CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No.
61/639,315, filed April 27,2012, which is incorporated by reference herein in its
entirety.
The subject matter of this application may be related to the subject matter of
copending U.S. Patent Application No. 13/713,018, titled "WIDE DISCOURAGER
TOOTH," filed on even date herewith, which is incorporated by reference herein its
entirety.
BACKGROUND
The subject matter disclosed herein relates generally to apparatuses and
methods for mitigating vortex pimiping of pressiuization air in a turbine engine.
More specifically, not by way of limitation, present embodiments relate to
apparatuses and methods for mitigating vortex pumping effect on air pressure around
an oil sump of a turbme engine.
In the turbine engine, air is pressurized in a compressor and mixed with fiiel in
a combustor for generating hot combustion gases which flow downstream through
turbine stages. These turbine stages extract energy fi"om the combustion gases. A
high pressure tiu:bine includes a first stage nozzle and a rotor assembly including a
disk and a plurality of turbine blades. The high pressiure turbine first receives the hot
combustion gases firom the combustor and includes a first stage stator nozzle that
directs the combustion gases downstream through a row of high pressure turbine rotor
blades extending radially outwardly firom a first rotor disk. In a two stage tia-bine, a
second stage stator nozzle is positioned downstream of the first stage blades followed
in turn by a row of second stage turbine blades extending radially outwardly from a
second rotor disk. The stator nozzles turn the hot combustion gas in a manner to
maximize extraction at the adjacent downstream turbine blades.
[0005] The first and second rotor disks are joined to the compressor by a
corresponding rotor shaft for powering the compressor during operation. The turbine
engine may include a nimiber of stages of static air foils, commonly referred to as
vanes, interspaced in the engine axial direction between rotating air foils commonly
referred to as blades. A multi-stage low pressure turbine follows the two stage high
pressure turbine and is typically joined by a second shaft to a fan disposed upstream
from the compressor in a typical turbo fan aircraft engine configuration for powering
an aircraft in flight.
As the combustion gasses flow downstream through the turbine stages, energy
is extracted therefrom and the pressure of the combustion gas is reduced. The
combustion gas is used to power the compressor as well as a turbine output shaft for
power and marine use or provide thrust in aviation usage. In this manner, fuel energy
is converted to mechanical energy of the rotating shaft to power the compressor and
supply compressed air needed to continue the process.
One source of vortices in a turbine engine may be labyrinth seals which can
create significant tangential velocity. This may be caused by viscous drag effects
from the rotating components of the turbine engine, for example the seal or arm
extending to support a seal. In an otherwise non-swirling fluid flow, the creation of
these vortices can create significant pressure drop when associated with a change in
radius of the swirling fluid. In many cases, such a pressure drop may be highly
imdesirable.
In certain oil sumps, minimum pressure differential may be used to prevent oil
leakage and such pressure differential may be related to scavenge capability. When
the pressure differential around a sump is too high, oil leakage prevention
characteristics may be compromised. As utilized in the present disclosure, "pressure
differential around a sump" may refer to the maximum difference in air pressure on
the dry side of all oil seals for an individual sump.
The problem: In some oil sump configurations, excessive pressure differential
around an oil sump may cause undesirable oil leakage.
BRIEF DESCRIPTION OF THE INVENTION
At least one solution for the above-mentioned problem(s) is provided by the
present disclosure to include example embodiments, provided for illustrative teaching
and not meant to be limiting.
At least some aspects of the present disclosure may involve an oil sump and
the reduction of pressure loss upstream of an oil seal due to vortex pumping.
Pressiuized air flow may be directed away from a pathway wherein vortices may be
formed. The pressurized flow may be at least partially isolated from the effect of the
vortex on static air pressure by a pressurization tooth seal. Some example
embodiments may contribute to maintaining proper air pressure at an adjacent oil
sump seal and reducing leakage through that seal.
An example oil sump seal pressurization apparatus for a turbine engine
according to at least some aspects of the present disclosure may include an oil sump
comprising at least one bearing mounted therein, the bearing allowing rotation of a
shaft with respect to the sump; an oil seal operatively disposed between a non-rotating
structural member of the sump and the shaft, the oil sealing having an inward side
exposed to an interior of the oil sump and an outward side; a generally radially
inwardly oriented passage arranged to supply pressurization air to the outward side of
the oil seal; a generally radially outwardly oriented pathway arranged to receive at
least some of the pressurization air from the passage, the pathway being at least
partially defined by a generally radially outwardly extending arm disposed on the
shaft, the arm rotating with the shaft; and/or a windage shield at least partially
separating the passage and the pathway, the windage shield being operatively
moimted to the non-rotating structural member of the sump.
An example oil sump seal pressurization apparatus for a turbine engine
according to at least some aspects of the present disclosure may include a nonrotating
oil sump housing a bearing, the bearing supporting a rotatable shaft; an oil
seal at least partially isolating an interior of the oil sump, the oil seal operatively
acting between a non-rotating structural member of the siunp and the rotatable shaft; a
passage arranged to supply pressurization air to an outward side of the oil seal with
respect to the oil sump; a sump pressurization cavity disposed at least partially around
the oil sump, the sump pressurization cavity comprising a volume arranged to supply
the pressurization air to the passage; a non-rotatable windage shield disposed within
the sump pressurization cavity between the volume and a rotatable arm disposed on
the shaft; and/or a pressurization tooth fluidicly interposing the passage and the
rotatable arm, the pressurization tooth restricting flow of the pressurization air from
the passage towards the rotatable arm.
An example oil sump seal pressurization apparatus for a turbine engine
according to at least some aspects of the present disclosiure may include a nonrotating
oil sump housing a bearing, the bearing supporting a rotatable shaft; an oil
seal at least partially isolating an interior of the oil sump, the oil seal operatively
acting between a non-rotating structural member of the sump and the rotatable shaft; a
passage arranged to supply pressurization air to an outward side of the oil seal with
respect to the oil sump; a sump pressiuization cavity disposed at least partially around
the oil sump, the sump pressurization cavity comprising a volume arranged to supply
the pressurization air to the passage; a non-rotatable windage shield disposed within
the sump pressurization cavity between the volume and a rotatable arm disposed on
the shaft; a pressurization tooth fluidicly interposing the passage and the rotatable
arm, the pressurization tooth restricting flow of the pressurization air from the
passage towards the rotatable arm; and/or a discourager tooth disposed on the shaft
and extending radially outward towards a non-rotating land, the land being disposed
axially between the passage and the drain, the discourager tooth being spaced apart
from the land in a generally radial direction by a gap having a width, the discourager
tooth including an upper surface having a width. The pressurization tooth may extend
radially outwardly from the shaft generally towards the windage shield. The windage
shield may extend generally radially outward with respect to the shaft.
All of the above outlined features are to be imderstood as exemplary only and
many more features and objectives of the invention may be gleaned from the
disclosure herein. Therefore, no limiting interpretation of this summary is to be
understood without fiuther reading of the entire specification, claims, and drawings
included herewith.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject matter for which patent claim coverage is sought is particularly
pointed out and claimed herein. The subject matter and embodiments thereof,
however, may be best imderstood by reference to the following description taken in
conjunction with the accompanying drawing figures in which:
FIG. 1 is a side section view of a gas turbine engine;
FIG. 2 is a side section view of an example oil sump and related seal
structure; and
FIG. 3 is a detailed view of an example oil sump and related seal
structure, all in accordance with at least some aspects of the present
disclosure.
DETAILED DESCRIPTION
In the following detailed description, reference is made to the accompanying
drawings, which form a part hereof. In the drawings, similar symbols typically
identify similar components, unless context dictates otherwise. The illustrative
embodiments described in the detailed description, drawings, and claims are not
meant to be limiting. Other embodiments may be utilized, and other changes may be
made, without departing from the spirit or scope of the subject matter presented here.
It will be readily understood that the aspects of the present disclosure, as generally
described herein, and illustrated in the figures, can be arranged, substituted,
combined, and designed in a wide variety of different configurations, all of which are
explicitly contemplated and make part of this disclosure.
The present disclosure includes, inter alia, gas turbine engines, and, more
specifically, apparatuses and methods for mitigating vortex pumping of pressurization
air in a turbine engine. Some example embodiments according to at least some
aspects of the present disclosure may relate to apparatuses and methods for mitigating
vortex pimiping effect on air pressure aroimd an oil sump of a turbine engine.
Reference now will be made in detail to embodiments provided, one or more
examples of which are illustrated in the drawings. Each example is provided by way
of explanation, not limitation of the disclosed embodiments. In fact, it will be
apparent to those skilled in the art that various modifications and variations can be
made in the present embodiments without departing from the scope or spirit of the
disclosure. For instance, features illustrated or described as part of one embodiment
can be used with another embodiment to still yield further embodiments. Thus it is
intended that the present invention covers such modifications and variations as come
within the scope of the appended claims and their equivalents.
Some example embodiments may apply to gas turbine engines used in
connection with aviation, power generation, industrial, or marine uses in which a
combustor bums fiiel and discharges hot combustion gas into a high pressure turbine.
The instant stmctures and methods may help balance pressure across an oil sump for
either a low or a high speed turbine shaft and, more specifically, may limit pressure
loss due to vortex pumping of air upstream of an oil seal for the oil sump. Various
example embodiments according to at least some aspects of the present disclosure
may be applicable to vented as well as non-vented oil sump configurations.
The terms fore (or forward) and aft are used with respect to the engine axis
and generally mean toward the front of the turbine engine or the rear of the turbine
engine in the direction of the engine axis.
Figures 1-3 illustrate various example oil sump seal pressurization
apparatuses and methods of maintaining limited pressure drop across an oil sump,
according to at least some embodiments of the present disclosure. Some example
embodiments may limit the effect of vortex pumping on static pressure and thereby
limit pressure differential around the oil simip.
Referring initially to FIG. 1, a schematic side section view of a gas turbine
engine 10 is shown having an engine inlet end 12, a compressor 14, a combustor 16
and a multi-stage high pressure turbine 18. The gas turbine 10 may be used for
aviation, power generation, industrial, marine, or like applications. The gas turbine
10 is generally axis-symmetrical about axis 24. Depending on the usage, the engine
inlet end 12 may altematively contain multistage compressors rather than a fan. In
operation, air enters through the air inlet end 12 of the engine 10 and moves through
at least one stage of compression where the air pressure is increased and directed to
the combustor 16. The compressed air is mixed with fiiel and burned providing the
hot combustion gas which exits a combustor 16 toward the high pressure turbine 18.
At the high pressure turbine 18, energy is extracted from the hot combustion gas
causing rotation of turbine blades which in turn cause rotation of the high pressure
shaft 26, which passes toward the front of the engine to continue rotation of the one or
more compressors 14. A second shaft, low pressure shaft 28, mechanically couples a
low pressure turbine 21 and a turbo fan 20 or inlet fan blades, depending on the
turbine design.
The high pressure shaft 26 rotates about the axis 24 of the engine. The high
pressure shaft 26 extends through the turbine engine 10 and is supported by bearings.
The bearings operate in oil sumps to cool parts during the high speed revolution.
Fluid leakage in and around rotating parts may significantly increase fiiel
consumption and reduce engine efficiency resulting in undesirable operating
parameters for the turbine engine. Additionally, high pressiu-e gasses, such as
combustion gasses within the turbine and compressor discharge area, may leak from
high pressure areas to low pressure areas and controlling such leakage is preferred.
Control or inhibition of such leakage is performed in a variety of manners including,
for example, labyrinth seals and brush seals positioned between areas of differential
pressure. Over time, however, increased exposure to these high pressure and thermal
areas may result in loss of seal effectiveness.
In gas turbine engines it is frequently necessary or desirable to isolate a
volume, which may include one or more rotating parts, in order to confine a fluid,
such as oil, and to prevent such fluid from flowing into adjacent areas or flowing out
of the volume. For example, in a gas turbine engine, it may be necessary to confine a
liquid lubricant associated with shaft bearings to a volume surrounding the bearing in
order to prevent amounts of the fluid or oil from leaking from the volume or sump. In
oil sump structures, pressurized air may be utilized to pass aroxmd and/or through the
sump area in order to pressurize seals and prevent leakage as well as cool oil or
operating components. An exemplary sump area 30 is depicted at an aft end of the
shaft 26.
Some siunps, such as vented and non-vented oil sumps having a plurality of oil
seals comprising labyrinth type, carbon type, or other types, may rely on a minimal
pressure differential around the sump and/or between the oil seals to limit leakage.
When pressure differential is too high, seals may not fiinction appropriately, which
may be undesirable. The present disclosure contemplates that, in one structure, a
labyrinth seal operating at a high rate of revolution and having an adjacent passage
which varies in diameter and extends to a labyrinth oil seal operating at the same rate
of revolution but at a smaller diameter may result in a vortex of air upstream of the oil
seal. Additionally, the present disclosure contemplates that the decrease of the radius
of the vortex created by the rotation of the air near the labyrinth seal may result in
pressure loss between the two seals. As a result, it may be difficult to balance the
pressure differential between the seals to an acceptable level.
Referring now to FIG. 2, a side view of an aft oil sump is shown. In the aft
area of the turbine engine 10, one or more sumps may be located which service
bearings providing for rotation of a radially irmer or low pressure shaft 28 and a
radially outer shaft or high pressure shaft 26. The high pressure shaft 26
interconnects the high pressure turbine 18 and high pressure compressor 14, while the
inner shaft interconnects the low pressure compressor and low pressure turbine.
During operation of the turbine engine, both shafts will rotate at different speeds
relative to each other. Both shafts 26,28 may rotate in the same direction or in
opposite directions.
As shown in FIG. 2, at the left-hand side of the page a high pressure turbine 18
is represented by a rotor assembly 22 which is connected to the high pressure shaft 26
extending about and rotating about the center line axis 24 as well. Also depicted
radially below the high pressure shaft 26 is the low pressure shaft 28 which also
rotates about the engine axis 24.
Axially aft of the rotor assembly 22 is an oil sump housing, which is defined
by a pliurality of structural members 34, 36, 38,40,42,44 and 66. These members
generally define a volume 32 above the high pressure shaft 26 wherein oil is retained
for cooling and lubrication of at least one shaft bearing, and a sump pressurization
cavity comprising volumes 72,46 and 62 that surrounds the sump 32, through which
pressurization air 90 is supplied to the sump seals 68, 70. Oil seal 68 may be
operatively disposed between a non-rotating structural member of sump 32 (e.g.,
structural member 44) and shaft 26. Depending fi-om member 38 is a sump forward
air seal land 50 having a rub strip 52 located along a lower surface thereof Beneath
the sump forward air seal land 50 and engaging the rub strip 52 is a sump forward air
labyrinth seal 54. Labyrinth seal 54 includes a plurality of seal teeth which extend
radially upwardly to engage the rub strip 52. Axially aft of the labyrinth seal 54 and
extending radially outwardly along an arm 56 is a pathway 58. Arm 56 may extend
generally radially outwardly from the shaft 26 and/or may rotate with the shaft 26. In
this flow path 58, due to the rotation of the arm 56 and the labyrinth seal 54, a vortex
may be created, which may cause points more radially inward in the pathway 58 to be
at relatively lower static pressure than points more radially outward. This variation in
pressure may result in a pressure drop if air were to flow radially inwardly through
pathway 58 to oil seal 68. Subsequently, a pressure differential of the pressurization
flow 90 around the sump between aft seal 70 and forward seal 68 may be realized.
Moving axially aft from the windage shield 60 is a bypass flow path 62.
Beneath the windage shield 60 is a tooth seal or a pressurization tooth 64 (e.g., a
single tooth). The pressurization tooth 64 may substantially seal the flow path 58
and/or may substantially inhibit air in the lower pressure pathway (e.g., flow path 58),
wherein the vortex may be created, from decreasing the pressure on the aft side of the
pressurization tooth 64. To the aft of pressurization tooth 64 is a labyrinth oil seal 68,
which defines a forward seal for the oil sump 32. The aft seal 70 defines the opposite
seal for the oil sump 32. Within the sump 32 is a bearing assembly 80, for example a
roller bearing assembly, which may allow rotation of shaft 26.
As shown in the figure, pressurization air 90 moves radially upwardly into a
flow path 72 aft of the sump 32. The flow 90 moves upwardly through the flow path
72 and through an aperture in the structural member 40 and, for purposes of this
description, turns forward relative to the axial direction of the engine 10, toward the
windage shield 60. In the structural member 42, the flow 90 passes through a member
66 and moves downwardly through the bypass flow path 62 extending along the aft
side of the windage shield 60. As a result, the vortex created by rotation in the flow
area 58 may be substantially separated by the windage shield 60 fi-om the flow 90
moving through the bypass flow path 62.
As shown in the flgure, it is desirable that the pressure at the flow path area 72
adjacent to aft seal 70 and the pressure at the labyrinth oil seal 68 be close to equal or
that the pressure at the labyrinth oil seal 68 be very slightly lower than the pressure at
the aft seal 70. The air flow 90 at the seal 68 creates a barrier to oil fi-om the sump 32.
When the pressure differential is too high, as was the case with the vortex in path 58,
oil from the sump 32 could leak across the labyrinth oil seal 68. Thus, the pressure
differential around the oil sump 32 is minimized, thereby ensuring proper seal
performance and inhibiting leakage firom the seals.
FIG. 3 is a detailed view of the labyrinth seal 54 and a windage shield 60
adjacent the oil sump 32. The windage shield 60 extends upwardly above a
10
pressurization tooth 64 and may be moimted to a non-rotating structural member of
the sump (e.g., structural member 44). Axially forward of the windage shield 60 is
the flow path 58, which has a varying diameter wherein a vortex may form due to the
high speed rotation of the labyrinth seal 54 and arm 56 and varying diameter of path
58. However, the windage shield 60 directs a portion of the flow 90 to the aft side of
the shield 60 and through a passage 63, which may be generally radially inwardly
oriented. As a result, the vortex in the area of the pathway 58 is inhibited from
interacting with the flow path 62 on the aft side of the windage shield 60.
The pressurization tooth 64 limits the pressure drop associated with the vortex
on the forward side of the windage shield 60 from substantially adversely affecting
pressure on the aft side of the pressurization tooth 64. This results in higher pressure
downstream of passage 63. Pressurization tooth 64 may generally restrict flow of
pressurization air 90 therepast.
As the flow of pressurized air 90 moves into the pathway 62 aft of the windage
shield 60, some of the pressurized air 90 may turn toward the pressurization tooth 64,
move through that seal into the pathway 58, and experience a drop in pressure as it
passes through the restriction created by the seal. As the other portion of the flow 90
moves aft toward the labyrinth seal 68, pressure may be substantially maintained at
the seal 68 to inhibit oil from sump 32 from moving forward through the seal 68 and
leaking. Since the oil seal 68 fimctions as a seal for the oil sump 32, the pressurized
flow 90 on the forward side of the seal 68 inhibits the passage of oil from the aft side
of the oil seal 68 to the forward side.
As one skilled in the art will understand, the windage shield 60 directs
pressurized flow 90 to bypass an area 58 wherein a vortex is formed due to rotation.
Additionally, the pressurization tooth 64 may prevent the necessarily lower pressure
zone on the forward side of the tooth 64 from substantially affecting the static
pressure of the air on the aft side of the tooth 64.
Some example embodiments may include an aperture 65, which may operate
as a drain for leaked oil and/or may vent at least some of the pressurization air 90.
Aperture 65 may be positioned axially between passage 63 and oil seal 68.
Referring to Figures 2 and 3, a discourager tooth 74 may be located between
passage 63 and labyrinth oil seal 68. Discourager tooth 74 may be disposed on shaft
11
26 and/or may extend radially outwards towards a non-rotating land 76. Land 76 may
be disposed axially between passage 63 and oil seal 68. Discourager tooth 74 may be
spaced apart from land 76 in a generally radial direction by a gap 77 having a width
78. Discourager tooth 74 may include an upper surface having a width 175.
Pressurization tooth 64 may have a width 164 which may be measured in a generally
axial direction with respect to engine axis 24 (FIG. 1). Oil seal 68 may include one or
more teeth 69 having a width 169 which may be measured in a generally axial
direction with respect to engine axis 24 (FIG. 1).
In some example embodiments, the discoitfager tooth 74 may be at least about
1.5,2.0, or 2.5 times the width of adjacent teeth on the high pressure shaft 26, such as
the pressurization tooth 64 and the exemplary teeth 69 of the labyrinth seal 68. In
other words, in some example embodiments, discoxirager tooth width 175 may be at
least about 1.5 times pressurization tooth width 164 and/or seal tooth width 169. In
some example embodiments, discourager tooth width 175 may be at least about 2.0
times pressurization tooth width 164 and/or seal tooth width 169. In some example
embodiments, discourager tooth width 175 may be at least about 2.5 times
pressurization tooth width 164 and/or seal tooth width 169.
In some example embodiments, a ratio of discourager tooth width 175 to gap
width 78 may be greater than about 0.5. In some example embodiments, a ratio of
discourager tooth width 175 to gap width 78 may be greater than about 1.0. In some
example embodiments, a ratio of discourager tooth width 175 to gap width 78 may be
greater than about 4.0.
Accordingly, embodiments of the instant apparatus provides mitigation of
pimiping effect in the area of the sump forward air seal 54 and arm 56 and/or
minimize pressure loss across the oil sump 32 from the aft seal 70 to the labyrinth oil
seal 68. By inhibiting pressure loss across the sxmip, pressiuization air 90 may be
more effectively utilized at the labyrinth seal 68 to deter oil leakage from the siunp
32.
While multiple inventive embodiments have been described and illustrated
herein, those of ordinary skill in the art will readily envision a variety of other means
and/or structures for performing the fimction and/or obtaining the results and/or one
or more of the advantages described herein, and each of such variations and/or
12
modifications is deemed to be within the scope of the invent of embodiments
described herein. More generally, those skilled in the art will readily appreciate that
all parameters, dimensions, materials, and configurations described herein are meant
to be exemplary and that the actual parameters, dimensions, materials, and/or
configurations will depend upon the specific application or applications for which the
inventive teachings is/are used. Those skilled in the art will recognize, or be able to
ascertain using no more than routine experimentation, many equivalents to the
specific inventive embodiments described herein. It is, therefore, to be imderstood
that the foregoing embodiments are presented by way of example only and that,
within the scope of the appended claims and equivalents thereto, inventive
embodiments may be practiced otherwise than as specifically described and claimed.
Inventive embodiments of the present disclosure are directed to each individual
feature, system, article, material, kit, and/or method described herein. In addition, any
combination of two or more such features, systems, articles, materials, kits, and/or
methods, if such features, systems, articles, materials, kits, and/or methods are not
mutually inconsistent, is included within the inventive scope of the present disclosure.
Examples are used to disclose the embodiments, including the best mode, and
also to enable any person skilled in the art to practice the apparatus and/or method,
including making and using any devices or systems and performing any incorporated
methods. These examples are not intended to be exhaustive or to limit the disclosure
to the precise steps and/or forms disclosed, and many modifications and variations are
possible in light of the above teaching. Features described herein may be combined in
any combination. Steps of a method described herein may be performed in any
sequence that is physically possible.
All definitions, as defined and used herein, should be understood to control
over dictionary definitions, definitions in documents incorporated by reference,
and/or ordinary meanings of the defined terms. The indefinite articles "a" and "an,"
as used herein in the specification and in the claims, unless clearly indicated to the
contrary, should be understood to mean "at least one." The phrase "and/or," as used
herein in the specification and in the claims, should be imderstood to mean "either or
both" of the elements so conjoined, i.e., elements that are conjunctively present in
some cases and disjunctively present in other cases.
13
It should also be understood that, imless clearly indicated to the contrary, in
any methods claimed herein that include more than one step or act, the order of the
steps or acts of the method is not necessarily limited to the order in which the steps or
acts of the method are recited.
In the claims, as well as in the specification above, all transitional phrases such
as "comprising," "including," "carrying," "having," "containing," "involving,"
"holding," "composed of," and the like are to be understood to be open-ended, i.e., to
mean including but not limited to. Only the transitional phrases "consisting o f and
"consisting essentially o f shall be closed or semi-closed transitional phrases,
respectively, as set forth in the United States Patent Office Manual of Patent
Examining Procedures, Section 2111.03.
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 fi-om the literal language of the claims, or if they include equivalent
structural elements with insubstantial differences fi-om the literal languages of the
claims.
14

We Claims:
1. An oil sump seal pressurization apparatus for a turbine engine, the oil sump seal
pressurization apparatus comprising:
an oil sump comprising at least one bearing mounted therein, the bearing
allowing rotation of a shaft with respect to the sump;
an oil seal operatively disposed between a non-rotating structural member of
the sump and the shaft, the oil sealing having an mward side exposed to an interior of
the oil sump and an outward side;
a generally radially inwardly oriented passage arranged to supply
pressurization ak to the outward side of the oil seal;
^ a generally radially outwardly oriented pathway arranged to receive at least
some of the pressurization air fi-om the passage, the pathway being at least partially
defined by a generally radially outwardly extending arm disposed on the shaft, the
arm rotating with the shaft; and
a windage shield at least partially separating the passage and the pathway, the
windage shield being operatively mounted to the non-rotating structural member of
the sump.
2. The oil sump seal pressurization apparatus of claim 1, fiirther comprising a
pressurization tooth operatively disposed between the passage and the pathway, the
pressurization tooth restricting flow of the pressurization air therepast.
3. The oil sump seal pressiuization apparatus of claim 2,
^ ^ fiuther comprising a discourager tooth disposed on the shaft and extending
radially outward towards a non-rotating land, the land being disposed axially between
the passage and the oil seal, the discourager tooth being spaced apart from the land in
a generally radial direction by a gap having a width, the discourager tooth including
an upper surface having a width;
wherein the discourager tooth width is at least about 1.5 times a width of the
pressurization tooth.
4. The oil sump seal pressurization apparatus of claim 2, wherein the pressurization
tooth extends radially outwardly from the shaft generally towards the windage shield.
15
5. The oil sump seal pressurization apparatus of claim 1, wherein the windage shield
extends generally radially outward with respect to the shaft.
6. The oil sump seal pressurization apparatus of claim 1, wherein an air seal is
disposed on the arm.
7. The oil sump seal pressurization apparatus of claim 1, fiuther comprising
a drain arranged to allow draining of oil and venting of at least some of the
pressurization air, the drain being positioned axially between the passage and the oil
seal; and
a discourager tooth disposed on the shaft and extending radially outward
A towards a non-rotating land, the land being disposed axially between the passage and
the drain, the discourager tooth being spaced apart fi-om the land in a generally radial
direction by a gap having a width, the discourager tooth including an upper surface
having a width.
8. The oil sump seal pressurization apparatus of claim 7, wherein the discoxu-ager
tooth width is at least about 2.0 times a width of the pressurization tooth.
9. The oil sump seal pressurization apparatus of claim 7, wherein a ratio of
discourager tooth width to gap width is greater than about 0.5.
10. An oil sump seal pressiirization apparatus for a turbine engine, the oil sump seal
pressurization apparatus comprising
9 ^ non-rotating oil sump hoiising a bearing, the bearing supporting a rotatable
shaft;
an oil seal at least partially isolating an interior of the oil sump, the oil seal
operatively acting between a non-rotating structural member of the sump and the
rotatable shaft;
a passage arranged to supply pressurization air to an outward side of the oil
seal with respect to the oil sxmip;
a sump pressurization cavity disposed at least partially around the oil sump,
the sump pressurization cavity comprising a volume arranged to supply the
pressurization air to the passage;
16
a non-rotatable windage shield disposed within the sxrnip pressurization cavity
between the volume and a rotatable arm disposed on the shaft; and
a pressurization tooth fluidicly interposing the passage and the rotatable arm,
the pressurization tooth restricting flow of the pressurization air from the passage
towards the rotatable arm.
11. The oil sump seal pressurization apparatus of claim 10, wherein the
pressurization tooth extends radially outwardly from the shaft generally towards the
windage shield.
12. The oil sump seal pressurization apparatus of claim 10, wherein the windage
^ shield extends generally radially outward with respect to the shaft.
13. The oil simip seal pressurization apparatus of claim 10, wherein an air seal is
disposed on the arm.
14. The oil simip seal pressurization apparatus of claim 10,
fruther comprising a discourager tooth disposed on the shaft and extending
radially outward towards a non-rotating land, the land being disposed axially between
the passage and the oil seal, the discourager tooth being spaced apart from the land in
a generally radial direction by a gap having a width, the discourager tooth including
an upper surface having a width;
15. The oil sump seal pressurization apparatus of claim 14, wherein the discoiu*ager
9 tooth width is at least about 1.5 times a width of the pressurization tooth.
16. An oil sump seal pressurization apparatus for a turbine engine, the oil sump seal
pressurization apparatus comprising
a non-rotating oil sump housing a bearing, the bearing supporting a rotatable
shaft;
an oil seal at least partially isolating an interior of the oil sump, the oil seal
operatively acting between a non-rotating structural member of the sump and the
rotatable shaft;
a passage arranged to supply pressiirization air to an outward side of the oil
seal with respect to the oil sump;
17
a sump pressurization cavity disposed at least partially around the oil sump,
the sump pressurization cavity comprising a volume arranged to supply the
pressurization air to the passage;
a non-rotatable windage shield disposed within the sump pressurization cavity
between the volume and a rotatable arm disposed on the shaft;
a pressurization tooth fluidicly interposing the passage and the rotatable arm,
the pressurization tooth restricting flow of the pressurization air from the passage
towards the rotatable arm; and
a discourager tooth disposed on the shaft and extending radially outward
towards a non-rotating land, the land being disposed axially between the passage and
^k the drain, the discourager tooth being spaced apart from the land in a generally radial
direction by a gap having a width, the discourager tooth including an upper surface
having a width;
wherein the pressurization tooth extends radially outwardly from the shaft
generally towards the windage shield; and
wherein the windage shield extends generally radially outward with respect to
the shaft.
17. The oil sump seal pressurization apparatus of claim 16, fiirther comprising a drain
arranged to allow draining of oil and venting of at least some of the pressurization air,
the drain being positioned axially between the passage and the oil seal.
18. The oil sump seal pressurization apparatus of claim 16, wherein the discourager
^ tooth width is at least about 1.5 times a width of the pressurization tooth.
19. The oil sump seal pressurization apparatus of claim 16, wherein the discourager
tooth width is at least about 2.0 times a width of the pressurization tooth.
20. The oil sump seal pressurization apparatus of claim 16, wherein the discourager
tooth width is at least about 2.5 times a width of the pressurization tooth.