass
has a viscosity that changes with a temperature of the glass generally in
accordance with one of FIG. 11 or FIG. 12.
[00128] A vibrational dampening element attached to a turbine component and
configured to adjust an amplitude of oscillations of the turbine component, the
vibrational dampening element comprising: a mass; a casing encapsulating the
mass; and a fluidic chamber defined between the mass and the casing and filled
with glass.
[00129] The vibrational dampening element as in one or more of these clauses,
wherein the glass has a softening temperature of between about 100°C to about
900°C.
[00130] The vibrational dampening element as in one or more of these clauses,
wherein the glass includes a viscosity of between about 10-4 pascal seconds (Pa-s)
and about 10-2 Pa-s at a temperature of between about 600°C and about 900°C.
[00131] The vibrational dampening element as in one or more of these clauses,
wherein the glass is a chalcogenide glass.
[00132] The vibrational dampening element as in one or more of these clauses,
wherein the glass has a viscosity that changes with a temperature of the glass
generally in accordance with one of FIG. 11 or FIG. 12.
39
[00133] A method of adjusting an amplitude of oscillations of a turbine
component disposed in a turbine section of a turbomachine, the method
comprising: providing the turbine component having a fluid chamber and a mass
disposed within the fluid chamber; and disposing glass within the fluid chamber;
wherein operation of the turbine results in a decrease of a viscosity of the glass to
produce a molten-state glass, the mass being translated through the molten-state
glass to adjust the amplitude of oscillations of the turbomachine component.
[00134] The method as in one or more of these clauses, wherein the
turbomachine component is a rotor blade.
[00135] The method as in one or more of these clauses, wherein the
turbomachine component is a vibrational dampening element.
[00136] The method as in one or more of these clauses, wherein the glass has a
softening temperature of between about 100°C to about 900°C.
[00137] The method as in one or more of these clauses, wherein the glass
includes a viscosity of between about 10-4 pascal seconds (Pa-s) and about 10-2
Pa-s at a temperature of between about 600°C and about 900°C.
[00138] The method as in one or more of these clauses, wherein the glass
possesses shear thinning characteristics such that as an acceleration of the mass
increases a resistive shear force of the molten-state glass decreases.
[00139] The method as in one or more of these clauses, wherein the glass has a
viscosity that changes with a temperature of the glass generally in accordance
with one of FIG. 11 or FIG. 12.

Claims:

We claim:
1. A rotor blade for a turbomachine, the rotor blade comprising:
a platform;
a shank extending radially inward from the platform; and
an airfoil extending radially outward from the platform, wherein one or
more fluid chambers are defined within the rotor blade;
glass disposed within each fluid chamber of the one or more fluid
chambers; and
a mass disposed within each fluid chamber of the one or more fluid
chambers, the mass movable within the glass relative to the airfoil.
2. The rotor blade as in claim 1, wherein the airfoil includes a leading edge, a
trailing edge, a pressure side wall extending between the leading edge and the
trailing edge, and a suction side wall extending between the leading edge and the
trailing edge, wherein the one or more fluid chambers is defined collectively by
the leading edge, the trailing edge, the pressure side wall, and the suction side
wall.
3. The rotor blade as in claim 2, wherein the mass includes a first portion
extending between the leading edge and the trailing edge and a second portion
extending generally perpendicularly to the first portion.
4. The rotor blade as in claim 3, wherein a first pair of guides extend from
the pressure side wall and a second pair of guides extend from the suction side
wall, and wherein the second portion is disposed between the first pair of guides
and the second pair of guides.
5. The rotor blade as in claim 3, wherein the airfoil extends from a root
coupled to the platform to a tip, and wherein the mass is attached at the root of the
airfoil.
41
6. The rotor blade as in claim 2, wherein the airfoil defines a radial channel,
and wherein separating walls extend within the radial channel and at least partially
define the one or more fluid chambers.
7. The rotor blade as in claim 1, wherein the glass includes a viscosity of
between about 10-4 pascal seconds (Pa-s) and about 10-2 Pa-s at a temperature of
between about 600°C and about 900°C.
8. The rotor blade as in claim 1, wherein the glass has a viscosity that
changes with a temperature of the glass generally in accordance with one of FIG.
11 or FIG. 12.
9. A vibrational dampening element attached to a turbine component and
configured to adjust an amplitude of oscillations of the turbine component, the
vibrational dampening element comprising:
a mass;
a casing encapsulating the mass; and
a fluidic chamber defined between the mass and the casing and filled with
glass.
10. The vibrational dampening element as in claim 9, wherein the glass has a
softening temperature of between about 100°C to about 900°C.
11. The vibrational dampening element as in claim 9, wherein the glass
includes a viscosity of between about 10-4 pascal seconds (Pa-s) and about 10-2
Pa-s at a temperature of between about 600°C and about 900°C.
12. The vibrational dampening element as in claim 9, wherein the glass is a
chalcogenide glass.
42
13. The vibrational dampening element as in claim 9, wherein the glass has a
viscosity that changes with a temperature of the glass generally in accordance
with one of FIG. 11 or FIG. 12.
14. A method of adjusting an amplitude of oscillations of a turbine component
disposed in a turbine section of a turbomachine, the method comprising:
providing the turbine component having a fluid chamber and a mass
disposed within the fluid chamber; and
disposing glass within the fluid chamber;
wherein operation of the turbine results in a decrease of a viscosity of the
glass to produce a molten-state glass, the mass being translated through the
molten-state glass to adjust the amplitude of oscillations of the turbomachine
component.
15. The method as in claim 14, wherein the turbomachine component is a
rotor blade.
16. The method as in claim 14, wherein the turbomachine component is a
vibrational dampening element.
17. The method as in claim 14, wherein the glass has a softening temperature
of between about 100°C to about 900°C.
18. The method as in claim 14, wherein the glass includes a viscosity of
between about 10-4 pascal seconds (Pa-s) and about 10-2 Pa-s at a temperature of
between about 600°C and about 900°C.
19. The method as in claim 14, wherein the glass possesses shear thinning
characteristics such that as an acceleration of the mass increases a resistive shear
force of the molten-state glass decreases.
43
20. The method as in claim 14, wherein the glass has a viscosity that changes
with a temperature of the glass generally in accordance with one of FIG. 11 or
FIG. 12.