U.S. patent application number 15/091320 was filed with the patent office on 2016-11-10 for rotor drum for a turbomachine and compressor.
The applicant listed for this patent is MTU Aero Engines AG. Invention is credited to Stefan Boewing.
Application Number | 20160327065 15/091320 |
Document ID | / |
Family ID | 53054925 |
Filed Date | 2016-11-10 |
United States Patent
Application |
20160327065 |
Kind Code |
A1 |
Boewing; Stefan |
November 10, 2016 |
ROTOR DRUM FOR A TURBOMACHINE AND COMPRESSOR
Abstract
A rotor drum (100) for a turbomachine, the rotor drum (100)
including portions of at least a first rotor main body (3) and a
second rotor main body (5), and the second rotor main body (5)
having at least one rotor arm (7) is provided. The rotor drum (100)
has at least one opening (1) as a passage opening for allowing
fluids to pass therethrough from an inner rotor space (22) to an
outer rotor space (23), the opening (1) being disposed radially
outwardly at the greatest radius (19) of an inner contour (21) of
the rotor drum (100). A compressor is also provided.
Inventors: |
Boewing; Stefan; (Muenchen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MTU Aero Engines AG |
Muenchen |
|
DE |
|
|
Family ID: |
53054925 |
Appl. No.: |
15/091320 |
Filed: |
April 5, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F05D 2260/609 20130101;
F04D 29/321 20130101; F04D 29/701 20130101; F01D 5/06 20130101;
F01D 11/001 20130101; F01D 5/027 20130101; F04D 29/083 20130101;
F01D 17/162 20130101 |
International
Class: |
F04D 29/70 20060101
F04D029/70; F04D 29/08 20060101 F04D029/08; F04D 29/32 20060101
F04D029/32 |
Foreign Application Data
Date |
Code |
Application Number |
May 7, 2015 |
EP |
EP15166681.5 |
Claims
1. A rotor drum for a turbomachine, the rotor drum comprising:
portions of at least a first rotor main body and a second rotor
main body, the second rotor main body having at least one rotor
arm, and at least one opening as a passage opening for allowing
fluids to pass therethrough from an inner rotor space to an outer
rotor space, the opening being disposed radially outwardly at a
greatest radius of an inner contour of the rotor drum.
2. The rotor drum as recited in claim 1 wherein the rotor arm
includes the opening.
3. The rotor drum as recited in claim 1 wherein the rotor arm has
at least one sealing tip to form a clearance seal with respect to a
stator.
4. The rotor drum as recited in claim 3 wherein the opening is
disposed between the at least one sealing tip and a radially
inwardly oriented rotor disk of the second rotor main body.
5. The rotor drum as recited in claim 1 wherein a balancing ring is
disposed radially outwardly on the rotor arm.
6. The rotor drum as recited in claim 5 wherein the balancing ring
is disposed at the upstream or downstream end portion of the rotor
arm of the second rotor main body.
7. The rotor drum as recited in claim 1 wherein the first and
second rotor main bodies are prepared for receiving rotor blades to
form a first and a second rotor stage.
8. A compressor of a turbomachine, the compressor comprising at
least one rotor drum as recited in claim 1.
9. The compressor as recited in claim 8 wherein the compressor is a
high-pressure compressor of an aircraft engine.
Description
[0001] This claims the benefit of European Patent Application
EP15166681.5, filed May 7, 2015 and hereby incorporated by
reference herein.
[0002] The present invention relates to a rotor drum for a
turbomachine.
BACKGROUND
[0003] In turbomachine rotors, liquid accumulations may occur in
certain operating situations and may collect in cavities of rotor
drums due to centrifugal force during the operation of the rotors.
It is only when the rotors are at rest that this accumulated liquid
may flow into other regions of the rotors and possibly cause
various disadvantages. For example, when the rotor is restarted,
oil in liquid form may be distributed to regions of the
turbomachine where such oil accumulations result in considerable
disadvantages. In a possible application of the turbomachine as an
aircraft engine, the oil may, for example, enter the cabin supply
air through casing channels after restarting of the rotors, and
there result in oil smell and contaminations.
SUMMARY OF THE INVENTION
[0004] It is an object of the present invention to provide a rotor
drum for a turbomachine, in which fluid accumulations can be
prevented. It is also an object of the present invention to provide
a compressor.
[0005] The present invention provides a rotor drum for a
turbomachine, the rotor drum including portions of at least a first
rotor main body and a second rotor main body. The second rotor main
body has at least one rotor arm. The rotor drum further has at
least one opening as a passage opening, in particular as a hole,
for allowing fluids, in particular bearing oil or condensed bearing
oil mist of a rotor bearing, to pass therethrough from an inner
rotor space to an outer rotor space. The opening is disposed
radially outwardly with respect to the main flow axis of the
turbomachine. Furthermore, the opening is disposed at the greatest
radius of an inner contour of the rotor drum. It can thus
advantageously be achieved that, during operational rotation of the
rotor drum, bearing oil collects at the opening and is spun off
from the rotor drum into the main flow passage due to centrifugal
force. The spun-off oil can be carried with the main flow out of
the turbomachine and discharged therefrom.
[0006] Advantageous refinements of the present invention are the
subject matter of the respective specific embodiments, for
example.
[0007] Specific exemplary embodiments of the present invention may
include one or more of the features mentioned below.
[0008] The term "rotor," as used herein, refers to a rotating body
in a turbomachine, which rotates about an axis of rotation of the
turbomachine during normal operational use. The rotor includes at
least one rotor stage. A rotor stage may be referred to as a blade
wheel or include a blade wheel. A rotor stage includes at least a
plurality of rotor blades and a rotor main body. The rotor main
body may be referred to as, or include, a disk, rotor disk, ring,
or rotor ring. A rotor may have one or more rotor stages.
[0009] A rotor may be mounted and installed in a turbomachine, in
particular in a gas turbine. An aircraft engine may be a gas
turbine or include a gas turbine. An aircraft engine may include a
compressor having a plurality of compressor stages and a turbine
having a plurality of turbine stages. Compressor stages and turbine
stages may each have rotor stages and stator stages.
[0010] The rotor blades may be referred to as blades and each have
at least an airfoil portion, a root portion and a platform portion.
The blades may be connected to the rotor main body either
integrally therewith or separately, for example, form-fittingly by
means of releasable connections known as dovetail connections.
Separate blades may be connected to the rotor main body either
releasably and/or form-fittingly and/or by a material-to-material
bond. An integral connection is, in particular, a
material-to-material bond. An integral connection may be produced
using an additive manufacturing process. A rotor main body having
blades integrally connected therewith may be referred to as
integrally bladed rotor. An integrally bladed rotor may be what is
known as a BLISK (bladed disk) or a BLING (bladed ring).
[0011] The rotor main body may include radially inwardly directed
rotor disks and/or axially oriented rotor arms. The radially
inwardly directed rotor disks may be referred to as extensions or
T-shaped extensions of the rotor blades.
[0012] The rotor arms may be referred to as drum members. The rotor
is designed or prepared for direct or indirect connection to a
shaft of the turbomachine. An indirect connection may be via a hub
and/or via further rotors. In the case of a direct connection, the
rotor may be flange-mounted directly to the shaft.
[0013] The term "rotor drum," as used herein, refers to sections of
at least two axially interconnected rotor main bodies. In
particular, rotor arms may form a rotor drum. A rotor drum may also
be configured to extend over more than two rotor main bodies, and
optionally over a plurality of rotor arms and rotor disks. For
example, a plurality of rotor main bodies of an eight-stage
compressor in a turbomachine may form one rotor drum.
[0014] The terms "inner rotor space" and "outer rotor space," as
used herein, refer to the spaces inside and outside of the rotor
drum of rotors. Thus, the inner rotor space is radially outwardly
bounded essentially by one or more rotor arms. The inner rotor
space is axially bounded essentially by rotor disks. Generally, a
gap is formed between a shaft to which the rotor drum is directly
or indirectly connected and the rotor disks. The outer rotor space
is radially inwardly bounded essentially by one or more rotor arms.
The outer rotor space substantially includes the main flow passage
of the turbomachine. Furthermore, between a rotor arm and the main
flow passage, there may be disposed, for example, inner stator
rings, either with or without abradable seals. The inner rotor
space and/or the outer rotor space may include a plurality of rotor
stages.
[0015] Rotor main bodies arranged axially one behind the other may
be interconnected by rotor arms and/or rotor disks. The connection
is, in particular, by form-fitting engagement and/or frictional
engagement.
[0016] Annular balancing collars may be disposed inside the rotor
drum, in particular on the inner surface of the rotor arms. The
balancing collars may be connected to the rotor arms by frictional
engagement. Alternatively or additionally, further balancing
devices, such as flanges having balancing weights mounted
circumferentially therearound, may be disposed inside the rotor
drum.
[0017] In several embodiments of the present invention, the
turbomachine is an axial turbomachine, in particular a gas turbine,
and, more particularly, an aircraft gas turbine.
[0018] The rotor drum according to the present invention may be
adapted for use in a high-pressure compressor, in a low-pressure
compressor, in a high-pressure turbine, or in a low-pressure
turbine of an aircraft engine.
[0019] A rotor arm may have one or more openings. The openings may
be disposed either radially (perpendicularly to the centerline of
the rotor drum) or at a different angle in or on the rotor arm. The
openings open toward the inner rotor drum space and toward the
outer rotor drum space, and provide a port between these two spaces
or regions. Thus, the opening penetrates the rotor arm in a
direction from radially inward to radially outward.
[0020] The opening at the radially widest or greatest radius of the
inner contour of the rotor drum may advantageously allow or cause
fluids, in particular bearing oil, to flow out of the rotor drum
into the outer rotor drum space (radially outside of the rotor
drum) due to centrifugal force during rotation, in particular
during normal operational use of the rotor drum. For example, when
the rotor drum according to the present invention is used in an
aircraft engine, it is possible to eliminate, or at least reduce,
the risk of oil flowing from the rotor drum into the engine casing
after a standstill of the engine. When the aircraft engine is
restarted, this oil in the engine casing could then enter the
supply air to the cabin and thus contaminate the cabin air.
[0021] The inner space of the rotor drum is particularly configured
such that oil accumulations resulting from centrifugal force may
flow off or escape through one or more openings into the outer
space of the rotor drum. The inner space is in particular
fluidically optimized for this purpose.
[0022] In several embodiments of the present invention, bearing oil
in the bearing region, for example in a so-called front-hub and/or
rear-hub bearing assembly of a rotor, may evaporate due to
increased frictional heat in the bearing and may then condense in
the inventive rotor drum. The condensation process may occur in
particular in a rotor drum that is located in the immediate
vicinity of the bearing. During operation of the turbomachine;
i.e., during rotation of the rotor drum, the condensed bearing oil
may escape, i.e., be thrown out into the main flow passage, through
the radial opening of the inventive rotor drum, and may then
advantageously exit the turbomachine with the main flow. Thus, when
the turbomachine is started after a temporary stoppage, oil which
has accumulated in the rotor drum in cavities can advantageously be
prevented from escaping and then entering the bleed air tapped or
bled off from the main flow due to low rotational speeds and a low
flow rate of the main flow. The bleed air provided, inter alia, for
the cabin air in aircraft could be contaminated by entrained
oil.
[0023] In some embodiments of the present invention, bearing oil
mist may escape through the radial opening of the inventive rotor
drum. During operation of the turbomachine, the bearing oil mist
may escape into the main flow passage and exit the turbomachine
with the main flow.
[0024] In certain embodiments of the present invention, the rotor
arm has at least one sealing tip to form a clearance seal with
respect to a stator. The stator may be a stator stage or a stator
vane assembly, in particular a stator vane assembly having variable
stator vanes.
[0025] In several embodiments of the present invention, the opening
is disposed axially between the at least one sealing tip and a
radially inwardly oriented rotor disk of the second rotor main
body.
[0026] In some embodiments of the present invention, the at least
one rotor arm of the inventive rotor drum has a balancing ring. In
particular, the balancing ring is disposed radially outwardly on
the rotor arm. A balancing ring that is disposed radially outwardly
on the rotor arm advantageously makes it possible to prevent
cavities inside the rotor drum.
[0027] A balancing ring may be referred to as a balancing
collar.
[0028] In several embodiments of the present invention, the
balancing ring is disposed at the upstream and/or downstream end or
end portion of the rotor arm. The terms "upstream" and "downstream"
refer to the main flow direction of the turbomachine. The end
portion or portions of the rotor arms may be portions for
connection to further components of the turbomachine. In
particular, the end portions may be form-fittingly connected to
further rotor main bodies. The end portions may also be
flange-mounted to further rotor main bodies by means of threaded
connections. An end portion of a rotor arm may have a balancing
ring and at the same time be form-fittingly connected to a further
rotor disk. Such an end portion may be referred to as an integral
end portion, since it implements two functions at the same time,
namely a balancing function and a connecting function.
[0029] In some embodiments of the present invention, a rotor main
body not having a rotor arm does not have a balancing device. A
balancing device may be, for example, a balancing ring or balancing
weights disposed on a flange.
[0030] In certain specific embodiments according to the present
invention, the balancing ring is connected to the rotor arm by
frictional engagement. A frictional connection may be achieved, for
example, by shrink-fitting. A frictional connection may be an
interference-fit connection. In particular, the connection of the
balancing ring to the rotor arm does not have a threaded
connection. A balancing ring mounted by means of a frictional
connection may advantageously be balanced using a material-removal
process, such as milling, drilling or grinding, without having to
remove the balancing ring from the rotor arm.
[0031] In certain specific embodiments according to the present
invention, the balancing ring is connected to the rotor arm by a
material-to-material bond. A material-to-material bond is, for
example, an adhesive bond, a welded connection or a connection
produced by means of an additive manufacturing process.
[0032] In some embodiments of the present invention, the rotor arm
is made from or contains a first material. The balancing ring may
be made from or contain a second material. The first material and
the second material are different. This advantageously makes it
possible, for example, to simplify shrink-fitting of the balancing
ring onto rotor arm and/or removal of material from the balancing
ring for balancing purposes.
[0033] In several embodiments of the present invention, the
balancing ring has on its periphery at least one region for
material removal for balancing of the rotor. Examples of
material-removal processes for removal of material from the
balancing ring include milling, drilling and grinding.
[0034] The term "balancing device" may include one or more
balancing rings, one or more balancing weights, as well as other
devices for balancing or counterbalancing a component.
[0035] Some or all of the embodiments of the present invention may
have one, several or all of the advantages mentioned above and/or
hereinafter.
[0036] The rotor drum according to the present invention
advantageously makes it possible to prevent oil accumulations, for
example, accumulations of bearing oil, inside the rotor drum. In a
rotating rotor drum according to the present invention, bearing oil
or bearing oil mist can be carried directly through the opening at
the greatest radius of the inner contour of the rotor drum into the
main flow through the stator vanes and rotor blades, and passed on
to the outlet of the turbomachine. This quick removal makes it
possible to at least reduce a potential fire hazard posed by the
oil. It is advantageously possible to prevent oil from accumulating
and/or oil mist from condensing while the rotor drum is at rest,
and to prevent oil from subsequently being carried from the main
flow into branches for the bleed air, for example for the cabin air
in aircraft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The present invention will now be described, by way of
example only, with reference to the accompanying drawings, in which
identical or similar components are indicated by the same reference
numerals. The figures are simplified schematic views in which:
[0038] FIG. 1 is a cross-sectional view of an inventive rotor drum
having two rotor main bodies, one rotor arm, and a spin-off hole;
and
[0039] FIG. 2 is a view showing another rotor drum according to the
present invention, where the spin-off hole is arranged differently
than in FIG. 1.
DETAILED DESCRIPTION
[0040] FIG. 1 shows, in cross-sectional view, an inventive rotor
drum 100 having an opening as a spin-off hole 1, a first rotor main
body 3, a second rotor main body 5, a rotor arm 7, and a balancing
ring 9. Spin-off hole 1 is an opening of rotor drum 100 in its
radially outward boundary. Rotor drum 100 has a radially inwardly
open shape.
[0041] Rotor drum 100, which is open radially inwardly (in a
direction opposite to radial direction r toward axis of rotation 11
of rotor drum 100), is bounded in axial direction a by a first
rotor disk 13 and a second rotor disk 15. The two rotor disks 13,
15 are sections of the two rotor main bodies 3, 5. First rotor disk
13 is disposed at the upstream end and second rotor disk 15 is
disposed at the downstream end. Main flow direction 17 is indicated
by an arrow.
[0042] Spin-off hole 1 is disposed at the greatest radius 19 of an
inner contour 21 of rotor drum 100.
[0043] Further spin-off holes 1 (not shown in FIG. 1) may be
disposed, in particular, in rotor arm 7.
[0044] In other embodiments, rotor drum 100 may extend further in
the upstream direction and/or in the downstream direction and may
include further rotor arms. Also, further spin-off holes may be
disposed in the further rotor arms. For example, a multi-stage
high-pressure compressor (or low-pressure compressor, high-pressure
turbine, low-pressure turbine) of an aircraft engine may include
one rotor drum.
[0045] During rotation of rotor drum 100 about axis of rotation 11
(during intended operation of rotor drum 100, for example, in an
aircraft engine), bearing oil, bearing oil mist or other fluids can
be carried from rotor drum 100 through spin-off hole 1 into an
outer rotor space 23. Such removal or draining of a fluid is due to
or caused by the centrifugal force of the fluid. The flow
properties are influenced by viscosity and temperature, for
example. Furthermore, the flow of a fluid out of rotor drum 100
into outer rotor space 23 is influenced by the size of a cross
section (or diameter) of spin-off hole 1.
[0046] Furthermore, in the exemplary embodiment of FIG. 1,
balancing ring 9 is disposed on the outer surface of rotor drum 100
(as viewed in radial direction r). This makes it easier for oil
present in rotor drum 100 to flow off through flow-out hole 1. If
balancing ring 9 were disposed on rotor arm 7 on the inner surface
of rotor drum 100 (not illustrated in FIG. 1), the oil could be
dammed up in inner rotor space 22 due to centrifugal force. This
dammed-up oil would then not flow off into the inner space until
rotor drum 100 is at rest. When rotor drum 100 is set into rotation
again, this oil could then escape through spin-off hole 1. In this
process, due to operational conditions, oil from outer rotor space
23 could enter the cabin air of an aircraft with the bleed air that
is tapped or bled off from the main flow, and could cause
contamination. This risk of contamination is advantageously
prevented, or at least reduced, by disposing balancing ring 9 on
the outer surface of rotor drum 100.
[0047] In the region of balancing ring 9, first rotor main body 3
is form-fittingly connected to second rotor main body 5 via rotor
arm 7 (as indicated by dashed-line circle 25).
[0048] In the exemplary embodiment of FIG. 1, rotor main bodies 3,
5 are integrally connected to rotor blades 27. Furthermore, rotor
arm 7 has sealing tips 29 which may form a gap with an abradable
seal 31 that minimizes leakage flow between rotor drum 100 and a
stator vane assembly 200. Abradable seal 31 is connected to an
inner ring 33. Inner ring 33 is connected to variable stator vanes
35 of stator vane assembly 200. Stator vanes 35 are mounted and
supported rotatably about their longitudinal axis by means of an
inner trunnion 37.
[0049] FIG. 2 shows another rotor drum 100 according to the present
invention, where spin-off hole 1 is arranged differently than in
FIG. 1. The longitudinal orientation of spin-off hole 1 is
perpendicular to the centerline of rotor drum 100.
LIST OF REFERENCE NUMERALS
[0050] 100 rotor drum [0051] 200 stator vane assembly [0052] a
axial; axial direction [0053] r radial; radial direction [0054] 1
spin-off hole [0055] 3 first rotor main body [0056] 5 second rotor
main body [0057] 7 rotor arm [0058] 9 balancing ring [0059] 11 axis
of rotation [0060] 13 first rotor disk [0061] 15 second rotor disk
[0062] 17 main flow direction [0063] 19 greatest radius of the
inner contour of the rotor drum [0064] 21 inner contour of the
rotor drum [0065] 22 inner rotor space [0066] 23 outer rotor space
[0067] 25 form-fitting connection [0068] 27 rotor blade [0069] 29
sealing tips [0070] 31 abradable seal [0071] 33 inner ring [0072]
35 variable stator vane [0073] 37 inner trunnion
* * * * *