BACKGROUND OF THE INVENTION
[0001] The subject matter disclosed herein relates to turbine exhaust diffuser systems and,
more particularly, to manways in turbine exhaust diffuser systems.
[0002] A turbine system may include an exhaust diffuser system coupled to a turbine section
downstream of the turbine section. Such a turbine system may be either a gas turbine
system or a steam turbine system. For example, a gas turbine system combusts a mixture
of fuel and air to generate hot combustion gases, which in turn drive one or more
turbines. In particular, the hot combustion gases force turbine blades to rotate,
thereby driving a shaft to cause rotation of one or more loads, e.g., electrical generators,
and so forth. The exhaust diffuser system receives the exhaust from the turbine. As
the exhaust flows through diverging passages of the exhaust diffuser system, dynamic
pressure of the exhaust flow may cause the static pressure in the exhaust diffuser
system to increase.
[0003] Exhaust diffuser systems may contain manways that extend through the exhaust diffuser
system radially from an outer wall to an inner hub, or wall, that surrounds an access
tunnel. The manways may contain pipes that provide lubrication oil and/or cooling
air to the turbine system. The pipes extend into the access tunnel of the exhaust
diffuser system and may limit entry and/or use of the access tunnel, such as by blocking
entry through an access door. Further, the arrangement of the manways may cause exhaust
to flow around the manways and generate wakes. Undesirable vortex shedding may result
from the wakes and may affect the structure of the exhaust diffuser system. Further,
the vortex shedding may increase pressure loss of the exhaust diffuser system, increase
noise of the exhaust diffuser system, and decrease the overall performance of the
exhaust diffuser system.
BRIEF DESCRIPTION OF THE INVENTION
[0004] Certain embodiments commensurate in scope with the originally claimed invention are
summarized below. These embodiments are not intended to limit the scope of the claimed
invention, but rather these embodiments are intended only to provide a brief summary
of possible forms of the invention. Indeed, the invention may encompass a variety
of forms that may be similar to or different from the embodiments set forth below.
[0005] In a first aspect, the invention resides in a turbine exhaust diffuser system includes
an outer wall. The turbine exhaust diffuser system also includes an inner wall formed
by a converging inner passageway. Turbine exhaust is configured to flow through an
area between the outer wall and the inner wall. The turbine exhaust diffuser system
includes at least one manway extending from the outer wall to the inner wall. The
at least one manway extends from the outer wall to the inner wall at an angle that
is not perpendicular to a central axis of the turbine exhaust diffuser system.
[0006] In a second aspect, a turbine exhaust diffuser system includes an outer wall of a
turbine exhaust passageway. The turbine exhaust diffuser system also includes an access
passageway defined by an inner wall of the turbine exhaust passageway. The access
passageway is configured to enable an operator to enter the access passageway to perform
maintenance on the turbine exhaust diffuser system. The turbine exhaust diffuser system
includes a plurality of manways extending from the outer wall of the turbine exhaust
passageway to the access passageway. Each manway extends from the outer wall of the
turbine exhaust passageway to the access passageway at an angle that is not perpendicular
to a central axis of the turbine exhaust diffuser system.
[0007] In a third aspect, a turbine exhaust diffuser system includes a plurality of manways
extending between an outer wall and an interior access tunnel at an angle that is
not perpendicular to a central axis of the turbine exhaust diffuser system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Embodiments of the present invention will now be described, by way of example only,
with reference to the accompanying drawings in which:
FIG. 1 is a cross-sectional side view of an embodiment of a gas turbine engine;
FIG. 2 is a perspective view of an embodiment of a gas turbine exhaust diffuser system
that may be used with the gas turbine engine of FIG. 1;
FIG. 3 is a side view of an embodiment of the gas turbine exhaust diffuser system
of FIG. 2; and
FIG. 4 is a cross-sectional side view of an embodiment of a gas turbine exhaust diffuser
system that may be used with the gas turbine engine of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0009] One or more specific embodiments of the present invention will be described below.
In an effort to provide a concise description of these embodiments, all features of
an actual implementation may not be described in the specification. It should be appreciated
that in the development of any such actual implementation, as in any engineering or
design project, numerous implementation-specific decisions must be made to achieve
the developers' specific goals, such as compliance with system-related and business-related
constraints, which may vary from one implementation to another. Moreover, it should
be appreciated that such a development effort might be complex and time consuming,
but would nevertheless be a routine undertaking of design, fabrication, and manufacture
for those of ordinary skill having the benefit of this disclosure.
[0010] When introducing elements of various embodiments of the present invention, the articles
"a," "an," "the," and "said" are intended to mean that there are one or more of the
elements. The terms "comprising," "including," and "having" are intended to be inclusive
and mean that there may be additional elements other than the listed elements.
[0011] As discussed below, certain embodiments of a turbine exhaust diffuser system include
manways that extend through the exhaust diffuser system at an angle that is not perpendicular
to a central axis of the exhaust diffuser system. For example, the manways may extend
through the exhaust diffuser system at an angle that is shifted within the range of
approximately 5 to 25 degrees, 3 to 15 degrees, or 10 to 30 degrees from being perpendicular
to the central axis of the diffuser system (e.g., the angle between the manways and
the central axis may be within a range of approximately 95 and 115 degrees, 93 to
105 degrees, or 100 to 120 degrees). Specifically, in certain embodiments, the manways
may extend through the exhaust diffuser system at an angle that is shifted approximately
15 degrees from being perpendicular to the central axis of the diffuser system. Consequently,
due to the manways not being perpendicular to the central axis of the exhaust diffuser
system, the amount of space for operator entry into an access tunnel of the exhaust
diffuser system is increased. Further, the amplitude and frequency of vortex shedding
(i.e., the unsteady flow of exhaust around the manways) is decreased when compared
to systems that have manways perpendicular to the central axis of the exhaust diffuser
system. As such, the exhaust diffuser systems described herein not only facilitate
maintenance of the exhaust diffuser systems by human operators, but also enhance operational
characteristics of the exhaust diffuser systems.
[0012] Turning now to the drawings and referring first to FIG. 1, an embodiment of a gas
turbine engine 100 is illustrated. The gas turbine engine 100 extends in an axial
direction 102. A radial direction 104 illustrates a direction extending outward from
a central axis 105 of the gas turbine engine 100. Further, a circumferential direction
106 illustrates the rotational direction around the central axis 105 of the gas turbine
engine 100. The gas turbine engine 100 includes one or more fuel nozzles 108 located
inside a combustor section 110. In certain embodiments, the gas turbine engine 100
may include multiple combustors 120 disposed in an annular (e.g., circumferential
106) arrangement within the combustor section 110. Further, each combustor 120 may
include multiple fuel nozzles 108 attached to or near a head end of each combustor
120 in an annular (e.g., circumferential 106) or other arrangement.
[0013] Air enters through an air intake section 122 and is compressed by a compressor 124
of the gas turbine engine 100. The compressed air from the compressor 124 is then
directed into the combustor section 110, where the compressed air is mixed with fuel.
The mixture of compressed air and fuel is generally burned within the combustor section
110 to generate high-temperature, high-pressure combustion gases, which are used to
generate torque within a turbine section 130 of the gas turbine engine 100. As noted
above, multiple combustors 120 may be annularly (e.g., circumferentially 106) disposed
within the combustor section 110 of the gas turbine engine 100. Each combustor 120
includes a transition piece 172 that directs the hot combustion gases from the combustor
120 to the turbine section 130 of the gas turbine engine 100. In particular, each
transition piece 172 generally defines a hot gas path from the combustor 120 to a
nozzle assembly of the turbine section 130, included within a first stage 174 of the
turbine section 130 of the gas turbine engine 100.
[0014] As illustrated in FIG. 1, the turbine section 130 includes three separate stages
or sections 174 (i.e., first stage or section), 176 (i.e., second stage or section),
and 178 (i.e., third stage or section, or last turbine bucket section). Although illustrated
as including three stages 174, 176, 178, it will be understood that, in other embodiments,
the turbine section 130 may include any number of stages. Each stage 174, 176, and
178 includes blades 180 coupled to a rotor wheel 182 rotatably attached to a shaft
184. As may be appreciated, each of the turbine blades 180 may be considered a turbine
bucket, or a bucket. Each stage 174, 176, and 178 also includes a nozzle assembly
186 disposed directly upstream of each set of blades 180. The nozzle assemblies 186
direct the hot combustion gases toward the blades 180 where the hot combustion gases
apply motive forces to the blades 180 to rotate the blades 180, thereby turning the
shaft 184. As a result, the blades 180 and shaft 184 rotate in the circumferential
direction 106. The hot combustion gases flow through each of the stages 174, 176,
and 178 applying motive forces to the blades 180 within each stage 174, 176, and 178.
The hot combustion gases may then exit the gas turbine section 130 into an exhaust
diffuser system 188 of the gas turbine engine 100. The exhaust diffuser system 188
reduces the velocity of fluid flow of the exhaust combustion gases from the gas turbine
section 130, and also increases the static pressure of the exhaust combustion gases
to increase the work produced by the gas turbine engine 100.
[0015] In the illustrated embodiment, the last turbine bucket section 178 of the turbine
section 130 includes a clearance 194 between ends of a plurality of last turbine bucket
blades 195 (e.g., the last blade 180 of the gas turbine section 130) and a stationary
shroud 196 disposed about the plurality of last turbine bucket blades 195. Further,
an outer wall 198 of the exhaust diffuser system 188 extends from the stationary shroud
196. A strut 200 is illustrated abutting the outer wall 198. Struts 200 are used to
support the structure of the exhaust diffuser section 188.
[0016] As illustrated, a manway 202 extends between the outer wall 198 and an inner wall
204 of the exhaust diffuser system 188. In certain embodiments, the manway 202 may
encompass pipes or tubes that are used to transport fluids from outside the exhaust
diffuser system 188 for use within the exhaust diffuser system 188. The inner wall
204 is formed by the outside of an access tunnel or converging passageway 206. In
certain embodiments, the inner wall 204 may extend at an angle 205 that is not parallel
to the central axis 105. For example, the angle 205 between the inner wall 204 and
the central axis 105 may be approximately 5 to 10 degrees, 3 to 7 degrees, or 8 to
15 degrees. As described in greater detail below, the manway 202 extends through the
exhaust diffuser system 188 at an angle that is not perpendicular to the central axis
105. When exhaust (e.g., the exhaust combustion gases from the gas turbine section
130) flows through the exhaust diffuser system 188, the exhaust flow is directed around
the manway 202 to exit the exhaust diffuser system 188. As such, the manway 202 may
cause vortex shedding to occur. However, the amplitude and frequency of the vortex
shedding may be lower in the present embodiments than in systems with manways 202
that are perpendicular to the central axis 105. Thus, there may be a decrease in pressure
loss, a decrease in noise, and an increase in overall diffuser performance in the
present embodiments when compared to systems with manways 202 that are perpendicular
to the central axis 105.
[0017] FIG. 2 is a perspective view of an embodiment of the gas turbine exhaust diffuser
system 188. In particular, the struts 200 are disposed around the inner wall 204 of
the exhaust diffuser system 188 and extend radially 104 from the inner wall 204 to
the outer wall 198 of the exhaust diffuser system 188 and thereby structurally support
the outer wall 198 of the exhaust diffuser system 188. When turbine exhaust flows
into the exhaust diffuser system 188, the exhaust flows through an area between the
inner wall 204 and the outer wall 198. Thus, the exhaust flows around the struts 200,
which alters the exhaust flow. Therefore, the properties of how the exhaust flows
through the exhaust diffuser system 188 are affected by the shape and position of
the struts 200. Further within the exhaust diffuser system 188, the exhaust flows
around one or more manways 202. Again, the properties of how the exhaust flows through
the exhaust diffuser system 188 are affected by the shape and position of the manways
202, as will be described in greater detail below. FIG. 3 is a side view of an embodiment
of the gas turbine exhaust diffuser system 188. FIG. 3 illustrates how multiple struts
200 may be arranged around the inner wall 204 of the exhaust diffuser system 188.
Further, the manways 202 are located behind the struts 200 (within the exhaust diffuser
system 188). As illustrated, the manways 202 also extend between the inner wall 204
and the outer wall 198 and may provide further support between the inner wall 204
and the outer wall 198. In particular, three manways 202 are illustrated, however,
other embodiments of the exhaust diffuser system 188 may have fewer or more manways
202.
[0018] FIG. 4 is a cross-sectional side view of an embodiment of the gas turbine exhaust
diffuser system 188. In particular, two manways 202 are depicted, a first manway 236
and a second manway 238. As previously described, the manways 202 extend from the
outer wall 198 to the inner wall 204 and extend through an exhaust flow area 240 through
which the turbine exhaust from the turbine section 130 flows. Although the manways
202 are illustrated as having a generally race-track shaped wall, the manways 202
walls may have any suitable shape (e.g., cylindrical, airfoil, etc.). Further, the
shape of the manways 202 may be designed to achieve optimal flow of exhaust around
the manways 202. In certain embodiments, pipes 241 and 242 may be disposed within
the manways 202 and extend from the manways 202 into the access tunnel 206 defined
within the inner wall 204 of the exhaust diffuser system 188. As discussed above,
the pipes 241 and 242 may be used for transporting fluid to be used by the turbine
exhaust diffuser system 188. For example, the pipe 241 may be used to transport lubricating
fluid (e.g., oil) through the manway 236 to the access tunnel 206 to be used by the
exhaust diffuser system 188 (e.g., to lubricate bearings). As another example, the
pipe 242 may be used to transport cooling air or fluid through the manway 238 to the
access tunnel 206 to be used for reducing the temperature of components within the
exhaust diffuser system 188.
[0019] The pipes 241 and 242 extend through the access tunnel 206 from an entry location
243 (e.g., where the manways 202 intersect with the access tunnel 206) toward a strut
region 244 of the access tunnel 206. As illustrated, the access tunnel 206 forms a
cone like shape which generally increases in diameter as the access tunnel 206 extends
from the entry location 243 toward the strut region 244. Therefore, a distance 246
between the pipes 241 and 242 may be based on the entry location 243 of the pipes
241 and 242 into the access tunnel 206. As may be appreciated, the distance 246 between
the pipes 241 and 242 may affect heat transfer that occurs between the pipes 241 and
242. Further, the distance 246 as well as the distances between the pipes 241 and
242 and the inner wall 204 may affect the ability of an operator to move through the
access tunnel 206, such as to perform maintenance. As such, in certain embodiments,
the manways 202 extend at an angle from the outer wall 198 toward the inner wall 204
that is not perpendicular to the central axis 105. By extending the manways 202 at
an angle not perpendicular to the central axis 105, the location of the manways 202
may cause the pipes 241 and 242 to enter the access tunnel 206 at a location where
the access tunnel 206 has a larger diameter than if the manways 202 extended toward
the access tunnel 206 at an angle perpendicular to the central axis 105, assuming
that the manways 202 extend from the same location of the outer wall 198 in both instances.
As a result, the distance 246 may increase and allow more space for an operator to
move within the access tunnel 206. For example, the distance 246 may increase because
the pipes 241 and 242 may extend from an entry location 243 where the access tunnel
206 has a larger diameter than in other entry locations. The larger diameter enables
the pipes 241 and 242 to remain a greater distance 246 from each other as they extend
into the access tunnel 206, remain close to the inner wall 204, and extend toward
the strut region 244. In certain embodiments, heat transfer between the pipes 241
and 242 may decrease as the distance 246 increases.
[0020] An entry distance 248 is the distance between the pipes 241 and 242 and an access
door 249 (at a downstream end of the access tunnel 206), which is used by an operator
to enter the access tunnel 206. As may be appreciated, as the entry distance 248 increases,
there is greater space for the operator to enter the access tunnel 206 through the
access door 249. The entry distance 248 is greater in the present embodiments than
in systems where the manways 202 extend perpendicular to the central axis 105, again
assuming that the manways 202 extend from the same location of the outer wall 198
in both instances.
[0021] There are generally two sides of each manway 202. Specifically, an upstream end 250
(e.g., the side of the manway 202 closest to the struts 200) and a downstream end
252 (e.g., the side of the manway 202 farthest from the struts 200). As illustrated,
the angle between the manways 202 and the central axis 105 may be described using
an upstream angle 254 (e.g., the angle between the upstream end 250 and the central
axis 105) or a downstream angle 256 (e.g., the angle between the downstream end 252
of the manway 202 and the central axis 105). The upstream angle 254 may be any suitable
angle greater than 90 degrees (e.g., not perpendicular), and the downstream angle
256 may be any suitable angle less than 90 degrees (e.g., not perpendicular). For
example, the upstream angle 254 may be within a range of approximately 95 to 115 degrees,
93 to 105 degrees, or 100 to 120 degrees. Specifically, the upstream angle 254 may
be approximately 105 degrees. On the other hand, the downstream angle 256 may be within
a range of approximately 65 to 85 degrees, 75 to 87 degrees, or 60 to 80 degrees.
In particular, the downstream angle 256 may be approximately 85 degrees. Further,
the upstream angle 254 and the downstream angle 256 are supplementary angles (i.e.,
they combine to equal 180 degrees).
[0022] As described above, during operation of the gas turbine engine 100, exhaust flows
through the exhaust diffuser system 188. The exhaust enters the exhaust diffuser system
188, flows around the struts 200, then flows through the exhaust flow area 240 and
around the manways 202 before the exhaust exits the exhaust diffuser system 188. As
such, the manways 202 may cause vortex shedding to occur. However, the amplitude and
frequency of the vortex shedding may be lower than in systems with manways 202 that
are perpendicular to the central axis 105. More specifically, because the manways
202 are angled away from the impinging flow of the exhaust, the amplitude and frequency
of vortex shedding may be drastically reduced as compared to perpendicular manways
202.
[0023] In summary, the technical effects of the present invention include providing greater
access for an operator to enter and maneuver within the access tunnel 206. Further,
heat transfer between pipes within the access tunnel 206 is decreased as the pipes
are moved away from each other within the access tunnel 206. In addition, the amplitude
and frequency of the vortex shedding is decreased (e.g., the flow of exhaust through
the exhaust diffuser system 188 is disturbed less). As a result, there may be a decrease
in pressure loss, a decrease in noise, and an increase in overall diffuser performance
in the present embodiments when compared to systems with manways 202 that are perpendicular
to the central axis 105.
[0024] 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 have 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 languages of the claims.
1. A turbine exhaust diffuser system (188), comprising:
an outer wall (198);
an inner wall (204) formed by a converging inner passageway (206), wherein turbine
exhaust is configured to flow through an area between the outer wall (198) and the
inner wall (204); and
at least one manway (202) extending from the outer wall (198) to the inner wall (204),
wherein the at least one manway (202) extends from the outer wall (198) to the inner
wall (204) at an angle (254) that is not perpendicular to a central axis (105) of
the turbine exhaust diffuser system (188).
2. The turbine exhaust diffuser system of claim 1, wherein the angle (254) at between
the at least one manway (202) and the central axis (105) is greater than approximately
95 degrees.
3. The turbine exhaust diffuser system of claim 1 or 2, wherein the angle (254) between
the at least one manway (202) and the central axis (105) is between approximately
100 and approximately 115 degrees.
4. The turbine exhaust diffuser system of claim 1, comprising a plurality of manways
(202) extending from the outer wall (198) to the inner wall (204), wherein each of
the plurality of manways (238) extends from the outer wall (198) to the inner wall
(204) at an angle that is not perpendicular to the central axis (105) of the turbine
exhaust system (188).
5. The turbine exhaust diffuser system of claim 4, wherein the plurality of manways (202)
comprises a first manway (236), a second manway (238), and a third manway.
6. The turbine exhaust diffuser system of claim 5, wherein the angles (256) between the
first (236), second (238), and third manways (202) and the central axis (105) are
between approximately 95 and approximately 115 degrees.
7. The turbine exhaust diffuser system of claim 5 or 6, wherein the second manway (236)
comprises pipes (241) for providing lubricating fluid to a turbine.
8. The turbine exhaust diffuser system of claim 5, 6 or 7, wherein the third manway (238)
comprises pipes (242) for providing cooling fluid to a turbine.
9. The turbine exhaust diffuser system of any preceding claim, wherein the converging
passageway (206) is configured to allow an operator to enter the converging passageway
(206) through an access door (249) and move within the converging passage (206).
10. The turbine exhaust diffuser system of claim 9, wherein the converging passageway
(206) comprises a conical shape having a smaller interior diameter toward a downstream
(244) end of the converging passageway (206).
11. The turbine exhaust diffuser system of any of claims 4, 9 or 10, wherein each of the
plurality of manways (202) comprises an upstream end (250) and a downstream end (252),
the manway (202) forming a first angle (254) between the upstream end (250) and the
central axis (105) and a second angle (256) between the downstream end (252) and the
central axis (105).
12. The turbine exhaust diffuser system of claim 11, wherein the first angle (254) is
greater than the second angle (256).
13. The turbine exhaust diffuser system of claim 11 or 12, wherein the first angle (254)
is between 95 and 110 degrees and the second angle (256) is between 70 and 85 degrees.