U.S. patent application number 12/837250 was filed with the patent office on 2011-01-20 for rotary drum of an axial compressor having a composite web.
Invention is credited to Andre Lhoest.
Application Number | 20110014041 12/837250 |
Document ID | / |
Family ID | 41168466 |
Filed Date | 2011-01-20 |
United States Patent
Application |
20110014041 |
Kind Code |
A1 |
Lhoest; Andre |
January 20, 2011 |
Rotary Drum of an Axial Compressor Having a Composite Web
Abstract
A rotary drum of an axial compressor having a web made of
composite material has an upstream flange for fastening the fan, a
segment having a sealing flange upstream, a segment with a groove
adapted to receive the bases of the vane of a first row of vanes, a
segment with a groove adapted to receive the bases of the vane of a
second row of vanes, and a segment with a groove adapted to receive
the bases of the vane of a third row of vanes. These segments are
made of metallic material mostly for reasons of mechanical
resistance to the centrifugal forces. The segments are connected to
each other with web segments made of composite material. The ends
of the metallic segments have a dovetail-shaped section in a
longitudinal plane that is able to ensure a positive connection
with the composite material.
Inventors: |
Lhoest; Andre; (Huy,
BE) |
Correspondence
Address: |
LAW OFFICES OF JAMES E. WALTON, PLLC
1169 N. BURLESON BLVD., SUITE 107-328
BURLESON
TX
76028
US
|
Family ID: |
41168466 |
Appl. No.: |
12/837250 |
Filed: |
July 15, 2010 |
Current U.S.
Class: |
415/209.3 ;
29/889.21 |
Current CPC
Class: |
F01D 5/066 20130101;
F05D 2300/603 20130101; Y10T 29/49321 20150115 |
Class at
Publication: |
415/209.3 ;
29/889.21 |
International
Class: |
F01D 9/06 20060101
F01D009/06; F04D 29/54 20060101 F04D029/54; B21K 25/00 20060101
B21K025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 16, 2009 |
EP |
EP 09165612.4 |
Claims
1. A rotary drum of an axial turbomachine, comprising: a first
segment; a second segment; and a third segment adjacent to the
first segment and the second segment, the third segment forming a
web for connecting the first segment to the second segment; wherein
the first segment, the second segment, and the third segment form a
generally symmetrical wall revolving about a longitudinal axis; and
wherein the third segment is made of composite material and is
connected to at least one of the first segment and the second
segment by molding the composite material onto an end of at least
one of the first and the second segment.
2. The rotary drum according to claim 1, wherein at least one of
the first segment and the second segment is adapted to receive a
row of vanes.
3. The rotary drum according to claim 1, wherein at least one of
the first and the second segment comprises: a cavity in the form of
a circular groove adapted to receive bases of the vanes.
4. The rotary drum according to claim 3, wherein the cavity
includes a section that is diminished toward the outside of the
cavity, so as to enable a fixation by mechanically embedding the
bases of vanes.
5. The rotary drum according to claim 1, wherein the end of each
segment in contact with the composite material of the third segment
has a shape that facilitates the connection between such segment
and the third segment.
6. The rotary drum according to claim 1, wherein the end of each
segment in contact with the composite material of the third segment
has a section in a longitudinal plane in the form of a
dovetail.
7. The rotary drum according to claim 1, wherein the third segment
has a generally constant thickness between the connecting areas
with the first segment and the second segment.
8. The rotary drum according to claim 1, wherein the composite
material of the third segment covers both the outer surface and the
inner surface of the end of each segment connected thereto.
9. The rotary drum according claim 1, wherein the third segment
comprises: at least one knife edge on an outer surface thereof, the
knife edge being adapted to cooperate with a ring made of abradable
material of a guide vane grid in order to ensure sealing.
10. The rotary drum according to claim 1, wherein at least one of
the first segment and the second segment is made of a metallic
material.
11. The rotary drum according to claim 10, wherein at least one of
the first segment and the second segment is made of titanium.
12. A method for manufacturing a rotary drum of an axial
turbomachine, comprising: providing a first segment; providing a
second segment, distinct from the first segment; setting the first
segment and the second segment in place about a longitudinal axis;
and providing a third segment made of composite material, the third
segment forming a connection web between the first segment and the
second segment.
13. The method according to claim 12, comprising: using a device to
set the first segment and the second segment in place and to form
the connection web between the first segment, the second segment,
and the third segment.
14. The method according to claim 13, wherein the device comprises:
a means for molding the third segment.
15. The method according to claim 13, wherein the device comprises:
a means for counter-molding the third segment.
16. The method according to claim 12, wherein the forming a
connection web between the first segment, the second segment, and
the third segment comprises: applying a composite material on at
least one of an outer surface and an inner surface of the end of at
least one of the first segment and the second segment.
17. The method according to claim 12, wherein the forming a
connection web between the first segment, the second segment, and
the third segment comprises: providing a rib on an outer surface of
the third segment adapted to cooperate with a ring made of
abradable material of a guide vane grid to ensure sealing.
Description
[0001] This application claims priority under 35 U.S.C. .sctn.119
to European Patent Application No. 09065612.4, filed 16 Jul. 2009,
titled "Rotary Drum of an Axial Compressor Having a Composite Web,"
which is incorporated herein by reference for all purposes.
BACKGROUND
[0002] 1. Field of the Application
[0003] The application relates to a rotary drum of an axial
turbomachine, more particularly to a drum of an axial
compressor.
[0004] 2. Description of Related Art
[0005] A compressor of an axial turbomachine conventionally
comprises several compression stages, and therefore several rows of
vanes, these rows being axially spaced apart from one another in
order to arrange for annular spaces for the guide vane grids. The
rotor conventionally comprises a drum and rows of vanes affixed to
the drum. The drum thus has two main functions: to maintain the
fixed vanes with respect to one another, and to set them in motion.
To secure the vanes, an increased drum strength is required,
particularly due to high centrifugal forces generated by the mass
of the vanes and high rotation speeds when guiding the fluid stream
more greatly requires a surface which is optimized from an
aerodynamic standpoint and sealing means with the straightening
stages.
[0006] Having several stages (typically 3 or 4) makes the drum
quite long. Machining is thus made particularly difficult and
costly, as shown in FIG. 1. FIG. 1 is a cross-sectional view
showing a blank 1 made of a metallic material, conventionally
titanium, adapted to be machined so as to make a finished drum. The
drum has the general shape of an ogive and comprises three grooves
4, 6, and 8, adapted to receive three rows of vanes forming, with
the vanes of the guide vane grid (not shown), three compression
stages. The drum comprises an upstream flange in the area of the
rotation and symmetry axis adapted to be fixed to an entry rotor
blading, commonly referred to as "fan". It comprises a sealing
flange 3 adapted to cooperate with some "abradable" of the stator
to prevent a leak upstream of the fluid stream displaced and
compressed by the "fan". It also comprises ribs, commonly referred
to as knife edges, on both sides of each groove 4, 6, 8 of the row
of vanes. These knife edges are adapted to cooperate in a tight
manner, with the inner shrouds of the stators (not shown). A
stiffener 9 is provided on the inner surface of the drum in the
vicinity of the last groove 8. It must be noted that the general
layout of the drum is such that a greater portion, typically on the
order of 80%, of the material of the blank 1 must be removed by
machining in order to achieve the drum 2 shown. Manufacturing the
drum involves very high material and machining costs. Furthermore,
machining in the concave portion of the drum is difficult due to
its length and to the difficulty of accessing the inner surface of
the drum.
[0007] Different constructions of rotary drums of axial
turbomachines having several elements are known by one having
ordinary skill in the art.
[0008] The document GB 1 272 200 discloses a drum made of several
segments extending along the axis of rotation, whereby each segment
comprises a recess adapted to receive a row of vanes and a section
of web adjacent to the recess. These various segments are assembled
and welded together in order to make a complete drum. The sections
of the web are reinforced by applying fibers and an epoxy resin in
a trough of their outer surfaces provided for this purpose. The
purpose of these strips of composite material is to reinforce the
drum with respect to the centrifugal forces, in particular those
generated in the area of the rotor vanes. However, this design
requires multiple operations such as applying the composite
material, assembling the segments with each other and welding them,
which means that the cost for making a drum still remains quite
high.
[0009] The documents US 2007/0231144 and EP 1 406 019 A1 disclose
similar teachings to those of the previous document.
[0010] The document U.S. Pat. No. 5,632,600 discloses a principle
for building a rotor of an axial turbomachine whereby the rotor is
constituted of a series of disks carrying the rows of vanes. The
disks are assembled and fixed to one another by a mechanical
connection such as putting into contact the corresponding teeth and
by applying a strip of composite material to the mechanical
connection. This substantial construction typical of a rotor with
disks is not suitable for the construction of a drum such as
described and shown in FIG. 1, particularly due to the thickness
and shape of the strip of composite material.
[0011] Although great strides have been made in the area of rotary
drums of axial compressors, many shortcomings remain.
DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a cross-sectional view of an upper half of a known
drum and of a blank made of a metallic material necessary to making
it by machining said blank.
[0013] FIG. 2 is a cross-sectional view of an upper half of a drum
in accordance with the present application, the drum being
partially composite.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] The present application involves a rotary drum of an axial
turbomachine, the drum comprising a wall, generally symmetrical,
revolving about a longitudinal axis, said wall comprising, along
said longitudinal axis: a first segment; a second segment; a third
segment adjacent to the first and second segments and forming a web
for connecting the first segment to the second segment; whereby the
third segment is made of composite material and is connected to the
first and/or second segment by molding said composite material onto
an end of the first and/or second segment.
[0015] This construction has several advantages. Indeed, it makes
it possible to make the segments to be machined from blanks such
that they require less material to be removed in comparison with
the machining of a drum made of one piece from a single blank.
Moreover, fractioning the drum into segments diminishes the
financial losses due to machining discards. Indeed, the fact of
discarding one segment obviously makes for a much reduced financial
loss than in the case where the entire drum is discarded. Machining
metal segments is easier and therefore faster and less costly. The
accessibility from the machining perspective provides a certain
freedom when it comes to choosing the shape of a stiffener. The
latter can be optimized from a functional point of view and not as
a function of machining and of obtaining the blank. The composite
material is used at the location where the stresses are the
weakest, which results in a general optimization in terms of the
weight while enjoying the advantages hereinabove mentioned. This
construction also opens up new possibilities for repairing a
drum.
[0016] According to an advantageous embodiment of the present
application, the first and/or second segment is able to receive a
row of vanes, preferably the first and/or second segment comprises
a cavity in the form of a circular groove adapted to receive the
bases of the vanes.
[0017] According to an advantageous embodiment of the present
application, the cavity of the first segment has a section which
diminishes toward the outside of the cavity so as to enable a
fixation by mechanical embedding of the bases of the vanes.
[0018] According to another advantageous embodiment of the present
application, the end of the first and/or second segment in contact
with the composite material of the third segment has a shape
adapted to facilitate the connection between the two segments.
[0019] According to an advantageous embodiment of the present
application, the end of the first and/or second segment in contact
with the composite material of the third segment has a section in a
longitudinal plane in the form of a dovetail.
[0020] According to an advantageous embodiment of the present
application, the third segment has a generally constant thickness
between the connecting areas with the first and second
segments.
[0021] According to an advantageous embodiment of the present
application, the composite material of the third segment covers the
end of the first and/or second segment on its outer surface and on
its inner surface.
[0022] According to an advantageous embodiment of the present
application, the third segment comprises at least one rib referred
to as knife edge, on its outer surface, the knife edge being
adapted to cooperate with a ring made of abradable material of a
guide vane grid to ensure sealing.
[0023] According to an advantageous embodiment of the present
application, the first and/or second segment is made of metallic
material, preferably titanium.
[0024] The present application also involves a method of
fabricating a rotary drum of an axial turbomachine, the drum
comprising a generally symmetrical wall revolving about a
longitudinal axis, the method comprising the following steps:
[0025] (a) preparing a first segment;
[0026] (b) preparing a second segment, distinct from the first
segment;
[0027] (c) setting the first and the second segments in place;
and
[0028] (d) fabricating a third segment made of composite material
forming a connection web between the first segment and the second
segment.
[0029] According to an advantageous embodiment of the present
application, the method comprises the use of a device used for the
steps (c) and (d).
[0030] According to an advantageous embodiment of the present
application, the device comprises means for molding the third
segment.
[0031] According to an advantageous embodiment of the present
application, the device comprises means for counter-molding the
third segment.
[0032] According to an advantageous embodiment of the present
application, step (d) comprises applying the composite material
onto an outer and/or inner surface of the end of the first and/or
second segment.
[0033] According to an advantageous embodiment of the present
application, step (d) comprises making a rib on the outer surface
of the third segment adapted to cooperate with a ring made of an
abradable material of a guide vane grid in order to provide
sealing.
[0034] The drum 12 shown in FIG. 2 is the preferred embodiment of
the present application. It is made of a series of metallic
segments extending along the longitudinal axis which is also the
rotation axis of the drum, these segments having generally
mechanical properties and being connected to one another by web
segments made of composite material.
[0035] The drum 12 has the general shape of an ogive. It comprises
a fastening flange 20 at its upstream end. This flange is adapted
to fasten the drum to the vaned disk, or "fan", at the most
upstream point of the compressor. The drum also comprises a segment
22 with an upstream sealing flange 13. The flange is adapted to
cooperate in a sealing manner with a stationary element of the
stator (not shown) in order to prevent a leak upstream of the fluid
stream after the compression carried out by the "fan". The drum
also comprises three segments 24, 27, and 30, each comprising a
groove or recess 14, 16, and 18, respectively, adapted to receive
the bases of the vane. These different metal sections 20, 22, 24,
27, and 30 are connected to one another by web segments of the drum
21, 23, 26, and 29 made of composite material. This construction
results in that the segments or sections of the drum subjected to
greater mechanical stresses are conventionally made of metallic
material and in that the segments or sections forming the web of
the drum and being subjected to substantially weaker mechanical
stresses are made of composite material.
[0036] The ends of the segments made of metallic material 20, 22,
24, 27, and 30 adapted to be connected to a segment made of
composite material have a section in a longitudinal plane in the
form of a dovetail in order to enable a positive-contact connection
with the composite segment to which they are connected. The
composite material covers the upper and lower surfaces of the
dovetailed end.
[0037] The connection between the composite segments and the
metallic segments shown in FIG. 2 is given only by way of example.
Indeed, numerous alternatives are possible. The mechanical
connection is typically ensured by cohesion between the composite
material and the contact surface of the metallic material. Just as
the example of connection shown in FIG. 2, the connection can also
be reinforced by a retention shape of the metallic part, namely,
able to ensure a positive contact with the composite material. An
L-shape, hook shape, or any other shape section with a positive
contact, for example, could be considered.
[0038] The material of the metallic segments is typically titanium,
for reasons of weight. Other materials or variations known by one
having ordinary skill in the art can, of course, be considered.
[0039] The composite material of the segments forming the web
typically comprises reinforcement fibers and a resin forming a
matrix and making the fibers cohesive. The fibers can be glass,
carbon, aramid (Kevlar.RTM.), boron, silica, or high-modulus
polyethylene fibers. They are applied in the form of uni- or
multi-directional naps. The resin is typically a thermosetting
resin of the unsaturated polyester, phenolic, epoxide,
polyurethane, polyimide type, or other.
[0040] According to an embodiment of the present application, the
assembly of the different segments in view of fabricating a
finished drum comprises the use of a device (not shown) used for
positioning the preformed segments with respect to one another in a
precise manner. This device is also used as a mold for applying
composite materials making up the connecting segments. For example,
the device can comprise sections of an inner or outer mold on which
the reinforcement naps are laid and the resin is manually applied
(contact molding). Alternatively, the materials can be applied by
simultaneously spraying up resin and fibers. Preferably, the device
comprises a mold and a counter-mold, the reinforcement naps being
arranged in the air gap of the mold. This makes it possible to
inject liquid resin between the mold and the counter-mold through
the reinforcement until the cavity is entirely filled up. After the
resin has set, the mold is opened and the piece is taken out of the
mold. Other methods known by one having ordinary skill in the art
are possible, such as, for example, matched-die molding, or molding
by compound injection (mass to be molded made of resin, various
charges and adjuvants, reinforced by chopped strands).
[0041] The web segments 26 and 29 comprise knife edges 15 and 17,
respectively, directly molded with the segments. The knife edges
are thin circular ribs directed toward the outside of the drum.
They are adapted to cooperate by friction in a sealing manner with
the inner surface of a ring of friable material, commonly referred
to as "abradable", mounted on an inner shroud of a blade row,
adapted to rectify the airflow which is compressed and accelerated
by the rotation of a row of rotary vanes directly upstream.
[0042] It must be noted that these knife edges do not necessarily
have to be molded in one piece with the web of the segment. Indeed,
they can be made out of another material, more conventionally a
metallic material, and then be embedded in the composite
material.
[0043] The metallic segments, more particularly those subjected to
great centrifugal forces, particularly due to the presence of the
vanes, can be equipped on their inner surfaces with reinforcements
25, 28, and 31 machined or forged directly in the mass. Machining
such reinforcements is made much easier and therefore less costly
by the construction of the segment around the drum. The presence of
these reinforcements can result in a gain of material which would
otherwise be distributed over the thickness of the segment in order
to provide a stiffness and a resistance equivalent to the
centrifugal forces exerted.
[0044] It must be noted that all the web portions of the drum do
not necessarily have to be made of composite material. Indeed,
although the example in FIG. 2 shows a composite segment between
each pair of neighboring segments adapted to be subjected to great
forces, it is absolutely possible to provide composite segments
only between certain segments and to leave one or several webs made
of a conventional metallic material, as a function of various
design parameters such as for example the manufacturing cost and
the available machining capacities. The contrary is also
applicable, which means that it is also possible to provide for
making more elements of the drum from composite as a function of
the feasibility in terms of mold and mechanical resistance
forces.
[0045] A segment extending along the longitudinal axis of a rotary
drum of an axial turbomachine is also disclosed, the drum
comprising a generally symmetrical wall revolving about a
longitudinal axis, the segment being adapted to receive a row of
vanes and comprising an edge extending along the longitudinal axis
whose section on a longitudinal plane has a shape, preferably
dovetailed, which is adapted to enable a positive-contact
connection extending along the longitudinal axis with an element
made of composite material molded on said edge. The various
alternatives described in the present application and in particular
in relation to FIG. 2 apply only to the segment such as described
hereinabove.
* * * * *