U.S. patent application number 09/742169 was filed with the patent office on 2001-06-21 for profiled surface used as an abradable in flow machines.
This patent application is currently assigned to Sulzer Metco AG. Invention is credited to Chasripoor, Farshad, Muller, Eduard.
Application Number | 20010004436 09/742169 |
Document ID | / |
Family ID | 8243195 |
Filed Date | 2001-06-21 |
United States Patent
Application |
20010004436 |
Kind Code |
A1 |
Chasripoor, Farshad ; et
al. |
June 21, 2001 |
Profiled surface used as an abradable in flow machines
Abstract
The profiled surface is used as an abradable (1) in flow
machines. In these machines blade tips (2) move over the profiled
abradable in a predetermined direction (v). In so doing they
produce a partial surface, an abraded surface (10), which is formed
by material ablation. The profiling of the surface is formed by
ribs (15) which surround chamber-like depressions (11). A rib
direction can in each case be associated with the ribs. The
abradable (1) forms a pattern which is built up of strip-like
elements (5) and the elements of which lie in the directions of the
ribs on connection lines (45) between corner points (41, 42; 43,
44) of a reference grid (40). Largely at each location of the
abraded surface (10)--i.e. at least at more than 80 - 95% of the
abraded surface--the rib direction differs from the direction of
movement (v) of the blade tips (2). For at least two thirds of the
abraded surface the direction of movement deviates from the rib
direction by more than 30.degree., preferably more than 45.degree..
The strip-like elements (5) of the abraded surface can be curved as
well as discrete and/or partly connected strips.
Inventors: |
Chasripoor, Farshad;
(Scotia, NY) ; Muller, Eduard; (Winterthur,
CH) |
Correspondence
Address: |
J. George Seka
Townsend and Townsend and Crew LLP
8th Fl.
Two Embarcadero Center
San Francisco
CA
94111
US
|
Assignee: |
Sulzer Metco AG
|
Family ID: |
8243195 |
Appl. No.: |
09/742169 |
Filed: |
December 19, 2000 |
Current U.S.
Class: |
415/174.4 |
Current CPC
Class: |
F01D 11/122 20130101;
F05D 2250/282 20130101; F05D 2250/283 20130101; F05D 2230/90
20130101; Y10T 428/24149 20150115; F05D 2250/181 20130101; Y02T
50/60 20130101; Y10T 29/4932 20150115; F05D 2250/60 20130101 |
Class at
Publication: |
415/174.4 |
International
Class: |
F01D 011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 1999 |
EP |
99811170.2 |
Claims
1. Profiled surface which is used as an abradable (1) in flow
machines, in which blade tips (2) move over the profiled abradable
in a predetermined direction (v) and in so doing produce a partial
surface--an abraded surface (10)--which is formed by material
ablation, with the profiling of the abradable being formed by ribs
(15), with it being possible in each case to associate a rib
direction with the ribs and with the abraded surface forming a
pattern which is built up of strip-like elements (5) and the
elements of which lie in the directions of the ribs on connection
lines (45) between corner points (41, 42; 43, 44) of a reference
grid (40), characterized in that largely at each location of the
abraded surface (10)--i.e. at least at 80%, preferably at more than
90% of the abraded surface--the rib direction differs from the
direction of movement (v) of the blade tips (2); in that for at
least two thirds of the abraded surface the direction of movement
deviates from the rib direction by more than 30.degree., preferably
more than 45.degree.; and in that the strip-like elements (5) of
the abraded surface can be curved as well as discrete and/or
connected or partly connected strips.
2. Profiled surface in accordance with claim 1, characterized in
that three axes x.sub.1, x.sub.2, y can be associated with each
corner point (41, 42) of the reference grid (40) and angles
.alpha..sub.12, .alpha..sub.2, and .alpha..sub.1 respectively are
subtended between these axes; in that ribs a.sub.1, a.sub.2, b lie
on the axes X.sub.1, X.sub.2 and y respectively, with a.sub.1 and
a.sub.2 being longer by a factor of 2 or more in comparison with b
and with the angles .alpha..sub.1, .alpha..sub.2, .alpha..sub.12 in
each case being greater than 100.degree. and less than 150.degree.;
in that all axes y are at least approximately parallel to one
another, i.e. are oriented in a single y-direction; and in that the
direction of movement (v) of the blade tip (2) deviates from the
y-direction by a small angle, which is 30.degree. at the most.
3. Profiled surface in accordance with claim 1 or claim 2,
characterized in that connection lines (45) between in each case
six corner points (41, 42) of the reference grid (40) can be
associated with the ribs (15) of the chamber-like depression
(11).
4. Profiled surface in accordance with claims 2 and 3,
characterized in that a gap is present instead of the rib b; or in
that the ribs a.sub.1, a.sub.2 are longer than the rib b by a
factor of 3 or more; or in that the length of the rib b is
practically negligible.
5. Profiled surface in accordance with claim 1, characterized in
that three axes x.sub.1, x.sub.2, y can be associated with each
corner point (43, 44) of the reference grid (40) and angles
.alpha..sub.12, .alpha..sub.2, and .alpha..sub.1 respectively are
subtended between these axes; in that ribs a.sub.1, a.sub.2 lie on
the axes x.sub.1, x.sub.2, with the ribs a.sub.1 and a.sub.2 being
largely equally long and with the angles .alpha..sub.1,
.alpha..sub.2, .alpha..sub.12 in each case being greater than
100.degree. and less than 150.degree.; in that for one portion of
the corner points (43) one rib b lies on the axis y and for the
further corner points (44) in each case a branching about the axis
y with two ribs b.sub.1, b.sub.2 is given, with b and,
respectively, b.sub.1 and b.sub.2 being largely of length equal to
that of a.sub.1 or a.sub.2, with an angle .beta..sub.12 between
b.sub.1 and b.sub.2 being greater than 30.degree. and less than
45.degree. and with the direction of movement of the blade tip
being substantially parallel to the axis y of one of the
branchings.
6. Profiled surface in accordance with any one of the claims 1 to
5, characterized in that the widths of the strip-like elements (5)
are greater than about 1 mm and are on the same order of magnitude
as the cross-sectional width of the blade tip, in particular less
than one to three times this width.
7. Profiled surface in accordance with any one of the claims 1 to
6, characterized in that it is manufactured by thermal spraying
onto a metallic substrate (3) with a material which is suitable for
known, non profiled abradables and which in particular contains
ceramic material, with the substrate having a profiled surface
having webs (35) and with it being possible for the profiling to be
present in different forms: as a cast profiling of a cast body; as
a profiling of woven or individual metallic wires which are applied
to a metallic body through soldering or by means of a laser welding
or diffusion welding; or as a profiling in the form of ribs which
are applied in a micro-casting manner through a laser application
welding.
8. Flow machine, in particular a gas turbine, comprising a profiled
surface which is used as an abradable (1) in accordance with any
one of the claims 1 to 7, characterized in that the blade tip (2)
is part of a rotor blade.
9. Flow machine in accordance with claim 8, characterized in that
the blade tip (2) is formed by a shrouded blade which has one or
more lamella which extend in the direction of movement (v) of the
blade tip and are therein formed in particular as sealing lips of a
labyrinth seal.
10. Flow machine, in particular a gas turbine, with a profiled
surface which is used as an abradable (1) in accordance with any
one of the claims 1 to 7, characterized in that the blade tip (2)
is part of a stationary guide blade and a sealing gap is located
between the blade tip and a moved machine part, with it being
possible for the abradable to be attached to a shrouded blade at
the tip of the stationary blade or to the surface of a rotor shaft
and the movement of the blade tip which is named in claim 1 being
understood as a relative movement.
Description
[0001] The invention relates to a profiled surface in accordance
with the preamble of claim 1 which is used as an abradable in flow
machines and to a flow machine with an abradable of this kind. The
profiled surface which is used as an abradable will be named an
abradable for short in the following.
[0002] In flow machines such as airplane propulsion units,
stationary gas turbines, turbocompressors and pumps it is necessary
for a high efficiency that at the periphery of a rotor carrying
rotor blades a sealing gap between the blade tips and the housing
be very narrow during operation. With the use of abradables on the
inner surface of the housing over which the tips of the rotor
blades move, it is possible to produce minimum sealing gaps without
the blade tips thereby being damaged. For high operating
temperatures, which lie above about 800.degree. C., the abradables
must be manufactured with a ceramic material, which is applied by
means of thermal spraying methods, flame spraying or atmospheric
plasma spraying. Through the admixing of a phase which can be
burned out (polymer powder) to a ceramic spraying powder, a
porosity of the abradable can be achieved thanks to which fine
particles can be released from the surface of the abradable by the
blade tips of the rotating rotor.
[0003] In ceramic abradables with non profiled surface the blade
tips must usually be armored, for example through laser re-melting
with the simultaneous addition of hard particles in order that they
are not damaged during the abrasion. Released abrasion particles
must be able to escape from the sealing gap without substantial
resistance. An abradable with a profiled surface is known from
EP-A-0 935 009. It was expected from the latter that abrasion
particles could escape without problems from the sealing gap and
that an armoring of the blade tips could be dispensed with. Tests
showed however that material was abraded at the non armored blade
tips during the abrasion in a manner which led to a corrugated edge
of the blade tips. A material ablation of this kind at the blade
tips can not be tolerated.
[0004] The object of the invention is to create an abradable which
is suitable for non armored blade tips. This object is satisfied by
the abradable which is characterized in claim 1.
[0005] The profiled surface is used as an abradable in flow
machines. In these machines blade tips move over the profiled
abradable in a predetermined direction. In so doing they produce a
partial surface, an abraded surface, which is formed by material
ablation. The profiling of the surface is formed by ribs which
surround chamber-like depressions. A rib direction can in each case
be associated with the ribs. The abraded surface forms a pattern
which is built up of strip-like elements and the elements of which
lie in the directions of the ribs on connection lines between
corner points of a reference grid. Largely at each location of the
abraded surface--i.e. at least at 80% to 95% of the abraded
surface--the rib direction differs from the direction of movement
of the blade tips. For at least two thirds of the abraded surface
the direction of movement deviates from the rib direction by more
than 30.degree., preferably more than 45.degree.. The strip-like
elements of the abraded surface can be curved as well as discrete
and/or partly connected strips.
[0006] Thanks to the design of the profiling of the abradable in
accordance with the invention, which is carried out taking the
direction of movement of the blade tips into account, there results
a lower material ablation at the non armored blade tips and in
addition a material ablation which is uniformly distributed over
the entire edge of a tip. In order to reduce the material ablation
at the blade tips still further, it can also be provided to armor
the blade tips.
[0007] Subordinate claims 2 to 7 relate to advantageous embodiments
of the abradable in accordance with the invention. The subject of
claims 8 to 10 is a flow machine with an abradable of this
kind.
[0008] The invention will be explained in the following with
reference to the drawings. Shown are:
[0009] FIG. 1 a cross-section through an abradable with a blade tip
running over an abraded surface,
[0010] FIG. 2 an oblique view of the abradable,
[0011] FIG. 3 a first pattern of the abraded surface of an
abradable in accordance with the invention,
[0012] FIGS. 4, 5 modifications of the first pattern,
[0013] FIGS. 6 - 10 patterns of further abraded surfaces in
accordance with the invention,
[0014] FIG. 11 a reference grid with a "Penrose" structure
comprising equilateral pentagons and rhombi,
[0015] FIG. 12 a corresponding pattern of an abraded surface
and
[0016] FIG. 13 a blade tip with a shrouded blade.
[0017] The abradable 1 which is illustrated in FIG. 1 as a
cross-section has a profiled surface, over which a blade tip 2
moves in a plane 20 in a predetermined direction v. Ribs 15 form
the profiling of the surface; they surround chamber-like
depressions 11. An original surface 10" of the abradable 1 is
indicated in chain-dotted lines. An abraded surface 10 in a plane
10' has been formed by the blade tip 2 through material ablation. A
narrow gap between the plane 20 and the abraded surface 10 is a
sealing gap which is produced by the material ablation. The abraded
surface 10 forms a pattern which can be imagined as being built up
of strip-like elements 5. The abradable 1 with the abraded surface
10 and depressions 11 is illustrated in an oblique view in FIG. 2.
The following FIGS. 3 to 12 show diverse patterns of the abraded
surface 10, such as result through material ablation of the
abradables 1 in accordance with the invention. The strip-like
elements 5 of the abraded surface 10 can be curved; they can also
be present as discrete and/or as partly connected strips.
[0018] The abradable 1 is applied to a metallic substrate 3 through
thermal spraying, with a material being used which for example
contains ceramic material for use at high temperatures and which
can already be known for the use in non profiled abradables (see
e.g. U.S. Pat. No. 5,434,210). The substrate 3 has a profiled
surface with webs 35. This profiling can be present in different
forms: as a cast profiling of a cast body; as a profiling which is
produced on an originally flat metallic body by means of
countersink erosion or by means of a mechanical cutting process; as
a profiling of woven or individual metallic wires which are applied
to a metallic body through soldering or by means of a laser welding
or diffusion welding; or as a profiling in the form of ribs which
are applied in a micro-casting manner through a laser application
welding.
[0019] In order that a build-up of ribs 15 is possible in the
thermal spraying onto the webs 35, it must be provided that the
widths of the strip-like elements 5 are greater than about 1 mm. In
order that no damage arises in the ablation of material from the
abradable 1, these widths must be on the same order of magnitude as
the cross-sectional width of the blade tip (width in the direction
of travel v); they should not exceed one to three times this
cross-sectional width.
[0020] The webs 35 have cross-sections which narrow in the
direction towards a rump 30 of the substrate 3. They can also form
gaps to the rump 30, as is known from the above named EP-A-0 935
009. As a result of this shaping the material which forms the
abradable 1 is anchored in depressions 31 between the webs 35.
[0021] A rib direction can be associated in each case with the ribs
15. In accordance with the invention the rib direction must differ
largely at each location of the abraded surface 10 from the
direction of movement v of the blade tip 2. In this, the term
"largely" is to be understood to mean that a like orientation of
the blade movement and the ribs is present for at most 5 - 15% or
20% of the abraded surface 10. To which extent these orientations
can be the same must be determined empirically. For at least two
thirds of the abraded surface 10 the direction of movement v must
deviate in accordance with the invention from the rib direction by
more than 30.degree., preferably more than 45.degree.. If these
conditions are met, then a non armored blade tip 2 can be used.
[0022] In FIG. 3 a first pattern of the abraded surface 10 of an
abradable 1 in accordance with the invention is shown. The pattern
is built up of the strip-like elements 5. These elements 5 lie in
the directions of the ribs 15 on connection lines 45 between corner
points 41, 42 of a reference grid 40. Three axes x.sub.1, x.sub.2,
y can be associated with each corner point 41 or 42 of the
reference grid 40. Angles .alpha..sub.12, .alpha..sub.2, and
.alpha..sub.1 respectively are subtended between these axes. Ribs
15, which are designated by a.sub.1, a.sub.2, b lie on the axes
x.sub.1, x.sub.2 and y respectively. The ribs a.sub.1 and a.sub.2
are longer than the rib b by a factor of 2 or more. The angles
.alpha..sub.1, .alpha..sub.2, a.sub.12 are in each case greater
than 100.degree. and less than 150.degree. (total sum 360.degree.).
The pattern shown has a generalized honeycombed structure:
connection lines 45 between in each case six corner points of the
reference grid 40, namely three corner points 41 and three corner
points 42, can be associated with the ribs 15 of the chamber-like
depressions 11.
[0023] Each axis y is at least approximately parallel to a single
y-direction. The direction of movement v of the blade tip 2
deviates from the y-direction by a small angle, which is 30.degree.
at the most. The rib b is preferably much smaller in comparison
with the ribs a.sub.1, a.sub.2, namely by a factor which is greater
than 3. The corner points 41 and 42 which are associated with the
rib b can be so close to one another that the rib b is practically
negligible, i.e. does not exist.
[0024] FIGS. 4 and 5 show modifications of the first pattern (FIG.
3). In FIG. 4 the pattern has a structure which resembles a
covering with fish scales. The ribs 15 are curved. In FIG. 5 the
pattern is composed of discrete elements 5. Only ribs a.sub.1 and
a.sub.2 are present; instead of the ribs b there are gaps.
[0025] FIG. 6 again shows a pattern of the abraded surface 10 which
is honeycomb-like. Elements 5' are arranged like islands in the
individual depressions 11. In FIG. 7 the strip-like elements 5 are
arranged connectedly on zigzag lines. The angles between the rib
directions and the direction of movement v is preferably 45.degree.
or else somewhat greater. The boundaries of the chamber-like
depressions 11 can not be given here uniquely; they can for example
be considered to be the rectangles 11' which are drawn in
chain-dotted lines. FIG. 8 again shows a pattern with discrete
elements 5, as does FIG. 5. This pattern has a certain relationship
with the zigzag pattern of FIG. 7 in that in this pattern every
other element 5 of the zigzag pattern is removed and the remaining
elements 5 are each prolonged at both ends. FIG. 9 shows a pattern
with depressions 11 which are rectangular and are arranged to be
displaced with respect to one another. A rhombic pattern is
illustrated in FIG. 10 in which the one rib direction is
perpendicular to the direction of movement v and the other rib
direction subtends an angle of about 45.degree. with the direction
of movement v.
[0026] In the exemplary embodiments of FIGS. 3 to 10 the abraded
surfaces 10 have in each case a profiling of which the reference
grid 40 can be built up of periodically arranged elementary cells
(hexagons or squares). A non periodic profiling is also possible,
the reference grid 40 of which for example has a "Penrose
structure" in accordance with FIG. 11. FIG. 12 shows a
corresponding pattern of an abraded surface 10 with depressions 11'
and 11" which are pentagonal or rhomboidal. This reference grid 40
comprises equilateral pentagons (angles between adjacent sides:
108.degree.) and rhombi (angle: 36.degree. and 144.degree.).
Whereas in the periodic grids two or three main directions are
present, there are five main directions in the "Penrose structure".
The direction of movement v of the blade tips 2 advantageously
deviates from one of these main directions by about 18.degree..
[0027] For a reference grid 40 which at least approximately has a
"Penrose structure", the following statements hold (cf. FIGS. 11,
12): Three axes x.sub.1, x.sub.2, y can be associated with each
corner point 43 or 44 of the reference grid 40. Angles
.alpha..sub.12, .alpha..sub.2, and .alpha..sub.1 respectively are
subtended between these axes. Ribs a.sub.1, a.sub.2 lie on the axes
x.sub.1, x.sub.2. The ribs a.sub.1 and a.sub.2 are largely equally
long. The angles .alpha..sub.1, .alpha..sub.2, .alpha..sub.12 are
in each case greater than 100.degree. and less than 150.degree.
(total sum 360.degree.). For one portion of the corner points,
namely the corner points 43, one rib b lies on the axis y. For the
further corner points 44 a branching about the axis y with two ribs
b.sub.1, b.sub.2 is given in each case. The ribs b and,
respectively, b.sub.1 and b.sub.2 are largely of length equal to
that of a.sub.1 or a.sub.2. An angle .beta..sub.12 between b.sub.1
and b.sub.2 is greater than 30.degree. and less than 45.degree..
The direction of movement v of the blade tip 2 is substantially
parallel to the axis y of one of the branchings.
[0028] The above described abradables can also be applied to a
movable machine part instead of to a housing wall, namely when the
blade is stationarily arranged, in particular is a rotor blade, and
the sealing gap is located between the blade tip at rest and the
moved machine part, with the machine part being in particular a
rotor shaft. Abradables can also be applied to shrouded blades at
the tips of stationary blades. The movement of the blade tip named
in claim 1 is therefore to be understood as a relative
movement.
[0029] A flow machine with an abradable 1 in accordance with the
invention can also contain blades of which the tips 2 are in each
case formed as a shrouded blade 21: see FIG. 13. The shrouded blade
21 has one or more lamella 22, 22' which extend in the direction of
movement v of the blade tip 2. When a plurality are present the
lamella 22, 22' form a labyrinth seal.
* * * * *