U.S. patent application number 13/258624 was filed with the patent office on 2012-03-22 for axial turbomachine rotor having blade cooling.
Invention is credited to Fathi Ahmad.
Application Number | 20120070310 13/258624 |
Document ID | / |
Family ID | 41347504 |
Filed Date | 2012-03-22 |
United States Patent
Application |
20120070310 |
Kind Code |
A1 |
Ahmad; Fathi |
March 22, 2012 |
AXIAL TURBOMACHINE ROTOR HAVING BLADE COOLING
Abstract
An axial turbomachine rotor is provided. The rotor includes a
rotor disk and a rotor blade ring, which includes a plurality of
rotor blades, each of which include a blade root, with which the
rotor blade is fixed radially outward on the rotor disk, wherein
the blade root is engaged with the rotor disk at the outer edge of
the rotor disk in a form-closed manner in such a way that during
operation of the rotor, a gap is formed between the rotor blade and
the rotor disk at a predetermined surface area of the rotor disk,
in which area, a plurality of impingement cooling openings is
arranged, through which a cooling medium may flow from the interior
of the rotor disk into the gap whereby the rotor blade is cooled
using the cooling medium by means of impingement cooling.
Inventors: |
Ahmad; Fathi; (Kaarst,
DE) |
Family ID: |
41347504 |
Appl. No.: |
13/258624 |
Filed: |
March 25, 2010 |
PCT Filed: |
March 25, 2010 |
PCT NO: |
PCT/EP10/53866 |
371 Date: |
December 1, 2011 |
Current U.S.
Class: |
416/97R |
Current CPC
Class: |
F01D 25/12 20130101;
F01D 5/087 20130101; F05D 2260/201 20130101 |
Class at
Publication: |
416/97.R |
International
Class: |
F01D 5/18 20060101
F01D005/18 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2009 |
EP |
09004471.0 |
Claims
1.-9. (canceled)
10. An axial turbomachine having a rotor disk and a rotor blade
ring, comprising: a plurality of rotor blades, each including a
blade root by which the rotor blade is fixed radially outwards on
the rotor disk; and a plurality of impingement-cooling openings,
wherein the blade root engages with the rotor disk on an outer edge
of the rotor disk in a form-fitting manner in such a way that
during operation of the axial turbomachine rotor, a gap is formed
between the rotor blade and the rotor disk in a predetermined
surface region of the rotor disk, and wherein in the gap are
arranged the plurality of impingement-cooling openings through
which a cooling medium may flow from an interior of the rotor disk
into the gap, as a result of which the rotor blade is cooled by the
cooling medium by means of impingement cooling and the rotor disk
is cooled by the cooling medium by means of convective cooling.
11. The axial turbomachine rotor as claimed in claim 10, wherein
the rotor disk, on its outer edge, includes a retaining recess, in
which the blade root engages by its root neck which projects
radially inwards and includes a root tooth which projects from the
root neck in a circumferential direction and/or in the axial
direction and includes a radially outer flank and a radially inner
flank, wherein the root tooth is encompassed by a root tooth recess
which is provided in the retaining recess in such a way that during
operation of the turbomachine rotor the blade root bears by the
radially outer flank against the root tooth recess and a first gap
is formed between the radially inner flank and the root tooth
recess, and wherein in a surface region of the root tooth recess
facing the inner flank provision is made for a first
impingement-cooling opening so that the blade root may be
impingement-cooled on the radially inner flank by the cooling
medium which flows through the first impingement-cooling
opening.
12. The axial turbomachine rotor as claimed in claim 11, wherein
the root tooth is arranged and formed on the root neck in such a
way that the blade root includes a firtree profile, and wherein the
root tooth recess is formed as a groove.
13. The axial turbomachine rotor as claimed in claim 12, wherein
the root tooth and the groove extend in the axial direction.
14. The axial turbomachine rotor as claimed in claim 10, wherein
the gap is outwardly open so that the cooling medium may flow from
the gap to outside the rotor disk.
15. The axial turbomachine rotor as claimed in claim 10, wherein
the rotor blade includes an aerodynamically effective blade airfoil
and an aerodynamically effective blade platform which is arranged
radially between the blade airfoil and the blade root and by its
radially inner side is arranged at a radial distance from the outer
edge of the rotor disk, forming a second gap, and wherein in a
surface region of the outer edge facing an inner side provision is
made for a second impingement-cooling opening so that the blade
platform may be impingement-cooled on its radially inner side by
the cooling medium which flows through the second
impingement-cooling opening.
16. The axial turbomachine rotor as claimed in claim 10, wherein
the plurality of impingement-cooling openings are formed in such a
way that the cooling medium, which flows out of the
impingement-cooling openings, impinges essentially perpendicularly
upon a surface of the rotor blade.
17. The axial turbomachine rotor as claimed in claim 15, wherein
the rotor disk includes a plurality of cooling passages which open
out into the second gap via the second impingement-cooling
opening.
18. The axial turbomachine rotor as claimed in claim 10, wherein
the rotor disk includes a plurality of cooling passages which open
out into the gap via the plurality of impingement-cooling
openings.
19. The axial turbomachine rotor as claimed in claim 10, wherein
the axial turbomachine rotor is an axial turbine rotor and the
cooling medium is cooling air.
20. The axial turbomachine rotor as claimed in claim 15, wherein
the axial turbomachine rotor is an axial turbine rotor and the
cooling medium is cooling air.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2010/053866, filed Mar. 25, 2010 and claims
the benefit thereof. The International Application claims the
benefits of European Patent Office application No. 09004471.0 EP
filed Mar. 27, 2009. All of the applications are incorporated by
reference herein in their entirety.
FIELD OF INVENTION
[0002] The invention refers to an axial turbomachine rotor having
blade cooling, especially an axial turbomachine rotor with a blade
ring which is formed from a multiplicity of rotor blades which can
be cooled by means of impingement cooling.
BACKGROUND OF INVENTION
[0003] A turbomachine, such as a gas turbine, has a compressor and
a turbine which are coupled via a rotor. The rotor has rotor blades
for the compressor and rotor blades for the turbine, wherein work
is performed on an operating medium in the compressor and work is
produced from the operating medium in the turbine. The operating
medium is heated upstream of the turbine so that the components of
the turbine are subjected to a high temperature load. The rotor is
conventionally provided with disks which are lined up on a shaft
and on their outer edge have in each case the rotor blades which
form a blade ring. On account of high mechanical and thermal loads,
the service life of the disks and of the rotor blades is limited.
As a measure for extending the service life, a cooling device for
cooling the rotor blades and the disks is known, with which device
an increase of the brittleness, especially of the material of the
disks, during operation of the gas turbine is essentially limited.
Furthermore, the creep behavior of the disks and of the rotor
blades lies in the non-critical region so that an extended service
life (or LCF: "life cycle fatigue") is achieved.
[0004] To this end, impingement cooling of blade platforms, which
is made possible by means of a separate component which is arranged
between the necks of two directly adjacent rotor blades, is known
from WO 2009/008944 A2.
[0005] The production and the installation of the additional
component, however, are very costly.
SUMMARY OF INVENTION
[0006] It is the object of the invention to create an axial
turbomachine rotor in which rotor disk and rotor blades have a long
service life.
[0007] The axial turbomachine rotor according to the invention has
a rotor disk and a rotor blade ring which has a multiplicity of
rotor blades which in each case have a blade root by which the
rotor blade is fixed radially outwards on the rotor disk, wherein
the blade root engages with the rotor disk on its outer edge in a
form-fitting manner in such a way that during operation of the
axial turbomachine rotor a gap is formed between the rotor blade
and the rotor disk in a predetermined surface region of the rotor
disk, in which gap are arranged a multiplicity of
impingement-cooling openings through which a cooling medium can
flow from the interior of the rotor disk into the gap, as a result
of which the rotor blade, and especially its platform, can be
cooled by the cooling medium by means of impingement cooling and
the rotor disk can be cooled by the cooling medium by means of
convective cooling.
[0008] Consequently, effective cooling of the rotor disk and of the
rotor blades is achieved, as a result of which the service life of
the rotor blades and of the rotor disk is long. Particularly in the
case of rotor disks which for each rotor blade have a retaining
recess, the steeples which are provided between the retaining
recesses can be particularly efficiently cooled by means of the
arrangement according to the invention of the cooling passages
which open out as impingement-cooling openings. Furthermore, in the
case of the turbomachine rotor according to the invention the
cooling medium is used efficiently, as a result of which the axial
turbomachine rotor can be operated with economy of resources.
[0009] It is preferred that for each rotor blade the rotor disk, on
its outer edge, has a retaining recess in which the blade root
engages by its root neck which projects radially inwards and has at
least one root tooth which projects from the root neck in the
circumferential direction and/or in the axial direction and has a
radially outer flank and a radially inner flank, wherein the root
tooth is encompassed by a root tooth recess, which is provided in
the retaining recess, in such a way that during operation of the
turbomachine rotor the blade root bears by the radially outer flank
against the root tooth recess and the gap is formed between the
radially inner flank and the root tooth recess, wherein in the
surface region of the root tooth recess facing the inner flank
provision is made for at least one of the impingement-cooling
openings so that the blade root can be impingement-cooled on the
radially inner flank by the cooling medium which flows through the
impingement-cooling opening. As a result, the rotor disk is
advantageously exposed to throughflow by the cooling medium, and
therefore cooled, in the region of the retaining recess in which
stress peaks occur during operation of the axial turbomachine
rotor. Furthermore, the blade root is cooled by the impingement
cooling, as a result of which heat is effectively dissipated by the
cooling medium from the blade root. As a result, the effect is
advantageously achieved of a temperature level being established in
the rotor disk in the region of the retaining recess, and in the
rotor blade, in which the service life of the rotor disk and of the
rotor blades is long.
[0010] Preferably, the root teeth are arranged and formed on the
root neck in such a way that the blade root has a firtree profile,
wherein the root tooth recesses are formed as grooves. The root
teeth and the grooves preferably extend in the axial direction of
the axial turbomachine rotor. Furthermore, it is preferred that the
gaps are outwardly open so that the cooling medium can flow from
the gaps to outside the rotor disk. As a result, cooling medium can
flow constantly through the impingement-cooling openings, as a
result of which continuous cooling of the rotor disk and of the
rotor blades is achieved.
[0011] The rotor blade preferably has an aerodynamically effective
blade airfoil and an aerodynamically effective blade platform which
is arranged radially between the blade airfoil and the blade root
and by its radially inner side is arranged at a radial distance
from the outer edge of the rotor disk, forming the gap, wherein in
the surface region of the outer edge facing the inner side
provision is made for at least one of the impingement-cooling
openings so that the blade platform can be impingement-cooled on
its radially inner side by the cooling medium which flows through
the impingement-cooling opening. Consequently, both the blade root
and the blade platform can be advantageously cooled by the cooling
medium, as a result of which an effective cooling of the rotor
blade is achieved. It is preferred that the impingement-cooling
openings are formed in such a way that the cooling medium, which
flows out of the impingement-cooling openings, impinges essentially
perpendicularly upon the surface of the rotor blade. As a result,
the thermal efficiency of the impingement cooling is effectively
high. Preferably, the rotor disk has a multiplicity of cooling
passages which open out into the gaps via the impingement-cooling
openings. Also, the axial turbomachine rotor is preferably an axial
turbine rotor and the cooling medium is preferably cooling air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the following text, a preferred embodiment of an axial
turbine rotor according to the invention is explained with
reference to the attached schematic drawings. In the drawings:
[0013] FIG. 1 shows a perspective view of a detail of a disk of an
axial turbine rotor according to the invention, and
[0014] FIG. 2 shows a perspective view of a detail of a disk with a
rotor blade of the axial turbine rotor according to the
invention.
DETAILED DESCRIPTION OF INVENTION
[0015] As is evident from FIGS. 1 and 2, an axial turbine rotor 1
has a disk which is arranged rotationally symmetrically around the
rotational axis of the axial turbine rotor 1. Arranged on the outer
edge 13 of the disk 2 are a multiplicity of rotor blades 3 which
lie next to each other over the circumference of the disk 2,
wherein the rotor blades 3 faun a rotor blade ring. Each rotor
blade 3 has a blade airfoil 4 by which the rotor blade 3 interacts
with an operating medium of the axial turbine rotor 1. The blade
airfoil 4 is arranged on the disk 2 in a radially outwards
extending manner, wherein the rotor blade 3, on the radially inner
end of the blade airfoil 4, has a blade root 5 by which the blade
airfoil 4 is fastened on the disk 2. Between the blade airfoil 4
and the blade root 5, a blade platform 6 is formed on the rotor
blade 3 and extends in the axial direction and in the
circumferential direction of the axial turbine rotor 1, wherein the
radially outer side of the blade platform 6 is arranged facing the
operating medium and the radially inner side 18 of the blade
platform 6 is arranged facing the disk 2.
[0016] The blade root 5 has a root neck 7 which extends radially
inwards from the blade platform 6. A multiplicity of root teeth 8
are foamed on the root neck 7, pointing in the circumferential
direction of the axial turbomachine rotor 1, wherein the root teeth
8 are arranged symmetrically to the longitudinal axis of the root
neck 7. A retaining recess 9 is formed for each blade root 5 on the
outer periphery of the disk 2 and has grooves 10 in which engage
the root teeth 8. The retaining recess 9 with its grooves 10 is
patterned on the contour of the blade root 5 with the root teeth 8
so that the blade root 5 engages in a form-fitting manner with the
retaining recess 9. Owing to the fact that each root tooth 8
engages in the groove 10 assigned to it and is encompassed by the
material of the disk 2, the blade root 5 is fixed in the retaining
recess 9 in the radial direction. The outer region of the rotor
disk 2 between two directly adjacent retaining recesses 9 is also
referred to as a steeple in this case.
[0017] The root teeth 8 are arranged on the root neck 7 essentially
in a manner in which they extend in the axial direction of the
axial turbine rotor 1 so that in the same way the grooves 10 also
have an extent in the axial direction of the axial turbine rotor 1.
Furthermore, the root teeth 8 are arranged parallel to each other
and consequently the grooves 10 are also arranged parallel to each
other so that the rotor blade 3, for mounting on the disk 2 or for
removing from the disk 2, can be inserted in the retaining recess 9
or withdrawn from the retaining recess 9 by its blade root 5 in the
axial direction. Furthermore, the root teeth 8 are designed with a
round contour and the grooves 10 are similarly designed with a
corresponding round contour so that on account of notch stress
effects the stress level in the disk 2 and in the blade root 5 is
low during operation of the axial turbine rotor 1.
[0018] Each root tooth 8 has a radially inner flank 16 and a
radially outer flank 17, wherein the flanks 16, 17 are formed in an
inclined manner to each other. In particular, the radially outer
flank 17 is inclined to the circumferential direction of the disk 2
in such a way that the radius of the radially outer flank 17
reduces away from the root neck 7. During operation of the axial
turbine rotor 1, a centrifugal force, which acts radially outwards,
acts upon the rotor blade 3. On account of the inclination of the
radially outer flank 17 and the corresponding contouring of the
groove 10, a self-centering effect of the blade root 5 in the
retaining recess 9 is created. In this case, the radially outer
flank 17 bears against the groove 10 so that the root tooth 8 is
supported in the groove 10 radially towards the outside on the
radially outer flank 17. The groove 10 is formed around the root
tooth 8 with clearance so that an undesirable seizing of the blade
root 5 in the retaining recess 9 is prevented, as a result of which
the self-centering effect by means of the root teeth 8 and the
grooves 10 is undisturbed. Owing to the fact that during operation
of the axial turbine rotor 1 the root tooth 8 is in touching
contact by its radially outer flank 17 with the groove 10, a gap 11
ensues on account of the clearance on the radially inner flank 16.
In the region of the groove 10 which is freed as a result of the
gap 11, provision is made for a multiplicity of impingement-cooling
openings 12 through which cooling air flows. If the cooling air
discharges from the impingement-cooling openings 12, the cooling
air flows into the gap 11 and cools the root tooth 8 on the
radially inner flank 16 by means of impingement cooling. The
retaining recess 9 is formed on the disk 2, being open on the end
face side, so that as a result of the gaps 11 on the radially inner
flanks 16, outwardly open cooling passages are formed. The cooling
air enters the cooling passages through the impingement-cooling
openings 12 and flows through the cooling passages and discharges
on the end face side on the disk 2.
[0019] The blade platform 6 is arranged at a radial distance on the
outer edge 13 of the disk 2 so that a gap 14 is formed between the
outer edge 13 of the disk and the radially inner side 18 of the
blade platform 6, beneath the radially inner side 18. A
multiplicity of impingement-cooling openings 15, through which
cooling air flows, are formed in the region of the gap 14 in the
outer edge 13 of the disk. The cooling air impinges upon the
radially inner side 18 so that the blade platform 6 is cooled by
the cooling air by means of impingement cooling. As a result of the
gap 14, a cooling passage is fanned on the outer edge 13 of the
disk and is outwardly open around the blade platform 6. As a
result, the cooling air from the impingement-cooling openings 15 on
the outer edge 13 of the disk can discharge to the outside past the
blade platform 6. During operation of the axial turbine rotor 1,
the radially outer side of the blade platform 6 is in contact with
hot gas, as a result of which there is a high heat yield to the
blade platform 6 during operation of the axial turbine rotor 1. The
heat which is transferred to the cooling air on the radially inner
side 18 of the blade platform 6 is transported away from the blade
platform 6 by means of convection.
* * * * *