U.S. patent application number 11/518018 was filed with the patent office on 2008-03-13 for turbine blade tip gap reduction system for a turbine engine.
This patent application is currently assigned to Siemens Power Generation, Inc.. Invention is credited to Gennadiy Afanasiev.
Application Number | 20080063513 11/518018 |
Document ID | / |
Family ID | 38776301 |
Filed Date | 2008-03-13 |
United States Patent
Application |
20080063513 |
Kind Code |
A1 |
Afanasiev; Gennadiy |
March 13, 2008 |
Turbine blade tip gap reduction system for a turbine engine
Abstract
A turbine blade gap control system configured to move a vane
carrier and attached ring segments of a turbine engine axially
relative to a turbine blade assembly to reduce the gaps between the
tips of the turbine blades and the ring segments to increase the
efficiency of the turbine engine once operating in a steady state
condition. The turbine blade assembly may be formed from a
plurality rows of turbine blades extending radially from a rotor,
wherein each row may be formed from a plurality of turbine blades
and wherein the turbine blades may have tips positioned at an acute
angle relative to a rotational axis of the turbine blade assembly.
A vane carrier may be positioned concentric with the rotor and
positioned radially outward from the turbine blades, and a
plurality of ring segments may be attached to the vane carrier.
Inventors: |
Afanasiev; Gennadiy;
(Orlando, FL) |
Correspondence
Address: |
Siemens Corporation;Intellectual Property Department
170 Wood Avenue South
Iselin
NJ
08830
US
|
Assignee: |
Siemens Power Generation,
Inc.
|
Family ID: |
38776301 |
Appl. No.: |
11/518018 |
Filed: |
September 8, 2006 |
Current U.S.
Class: |
415/138 |
Current CPC
Class: |
F05D 2240/11 20130101;
F01D 11/22 20130101; F05D 2250/40 20130101 |
Class at
Publication: |
415/138 |
International
Class: |
F01D 25/26 20060101
F01D025/26 |
Claims
1. A turbine engine, comprising: a turbine blade assembly formed
from a plurality rows of turbine blades extending radially from a
rotor, wherein each row is formed from a plurality of turbine
blades and wherein the turbine blades have tips positioned at an
acute angle relative to a rotational axis of the turbine blade
assembly; a vane carrier concentric with the rotor and positioned
radially outward from the turbine blades; a plurality of ring
segments attached to the vane carrier and positioned between the
vane carrier and the tips of the turbine blades in each row,
wherein an inner surface of each of the ring segments is offset
radially outward from the tips of the turbine blades creating gaps
and wherein the ring segments are positioned at an acute angle
substantially equal to the acute angle at which the turbine blade
tips are positioned; and a turbine blade gap control system
configured to move the vane carrier and attached ring segments
axially relative to the turbine blade assembly to reduce the gaps
between the tips of the turbine blades and the ring segments.
2. The turbine engine of claim 1, wherein the turbine blade gap
control system comprises at least one hydraulic arm attached to the
vane carrier for moving the vane carrier axially relative to the
turbine blade assembly.
3. The turbine engine of claim 2, wherein the at least one
hydraulic arm is attached to an outer cylinder positioned radially
outward from the vane carrier.
4. The turbine engine of claim 3, wherein the at least one
hydraulic arm comprises four hydraulic arms positioned around the
outer cylinder.
5. The turbine engine of claim 4, wherein the hydraulic arms are
positioned generally 90 degrees from each other around the outer
cylinder.
6. A turbine engine, comprising: a turbine blade assembly formed
from at least one row of turbine blades extending radially from a
rotor, wherein the at least one row is formed from a plurality of
turbine blades and wherein the turbine blades have tips positioned
at an acute angle relative to a rotational axis of the turbine
blade assembly; a vane carrier concentric with the rotor and
positioned radially outward from the turbine blades; a plurality of
ring segments attached to the vane carrier and positioned between
the vane carrier and the tips of the turbine blades in the at least
one row, wherein an inner surface of each of the ring segments is
offset radially outward from the tips of the turbine blades
creating gaps and wherein the ring segments are positioned at an
acute angle substantially equal to the acute angle at which the
turbine blade tips are positioned; and a turbine blade gap control
system configured to move the vane carrier and attached ring
segments axially relative to the turbine blade assembly to reduce
the gaps between the tips of the turbine blades and the ring
segment; wherein the turbine blade gap control system comprises at
least one hydraulic arm attached to the vane carrier for moving the
vane carrier axially relative to the turbine blade assembly.
7. The turbine engine of claim 6, wherein the at least one
hydraulic arm is attached to an outer cylinder positioned radially
outward from the vane carrier.
8. The turbine engine of claim 7, wherein the at least one
hydraulic arm comprises four hydraulic arms positioned around the
outer cylinder.
9. The turbine engine of claim 8, wherein the hydraulic arms are
positioned generally 90 degrees from each other around the outer
cylinder.
10. A method of reducing gaps between tips of turbine blades in a
turbine engine and adjacent ring segments, comprising: operating a
turbine engine by bringing the turbine engine to a steady state
operating condition, wherein the turbine engine comprises: a
turbine blade assembly formed from a row of turbine blades
extending radially from a rotor, wherein the row is formed from a
plurality of turbine blades and wherein the turbine blades have
tips positioned at an acute angle relative to a rotational axis of
the turbine blade assembly; a vane carrier concentric with the
rotor and positioned radially outward from the turbine blades; a
plurality of ring segments attached to the vane carrier and
positioned between the vane carrier and the tips of the turbine
blades in the row, wherein an inner surface of each of the ring
segments is offset radially outward from the tips of the turbine
blades creating gaps and wherein the ring segments are positioned
at an acute angle substantially equal to the acute angle at which
the turbine blade tips are positioned; and a turbine blade gap
control system configured to move the vane carrier and attached
ring segments axially relative to the turbine blade assembly to
reduce the gaps between the tips of the turbine blades and the ring
segment; and reducing the gaps between the tips of the turbine
blades and the ring segment by using the turbine blade gap control
system to move the vane carrier axially relative to the turbine
blade assembly.
11. The method of claim 10, wherein operating the turbine engine
comprises operating a turbine engine wherein the turbine blade gap
control system comprises at least one hydraulic arm attached to the
vane carrier for moving the vane carrier axially relative to the
turbine blade assembly.
12. The method of claim 11, wherein operating the turbine engine
comprises operating a turbine engine wherein the at least one
hydraulic arm is attached to an outer cylinder positioned radially
outward from the vane carrier.
13. The method of claim 12, wherein operating the turbine engine
comprises operating a turbine engine wherein the at least one
hydraulic arm comprises four hydraulic arms positioned around the
outer cylinder.
14. The method of claim 13, wherein operating the turbine engine
comprises operating a turbine engine wherein the hydraulic arms are
positioned generally 90 degrees from each other around the outer
cylinder.
Description
FIELD OF THE INVENTION
[0001] This invention is directed generally to turbine engines, and
more particularly to systems for reducing the gap between the tips
of rotatable turbine blades attached to a rotary turbine blade
assembly and ring segments attached to a vane carrier when the
turbine engine is operating at steady state conditions.
BACKGROUND
[0002] Typically, gas turbine engines include a compressor for
compressing air, a combustor for mixing the compressed air with
fuel and igniting the mixture, and a turbine blade assembly for
producing power. Combustors often operate at high temperatures that
may exceed 2,500 degrees Fahrenheit. Typical turbine combustor
configurations expose turbine blade assemblies to these high
temperatures. As a result, turbine blades must be made of materials
capable of withstanding such high temperatures. Turbine blades and
other components often contain cooling systems for prolonging the
life of the blades and reducing the likelihood of failure as a
result of excessive temperatures.
[0003] Turbine blades typically extend radially from a rotor
assembly and terminate at a tip within close proximity of the ring
segments attached to a vane carrier. The ring segments may be
exposed to the hot combustion gases and, similar to the turbine
blades, the ring segments often rely on internal cooling systems to
reduce stress and increase the life cycle. The ring segments are
spaced radially from the turbine blade tips to create a gap
therebetween to prevent contact of the turbine blade tips with the
ring segments as a result of thermal expansion of the turbine
blades. During conventional startup processes in which a turbine
engine is brought from a stopped condition to a steady state
operating condition, turbine blades and ring segments pass through
a pinch point at which the gap between the turbine blade tips and
the ring segments is at a minimal distance due to thermal
expansion. The turbine blade tips of many conventional
configurations contact or nearly contact the ring segments. Contact
of the turbine blade tips may cause damage to the blades.
Furthermore, designing the gap between the turbine blade tips and
the ring segments for the pinch point often results in a gap at
steady state conditions that is larger than desired because the gap
and combustion gases flowing therethrough adversely affect
performance and efficiency.
[0004] One conventional system includes moving the rotor axially to
reduce the gap. however, moving the rotor axially within the
turbine engine causes an increase in the gaps at the compressor
blade tips, thereby increasing inefficiencies in the compressor.
Thus, a need exists for a more effective way of enabling turbine
blade tips to pass through the pinch point without contacting the
ring segments, yet reduce the size of the gap at steady state
operating conditions.
SUMMARY OF THE INVENTION
[0005] This invention is directed to a turbine blade gap control
system for reducing a gap formed, between turbine blades and ring
segments in turbine engines. Reducing the gap increases the
efficiency of the turbine engine by reducing the amount of
combustion gases flowing around the turbine blades rather than
through the blades. The turbine blade gap control system may be
configured to enable the turbine engine to go through start up
conditions, through a pinch point in the start up process before
steady state operation where the tips of the turbine blades are
closest to the ring segments and into a steady state condition. The
turbine blade gap control system may be configured to reduce the
size of the gap at steady state operating conditions by moving a
vane carrier to which the ring segments are attached axially. Such
axial movement may reduce the gap between the tips of turbine
blades and ring segments in turbine engines in which the tips of
the turbine blades are positioned at an acute angle relative to a
rotational axis and the ring segments are positioned in a similar
manner.
[0006] The turbine engine may include a turbine blade assembly
formed from a plurality rows of turbine blades extending radially
from a rotor. Each row may be formed from a plurality of turbine
blades. The turbine blades may have tips positioned at an acute
angle relative to a rotational axis of the turbine blade assembly.
The turbine engine may also include a vane carrier concentric with
the rotor and positioned radially outward from the turbine blades.
A plurality of ring segments may be attached to the vane carrier
and positioned between the vane carrier and the tips of the turbine
blades in each row. An inner surface of each of the ring segments
may be offset radially outward from the tips of the turbine blades
creating gaps so that the turbine blades may rotate without
contact. The ring segments may be positioned at an acute angle
substantially equal to the acute angle at which the turbine blade
tips are positioned.
[0007] The turbine engine may also include a turbine blade gap
control system configured to move the vane carrier and attached
ring segments axially relative to the turbine blade assembly to
reduce the gaps between the tips of the turbine blades and the ring
segments. In one embodiment, the turbine blade gap control system
may include one or more hydraulic arms attached to the vane carrier
for moving the vane carrier axially relative to the turbine blade
assembly. The hydraulic arm may be attached to an outer cylinder or
other turbine engine support structure positioned radially outward
from the vane carrier. In one embodiment, the hydraulic arm may be
formed from four hydraulic arms positioned around the outer
cylinder. The hydraulic arms may be positioned generally 90 degrees
from each other around the outer cylinder.
[0008] The invention may also include a method of reducing gaps
between tips of turbine blades in a turbine engine and adjacent
ring segments. The method may include operating a turbine engine by
bringing the turbine engine to a steady state operating condition
and reducing the gaps between the tips of the turbine blades and
the ring segment by using the turbine blade gap control system to
move the vane carrier axially relative to the turbine blade
assembly. Operating a turbine engine may include using a turbine
blade gap control system including one or more hydraulic arms
attached to the vane carrier for moving the vane carrier axially
relative to the turbine blade assembly. The hydraulic arm may be
attached to an outer cylinder or other turbine engine support
structure positioned radially outward from the vane carrier. In one
embodiment, the hydraulic arm may include four hydraulic arms
positioned around the outer cylinder and may be spaced generally 90
degrees from each other around the outer cylinder.
[0009] During use, the turbine engine may be started and brought up
to a steady state operating condition. At start up, the turbine
blade gap control system may have the carrier vane and attached
ring segments moved axially away from the tips of the turbine
blades. In this position, the turbine engine may go from start up
through a pinch point at which the turbine blade tips are closest
to the ring segments without contact occurring. The turbine blades
and other turbine engine components may heat up to a steady state
operating temperature at which the turbine blades have ceased
growing due to thermal expansion. Once the steady state operating
conditions are reached, the turbine blade gap control system may be
used to reduce the size of the gap by moving the vane carrier
axially along the rotational axis relative to the turbine blade
assembly. The hydraulic arms may be used to move the vane carrier
axially relative to the turbine blade assembly.
[0010] An advantage of this invention is that the turbine blade gap
control system enables turbine blades to be brought through a pinch
point without the turbine blade tips contacting the ring segments
and enables the gaps between the turbine blades tips and the ring
segments to be reduced at steady state operating conditions to
increase the efficiency of the engine.
[0011] Another advantage of this invention is that the turbine
blade gap control system enables the gaps between the turbine
blades tips and the ring segments to be reduced at steady state
operating conditions to increase the efficiency of the engine
without negatively affecting the compressor. The net effect on the
turbine engine is an increase in efficiency.
[0012] These and other embodiments are described in more detail
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The accompanying drawings, which are incorporated in and
form a part of the specification, illustrate embodiments of the
presently disclosed invention and, together with the description,
disclose the principles of the invention.
[0014] FIG. 1 is a cross-sectional view of a turbine engine having
aspects of this invention.
[0015] FIG. 2 is a partial cross-sectional view of the turbine
engine shown in FIG. 1 taken along line 2-2.
[0016] FIG. 3 is a detailed partial cross-sectional view of a
turbine blade gap control system shown in FIG. 2 taken along line
3-3.
[0017] FIG. 4 is a detailed view of the turbine blade assembly
shown in FIG. 1 along line 4-4 before vane carrier shift.
[0018] FIG. 5 is a detailed view of the turbine blade assembly
shown in FIG. 2 along line 5-5 with the vane carrier shifted
axially relative to the turbine blade assembly.
DETAILED DESCRIPTION OF THE INVENTION
[0019] As shown in FIGS. 1-5, this invention is directed to a
turbine blade gap control system 10 for reducing a gap 12 formed
between turbine blades 14 and ring segments 16 in turbine engines
18. Reducing the gap 12 increases the efficiency of the turbine
engine 18 by reducing the amount of combustion gases flowing around
the turbine blades 14 rather than through the blades 14. The
turbine blade gap control system 10 may be configured to enable the
turbine engine 18 to go through start up conditions, through a
pinch point in the start up process before steady state operation
where the tips 20 of the turbine blades 14 are closest to the ring
segments 16 and into a steady state condition. The turbine blade
gap control system 10 may be configured to reduce the size of the
gap 12 at steady state operating conditions by moving a vane
carrier 22 to which the ring segments 16 are attached axially. Such
axial movement may reduce the gap 12 between the tips 20 of turbine
blades 14 and ring segments 16 in turbine engines 18 in which the
tips 20 of the turbine blades 14 are positioned at an acute angle
24 relative to a rotational axis 26 and the ring segments 16 are
positioned in a similar manner.
[0020] As shown in FIG. 1, the turbine engine 18 may include a
turbine blade assembly 28 formed from a plurality rows 30 of
turbine blades 14 extending radially outward from a rotor 32. The
rotor 32 may be any conventional rotor configured to rotate about
the rotational axis 26. Each row 30 may be formed from a plurality
of turbine blades 14 extending radially outward from the rotor 32.
The turbine blades 14 of a row may all extend substantially equal
distances from the rotor 32 such that the tips 20 are positioned
within close proximity of the ring segments 16, yet offset to form
the gap 12. During operation, the rotor 32 rotates as combustion
gases pass by the turbine blades 14.
[0021] The turbine blades 14 may have tips 20 positioned at an
acute angle 24 relative to a rotational axis 26 of the turbine
blade assembly 28. In at least one embodiment, as shown in FIGS. 1,
4 and 5, the tips 20 of the turbine blades 14 may be positioned at
an acute angle 24 of about 20 degrees. The ring segments 16 may
include inner surfaces 34 that are positioned at substantially at
the acute angle 24 relative to the rotational axis 26. The ring
segments 16 may be positioned between the vane carrier 22 and the
tips 20 of the turbine blades 14 in each row, wherein an inner
surface 34 of each of the ring segments 16 is offset radially
outward from the tips 20 of the turbine blades 14. The ring
segments 16 may be attached to the vane carrier 22. The vane
carrier 22 may be concentric with the rotor 32 and positioned
radially outward from the turbine blades 14. In such a position,
axial movement of the vane carrier 22 causes a reduction in the
size of the gap 12. In at least one embodiment, the vane carrier 22
may be move axially between about 4 millimeters and about 5
millimeters, which results in a reduction of the gap 12 of about 1
millimeter.
[0022] The turbine blade gap control system 10 may be configured to
move the vane carrier 22 and attached ring segments 16 axially
relative to the turbine blade assembly 28 to reduce the size of the
gaps 12 between the tips 20 of the turbine blades 14 and the ring
segments 16. The turbine blade gap control system 10 may be formed
from any device capable of moving the vane carrier 22 relative to
the turbine blade assembly 28, and in particular, relative to the
tips 20 of the turbine blades 14. In at least one embodiment, as
shown in FIGS. 2 and 3, the turbine blade gap control system 10 may
comprise at least one hydraulic arm 36 attached to the vane carrier
22 for moving the vane carrier 22 axially relative to the turbine
blade assembly 28. The hydraulic arm 36 may be attached to an outer
cylinder 38 or other support structure positioned radially outward
from the vane carrier 22. As shown in FIG. 3, the hydraulic arm 36
may include four hydraulic arms 36 positioned around the outer
cylinder 38. The hydraulic arms 36 may be positioned generally 90
degrees from each other around the outer cylinder 38. In other
embodiments, the turbine blade gap control system 10 may include
other numbers of hydraulic arms 36, and the hydraulic arms may be
positioned in other configurations.
[0023] During use, the turbine engine 18 may be started and brought
up to a steady state operating condition. At start up, the turbine
blade gap control system 10 may have the carrier vane 22 and
attached ring segments 16 positioned axially away from the tips 20
of the turbine blades 14. In this position, the turbine engine 18
may go from start up through a pinch point at which the turbine
blade tips 20 are closest to the ring segments 16 without contact
occurring. The turbine blades 14 and other turbine engine
components may heat up to a steady state operating temperature at
which the turbine blades 14 have ceased thermal expansion. Once the
steady state operating conditions are reached, the turbine blade
gap control system 10 may be used to reduce the size of the gap 12
by moving the vane carrier 22 axially along the rotational axis 26
relative to the turbine blade assembly 28. The hydraulic arms 36
may be used to move the vane carrier 22 axially relative to the
turbine blade assembly 28.
[0024] The foregoing is provided for purposes of illustrating,
explaining, and describing embodiments of this invention.
Modifications and adaptations to these embodiments will be apparent
to those skilled in the art and may be made without departing from
the scope or spirit of this invention.
* * * * *