商发四期航空发动机带热防护结构的燃油喷嘴5-专利全文ep2570727a2_h

1、TEPZZ 57Z7 7A T(19)EP 2 570 727A2(11)EUROPEAN PATENT APPLICATION(12)(43)(51) Int Cl.:F23R 3/14(2006.01)F23R 3/34(2006.01)Date of publication:20.03.2013 Bulletin 2013/12F23R 3/28 (2006.01)(21)Application number: 12182739.8(22)Date of filing: 03.09.2012(54)Systems and methods of pressure drop control

2、in fluid circuits through swirling flow mitigation(57)An injector (10) with swirling flow mitigationage of fluids out from the flow channels into a radial direction with respect to the longitudinal axis. A flow split- ter (80) is defined in each of the flow channels proximate the outlet orifice. Eac

3、h flow splitter (80) is configured and adapted to mitigate formation of swirling flow on fluids passing through the outlet orifice from the flow channels.cludes an injector body (12) defining a longitudinal axis. A fluid circuit is defined in the injector body (12) and in- cludes a plurality of flow

4、 channels (62a,62b) defined in a cylindrical region around the longitudinal axis and being in fluid communication with an outlet orifice (67) for pas-Printed by Jouve, 75001 PARIS (FR)EP 2 570 727 A2(84) Designated Contracting States:AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT

5、LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TRDesignated Extension States:BA ME(30) Priority: 16.09.2011 US 201113235125(71) Applicant: Delavan Inc.West Des Moines, IA 50265 (US)(72) Inventors: Buelow, Philip E OWest Des Moines, IA Iowa 50266 (US) Thomson, Neal AWest Des Moines, IA Iowa 50265 (US)(

6、74) Representative: Hargreaves, Timothy Edward Marks & Clerk LLPAurora120 Bothwell Street GlasgowG2 7JS (GB)1EP 2 570 727 A22DescriptionSUMMARY OF THE INVENTIONCROSS-REFERENCE TO RELATED APPLICATIONS0006 The subject invention is directed to a new and useful fluid circuit. The fluid circuit includes

7、a plurality of inlet flow channels configured for passage of fluids there- through. The flow channels join one another at a junction with an outlet orifice. A flow splitter is defined in each of the flow channels proximate the outlet orifice. Each flow splitter is configured and adapted to mitigate

8、formation of swirling flow on fluids passing through the outlet orifice from the flow channels.0007 In certain embodiments, there are two flow channels opposed to one another at the junction, how- ever any suitable number of flow channels can be used. The flow splitter of each of the two flow channe

9、ls can include an elongate flow splitter body dividing a portion of the respective flow channel into two branches and the two branches of each flow channel can be substantially equal to one another in flow area. The respective flow channel can have a flow area upstream of the two branch- es that is

10、substantially equal to that of the two branches combined. The four branches can be dimensioned and configured to mitigate formation of swirling flow on fluids passing through the orifice even when one of the branch- es has a flow blockage.0008 It is contemplated that each flow splitter can be elonga

11、te in a longitudinal direction and can have a sub- stantially rectangular cross-section normal to a longitu- dinal direction along the length thereof. Each flow chan- nel can include a bend therein extending from the junction to a point upstream of the junction. The respective flow splitter of each

12、of the flow channels can extend longitu- dinally through a majority of the bend in the respective flow channel. Each flow splitter can be spaced apart from the outlet orifice by a distance in a range of about 0.0 times to about 1.0 times the width of the outlet orifice. Each flow splitter can extend

13、 in a direction away from the outlet orifice to a point upstream of a bend in the respec- tive channel. It is also contemplated that the outlet orifice can have a shape that substantially deviates from a per- fect circle.0009 The invention also provides an injector havingan injector body that define

14、s a longitudinal axis. A fluid circuit is defined in the injector body. The fluid circuit in- cludes a flow channel defined in a cylindrical region around the longitudinal axis. The fluid circuit is in fluid communication with an orifice for passage of fluids out from the flow channel into a radial

15、direction with respect to the longitudinal axis. A flow splitter as described above is defined in the flow channel proximate the orifice. The fluid circuit can include first and second flow channels opposed to one another at a junction with the orifice, as described above. The flow splitter can be i

16、ntegral with the injector body.0010 The invention also provides a staged fuel injec- tor. The staged fuel injector includes a main fuel circuit for delivering fuel to a main fuel atomizer. The main fuel atomizer includes a radially outer prefilmer and a radially0001 This application is a continuatio

17、n-in-part of U.S. Patent Application Serial No. 12/932,958, filed March 10, 2011, which is incorporated by reference herein in its entirety.5BACKGROUND OF THE INVENTION101. Field of the Invention0002 The present invention relates to fuel injection, and more particularly to mitigation of swirling flo

18、w in fuel passages of fuel injectors.152. Description of Related Art0003 Staged fuel injectors for gas turbine engines are well known in the art. They typically include a pilot fuel atomizer for use during engine ignition and low power engine operation, and at least one main fuel atomizer for use du

19、ring high power engine operation. One difficulty associated with operating a staged fuel injector is that when the pilot fuel circuit is operating alone during low power operation, stagnant fuel located within the main fuel circuit can be susceptible to carbon formation or cok- ing due to the temper

20、atures associated with the operating environment. This can degrade engine performance over time.0004 To address these difficulties, efforts have been made to actively cool a staged fuel injector using the fuel flow from the pilot fuel circuit. U.S. Patent No. 7,506,510, which is incorporated herein

21、by reference in its entirety, discloses the use of active cooling to protect aga t car- bon formation in the main fuel circuit of a staged airblast fuel injector. Increasingly, applications have emerged where the staging requirements include operation on pilot stage fuel at up to 60% of the maximum

22、take-off thrust. This represents a substantial increase in the operational temperature for staged fuel injectors and tends to over- heat the stagnant fuel in the unstaged main atomizer. In order to provide the additional cooling needed for such applications, the pilot fuel circuits have become incre

23、as- ingly intricate, which can lead to significant pilot stage pressure drop.0005 Such conventional methods and systems havegenerally been considered satisfactory for their intended purpose. However, there is still a need in the art for in- jectors that allow for increased pilot staging levels with2

24、0253035404550improved pressure drop. There also remaa need inthe art for such injectors that are easy to make and use. The present invention provides a solution for these prob- lems.5523EP 2 570 727 A24inner fuel swirler, wherein portions of the main fuel circuit are formed in the prefilmer. A pilot

25、 fuel circuit is included for delivering fuel to a pilot fuel atomizer which is located radially inward of the main fuel atomizer. The pilot fuel circuit includes a plurality of flow channels defined in the prefilmer and the fuel swirler. The pilot fuel circuit also includes a conduit for conveying

26、fuel from the flow chan- nels to the pilot fuel atomizer. The conduit is in fluid com- munication with the flow channels at an orifice. A flow splitter is defined in each of the flow channels proximate the orifice. Each flow splitter is configured and adapted to mitigate formation of swirling flow o

27、n fluids passing through the orifice from the flow channels into the conduit. 0011 In certain embodiments, a portion of each flow channel of the pilot fuel circuit defined in the radially outer prefilmer is in fluid communication with a portion of the respective flow channel defined in the radially

28、inner fuel swirler by way of a radial passage. The radial passage can be circular or can have a non-circular cross-sectional shape selected from the group consisting of pill-shaped, oblong, ovoid, or any other suitable non-circular shape. The flow channel upstream of the radial passage can include a

29、 flow splitter configured and adapted to mitigate formation of swirling flow on fluids passing through the radial passage. The radially outer prefilmer, the radially inner fuel swirler, and the flow splitters can be integral with one another. It is also contemplated that the flow splitters can be in

30、tegral with the radially inner fuel swirler, which can be joined together with the radially outer pre- filmer at a braze joint. If a given channel is wide enough, two or more flow splitters can be included in the channel side by side without departing from the spirit and scope of the invention.0012

31、These and other features of the systems andmethods of the subject invention will become more read- ily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.portion of the injector of Fig. 1, showing the fuel

32、pas- sages formed in the radially outer surface thereof; Fig. 4B is a schematic view of the main fuel swirler portion of the injector of Fig. 1, showing the fuel pas- sages formed in the radially outer surface thereof, including the flow splitters;Fig. 5A is a perspective view of the main prefilmer

33、of Fig. 4A, showing the fuel passages formed in the radially outer surface thereof;Fig. 5B is a perspective view of the main fuel swirler of Fig. 4B, showing the fuel passages and flow split- ters formed therein;Fig. 6 is a cut away perspective view of a portion of the injector of Fig. 1, showing sc

34、hematically the swirl- ing flow resulting when there are no flow splitters proximate the bore leading to the pilot fuel atomizer; Fig. 7 is a cut away perspective view of a portion of the injector of Fig. 1, showing the flow splitters, wherein the flow into the bore is shown schematically wherein th

35、e flow splitters mitigate the formation of swirling flows proximate the bore leading to the pilot fuel atomizer;Fig. 8 is a cut away perspective view of the portion of the injector of Fig. 7, schematically showing the effects of a total blockage in one of the four branches of the fuel channels adjac

36、ent the flow splitters;Fig. 9 is a perspective view of a portion of the pre- filmer of Fig. 5A, showing the pill-shaped radial ports for passage of fuel into the fuel channels of the fuel swirler; andFig. 10 is a cut away perspective view of a portion of another exemplary embodiment of a staged fuel

37、 injector constructed in accordance with the subject invention, showing a single flow splitter extending over the bore leading to the pilot fuel atomizer.5101520253035DETAILED DESCRIPTION OF THE PREFERRED EM- BODIMENTSBRIEF DESCRIPTION OF THE DRAWINGS400014 Reference will now be made to the drawings

38、 wherein like reference numerals identify similar structural features or aspects of the subject invention. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of an injector in ac- cordance with the invention is shown in Fig. 1 and is designate

39、d generally by reference character 10. Other embodiments of injectors in accordance with the inven- tion, or aspects thereof, are provided in Figs. 2-10, as will be described. The systems and methods of the in- vention can be used to reduce pressure loss by mitigating swirling flow in flow channels,

40、 such as in fuel injectors for gas turbine engines.0015 Referring now to Fig. 1, fuel injector 10 is adapt- ed and configured for delivering fuel to the combustion chamber of a gas turbine engine. Fuel injector 10 is gen- erally referred to as a staged fuel injector in that it includes a pilot fuel

41、circuit, which typically operates during engine ignition and at low engine power and a main fuel circuit,0013 So that those skilled in the art to which the sub-ject invention appertawill readily understand how tomake and use the devices and methods of the subject invention without undue experimentat

42、ion, preferred em- bodiments thereof will be described in detail herein below with reference to certain figures, wherein:45Fig. 1 is a perspective view of an exemplary embod- iment of a staged fuel injector constructed in accord- ance with the present invention, showing the spray outlet;Fig. 2 is a

43、perspective view of the injector of Fig. 1, showing the inlet end portion of the injector;Fig. 3 is a cross-sectional side elevation view of the injector of Fig. 1, showing the fuel and air circuits for the main and pilot fuel stages;Fig. 4A is a schematic view of the main prefilmer505535EP 2 570 72

44、7 A26which typically operates at high engine power (e.g., at take-off and cruise) and is typically staged off at lower power operation.0016 Fuel injector 10 includes a generally cylindrical nozzle body 12, which depends from an elongated feed arm 14, and defines a longitudinal axis A. In operation,

45、main and pilot fuel is delivered into nozzle body 12 through concentric fuel feed tubes. As shown in Fig. 3, these feed tubes include an inner/main fuel feed tube 15 and an outer/pilot fuel feed tube 17 located within the feed arm 14. Although not depicted herein, it is envi- sioned that the fuel fe

46、ed tubes could be enclosed within an elongated shroud or protective strut extending from a fuel fitting to the nozzle body.0017 Referring now to Fig. 2, at the same time fuel is delivered to nozzle body 12 through feed arm 14, pres- surized combustor discharge air is directed into the inlet end 19 o

47、f nozzle body 12 and directed through a series of main and pilot air circuits or passages, which are shown in Fig. 3. The air flowing through the main and pilot air circuits interacts with the main and pilot fuel flows from feed arm 14. That interaction facilitates the atomi- zation of the main and

48、pilot fuel issued from the outlet end 21 of nozzle body 12 and into the combustion cham- ber of the gas turbine engine.0018 Referring now to Fig. 3, nozzle body 12 includes a main fuel atomizer 25 that has an outer air cap 16 and a main outer air swirler 18. A main outer air circuit 20 is defined be

49、tween the outer air cap 16 and the outer air swirler 18. Swirl vanes 22 are provided within the main outer air circuit 20, depending from outer air swirler 18, to impart an angular component of swirl to the pressu- rized combustor air flowing therethrough.0019 An outer fuel prefilmer 24 is positione

50、d radially inward of the outer air swirler 18 and a main fuel swirler 26 is positioned radially inward of the prefilmer 24. Pre- filmer 24 has a diverging prefilming surface at the nozzle opening. As described in more detail herein below with reference to Figs. 5A and 5B, portions of the main and pi

51、lot fuel circuits are defined in the outer diametrical sur- faces 24a and 26a of the prefilmer 24 and main fuel swirl- er 26, respectively.0020 With continuing reference to Fig. 3, the main fuel circuit receives fuel from the inner feed tube 15 and delivers that fuel into an annular spin chamber 28

52、located at the aft end of the main fuel atomizer. The main fuel atomizer further includes a main inner air circuit 30 de- fined between the main fuel swirler 26 and a converging pilot air cap 32. Swirl vanes 34 are provided within main inner air circuit 30, depending from pilot air cap 32, to impart

53、 an angular component of swirl to the pressurized combustor air flowing therethrough. In operation, swirling air flowing from main outer air circuit 20 and main inner air circuit 30 impinge upon the fuel issuing from spin chamber 28, to promote atomization of the fuel.0021 Nozzle body 12 further inc

54、ludes an axially lo- cated pilot fuel atomizer 35 that includes the converging pilot air cap 32 and a pilot outer air swirler 36. A pilotouter air circuit 38 is defined between pilot air cap 32 and pilot outer air swirler 36. Swirl vanes 40 are provided within pilot outer air circuit 38, depending f

55、rom air swirler 36, to impart an angular component of swirl to the air flowing therethrough. A pilot fuel swirler 42, shown here by way of example, as a pressure swirl atomizer, is co- axially disposed within the pilot outer air swirler 36. The pilot fuel swirler 42 receives fuel from the pilot fuel

56、 circuit5by way of the inner pilot fuel conduit 76upport flange1078. Pilot fuel conduit 76 is oriented radially, or perpen- dicularly with respect to longitudinal axis A.0022 Nozzle body 12 includes a tube mounting sec- tion 12a and an atomizer mounting section 12b of re- duced outer diameter. Tube

57、mounting section 12a in- cludes radially projecting mounting appendage that de- fines a primary fuel bowl for receiving concentric fuel tubes 15 and 17 of feed arm 14. A central main bore 52 extends from the fuel bowl for communicating with in- ner/main fuel tube 15 to deliver fuel to the main fuel

58、circuit. Dual pilot fuel bores (not shown, but see, e.g., bores 54a and 54b in Fig. 6 of the above-referenced U.S. Patent No. 7,506,510) communicate with and extend from the fuel bowl for delivering pilot/cooling fuel from outer/pilot fuel tube 17 to the pilot fuel circuit.0023 Referring now to Figs. 4A and 4B, the outer di- ametrical surface 24a of outer prefilmer 24 and the outer diametrical surface 26a of main fuel swirler 26 include channels or grooves that form portions of the main and pilot fuel circuits or pathways.