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`US 201l0293423Al
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`(19) United States
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`(12) Patent Application Publication (10) Pub. No.: Us 2011/0293423 A1
`Bunker et al.
`(43) Pub. Date:
`Dec. 1, 2011
`
`(54) ARTICLES WHICH INCLUDE CHEVRON
`FILM COOLING HOLES, AND RELATED
`PROCESSES
`
`(75)
`
`Inventors:
`
`Ronald Scott Bunker, Niskayuna,
`NY (US); Benjamin Paul Lacy,
`Greer, SC (US)
`
`(73) Assignee:
`
`GENERAL ELECTRIC
`COMPANY, SCHENECTADY, NY
`(US)
`
`(21) App]. No.;
`
`12/790,675
`
`(22)
`
`Filed:
`
`May 28, 2010
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`(2006.01)
`F01D 5/18
`(2005.01)
`B21D 53/73
`(52) U.s. Cl. ........................................... .. 416/95; 29/889
`(57)
`ABSTRACT
`
`An article is described, including an inner surface which can
`be exposed to a first fluid; an inlet; and an outer surface spaced
`from the inner surface, which can be exposed to a hotter
`second fluid. The article further includes at least one row or
`other pattem of passage holes. Each passage hole includes an
`inlet bore extending through the substrate from the inlet at the
`inner surface to a passage hole-exit proximate to the outer
`surface, with the inlet bore terminating in a chevron outlet
`adjacent the hole—exil. The chevron outlet includes a pair of
`wing troughs having a common surface region between them.
`The common surface region includes a valley which is adja-
`cent the hole-exit; and a plateau adjacent the’ valley. The
`article can be an airfoil. Related methods for preparing the
`passage holes are also described.
`
`UTC-2001.001
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`GE V. UTC
`Trial IPR2016-00862
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`GE-1005.001
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`Patent Application Publication
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`Dec. 1, 2011 Sheet 1 of 10
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`US 2011f0293423 Al
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`UTC-2001.002
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`GE-1005.002
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`UTC-2001.002
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`Patent Application Publication
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`Dec. 1, 2011 Sheet 2 of 10
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`US 20l1l0293423 Al
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`GE-1005.003
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`UTC-2001.003
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`UTC-2001.003
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`Patentsxpplication Publication
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`Dec. 1, 2011 Sheet 3 of 10
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`US 2011211293423 A1
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`ig.3
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`70
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`UTC-2001.004
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`GE-1005.004
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`UTC-2001.004
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`PatentApplication Publication
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`Dec. 1, 2011 Sheet 4 of 10
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`US 20lL’0293423 A]
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`Fig. 6
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`GE-1005.005
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`UTC-2001.005
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`Patent Application Publication
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`Fig.7
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`GE-1005.006
`UTC-2001.006
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`UTC-2001.006
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`PatentApplication Publication
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`Dec. 1, 2011 Sheet 6 of 10
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`US 2011/0293423 A1
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`V‘
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`GE-1005.007
`UTC-2001.007,‘ ;
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`UTC-2001.007
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`Patent Application Publication
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`Dec. 1, 2011 Sheet 7 of 10
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`US 201130293423 Al
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`UTC-2001.008
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`GE-1005.008
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`UTC-2001.008
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`PatentApplication Publication
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`Dec. 1, 2011 Sheet 8 of 10
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`UTC-2001.009
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`Patent Application Publication
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`Dec. 1, 2011 Sheet 9 of 10
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`US 201];'0293423 Al
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`UTC-2001.010
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`GE—1 005.010
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`UTC-2001.010
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`PatentApp]ication Publication
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`Dec. 1, 2011 Sheet 10 of 10
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`US 2011/0293423 A1
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`250
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`Laser
`Source
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`Laser Beam
`Delivery System /\/256
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`Motion
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`System
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`GE-1005.011
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`UTC-2001.011
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`US 201 U0293423 Al
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`Dec. 1,201]
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`.'\R'l'ICLES WHICH INCLUDE CHEVRON
`FILM COOLING HOLES, AND RELATED
`PROCESSES
`
`STATEMENT REGARDING FEDERALLY
`SPONSORED RESEARCH & DEVELOPMENT
`
`[000]] This invention was made with Government support
`under contract number Dl:‘-i-‘C26-0SN'l‘-12643. awarded by
`the Department oi‘Energy. The Govertttnetlt has certain rigits
`in the invention.
`
`BACKGROUND
`
`[0002] The general subject matter of this invention relates
`to gas turbine engines, and, more specifically. to structures for
`cooling various components of the engines.
`in
`[0003] A gas turbine engine includes a compressor,
`which engine air is pressurized. The engine also includes a
`combttstor. in which tl1e pressurized air is mixed with fuel. to
`generate hot combustion gases. ln a typical design (e.g._. for
`aircraft engines or stationary power systems), energy is
`extracted from the gases in a high pressure turbine [HPTJI
`which powers the compressor. and in a low pressure turbine
`(LPT). The low pressure turbine powers a fan in a tnrbofan
`aircraft engine application, or powers an external shaft for
`marine and industrial applications.
`[0004] The need for cooling systems in gas turbine engines
`is critical, since the engines usually operate in extremely hot
`environments. For exa mplc, the cngi ne contpon cuts are 0 ften
`exposed to hot gases having temperatures up to about 380{}‘’ F.
`(2093-“ C .). for aircraft applications. and up to about 2't'0{)" F.
`{l482° C .}_. for the stationary power generation applications.
`To cool the components exposed to the hot gases. these “hot
`gas path“ components typically have both internal convection
`and external film cooling.
`[0005]
`In the case of film cooling. at number of cooling
`holes may extend from a relatively cool surface of the coin-
`ponent to a “hot" surface ofthc component. The cooling holes
`are Ltsually cylindrical bores which are inclined at at shallow
`angle. through the metal walls ofthe component. Film cool-
`ing is an important mechanism for tetnperaturc control. since
`it decreases incident heat flux from hot gases to the surfaces of
`components. A number of techttiques may be used to form the
`cooling holes; depending on various factors.
`the neces-
`sary depth and shape of the hole. Laser drilling. water jet
`cutting. and elcctro-disclturge ntachining {FDMJ are tech-
`niques frcqttenlly used for fonttittg film cooling holes. Tltc
`lilm cooling holes are typically atrruttged in rows of closely-
`spaced holes. which collectively provide a lttt‘ge~aret:t cooling
`blanket over the cxtental surface.
`is
`[0006] The coolant air is typically compressed air that
`bled off the compressor. which is then bypassed ttround the
`cnginc‘s combustion mite. and fed through the cooling holes
`to the hot surface. The coolant forrns a protective “liltn“
`bet\\-"eon the hot component surface and the hot gas llow.
`thereby helping protect the component from heating. l-'ut1hcr-
`more. protective coatings. such as for example. thermal bar-
`ricr coatings (Tl3('s). may be employed on Iht: hot sttrlitcc to
`increase the operating temperature oftlte components.
`Ilow
`|lJ00'.-']
`|"ilnt cooling is highest when the coolant
`“ltugs“ the hot :S1lIli,lCI:. With this in mind. ntany dillcrcttt
`surface geometries and slutpcsliat-'cbcct1 tics igned for the exit
`region ollltc cooling holes. I-Ixamplcs iucltttletlitlcrent types
`oflrettcltcs and craters. vi-‘hich arc put'poscli.tl|_v limited on one
`
`or more of the component surfaces. these surface features
`can enable a longer duration of contact between the coolant
`flow and the hot surface, andfor can provide a cooler. effective
`gas temperature layer on the surface.
`]0008] Various considerations are important in designing
`the most appropriate film cooling system. For example. a
`certain volume of air is usually required to flow over the hot
`surface of the component, and as described above, it is also
`important that a significant portion oftltat air stay attached to
`the hot sttrface, for as long as possible. Moreover. since a
`large number of film cooling holes require a larger amount of
`air to be bled ofl" the engine compressor. engine efliciency
`may suffer if too many cooling holes are present. Further-
`more, since future turbine engine designs may involve even
`higher operating temperatures. improved film cooling sys-
`tems may take on even greater importance.
`[0009] With these considerations in mind. new methods
`and structures for improving film cooling capabilities in gas
`turbine engines would be welcome in the art. The imiovations
`should enhance the performance of the cooling stream. with-
`out significatttly decreasing engine efficiettcy. The [ilm cool-
`ing structures should also not interfere with the strength and
`integrity of the turbine engine part. Moreover. the new film
`cooling structures should be capable of being formed. aceti-
`rately and efficiently, by one or more of the drilling. cutting.
`and machining techniques mentioned above.
`
`BRIEF DESCRIPTJON OF THE JNVENTION
`
`in one embodiment of the invention. an article in the
`[001 0]
`form of at sttbstrate is disclosed, contprising an imler sttrfacc
`which can be exposed to a first fluid; and including an inlet:
`and an outer surface spaced from the inner surface, which can
`be exposed to a hotter second lluid. The article further
`includes at least one row or other patient of passage holes.
`wherein each passage hole includes an inlet bore extending
`through the substrate from the inlet at the inner surface to at
`passage hole—e>tit proximate to the outer sttrface. with the
`inlet bore lerminatittg in a chevron outlet adjacent the hole-
`exit. The chevron otttlct comprises at pair of wing troughs
`having at conunon surface region between them: wherein the
`common surface region comprises a valley which is adjacent
`the hole-exit; and lilrther cornpriscs a plateau adjacent the
`valley.
`[0011] Another emboditnent is directed to it [ilm-cooled
`airfoil or airfoil region conligttred with one or more chcvron
`lilnt cooling holes. The airfoil or airfoil region comprises:
`|tl0l2]
`a) at least one inner surface eitposcd to at
`lirst
`lluid: and including an inlet‘.
`[0013]
`b) an outer surface spaced from the said inner
`sttrface. and exposed to a hotter second fluid; and
`[0014]
`c) at least one row or other pattern of passage
`holcs. wherein each passage hole includes an inlet bore
`extending partially through the substrate frotn the inner
`sttrlhcc to ll passage hole-exit proximate to the outer
`surface. with the inlet bore terminating in it chevron
`outlet. as described herein.
`]0015]
`Still another embodiment is directed to LI method lot
`the fortitatiott ofa row orolltcr paltcm oliprissngc liolcs in a
`substrate which includes an inner surface and an on tor surlitct:
`spaced liottt the inner sulltcc. £lI1(.l litrthcr contptiscs an inlet
`bore cxlctltlittg. til lc'.t:~‘l partially ht.'t\\rL‘L‘1t
`the two sttrlttccs.
`said inlet bore terminating in at chevron outlct {Itl_l(I£.'I.'l't|
`(I
`liolc-exit proxirnate to the outer surface. \.\'ltt:l'\:ll't the cltct-run
`outlet ctititpriscs a pair of wing troughs ltatvittg El contnton
`
`GE—1 005.012
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`UTC-2001.012
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`UTC-2001.012
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`US 2011/0293423 Al
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`Dec. 1,201]
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`surface region between them. said common surlece region
`comprising a valley adjacent the hole—exit, and a plateau
`adjacent the valley. The method comprises forming each inlet
`bore and chevron outlet by directing a contacting device or a
`contacting medium to a pre-selected region of the substrate.
`in a computencontrollcd single- orrepeated plunging motion.
`sweeping motion, or combined plunging-and-sweeping
`motion.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. I is El perspective view ofan outer surface ol'a
`[0016]
`substrate. illustrating the general exit region ofthree passage
`holes which extend through the substrate.
`[0017]
`FIG. 2 is a transverse sectional view, taken along
`line 2-2 of FIG. 1. of one of the passage holes illustrated in
`FIG. 1.
`
`FIG. 3 is a plan view ofthe passage hole illustrated
`[0018]
`in FIG. 2. taken along li.ne 3-3.
`[0019]
`FIG. 4 is a transverse sectional view ofa passage
`hole according to another embodiment of this invention.
`[0020]
`FIG. 5 is atop view ofthe chevron outlet region ofa
`passage hole according to an embodiment of the invention.
`[002]]
`FIG. 6 is atop view ofa portion ofthe chevron outlet
`region of a passage hole according to embodiments of the
`invention.
`
`FIG. 7 is a transverse sectional view ofa passage
`[0022]
`hole according to another embodiment of this invention.
`[0023]
`FIG. 8 is a transverse sectional view ofa passage
`hole and exit site region, for a substrate covered by a coating.
`according to embodiments ofthc invention.
`[0024]
`FIG. 9 is a schematic perspective of a water jet
`cutting machine utilized in embodiments of the invention.
`[0025]
`FIG. 10 is a schematic perspective view ofa nozzle
`assembly for a waterjet cutting machine related to the present
`invention.
`
`FIG. I] is an illustration ofthe motion ofa plunging
`[0026]
`device liorrrting passage ltoles in a substrate, according to
`some of the inventive embodiments.
`[0037]
`FIG. 12 is an illustrated top view of the chevron
`region of a passage hole formed by a inulti-p Iunge technique.
`according to the invention.
`[0023]
`FIG. I3 is a schematic perspective of an electric
`discharge ruachining device useful for embodiments of the
`invent ion.
`
`l-‘ICE. 14 is a schematicillustration ol'a laser-based
`[D029]
`system for producing passage holes according to embodi-
`tttents ofthis invention.
`
`l)l".'l'.'\ll.l--Tl) DI-fS('Rll"l'lON OF "fl {Ii IN\r'EN'l'l0N
`
`[tlttfitt] The uunicrical ranges disclosed herein are inclusive
`and com binable (e.g.. ranges of “up to about 25 wt %". or.
`more specilically. “about 5 wt “/9 to about 20 wt %". are
`inclusive of the endpoints and all intertnt.-diate values of the
`rziitgesi. In terms ofany compositional ranges. weight levels
`are providetl on the basis of the weight of the entire compo-
`.~:ition. unless otherwise specified: and ratios are also provided
`on ;| vt eight basis. Moreover. the IL‘I'l‘l1 "co1nhinalitu1"is inclu-
`sin: of blends. mixtures. alloys. reaction products. and the
`like.
`
`Furtltertnore. the temis “lirst." “secont|." and the
`[llt|3l|
`like. herein do not denote any order. quantity. or importance.
`but rather are ttsed to distinguish one element from :u1otht:r.
`The terms “ti” and "an" herein do not denote a limitation of
`
`quantity. but rather denote the presence of at least one of the
`referenced items. The modifier “about“ used in connection
`with a quantity is inclusive of the stated value. and has the
`meaning dictated by context, (e.g., inclttdes the degree of
`error associated with measurement ofthe particularquantity).
`[0032] Moreover, in this specification. the sulfix “(s)" is
`usually intended to include both the singular and the plural of
`the tem that it modifies, thereby including one ormore ofthat
`term (e.g.. “the passage hole” may include one or more pas-
`sage holes, unless otherwise specified). Reference throughout
`the specification to "one embodiment", “another embodi-
`ment“. “an embodiment“, and so forth, means that a particular
`element
`(e.g..
`feature.
`structure, andfor characteristic)
`described in connection with the embodiment is included in at
`least one embodiment described herein, and may or may not
`be present in other embodiments. In addition,
`it
`is to be
`understood that the described inventive teantres may be com-
`bined in any suitable manner in the various embodiments.
`[0033] Any substrate which is exposed to high tempera-
`tures and requires cooling can be used for this invention.
`Examples include ceramics or metal-based materials. Non-
`limiting examples of the metals or metal alloys which might
`form the sttbstrate include steel, alumiuunt, titanium; refrac-
`tory metals such as molybdenum; and superalloys, such as
`those based on nickel, cobalt, or iron. The substrate can also
`be formed ofa composite material, such as a niobium silicide
`intermetallic composite.
`[8934] Very often, the substrate is at least one wall of a gas
`turbine engine component. This type of wall, and the turbine
`components themselves, are described in many references.
`Non-limiting examples include US. Pat. No. 6,234,755
`(Bunker et al) and U.S. Pat. No. 7,328,580 [(Lee et al; here-
`inafter "Le-2”). both of which are incorporated herein by
`reference.
`
`[0035] The Lee reference comprelrensively describes an
`aviation gas turbine engine which is axisymmetrical about a
`longitudinal or axial centerline axis. The engine includes. in
`ordered flow communication, a fan, a multistage axial com-
`pressor, and an annular combustor. which is followed in turn
`by a high pressure turbine (I--lP‘l‘) and a low pressure tttrbine
`(Ll"l‘).
`
`[003 6] The I IPT usually incl odes a turbine nozzle. having a
`row ofhollow stator vanes supported in inner and outer nozzle
`bands. A first stage turbine follows the lirst stage turbine
`nozzle and includes a row of hollow rotor blades extending
`radially outwardly from a supporting rotor disk and stir-
`rounded by an annu lar turbine shroud. A low pressure turbine
`{I..l"l') follows the high pressure turbine and includes addi-
`tional nozzles and rotor blades which may or may not include
`internal cooling circuits depending upon the engine design.
`An exhaust liner usually follows the low pressure turbine.
`[0037] During the operation of:1 gas turbine engine like that
`described in the Lee patent. ambient air is pressurized by the
`fan ntentioncd above. A portion oflhe ambient air enters the
`compressor for additional pressurization. while the outer por-
`tion is discltarged from ll fun outlet for providing propulsion
`thrust in a turbo fan engine application. The air pressurized in
`the compressor is mixed with fuel in the comhttstor for gen-
`eratiu-_A hot combustion gases. The combustion gases [low
`through the various turbine blade stages wltieh extntct energy
`therefrom for powering the conipressor and fan during openl-
`Iion. :\ddiIional details regarding the architecture ofsuclt an
`engine can he lound in the Lee patent. along with variotts
`other references.
`
`GE-1005.013
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`UTC-2001.013
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`UTC-2001.013
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`US 201 U0293423 A1
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`Dec. 1, 2011
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`turbine engine like that
`[0038] While a typical gas
`described above and in the Lee reference may have a conven-
`tional configuration and operation, such an engine is modified
`as described herein, to include improved film cooling. Thus.
`one or more of the various engine components which are
`subject to heating from the hot combustion gases of the
`engine may be suitably cooled by bleeding a portion of the
`pressttrizcd air from the compressor during operation, as
`mentioned previously.
`[003 9] These coniponents usually include at least one metal
`wall 20, as depicted in FIG. 1. The wall can be formed from a
`superalloy like those mentioned above, since those materials
`exhibit high strength at elevated temperatures. A portion of
`the wall is illustrated in plan view in FIG. 1; and a portion is
`also shown as a cross-section in FIG. 2. The thickness of the
`wall will vary, depending on the article in which it is incor-
`porated. In many instances, e.g., for many aviation compo-
`nents. lhe wall has athickness in the range ofabout 0.020 inch
`to about 0. 1 50 inch [508 microns to about 3810 microns). For
`land—based components, the wall often has a thickness in the
`range ofabottt 0.050 inch to about 0.300 inch (1270 microns
`to about 7620 microns].
`
`[0040] The wall includes opposite inner and outer wall
`surfaces 24. 26. The inner or inboard surface ofthe wall fo rms
`the outer boundary of a sttitable cooling circuit provided in
`the component which receives air bled from the compressor
`in any conventional manner. The outer surface 26 is exposed
`to the hot combustion gases 22 during operation (see FIG. 1).
`and requires suitable film cooling protection.
`[0041] The exemplary component wall 20 illustrated in
`FIGS. 1 and 2 may be found in various components. They
`include the inner or outer combustor liners, turbine nozzlc
`vanes, turbine nozzle bands, turbine rotor blades, the turbine
`shroud. or the exhaust liner. All of these components fre-
`quently incorporate various forms of film cooling holes or
`“passage holes“ therein.
`[0042]
`For embodiments ofthe present invention. passage
`holes 28 are arranged in a suitable row or other pat tem (FIG.
`1). along a selected span of the wall component 20. As in
`embodiments of the Lee patent, passage holes 28 are identi-
`fied by their "chevron“ contigttration. In preferred embodi-
`ments. each passage hole 28 extends longitudinally throtlgh
`the wall 20, and diverges both longitudinally along the hole.
`and laterally acnoss the width of the hole. 'l'hus. each hole
`extends liont an inlet 30 disposed llush at the inner surface 24
`(see FIG. 2} to a chevron outlet 32 disposed flush at the outer
`surface 26. As mentioned above. a portion of the prcssttrized
`air from the compressor is directed through the passage hole
`28 (FIG. 1) as coolant air 33. exiting at the chevron outlet 32.
`[0043]
`In preferred ct1tboditnet1ts.cach ofthe passage holes
`28 includes an inlet bore 34. The bore usually has :1 substati-
`tially constant flow area front its inlet end to its outlet end. As
`depicted in FIG. 2. the inlet bore has a longitttdinai or axial
`centerline axis 36. The bore itself can be thouyu ofas the
`portion of the passage hole which rt.-tnuins cylindrical or
`substantially cylindrical. i.c.. prior to the beginning of the
`chevron otttlet. 'l‘hus. in FIG. 2. the inlet bore can be tltougltt
`of as the section between points X and Y along axis 36. The
`upward tcnniuation site o I‘ the inlet bore can be referred to as
`"bort: outlet“ 38, whiclt still lies below outer wall surfuct:
`(exterior wall surface) 26. Tltc inlet bore can be inclined at a
`relatively sliallow angle
`rclzrtive to its inner or outer
`surfaces. which are typically parallel with each other. The
`
`inclination angle A of the inlet bore is usually related to the
`typical inclination used for lilm cooling holes. eg, about 20
`degrees to about 45 degrees.
`[0044]
`As mentioned previously, FIG. 3 is a plan view of
`the passage hole illustrated in FIG. 2. taken along line 3-3.
`The figure depicts passage hole inlet 30, effectively bisected
`by centerline axis 36. Inlet bore 34 is shown as extending
`from point X to point Y, i,e._. ending as here outlet 38. The
`remainder of the passage hole from bore outlet 38 toward
`surface 26 (i.e.. in a direction opposite that of inlet hole 30]
`can be thought of as the “passage hole—exit"
`[0045] With continued reference to FIG. 3, the bore outlet
`38 terminates at a chevron outlet, generally designated as
`feature 40. For most of its length “' ", the chevron outlet 40
`comprises a pair of wing troughs, 42 and 44. The wing
`troughs diverge longitudinally from a trough initiation site 39
`(the "upstream“ beginning ofthe troughs), to the exteriorwall
`surface 26 (FIG. 2). The trough initiation site is usually
`located about 15% to about 3 5% of the length front bore outlet
`38, based on the total length ofchevron outlet 40 along axis 36
`(FIG. 3).
`in some embodiments, the wing troughs are similar
`[0046]
`in size and shape to the wing troughs in the Lee patent men-
`tioned previously, and usually have a substantially elliptical
`cross-sectional shape. As an example, the wing troughs may
`be substantially circular or partially circular.
`[0047] The wing troughs 42. 44 have a common surface
`region 46 between them. 'l'he wing troughs can be said to
`diverge laterally along this surface region. in a direction away
`front inner wall surface 24. to eventually blend with outer
`wall surface 26.
`
`In some embodiments. the common surface region
`[0048]
`46 comprises a val Icy or "iloor“ 48. and a plateau 50, adjacent
`the valley 48. Plateau 50 rises above the valley. and extends
`along axis 36, in a direction opposite hole inlet 30. terminat-
`ing at a site 52, which is getterally liush with outer wall
`surface 26. It should be understood that the valley 48. while
`below the level ofplateau 50. is still generally higher than the
`depth ofthe wing troughs 42. 44. Moreover. valley -48 can be
`considered an extension ofthe lower surface 54 (FIG. 2) of
`inlet bore 34 (usually an arcuate surface). Asdescribed below.
`the passage hole zuid chevron outlet geometry described in
`embodiments of this invention can be obtained by using cer-
`tain types ofdrilling. ntacltining. and ctttting techniques.
`[0049] As generally depicted in FIG. 2. plateau 50 is typi-
`cally an elevated. relatively level feature rising above valley
`48. The top surface :36 of the plateau can be very flat. and
`sontewltat parallel to the surface of valley 48. llowevcr. as
`further described below. the shape. size and orientation of the
`plateau can vary considerably. as can any ofthe individual
`surfaces or “faccs“ of the plateau. As one example. the front
`face 58 ofllte plateau (see FIG. 3) can be .~:nbstantially per-
`pendicular to the surface of valley -18. Ilowever. as shown
`below. the front surface is usually sloped.
`gradually
`decreasing in size (like a ramp) until merging into the Valley
`surface 48. In general. the shape and size of the plateau and
`the valley front which it rises are iniportant lactors in maxi-
`ntiziug the diffusion o!'coolittg air that is cltannelt:tl tltrouglt
`the passage holes. .'\s further descrihctl below. uttot|1cr:id\'an-
`lugeotts result is El rctluccd llow separntimt of the cooling air
`from outer wall surface 26.
`
`|tltl50] With reference to FIG. 3. the position ofplotcatt 50
`Within the entire area of chevron outlet 40 nta_\' also be .'I
`signiftcattt featttt'o for sonic cnt botlitncnts. I7.-rclt Irougltcan be
`
`GE-1005.014
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`UTC-2001.014
`lL“:*
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`UTC-2001.014
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`

`
`
`
`US 201 l/0293423 AI
`
`Dec. 1,201}
`
`said to have a total length dimension extending from trough
`initiation site 39 to a terminus larthest downstream from t.he
`passage hole inlet 30. i.e._. to the point at which the troughs
`meet outer surface 26 (i.e.. site 52 in FIG. 3). In sortie embodi-
`ments. substantially all of the plateau is located in a region
`that is more than about 40% of the total length dimension
`away from site 39. In some other preferred eiubodinients,
`substantially all of the plateau is located in a region that is
`more than about 60% ofthe total length dimension away from
`site 39.
`
`In some embodiments. the plateau. from a plan view
`[0051]
`(“top view“) like that of FIG. 3, can have the shape of a
`triangle. a trapezoid. or any other polygon. FIG. 3 shows
`plateau 50 in the shape ofa trapezoid. FIG. 4 is illustrative of
`:1 plateau having the shape of a triangle. (In this figure. fea-
`tures similar or identical to those of FIGS. 2 and 3 are not
`labeled). In FIG. 4, the plateau 60 rises above valley 62. The
`triangle of the plateau includes an upstreant vertex 64. lying
`generally in a midpoint area between the two troughs 66, 68,
`in line with axis 70, and pointing toward passagehole inlet 72.
`I-Iowever, the vertex need not be aligned with axis 70, c.g., it
`can be “otI’—center“. Moreover, the triangle itselfneed not be
`equilateral. As mentioned previously. the precise shape for
`the plateau is determined in large part by the maiuier in which
`it is formed. (The two troughs can also vary somewhat from
`each other. e.g._. in depth and shape).
`[0052]
`FIG. 5 is an illustration ofanother embodiment ofa
`portion ofa passage hole 80, shown as a top view ofthe outer
`surface ("hot surface") 82 ofa substrate. In this figure (seine-
`what similar to FIG. 7, discussed below). plateau 92 is situ-
`ated between troughs 86 and 88. (The plateau can generally
`lie in the same plane as outer surface region 93, although the
`tigure seems to show platcau 92 as being angled upwardly
`front region 93). A valley 90 slopes downwardly from the
`plateau. toward an inlet bore (not specifically shown) extend-
`ing into the substrate. The plateau can vary in lieight. relative
`to surface 82. In some embodiments, the height ofthe plateau
`is about 2% to about 20% of the length-dimension extending
`from the passage hole-exit to a terminus farthest away from
`the hole-exit.
`
`which serve a number of purposes may be used. Frequently.
`coatings which provide thermal protection. andfor oxidation
`protection are applied. As one example. an article such as a
`gas t't.trbtne blade may be covered by a ceramic coating. e.g._.
`a themial ban-ier coating (TBCJI formed ofa zirconia material
`such as yttria-stabilized zirconia. In many cases for turbine
`blades. a bond layer is lirsl applied over the blade surface.
`e.g.. a inetal~ahtminide or MCrAlY niaterial. where “M"can
`be iron, nickel, cobalt. or mixtures thereof. Tltesc coating
`systems are described in many references. such as the Bunker
`"I55 patent rnerttioned previously.
`[0056]
`FIG. 8 is a transverse sectional view of another
`passage hole 123. extending through a substrate 125, accord-
`ing to some inventive embodinients. In this instance. the outer
`surface (“hot” surface) 124 of the substrate is covered by a
`protective coating system 126. which as described above, can
`constitute one or more individual coatings. The thickness of
`the protective coating can vary greatly (e.g._. about 0.005 inch
`(127 microns) to about 0.050 inch (I270 microns). depending
`on various factors. In the case of a nickel superalloy-based
`turbine blade used in the “hot“ section of a land-based gas
`turbine. protective coatings often have a thickness in the
`range ofabout 0.015 inch [38] microns) to about 0.045 inch
`(I 143 niicroiis). and most often, about 0.020 inch (500
`microns) to about 0.035 inch (889 microns). The passage hole
`123 is formed through the substrate 125 and through the
`coating 126 by one of the techniques described below.
`1005?] With continuing reference to FIG. 8, plateau 128
`extends from and rises above valley 13 0. In this instance, the
`“front face“ 132 of the plateau is sloped in the direction of
`
`in some embodiments, the features of
`[0053] Moreover.
`surtiace 90. trough 86. and trough 88 can all merge into the
`inlet bore. l’tirthermore. in some instances. the edges 98 and
`I 00. formed by the intersections ofsurfaces 86 and 90: and 88
`and 90. respectively. need not be "sharp". straight line edges.
`For example. they could.
`independently of each other, be
`curved or “rounded“. As depicted in FIG. 6. which is a sec-
`tional portion ofa passage hole like that of}-‘I0. 3. top surface!
`valley 102 could also be curved. along a general “arc" extend-
`ing :icni.~:.s from one trough to another trough (troughs not
`sltown here). or along some other line o l‘ curvature.
`[U05-II
`I-‘ICE.
`‘I is at view of a passage hole 108. having
`another chevron shape. according to embodiments of this
`iuvetition. ll-"cultures similar to those in FIGS. 2 and 3 may not
`be labeled here). A transverse sectional view is provided in
`the lower halfoftlic figure. sliowitig an inlet bore 110. sitti-
`:tIt.:tl alongaxis I I2. The upper |tall‘ol‘the figure is a plan view
`or “top view“. In this embodiment. plateau 114 is a raised
`legion. liirtliesl Jront inlet little I 18. A valley 120 is trtljacetit
`the plateau. extending along axis 112. The valley has a top
`sitrliice I22 \\-l'lIt.‘l'l slopes (lowtt. in the direction ofinlel hole
`I I8.
`
`_-\s tuentiottetl above. aniclcs like those described
`[tIII:'i5[
`herein tire often covered by one or more coatitigs. ("outings
`
`the surrounding valley can vary considerably. depending on
`various factors. They include the desired exit geometry for the
`coolant fluid which will travel through the passage hole. and
`also the technique by which the hole and chevron area are
`formed within coating 126 and substrate 125. The ability to
`modify film cooling characteristics through protective coat-
`ings, according to new coolant flow geometries, is an impor-
`tant aspect for embodiments of this invention.
`[0053] The passage holes of the present invention can be
`formed successfully by several specialized techniques. using
`selected types of equipment. The techniques can include
`water jet cutting systems. electric discharge maelnniiig
`(EDM) systems. and laser-drilling systems. Each of these
`systems is descri bed below. Moreover, in some cases. each of
`these techniques can be carried out by using the specific
`instrument in a single or repeated plunging motion. as also
`described below. (In this description. the EDM is said to
`involve treatment o f the substrate with a "contacting device“:
`while waterjet cutting systems and laser-drilling systems are
`said to involve treatment ofthe substrate with a “contacting
`ntediuni". as further described below).
`the
`[0059] As alluded to above.
`in some embodiments.
`passage holes are limited by a waterjet cutting process. e.g..
`an abrasive water jet cutting process. Such a process. some-
`tintes referred to as a "water saw“. is known in the art. and
`described in many relereiices. Non-l iniiting examples incltttlc
`U.E>'. Pat. No. (:.905.39t’a {Milleret al}: US. Pat. No. 5.979.t'i(i3
`(I-lerrmann etul): U.S. Pat. No. 5.851.139 (Xu); and U15. Put.
`No. 5.169.065 fBloch }. all incorpomted herein by reference.
`10060]
`In general.
`the \\'(IIL'l' jet process utilizes it high-
`velocity stream of abrasive particles (e.g.. abrasive "gril“).
`suspended in a stream olihigli pressure water. The pressure of
`the water tnay vat'_v coitsiderably. but is often iii the range of
`
`GE-1005.015
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`UTC-2001.015
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`UTC-2001.015
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`

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`US 201 110293423 Al
`
`Dec. 1,2011
`
`about 5.000-90.000 psi. A number of abrasive materials can
`be used. such as garnet. aluminum oxide. silicon carbide, and
`glass beads. The process can be used in various embodiments
`of this invention, e.g., for the formation of passage holes
`through a metal substrate, or through the substrate and a
`protective coating over the substrate. as described previously.
`Unlike some of the other cutting processes u