U.S. patent application number 12/310690 was filed with the patent office on 2009-10-08 for cooled turbine rotor blade.
Invention is credited to Heinz-Jurgen Gross.
Application Number | 20090252615 12/310690 |
Document ID | / |
Family ID | 37718882 |
Filed Date | 2009-10-08 |
United States Patent
Application |
20090252615 |
Kind Code |
A1 |
Gross; Heinz-Jurgen |
October 8, 2009 |
Cooled Turbine Rotor Blade
Abstract
A cooled turbine rotor blade for a gas turbine which is
traversed axially by flow and is equipped with an attachment area
and an airfoil profile is provided. Meandering cooling channels
with interposed deflecting regions are provided in the interior of
the airfoil profile. In the deflecting regions, it is possible to
prevent dead water regions, which are generated in the prior art,
by virtue of at least one of the ribs running so as to curve
towards the leading edge or towards the trailing edge in the region
of the airfoil tip. At the same time, an opening is provided in the
curvature of the rib. Through this opening a part of the coolant
flows in the deflecting region and can pass over into the adjacent
cooling duct.
Inventors: |
Gross; Heinz-Jurgen;
(Mulheim an der Ruhr, DE) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Family ID: |
37718882 |
Appl. No.: |
12/310690 |
Filed: |
June 27, 2007 |
PCT Filed: |
June 27, 2007 |
PCT NO: |
PCT/EP2007/056425 |
371 Date: |
March 3, 2009 |
Current U.S.
Class: |
416/97R |
Current CPC
Class: |
Y02T 50/673 20130101;
F01D 5/187 20130101; F05D 2260/2212 20130101; F05D 2250/185
20130101; Y02T 50/60 20130101; F05D 2240/304 20130101; F05D
2260/202 20130101; F05D 2240/122 20130101; Y02T 50/676
20130101 |
Class at
Publication: |
416/97.R |
International
Class: |
F01D 5/18 20060101
F01D005/18; F01D 25/12 20060101 F01D025/12 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 4, 2006 |
EP |
06018490.0 |
Claims
1.-6. (canceled)
7. A cooled turbine rotor blade for a stationary axial-flow gas
turbine, comprising: an airfoil profile formed by a suction-side
blade and a pressure-side blade wall; an airfoil tip; an attachment
area from which the airfoil profile extends as far as the airfoil
tip; a plurality of cooling channels which lie adjacent to one
another in an interior of the airfoil profile; a plurality of ribs;
a terminating wall bounding the plurality of cooling channels at
the airfoil tip end; and an opening arranged in a curvature of one
of the plurality of ribs connecting two adjacent cooling channels;
wherein the airfoil profile has a leading edge and a trailing edge,
wherein at least one of the plurality of ribs connects the
pressure-side blade wall to the suction-side blade wall and extends
from the attachment area to the airfoil tip, wherein at least one
of the plurality of ribs has an essentially constant rib thickness
and is curved toward the leading edge or the trailing edge forming
a cooling-channel corner area, which has an acute angle in a
longitudinal section, in the area of the airfoil tip, wherein the
plurality of cooling channels are at least partially separated from
one another by in each case one of the plurality of ribs, and
wherein a part of a coolant flow of one of the plurality of the
cooling channels, the cooling channel that is adjacent to a corner
area, can flow through the opening into an acute-angled corner area
of the adjacent cooling channel.
8. The cooled turbine rotor blade as claimed in claim 7, wherein
the rib adjacent to the trailing edge is curved in the area of the
airfoil tip.
9. The cooled turbine rotor blade as claimed in claim 7, wherein
the opening is arranged such that the terminating wall is
impingement-cooled.
10. The cooled turbine rotor blade as claimed in claim 7, wherein
an inner face of the terminating wall is equipped with
turbulators.
11. The cooled turbine rotor blade as claimed in claim 7, wherein
the coolant flows sequentially through the plurality of cooling
channels.
12. The cooled turbine rotor blade as claimed in claim 7, wherein
the coolant flows in parallel through the plurality of cooling
channels.
13. The cooled turbine rotor blade as claimed in claim 7, wherein
the cooled turbine rotor blade is cast.
14. The cooled turbine rotor blade as claimed in claim 7, wherein a
second rib which is the second one adjacent to the leading edge,
curves in the direction of the trailing edge into the terminating
wall in the tip area of the cooled turbine rotor blade with an
opening provided in a curvature.
Description
[0001] This application is the US National Stage of International
Application No. PCT/EP2007/056425, filed Jun. 27, 2007 and claims
the benefit thereof. The International Application claims the
benefits of European application No. 06018490.0 EP filed Sep. 4,
2006, both of the applications are incorporated by reference herein
in their entirety.
FIELD OF INVENTION
[0002] The invention relates to a cooled turbine rotor blade.
BACKGROUND OF INVENTION
[0003] By way of example, a turbine rotor blade of this generic
type and having an airfoil profile is known from EP 0 735 240 A1. A
plurality of mutually adjacent cooling channels are provided in
order to cool the airfoil profile, are arranged in a meandering
shape, and a coolant can flow through them sequentially. The
cooling channels in this case each run parallel to the leading
edge. Respectively adjacent cooling channels are separated from one
another by ribs, with the ribs ending in a direction-reversal area
in which the adjacent cooling channels merge into one another. In
order to avoid regions with lower flow rates and in consequence
inadequate cooling in these direction-changing areas, in which the
cooling air changes its direction, for example, from a flow
directed outward to a flow directed inward, direction-changing
blades (FIG. 12) are provided at these points. Despite the
direction-changing blades, it is, however, still possible for local
overheating to occur in the direction-changing area, and this then
reduces the life of the turbine blade.
[0004] Furthermore, a turbine blade is known from U.S. Pat. No.
5,246,340, which has a plurality of mutually parallel cooling
channels in the interior. In this case, the cooling channels are in
each case separated by a rib. An opening which connects two
adjacent cooling channels is provided in one of the ribs in the
area of the blade tip, through which opening a lateral flow can
pass for impingement cooling of the blade airfoil tip.
[0005] Furthermore, GB 2 106 996 discloses a turbine blade having
an impingement cooling insert in the form of a laminate.
SUMMARY OF INVENTION
[0006] The object of the present invention is to provide a turbine
rotor blade whose life is further improved.
[0007] The object relating to the provision of a turbine rotor
blade of this generic type is achieved by designing this turbine
rotor blade according to the characterizing part of claim 1. It is
proposed that at least one of the ribs--seen from the attachment
area to the tip area--has an essentially constant rib thickness and
is curved toward the leading edge or trailing edge forming a
cooling-channel corner area, which has an acute angle in
longitudinal section, in the area of the airfoil tip, and that at
least one opening is provided, which is arranged in the curvature,
connects two adjacent cooling channels and through which a part of
the coolant flow of the cooling channel which is adjacent to the
corner area can flow into the acute-angled corner area of the
cooling channel.
[0008] The curved rib results in the direction of the cooling air
flowing through the cooling channels being changed in a
considerably more aerodynamic manner. The direction change is an
integral component of the rib, as a result of which the regions
with a relatively low flow rate or no flow rate (dead-water
regions) in the direction-changing area can be avoided. The flow
rate is in consequence kept approximately constant in that cooling
channel toward which the rib is curved. However, the curvature of
the rib results in an acute-angled corner area in the adjacent
cooling channel, in which dead-water regions could now once again
occur. In order now to avoid the dead-water regions in the corner
area in the adjacent cooling channel, at least one opening is also
provided, which is arranged in the curvature and connects the two
adjacent cooling channels, and through which a part of the cooling
flow can pass over or flow over from one cooling channel into the
other cooling channel at an early stage.
[0009] Furthermore, the opening which is arranged in the curved rib
can be provided in a particularly simple form. The casting
apparatus which is used for casting the turbine rotor blades
comprises, in order to produce the cavities through which a coolant
can flow, a casting core which has core elements arranged in a
meandering shape. In order to support these adjacent core elements,
which are arranged in a meandering shape, with respect to one
another, a core support can be provided between two adjacent core
elements and, after removal of the casting core from the cast,
integral turbine blade, leaves behind it the opening within the
curved rib. This results in a stabilized casting core which
improves the accuracy of the production method.
[0010] Further advantageous refinements of the invention are
specified in the dependent claims.
[0011] In one particularly advantageous refinement, the terminating
wall, which is likewise frequently subject to local overheating and
is also referred to as a crown base, can also be impingement-cooled
on the basis of the coolant jet passing through the opening, in
such a way that this likewise makes it possible to cool the
terminating wall particularly efficiently. To do this, the opening
just has to be inclined such that its longitudinal extent is
directed at the terminating wall.
[0012] The rib which is adjacent to the trailing edge is preferably
curved in the area of the airfoil tip. In this case, the rib--seen
from the attachment area to the tip area--is curved toward the
leading edge thus making it possible to provide an essentially
constant flow cross-sectional area in a part of the
direction-changing area between two adjacent coolant channels. This
reduces the pressure losses in the coolant. In order to provide a
particularly lightweight turbine rotor blade, the rib has an
essentially constant rib thickness along its curvature.
[0013] In one advantageous development of the invention, the inner
face of the terminating wall is equipped with turbulators, thus
making it possible to improve the cooling of the terminating wall
or of the crown base in a simple manner. Depending on the
configuration of the turbine rotor blades, it is possible for a
coolant to flow sequentially or else in parallel through the
adjacent cooling channels. If the flow passes in parallel through
the coolant channels, care must be taken to ensure that there is an
adequate pressure gradient between them, in order to obtain a
coolant flow which passes through the opening.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention will be explained with reference to a drawing.
The single FIGURE in this case shows a longitudinal section through
a turbine rotor blade according to the invention with cooling
channels arranged in a meandering shape.
DETAILED DESCRIPTION OF INVENTION
[0015] The FIGURE shows a longitudinal section through a turbine
rotor blade 10 which is produced by a casting method. The turbine
rotor blade 10, which is therefore integral, has an attachment area
12, with a firtree-shaped cross section, with a platform 14 and an
airfoil profile 16 arranged thereon. The airfoil profile 16, which
has an aerodynamically profiled cross section, is formed by a
suction-side blade wall and a pressure-side blade wall, which each
extend from a leading edge 18 to a trailing edge 20 and in this
case surround a cavity, which is arranged in the interior of the
airfoil profile 16 and in which a plurality of cooling channels
22a, 22b, 22c, 22d are provided. The cooling channels 22 are
adjacent to one another and each run approximately parallel to the
leading edge 18. The mutually adjacent cooling channels 22 are each
separated from one another in places by a rib 24a, 24b, 24c which
connects the pressure-side blade wall to the suction-side blade
wall. The cooling channels 22 are bounded by a terminating wall 28
in the area of the airfoil tip 27 which is opposite the attachment
area 12. The terminating wall 28 is also referred to as a crown
base.
[0016] The turbine rotor blade 10 which is illustrated in the
FIGURE has a cooling channel 22a on the leading-edge side to which,
on the attachment side, a coolant 29, for example cooling air or
cooling vapor, can be supplied. The cooling air that is supplied
cools the area of the leading edge 18 of the airfoil profile 16
using conventional cooling methods, for example convection cooling,
impingement cooling and/or film cooling.
[0017] The coolant 29, which can be supplied to the root end of the
cooling channel 22b, flows along the channel 22b to the airfoil tip
27, and its direction is then changed in a direction-changing area
30 in order to reverse its flow direction, specifically toward the
attachment area 12. For this purpose, the rib 24c which is adjacent
to the trailing edge 20 is curved in the area of the airfoil tip
27, with a constant rib thickness D. The curvature 32 is such that
the rib 24c--seen from the attachment area 12 to the tip area
26--is curved toward the leading edge 18. This results in a part of
the direction-changing area 30 having a cooling channel width B
which is approximately constant in comparison to the cooling
channel 22c. This makes it possible to change the direction, in a
particularly aerodynamic manner, of the coolant 29 which flows
through the cooling channels 22b, 22c sequentially.
[0018] An acute-angled corner area 34 is formed by the curvature 32
of the rib 24c, which is adjacent to the trailing edge 20, in the
cooling channel 22d in the area of the airfoil tip 27. An opening
40 is provided in the rib 24c in the area of the curvature 32,
through which opening 40 the coolant 29 which is flowing in the
direction-changing area 30 can partially flow out therefrom and can
flow into the corner area 34 by virtue of the pressure ratio there.
If required, a plurality of openings 40 may also be provided in
order to influence the flow more specifically in the corner areas
34. The corner area 34 can therefore be adequately cooled. Areas
with reduced coolant flow rates and in consequence with inadequate
cooling are therefore reliably avoided at this point.
[0019] The coolant jet passing through the opening 40 impinges on
the inner face 42 of the terminating wall 28 and in this case
provides impingement cooling for the airfoil tip 27. In order to
further improve the cooling effect of the impingement cooling jet,
turbulators 44 can also be provided on the inner face 42 of the
terminating wall 28, further enlarging the surface area to be
cooled. In addition, the coolant 29 which flows along the inner
face 42 of the terminating wall 28 can further increase the heat
transfer coefficient on the cooling-air side by virtue of the
stimulation of turbulence, thus making it possible to achieve even
better cooling of the crown base.
[0020] It is also feasible according to the invention for the rib
24a to merge, curved in the direction of the trailing edge 20, into
the terminating wall 28 in the tip area 26 of the turbine rotor
blade 10, with one or more openings likewise being provided in the
curvature.
[0021] Overall, the invention specifies a turbine rotor blade 10
for an axial-flow gas turbine, in particular a stationary gas
turbine, which is equipped with an attachment area 12, an airfoil
profile 16 and a plurality of cooling channels 22 which are
arranged in a meandering shape in the interior of the airfoil
profile 16. In order to avoid areas with reduced flow rates of
coolant 29 in the direction-changing area 30 or at the channel end,
the invention proposes that at least one of the ribs 24 run in a
curved form toward the leading edge 18 or toward the trailing edge
20 in the area of the airfoil tip 27, with the rib thickness D
remaining constant, and that at least one opening 40 be provided in
the curvature 32 of the rib 24, through which opening 40 a portion
of the coolant 29 which is flowing in the direction-changing area
30 can pass into the adjacent cooling channel 22d.
* * * * *