GB2211594A - Fuel nozzle assembly - Google Patents
Fuel nozzle assembly Download PDFInfo
- Publication number
- GB2211594A GB2211594A GB8824501A GB8824501A GB2211594A GB 2211594 A GB2211594 A GB 2211594A GB 8824501 A GB8824501 A GB 8824501A GB 8824501 A GB8824501 A GB 8824501A GB 2211594 A GB2211594 A GB 2211594A
- Authority
- GB
- United Kingdom
- Prior art keywords
- fuel
- air
- delivery tube
- support flange
- fuel nozzle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000446 fuel Substances 0.000 title claims description 115
- 238000012384 transportation and delivery Methods 0.000 claims description 99
- 238000007789 sealing Methods 0.000 claims description 8
- 238000000034 method Methods 0.000 claims 1
- 238000000889 atomisation Methods 0.000 description 6
- 239000007921 spray Substances 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 4
- 239000000356 contaminant Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 208000034423 Delivery Diseases 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- RLQJEEJISHYWON-UHFFFAOYSA-N flonicamid Chemical compound FC(F)(F)C1=CC=NC=C1C(=O)NCC#N RLQJEEJISHYWON-UHFFFAOYSA-N 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 235000002020 sage Nutrition 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
- F23D11/005—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space with combinations of different spraying or vaporising means
- F23D11/007—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space with combinations of different spraying or vaporising means combination of means covered by sub-groups F23D11/10 and F23D11/24
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
- F23D11/24—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space by pressurisation of the fuel before a nozzle through which it is sprayed by a substantial pressure reduction into a space
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D2211/00—Thermal dilatation prevention or compensation
Description
--- 't 2 11594 1 FUEL NOZZLE ASSEMBLY FOR A GAS TURBINE ENGINE This
invention relates to a fuel nozzle assembly for a gas turbine engine, and more specifically, to such a fuel nozzle assembly for a gas turbine engine having a fuel tube and an air tube enclosing the fuel tube to define an annular air passage therebetween.
A typical fuel nozzle assembly capable of separately delivering both air and fuel to a combustion chamber generally comprises a fuel delivery tube supported from one end and having a fuel nozzle tip with a conical surface secured to the other, and an air delivery tube enclosing the fuel delivery tube in a spaced relationship to define therebetween an annular air flow channe 1. A swirl cap is.
is threaded onto the free end of the air delivery tube and tightened so that a conical opening in the swirl cap sealingly engages the conical surface of the nozzle tip. The swirl cap is further provided with a plurality of small apertures equilangularly spaced around the center of the swirl cap for directing atomizing air from the air flow channel in a direction convergent to the fuel which exits the fuel nozzle tip in an outwardly diverging conical pattern.
As the air delivered through the assembly is primarily used only at ignition of the gas turbine engine to atomize the fuel, it is important to provide an atomizing air pattern which is predictable and delivers an 2 atomized fuel-air mixture generally adjacent to either a flame cross-over tube or a spark ignitor, or both.
The fuel nozzle tip injects fuel in an outwardly diverging, generally conical, pattern. However, during low fuel flow, fuel pressure atomization is poor and air is introduced through the swirl cap to further atomize the fuel injected by nozzle. In such a manner, the conical pattern is altered to result in a nodular or 4- spoke spray pattern. This additional atomizing air is necessary during light-off ignition to provide greater atomization of the fuel as it is introduced through the nozzle to reduce unburned fuel emissions and to obtain better distribution of the air fuel mixture to insure that it is properly delivered to the turbine to propagate the combustion process in the turbine. After light-off ignition is complete, the atomization air is cut off and fuel only is delivered through the nozzle to continue the combustion process.
To ensure that the air flow atomizes the fuel stream to the nodular spray pattern desired during atomization, the air flow is channeled through apertures having the same geometric orientation as the opening in the fuel n ozzle tip through which the fuel is directed.
Conical surfaces are utilized in such prior art devices as the conical seal, once established, was thought to provide the best air-tight seal available. To make the conical seal a high quality, air-tight seal, however, it was necessary to apply a fine grinding paste to the conical nozzle tip prior to engaging the nozzle tip with the swirl cap. Further, and more seriously, the conical nozzle tip and swirl cap utilized in achieving such a sealing interface lead to the formation of gaps at the fuel nozzle/swirl cap interface during axial expansion of the air delivery tube. This causes severe deterioration in the ability of the fuel nozzle assembly to provide the desired atomized fuel spray characteristics. In addition, such gaps encourage the formation of contaminants which further deteriorate 3 the performance of the fuel nozzle assembly. Te prior art devices are also prone to the accumulation of deposits in the air 'delivery channel which tends to clog it and do not provide access to the air delivery channel for removing such deposits. One such prior art fuel nozzle having a conical engagement between the swirl cap and the fuel delivery tube is disclosed in U.S. Patent No. 4,154,056 entitled "Fuel Nozzle Assembly for a Gas Turbine Engine", issued May 15, 1979 and assigned to the assignee of the present invention.
The problems identified in the prior art devices may be traced to the fact that the temperature of the fuel flowing through the fuel delivery tube is generally about 380C. The temperature of the air in the space between the tubes, however, may reach 315'C. Such a temperature difference between the fuel tube and the air tube often causes varied axial expansion of the fuel tube and air tube, resulting in a disengagement of the conical seal between the fuel nozzle tip and the air delivery tube, thus 20. creating the above-mentioned gap at the sealing interface between the two. This gap provides an area where contaminants or carbon deposits caused by occasional reverse flow from the combustor, can accumulate to prevent the gap from resealing. The air tube itself may also become clogged with contaminants. During shutdowns, the conical seal interface may be contaminated by fuel oil from the nozzle tip.
As such, any gap between the air tube and the fuel nozzle tip provides an air leakage path that deleteri- ously affects the atomizing air distribution such that an unpredictable fuel-air pattern can exist which produces erratic and unpredictable light- off characteristics. if contamination of the air passage is severe enough, the flow of atomizing air may be completely cut off, preventing light-offs.
Further, once the fuel nozzle assembly of the known prior art is assembled and mounted in a combustion
4 chamber of a gas turbine engine, it becomes extremely difficult to mechanically clean the air delivery channel and remove the contaminants which may be causing either leakage at the sealing interface or blockage of the air 5 delivery pipe.
It is the principal object of this invention to provide a fuel nozzle assembly for a gas turbine engine which maintains a constant sealing interface without gapping between the fuel delivery tube and the air delivery tube during axial expansion of the air delivery tube.
With this object in view the present invention resides in a fuel nozzle assembly for a gas turbine, comprising a fuel delivery tube projecting from a support flange and having a delivery end opposite said support is flange and an air delivery tube concentrically surrounding said fuel delivery tube in spaced relationship therewith so as to define therebetween an annular passage for conducting air from said support flange to-said delivery end, characterized in that an integral fuel and air nozzle structure is mounted on the delivery end of said fuel delivery tube, said nozzle structure having a central fuel nozzle opening so as to receive fuel from said fuel delivery tube and air passages arranged around said central fuel nozzle opening and in communication with said annular passage for receiv- ing pressured atomizing air therefrom, said air delivery tube having a delivery end seated on said nozzle structure, and that means are provided on said support flanges for movably supporting said air delivery tube and for resiliently forcing said delivery end into engagement with said nozzle structure.
In the given arrangement the atomizing air passage is readily accessible for cleaning and the air delivery tube being biased by spring force into a secure, aligned fit with the integral fuel nozzle/end cap of the air delivery tube. The integral fuel nozzle/end cap, which is screwed onto the fuel delivery tube, may be easily detached from the fuel delivery tube to release the air delivery tube and permit ready access to the annular air passage for cleaning.
The invention will become more readily apparent from the following description of a preferred embodiment thereof shown, by way of example only, in the accompanying drawings, wherein:
Figure 1 is an axial cross-sectional view of the fuel nozzle assembly of the present invention.
As shown in Figure 1, the fuel nozzle assembly 30 includes an inner fuel delivery tube 32 and an outer air delivery tube 34 extending axially from a support flange 36 at one end. The air delivery tube 34 is concentric and substantially coextensive with the fuel delivery tube 32.
The fuel delivery tube 32 has an axial opening which is internally threaded at each end thereof. A fuel line (not shown) is normally received in the fuel inlet end 40. The delivery end 48 of the fuel delivery tube 32 terminates in an integral fuel nozzle/end cap 49 threaded onto the fuel delivery tube 32. The integral fuel nozzle/end cap 49 includes a threaded skirt portion 50 for attaching the integral fuel nozzle/end cap 49 to the delivery end 48, a flange 51 and an end cap portion 53 for engaging the end 60 of air delivery tube 34. A sealing washer 52 is interposed between the flange 51 and the threaded skirt portion 50 to prevent oil leaking from the fuel delivery tube. The end cap portion 53 is further provided with' a central opening 54 in communication with the central opening of delivery end 48 for delivery of fuel from the fuel delivery tube 32. End cap portion 53 is further provided with small apertures 56 equilangularly spaced around central opening 54 in communication with annular air passage 58 for delivery of air from passage 58 through aperture s. 56 for directing atomizing air in a predetermined convergent direction to intercept and atomize the fuel exiting the central opening 54 of the integral fuel nozzle/end cap 49.
6 The air delivery tube 34 extends axially with, and concentric to, the fuel delivery tube 32 to define the annular air passage 58 between the outer wall of fuel delivery tube 34 and the inner wall of.air delivery tube 34 throughout their common axial extent. The end 60 of air delivery tube 34 mates with end cap portion 53 of the integral fuel nozzle/end cap 49 in a manner to be described more fully later to provide the seal between air delivery tube 34 and fuel delivery tube 32.
The support flange 36, which mounts the fuel delivery tube on the gas turbine engine, extends radially outwardly from the fuel delivery tube 32. The support flange 36 has a threaded, radially extending atomizing air inlet 39 for receipt of an air line (not shown). The support flange also includes a spring receiving opening 42 for receipt of a biasing spring 44.
When mounting the air delivery tube 34 onto fuel delivery tube 32, biasing spring 44 compresses, exerting axial force onto bevelled washer 46. In turn, bevelled washer 46, acting through split piston ring 47, exerts axial pressure on air delivery tube 34. Integral fuel nozzle/ed cap 49 is attached to fuel delivery tube 34 by screwing threaded skirt portion 50 of integral fuel nozzle/end cap 49 into the delivery end 48 of fuel delivery tube 34 until tight. Once the integral fuel nozzle/end cap is secured to the fuel delivery tube 32, the air delivery tube 34, under the influence of axial pressure from biasing spring 44, engages the end cap portion 53 of the integral fuel nozzle/end cap 49 in a tight fit. Thus, the fuel delivery tube 32 and air delivery tube 34 are sealed together such that leakage of atomizing air which adversely affects the atomization of fuel is unlikely.
Further, split piston ring 47, acting under pressure exerted by bevelled washer 46, exerts radial pressure along its common circumference with support flange 36 to eliminate any gap between the support flange 36 and the air delivery tube 34. Thus, additional air leakage 7 which would otherwise occur at the support fange 36/air delivery tube 34 interface is eliminated by the air-tight seal between support flange 36 and split piston ring 47.
Alignment of annular air pas. sage 58 and apertures 56 is provided by a lip 62 of end cap -portion 53. As the threaded portion SO of integral fuel nozzle/end cap 49 is tightened onto fuel delivery tube 32, the protruding lip 62 of integral fuel nozzle/end cap 49 engages the protruding tip portion 61 of end 60. The engagement of protruding tip 61 and protruding lip 62 aligns the air delivery tube 34 and the integral fuel nozzle/end cap 49 in a desired orientation which simultaneously aligns annular air passage 58 and aperture 56 such that air flowing through air passage 58 is communicated to aperture 56.
is When the fuel nozzle assembly 30 of the present invention is subjected to normal temperature conditions, i.e. when there is no extreme temperature differential between the fuel flowing in the fuel delivery tube 32 and air delivery tube 34, the fuel and air delivery tubes are sealed at the interface of the end portion 53 of the integral fuel nozzle/end cap 49 and end 60 of air delivery tube 34 interface. No gapping is present at the interface, and contamination of the air passage 58 is unlikely. The air atomization of the fuel spray generally results in the desired atomized nodular spray pattern.
When the fuel nozzle assembly of the present invention is subject to axial expansion of the air delivery tube caused by the extreme thermal conditions which arise during operation of the gas turbine engine, the air deliv ery tube 34 expands axially to a greater extent than the fuel delivery tube 32. As the air delivery tube 34 ex pands, the end 60 of air delivery tube 34 expands axially with respect to end cap portion 53. The sealing interface between end 60 and end cap portion 53 is tightened, thus improving the seal between the two to prevent the leakage of atomizing air. Continued axial expansion of the air delivery tube 34 will compress biasing spring 44 and will a not cause separation of the seal between fuel delivery tube 32 and air delivery tube 34 as biasing spring 44 will accommodate axial expansion of the air delivery tube 34. The increased axial force due to compression of biasing spring 44 will also increase radial pressure of split piston ring 47 on support flange 36 to further decrease air leakage at the support flange 36/air delivery tube 34 interface by strengthening the air-tight seal between support flange 36 and split piston ring 47.
With this arrangement fuel nozzle and air nozzle openings are always in the same spatial relationship which is quite important for proper start-up operation and also any air leakage from the air delivery tube will not disturb the air flow from the nozzle. Finally, replacement of the is fuel nozzle automatically includes replacement of the air nozzles so that proper cooperation is assured.
Claims (4)
1 A fuel nozzle assembly for a gas turbine, comprising a fuel delivery tube (32) projecting from a support flange (36) and having a delivery end (48) opposite said support flange (36) and an air delivery tube (34) concentrically surrounding said fuel delivery tube (32) in spaced relationship therewith so as to define therebetween an annular passage (58) for conducting air from said support flange (36) to said delivery end (48), characterized in that an integral fuel and air nozzle structure (53) is mounted on the delivery end (48) of said fuel delivery tube, said nozzle structure (53) having a central fuel nozzle opening (54) so as to receive fuel from said fuel delivery tube (32) and air passages (56) arranged around said central fuel nozzle opening (54) and in communication with said annular passage (58) for receiving pressured atomizing air therefrom, said air delivery tube (34) having a delivery end (60) seated on said nozzle structure (53), and that means are provided on said support flanges (36) for movably supporting said air delivery tube (34) and for resiliently forcing said delivery end (60) into engagement with said nozzle structure (53).
2. A fuel nozzle assembly according to claim 1, characterized in that said air delivery tube is supported in said support flange (36) in slidingly sealing relation- ship therewith and that springs (44) are disposed in openings (42) in said support flange (36) for forcing said air delivery tube toward said nozzle structure (53).
3. A fuel nozzle assembly according to claim 2, characterized in that a split piston ring (47) is provided to provide a seal between said support flange and the end of the air tube slidingly received therein.
4. A fuel nozzle assembly according to claim 3, characterized in that said piston ring (47) is bevelled and a bevelled washer 46 is disposed on said piston ring and that said springs abut said bevelled washer so as to force said piston ring (47) outwardly for sealing engagement with the support flange wall.
Published 1989 atThe Patent OfEice, State House, 66171 High Holburn, Lond'cz-, WC1R4TP. Further copies maybe obtalnedfrom The PatentOfnee. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltzI, St Mary Gray, Kent, Con. 1187
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US11189087A | 1987-10-23 | 1987-10-23 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8824501D0 GB8824501D0 (en) | 1988-11-23 |
| GB2211594A true GB2211594A (en) | 1989-07-05 |
| GB2211594B GB2211594B (en) | 1991-05-29 |
Family
ID=22340987
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8824501A Expired - Lifetime GB2211594B (en) | 1987-10-23 | 1988-10-19 | Fuel nozzle assembly for a gas turbine engine |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPH01134028A (en) |
| CA (1) | CA1283551C (en) |
| DE (1) | DE3833279A1 (en) |
| FR (1) | FR2622252B1 (en) |
| GB (1) | GB2211594B (en) |
| IT (1) | IT1225431B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19539246A1 (en) * | 1995-10-21 | 1997-04-24 | Asea Brown Boveri | Airblast atomizer nozzle |
| US8561553B2 (en) * | 2009-12-17 | 2013-10-22 | Babcock Power Services, Inc. | Solid fuel nozzle tip assembly |
| US9404655B2 (en) * | 2012-01-20 | 2016-08-02 | General Electric Company | Process of fabricating a fuel nozzle assembly |
| US10060628B2 (en) * | 2015-03-26 | 2018-08-28 | General Electric Company | Systems and methods for creating a seal about a liquid fuel injector in a gas turbine engine |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2973150A (en) * | 1958-05-12 | 1961-02-28 | Chrysler Corp | Fuel nozzle for gas turbine engine |
| US2968925A (en) * | 1959-11-25 | 1961-01-24 | William E Blevans | Fuel nozzle head for anti-coking |
| US4154056A (en) * | 1977-09-06 | 1979-05-15 | Westinghouse Electric Corp. | Fuel nozzle assembly for a gas turbine engine |
| CA1259197A (en) * | 1985-02-13 | 1989-09-12 | Alan D. Bennett | High reliability fuel oil nozzle for a gas turbine |
-
1988
- 1988-09-30 DE DE3833279A patent/DE3833279A1/en not_active Withdrawn
- 1988-10-07 CA CA000579643A patent/CA1283551C/en not_active Expired - Lifetime
- 1988-10-18 JP JP63260709A patent/JPH01134028A/en active Granted
- 1988-10-19 GB GB8824501A patent/GB2211594B/en not_active Expired - Lifetime
- 1988-10-21 IT IT8841696A patent/IT1225431B/en active
- 1988-10-21 FR FR888813839A patent/FR2622252B1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| GB2211594B (en) | 1991-05-29 |
| IT8841696A0 (en) | 1988-10-21 |
| CA1283551C (en) | 1991-04-30 |
| DE3833279A1 (en) | 1989-05-03 |
| FR2622252A1 (en) | 1989-04-28 |
| IT1225431B (en) | 1990-11-13 |
| FR2622252B1 (en) | 1993-04-23 |
| GB8824501D0 (en) | 1988-11-23 |
| JPH01134028A (en) | 1989-05-26 |
| JPH05539B2 (en) | 1993-01-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19941019 |