TECHNICAL FIELD
[0001] The present application and the resultant patent relate generally to gas turbine
engines and more particularly relate to a flow guiding pin-fin array for use in gas
turbine airfoils and the like.
BACKGROUND OF THE INVENTION
[0002] A gas turbine includes a number of stages with buckets extending outwardly from a
supporting rotor disk. Each bucket includes an airfoil over which combustion gases
flow. The airflow must be cooled to withstand the high temperatures produced by the
combustion gases. Insufficient cooling may result in undue stress on the airfoil and
may lead or contribute to fatigue and/or damage. The airfoil thus is generally hollow
with one or more internal cooling flow channels. The internal cooling flow channels
may be provided with a cooling air bleed from the compressor or elsewhere. Convective
heat transfer may be enhanced between the cooling flow and the internal metal surfaces
of the airfoil by the use of pin-fin arrays, turbulators, and the like. The pin-fin
arrays or the turbulators create a disruption in a surrounding boundary layer so as
to increase heat transfer.
[0003] An airfoil generally has a single cooling flow feed leading to a pin array and multiple
outlets. Such a configuration, however, typically results in a flow through the pin
array that is at an angle relative to the outlets. This angled flow may lead to a
less effective heat transfer therein. Flow straighteners may be used but such add
space and complexity to the pin array region.
[0004] There is thus a desire for an airfoil with an improved internal cooling flow scheme
with a pin-fin array. Such an improved cooling flow scheme may provide a pin-fin array
for more effective heat transfer, better flow control, and lower manufacturing costs.
SUMMARY OF THE INVENTION
[0005] The present invention resides in an airfoil with a cooling flow therein. The airfoil
may include an internal cooling passage, a number of cooling holes in communication
with the internal cooling passage, and a number of pin-fins positioned within the
internal cooling passage. The pin-fins are arranged with one or more turning openings
and one or more guiding openings so as to direct the cooling flow towards the cooling
holes.
[0006] These and other features and improvements of the present application and the resultant
patent will become apparent to one of ordinary skill in the art upon review of the
following detailed description when taken in conjunction with the several drawings
and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Embodiments of the present invention will now be described, by way of example only,
with reference to the accompanying drawings in which:
Fig. 1 is a schematic view of a gas turbine engine.
Fig. 2 is a perspective view of a turbine bucket.
Fig. 3 is a side cross-sectional view of the turbine bucket of Fig. 2.
Fig. 4 is a schematic view of a known pin-fin array.
Fig. 5 is a schematic view of an example of a pin-fin array as may be described herein.
DETAILED DESCRIPTION
[0008] Referring now to the drawings, in which like numerals refer to like elements throughout
the several views, Fig. 1 shows a schematic view of gas turbine engine 10 as may be
used herein. The gas turbine engine 10 may include a compressor 12. The compressor
12 compresses an incoming flow of air 14. The compressor 12 delivers the compressed
flow of air 14 to a combustor 16. The combustor 16 mixes the compressed flow of air
14 with a compressed flow of fuel 18 and ignites the mixture to create a flow of combustion
gases 20. Although only a single combustor 16 is shown, the gas turbine engine 10
may include any number of combustors 16. The flow of combustion gases 20 is in turn
delivered to a turbine 22. The flow of combustion gases 20 drives the turbine 22 so
as to produce mechanical work. The mechanical work produced in the turbine 22 drives
the compressor 12 via a shaft 24 and an external load 26 such as an electrical generator
and the like.
[0009] The gas turbine engine 10 may use natural gas, various types of syngas, and/or other
types of fuels. The gas turbine engine 10 may be any one of a number of different
gas turbine engines offered by General Electric Company of Schenectady, New York,
including, but not limited to, those such as a 7 or a 9 series heavy duty gas turbine
engine and the like. The gas turbine engine 10 may have different configurations and
may use other types of components. Other types of gas turbine engines also may be
used herein. Multiple gas turbine engines, other types of turbines, and other types
of power generation equipment also may be used herein together.
[0010] Fig. 2 shows an example of a turbine bucket 28 that may be used with the turbine
22 described above. The turbine bucket 28 preferably may be formed as a one-piece
casting of a super alloy. The turbine bucket 28 may include a conventional dovetail
30 attached to a conventional rotor disk. A blade shank 32 extends upwardly from the
dovetail 30 and terminates in a platform 34 that projects outwardly from and surrounds
the shank 32.
[0011] A hollow airfoil 36 extends outwardly from the platform 34. The airfoil 36 has a
root 38 at the junction with the platform 34 and a tip 40 at its outer end. The airfoil
36 has a concave pressure sidewall 42 and a convex suction sidewall 44 joined together
at a leading edge 46 and a trailing edge 48. The airfoil 36 may include a number of
trailing edge cooling holes 50 and a number of leading edge cooling holes 52. The
airfoil 36 and the turbine bucket 28 as a whole are described herein for the purposes
of example only. The airfoil 36 and the turbine bucket 28 may have any size or shape
suitable for extracting energy from the flow of combustion gases 20. Other components
and other configurations may be used herein.
[0012] Fig. 3 shows a side cross-sectional view of the airfoil 36. As is shown, the airfoil
36 may include a number of internal cooling pathways 54. The airfoil 36 may be air
cooled, steam cooled, open circuit, or closed circuit. The leading edge cooling hole
52 may be in communication with one or more of the internal cooling pathways 54. Likewise,
the trailing edge cooling holes 50 may be in communication with one or more of the
internal cooling pathways 54. One or more of the internal cooling pathways 54 also
may include a pin array 56. The pin array 56 may be an array of pin-fins 58. The pin-fins
58 may have any desired size, shape, or configuration. In this example, the pin array
56 is positioned about the trailing edge cooling holes 50. Other types of heat transfer
techniques may be used herein.
[0013] Fig. 4 shows an example of the pin array 56. In this example, the pin-fins 58 are
arranged in a uniform array 60. As is shown, the pin-fins 58 are arranged with a generally
uniform distance between each pin-fin 58. As a result, a cooling flow 62 may flow
through the pin array 56 or other type of dump region at an angle relative to the
trailing edge cooling holes 50. As described above, such an angle may compromise overall
heat transfer.
[0014] Fig. 5 shows a portion of an airfoil 100 as may be described herein. The airfoil
100 includes a number of internal cooling pathways 110 and a number of cooling holes
120 therethrough. A cooling flow 130 may flow through the internal cooling pathways
110 and exit via the cooling holes 120 so as to cool the airfoil 100. The cooling
holes 120 may be positioned along the internal cooling pathway 110 such that the cooling
flow 130 is required to make a turn in order to pass therethrough. Other configurations
and other components may be used herein.
[0015] The airfoil 100 also includes a pin array 140 within one or more of the internal
cooling pathways 110. The pin array 140 may includes a number of pin-fms 150. The
pin-fins 150 may have any desired size, shape or configuration. Any number of the
pin-fins 150 may be used. Other types of flow disrupters such as turbulators and the
like also may be used herein.
[0016] In this example, the pin-fins 150 may be positioned in a non-uniform array 160. By
the term "non-uniform" array 160, we mean that the distances between the individual
pin-fins 150 may vary. Specifically, a turning opening 170 and a guiding opening 180
may be used between individual pin-fins 150. The turning opening 170 simply has a
larger open area between the pin-fins 150 as compared to the guide opening 180. Specifically,
the turning openings 170 may be about fifteen percent (15%) to about sixty percent
(60%) larger than the guiding openings 180, although other ranges may be used herein.
The larger open area of the turning openings 170 tends to turn the cooling flow 130
in the desired direction. The pin-fins 150 also may have a variable downstream staggered
positioning 190. The variable downstream staggered positioning 190 also aids in directing
the cooling flow 130 as desired. In the example shown, the pin array 140 may have
a number of columns: a first column 200, a second column 210, a third column 220,
and a fourth column 230. Any number of columns may be used herein. The staggered positioning
190 thus extends across the columns.
[0017] The cooling flow 130 thus turns into the turning opening 170 in the first column
200 and continues into the turning openings 170 of the second column 210, the third
column 220, and the fourth column 230. The cooling flow 130 largely takes about a
ninety (90) degree turn along the internal cooling pathway 110 into the cooling holes
120. The pin array 140 shown herein is for the purpose of example only. The positioning
of the individual pin-fins 150 may vary according to the geometry of the airfoil 100,
the internal cooling pathway 110, the cooling holes 120, the pin-fins 150, and the
like. The positioning also may vary due to any number of different operational and
performance parameters.
[0018] The use of the turning openings 170 so as to turn the cooling flow 130 thus results
in a more effective pin array 140 for improved heat transfer and flow control. The
cooling flow 130 will have significant momentum component normal thereto. The cooling
flow 130 thus is efficiently directed into the cooling holes 120 or other dump region.
Specifically, the cooling flow 130 stagnates alternatively on different pin rows so
as to provide this direction. Moreover, the pin-fins 150 are positioned so as to optimize
local flow velocity. Improved heat transfer may result in lower flow requirements
and enhance increased overall efficiency. The pin array 140 also has larger pin spacings
so as to reduce manufacturing costs and complexity while still providing effective
heat transfer and flow control.
[0019] It should be apparent that the foregoing relates only to certain embodiments of the
present application and the resultant patent. Numerous changes and modifications may
be made herein by one of ordinary skill in the art without departing from the general
spirit and scope of the invention as defined by the following claims and the equivalents
thereof.
[0020] Various aspects and embodiments of the present invention are defined by the following
numbered clauses:
- 1. An airfoil with a cooling flow therein, comprising:
an internal cooling passage;
a plurality of cooling holes in communication with the internal cooling passage; and
a plurality of pin-fms positioned within the internal cooling passage in a non-uniform
array;
the plurality of pin-fins comprising one or more turning openings and one or more
guiding openings in a staggered positioning so as to direct the cooling flow towards
the plurality of cooling holes.
- 2. The airfoil of clause 1, wherein the one or more turning openings comprise a first
distance between a first pair of the plurality of pin-fins, the one or more guiding
openings comprise a second distance between a second pair of the plurality of pin-fins,
and wherein the first distance is greater than the second distance.
- 3. The airfoil of clause 1 or 2, wherein the one or more turning openings turn the
cooling flow about ninety (90) degrees.
- 4. The airfoil of any of clauses 1 to 3, wherein the plurality of cooling holes comprises
a plurality of trailing edge cooling holes.
- 5. The airfoil of any of claims 1 to 4, further comprising a plurality of turning
openings over a plurality of columns.
- 6. The air foil of any of clauses 1 to 5, further comprising a plurality of guiding
openings over a plurality of columns.
- 7. An internal cooling passage with a cooling flow therein, comprising:
a plurality of cooling holes; and
a plurality of pin-fins positioned within the internal cooling passage;
the plurality of pin-fins comprising one or more turning openings with a first distance
between a first pair of the plurality of pin-fins, one or more guiding openings with
a second distance between a second pair of the plurality of pin-fins, and wherein
the first distance is greater than the second distance.
- 8. The internal cooling passage of clause 7, wherein the plurality of pin-fins comprises
a non-uniform array.
- 9. The internal cooling passage of clause 7 or 8, wherein the one or more turning
openings turn the cooling flow about ninety (90) degrees.
- 10. The internal cooling passage of any of clauses 7 to 9, further comprising a plurality
of turning openings over a plurality of columns.
1. An airfoil (100) with a cooling flow (130) therein, comprising:
an internal cooling passage (110);
a plurality of cooling holes (120) in communication with the internal cooling passage
(110); and
a plurality of pin-fins (150) positioned within the internal cooling passage (110);
the plurality of pin-fins (150) comprising one or more turning openings (170) and
one or more guiding openings (180) so as to direct the cooling flow (130) towards
the plurality of cooling holes (120).
2. The airfoil (100) of claim 1, wherein the plurality of pin-fins (150) comprises a
non-uniform array (160).
3. The airfoil (100) of claim 1 or 2, further comprising a plurality of internal cooling
passages (110).
4. The airfoil (100) of any of claims 1 to 3, wherein the plurality of pin-fins (150)
comprises a staggered positioning (190) across a pair of columns (200, 210).
5. The airfoil (100) of claim 4, wherein the plurality of pin-fins (150) comprises a
staggered positioning (190) across a plurality of columns (200, 210, 220, 230).
6. The airfoil (100) of any preceding claim, wherein the one or more turning openings
(170) comprise a first distance between a first pair of the plurality of pin-fins
(150), the one or more guiding openings (180) comprise a second distance between a
second pair of the plurality of pin-fins (150), and wherein the first distance is
greater than the second distance.
7. The airfoil (100) of any preceding claim, wherein the one or more turning openings
(180) turn the cooling flow (130) about ninety (90) degrees.
8. The airfoil (100) of any preceding claim, wherein the plurality of cooling holes (120)
comprises a plurality of trailing edge (48) cooling holes (120).
9. The airfoil (100) of any preceding claim, further comprising a plurality of turning
openings (170) over a plurality of columns (200, 210, 220, 230).
10. The air foil (100) of any preceding claim, further comprising a plurality of guiding
openings (180) over a plurality of columns (200, 210, 220, 230).