U.S. patent application number 09/750003 was filed with the patent office on 2002-02-14 for cooled flow deflection apparatus for a fluid-flow machine which operates at high temperatures.
Invention is credited to Ferber, Jorgen.
Application Number | 20020018711 09/750003 |
Document ID | / |
Family ID | 7934954 |
Filed Date | 2002-02-14 |
United States Patent
Application |
20020018711 |
Kind Code |
A1 |
Ferber, Jorgen |
February 14, 2002 |
Cooled flow deflection apparatus for a fluid-flow machine which
operates at high temperatures
Abstract
Apparatus is disclosed for providing cooling channels in the
interior of a gas turbine rotor blade. The cooling channels are
formed by metallic inserts which extend from adjacent the root of
the blade toward the tip. The inserts are substantially flat and
are secured in the interior of the airfoil section by means of
rails which engage the longitudinal edges of the inserts and serve
as a guide during insertion. The rails are preferable formed
integrally with the blade casting.
Inventors: |
Ferber, Jorgen; (Kussaberg,
DE) |
Correspondence
Address: |
Robert S. Swecker
BURNS, DOANE, SWECKER & MATHIS, L.L.P.
P.O. Box 1404
Alexandria
VA
22313-1404
US
|
Family ID: |
7934954 |
Appl. No.: |
09/750003 |
Filed: |
December 29, 2000 |
Current U.S.
Class: |
415/115 ;
416/97R |
Current CPC
Class: |
F01D 5/188 20130101 |
Class at
Publication: |
415/115 ;
416/97.00R |
International
Class: |
F01D 005/14 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 29, 1999 |
DE |
199 63 716.4 |
Claims
1. A cooled flow deflection apparatus (20) for a fluid-flow machine
which operates at high temperatures, which flow deflection
apparatus (20) has, in the interior, a number of parallel-running
cooling channels (27), which are separated from one another by
separating walls (23) for a cooling fluid to pass through,
characterized in that the separating walls (23) are in the form of
separate inserts which can be pushed into the flow deflection
apparatus (20) subsequently.
2. The flow deflection apparatus as claimed in claim 1,
characterized in that the flow deflection apparatus (20) is in the
form of a hollow casting, and in that holders (30), which are in
the form of rails and into which the separating walls (23) are
inserted, are integrally formed in the interior of the flow
deflection apparatus (20).
3. The flow deflection apparatus as claimed in one of claims 1 and
2, characterized in that the separating walls (23) are in the form
of flat strips composed of a metallic or heat-resistant
non-metallic material.
4. The flow deflection apparatus as claimed in one of claims 1 to
3, characterized in that the inserted separating walls (23) are
connected by an integral material joint, preferably by soldering or
welding, to the flow deflection apparatus (20), in order to reasure
them.
5. The flow deflection apparatus as claimed in one of claims 1 to
4, characterized in that the separating walls (23) are
straight.
6. The flow deflection apparatus as claimed in one of claims 1 to
4, characterized in that the cooling fluid flows in mutually
opposite directions in two adjacent cooling channels (27), in that
the cooling fluid is deflected from the outlet of the one cooling
channel into the inlet of the other cooling channel by means of a
deflection device (26), and in that the deflection (26) is produced
by a separating wall (23) which is bent into a U-shape.
7. The flow deflection apparatus as claimed in one of claims 1 to
6, characterized in that the flow deflection apparatus is a blade
(20) in a gas turbine.
8. The flow deflection apparatus as claimed in claim 7,
characterized in that the blade (20) is a rotor blade, in that the
cooling channels (27) and separating walls (23) extend essentially
in the radial direction with respect to the rotation axis of the
gas turbine, in that the inserted separating walls (23) are, for
security, connected by an integral material joint, preferably by
soldering or welding, to the blade (20), and in that the integral
material joint is arranged at the end of the separating walls (23)
close to the axis.
Description
TECHNICAL FIELD
[0001] The present invention relates to the field of thermal
machines. It relates in particular to a cooled flow deflection
apparatus for a fluid-flow machine which operates at high
temperatures, as claimed in the precharacterizing clause of claim
1.
[0002] Such a flow deflection apparatus is generally known from the
prior art, for example in the form of a cooled stator blade or
rotor blade for a gas turbine.
PRIOR ART
[0003] Present-day flow deflection apparatuses, especially stator
blades or rotor blades in a gas turbine, are subjected to ambient
temperatures which are above the maximum permissible material
temperature. The use of special internal cooling channels allows
the metal temperature to be reduced to a level which is required on
the basis of the life of the apparatus.
[0004] FIGS. 1 and 2 respectively show a cross section and
longitudinal section of an example of a rotor blade of a gas
turbine, as is currently used. The blade 10 essentially comprises a
blade airfoil section 11 and a blade root 12, by means of which it
is attached to the rotor of the gas turbine. A number of cooling
channels 17 run in the longitudinal direction of the blade 10 in
the interior of the (hollow) blade airfoil section 11, through
which cooling channels 17 a cooling fluid, generally cooling air
which enters through the blade root 12, flows. The cooling fluid
runs, with a cooling effect, in the cooling channels 17 along the
insides of the hot-gas walls 14 and then (for film cooling) emerges
to the outside through appropriate film-cooling openings which are
arranged on the leading edge 18, on the trailing edge 19 and at the
blade tip (the emerging cooling fluid is indicated by the arrows in
FIG. 2). The individual cooling channels 17 are separated from one
another by separating walls 13 which at the same time have
deflection devices 16 to ensure that the cooling fluid flows
successively through adjacent cooling channels in alternately
opposite directions.
[0005] Until now, and in this case specifically in the case of
rotating guide apparatuses such as rotor blades, the cooling
channels 17 and their separating walls 13 have been cast.
[0006] The known, cast separating walls 13 and deflection devices
16, which are also referred to as ribs, have a number of
disadvantages, however:
[0007] The transitional region (15 in FIG. 1) from the hot-gas wall
14 to the separating wall (rib) 13 is an area which is difficult to
cool owing to the large amount of material in that area. Increased
heat transfer together with increased cooling-air consumption is
required in order to ensure adequate strength there.
[0008] The cold separating walls (ribs) 13, around which the
cooling air flows, lead to thermal stresses with the hot-gas wall
14.
[0009] Casting of the internal channels leads to a high blade
weight, which can lead to high centrifugal-force stresses both for
the blade root 12 and for the blade airfoil section 11.
[0010] The complex casting lengthens casting development and
increases the amount of scrap.
DESCRIPTION OF THE INVENTION
[0011] The object of the invention is thus to provide a cooled flow
deflection apparatus which avoids the described disadvantages of
the known apparatus and in particular is simple to produce, can be
flexibly matched to the respective application, and is efficiently
cooled.
[0012] The object is achieved by the totality of features of claim
1. The essence of the invention is no longer to produce, in
particular to cast, the separating walls, which are used to bound
the cooling channels, jointly with the apparatus, but to construct
them as separate inserts which are subsequently inserted into the
apparatus, and are secured there. The invention is thus
considerably different to solutions such as those described in U.S.
Pat. No. 5,145,315 or U.S. Pat. No. 5,516,260, in which specific
inserts in cast cooling channels are used for specific guidance of
the cooling fluid.
[0013] The use of inserts (for example, in the case of blades,
inserted through the blade root or through the blade tip) composed
of metal or non-metal materials as a substitute for cast separating
walls and, possibly, deflection devices, has a number of
advantages:
[0014] There is no large amount of material in the transitional
region from the hot-gas wall to the insert (to the separating
wall).
[0015] There are no thermal stresses between the insert (separating
wall) and the hot-gas wall.
[0016] In the case of rotating blades, the blade weight and thus
the centrifugal-force stresses are reduced both in the blade root
and in the blade airfoil section.
[0017] In the case of cast blades, the cast core is simpler, as a
result of which both its capability to be produced and that of the
blade are simpler.
[0018] The cooling system can easily be adjusted by replacing the
inserts, for example by varying the deflection radius of deflection
devices or by introducing connecting cross sections between two
cooling channels.
[0019] A first preferred embodiment of the flow deflection
apparatus according to the invention is characterized in that the
flow deflection apparatus is in the form of a hollow casting, and
in that holders, which are in the form of rails and into which the
separating walls are inserted, are integrally formed in the
interior of the flow deflection apparatus. This considerably
simplifies assembly and attachment of the inserts, and ensures that
the separating walls or inserts are sealed well at the edges. The
separating walls are in this case preferably flat strips composed
of a metallic or heat-resistant non-metallic (ceramic or composite)
material.
[0020] A secure seating for the inserts is achieved if, according
to a second preferred embodiment of the invention, the inserted
separating walls are, for security, connected by an integral
material joint, preferably by soldering or welding, to the flow
deflection apparatus.
[0021] In the simplest form, the separating walls may be
straight.
[0022] It is particularly simple and advantageous if, according to
another embodiment, the cooling fluid flows in mutually opposite
directions in two adjacent cooling channels, if the cooling fluid
is deflected from the outlet of the one cooling channel into the
inlet of the other cooling channel by means of a deflection device,
and if the deflection is produced by a separating wall which is
bent into a U-shape.
[0023] One particularly preferred embodiment of the flow deflection
apparatus according to the invention is characterized in that the
flow deflection apparatus is a blade in a gas turbine. Owing to the
comparatively complex geometry of the blade, the invention in this
case results in considerable simplifications.
[0024] Another embodiment, which is particularly advantageous for
rotor blades which rotate at high speed, is characterized in that
the cooling channels and separating walls extend essentially in the
radial direction with respect to the rotation axis of the gas
turbine, in that the inserted separating walls are, for security,
connected by an integral material joint, preferably by soldering or
welding, to the blade, and in that the integral material joint is
arranged at the end of the separating walls close to the axis.
BRIEF DESCRIPTION OF THE FIGURES
[0025] The invention will be explained in more detail in the
following text with reference to exemplary embodiments and in
conjunction with the drawing, in which:
[0026] FIG. 1 shows the cross section through a turbine blade
having cast cooling channels according to the prior art;
[0027] FIG. 2 shows a longitudinal section through the blade shown
in FIG. 1;
[0028] FIG. 3 shows a cross section, comparable to that in FIG. 1,
through a blade according to one exemplary embodiment of the
invention; and
[0029] FIG. 4 shows a longitudinal section, comparable to that in
FIG. 2, through the blade shown in FIG. 3.
APPROACHES TO IMPLEMENTATION OF THE INVENTION
[0030] FIGS. 3 and 4 respectively show a cross section and
longitudinal section of an exemplary embodiment of a cooled flow
deflection apparatus according to the invention in the form of a
rotor blade for a gas turbine. The geometry of the blade 20 is
similar to that of the known blade 10 shown in FIGS. 1 and 2.
[0031] Once again, the blade 20 essentially comprises a blade
airfoil section 21 and a blade root 22, by means of which it is
attached to the rotor of the gas turbine. A number of cooling
channels 27, through which a cooling fluid which enters through the
blade root 22 flows, run in the longitudinal direction of the blade
20, in the interior of the (hollow) blade airfoil section 21. The
cooling fluid runs in cooling channels 27 along the insides of the
hot-gas walls 24, with a cooling effect, and in this case as well
emerges to the outside through appropriate film cooling openings
which are arranged on the leading edge 28, on the trailing edge 29,
and at the blade tip. The individual cooling channels 27 are
separated from one another by separating walls 23 which at the same
time have deflection devices 26 to ensure that the cooling fluid
flows successively through adjacent cooling channels in alternately
opposite directions.
[0032] In contrast to FIGS. 1 and 2, the separating walls 23 are in
this case not cast, however, that is to say produced together with
the blade 20 in one casting process, but are separate inserts, in
the form of strips, which, once the blade 20 has been cast, are
introduced through the blade root 22 or through the opposite blade
tip. In order to allow the separating walls 23 to be inserted as
required and to be secured after insertion, holders 30 which are in
the form of rails and in which the longitudinal edges of the
separating walls 23 are guided during insertion are integrally
formed on the insides of the hot-gas walls.
[0033] The separating walls (inserts) 23 may have any desired
shape. For example, they may be straight. If a number of cooling
channels are intended to be connected to one another by means of
deflection devices 26, it is advantageous for the separating walls
23 to be bent into a U-shape. The separating walls 23 can be
secured on one or more sides, for example by soldering or welding.
They may be fixed in the blade tip region or in the blade root
region. The latter has the advantage that the centrifugal forces
which occur load the insert or the separating wall in tension, thus
preventing them from bulging out.
[0034] In principle, the separating walls which can be inserted are
provided at the same time that the blades are produced. However, it
is also feasible within the scope of the invention for the cast
separating walls subsequently to be removed from completely cast
blades as shown in FIGS. 1 and 2 and for separate separating walls
to be inserted and to be secured as a substitute for them.
LIST OF REFERENCE SYMBOLS
[0035] 10, 20 Blade
[0036] 11, 21 Blade airfoil section
[0037] 12, 22 Blade root
[0038] 13 Separating wall (rib)
[0039] 14, 24 Hot-gas wall
[0040] 15, 25 Transitional region
[0041] 16, 26 Deflection device
[0042] 17, 27 Cooling channel
[0043] 18, 28 Leading edge
[0044] 19, 29 Trailing edge
[0045] 23 Insert
[0046] 30 Holder (in the form of a rail)
* * * * *